Physico-Chemical, Sensory, and Nutritional Properties of Shortbread Cookies Enriched with Agaricus bisporus and Pleurotus ostreatus Powders

Abstract

Mushrooms, due to their basic composition and the presence of numerous mycochemicals, can be used to improve various food matrices. The objective of this study was to determine the impact of replacing wheat flour (2%, 4%, 6% w/w) with mushroom lyophilisates from cultivated mushrooms—A. bisporus and P. ostreatus—on the technological quality, basic nutritional and elemental composition, antioxidant activity (ABTS, FRAP), total polyphenol content (TPC), and sensory evaluation of shortbread cookies. The functional properties of blended flours were also determined, such as bulk density (BD), water- and oil-holding capacity (WHC, OHC), swelling capacity (SW), and water solubility index (WSI). The results show that the amounts of protein, fiber, and ash were higher in cookies enriched with mushrooms than in control cookies. The enriched products, depending on the amount of mushroom powder used and the mushroom species, had a higher content of zinc, iron, magnesium, potassium, and copper. The increase in the addition of mushroom powder resulted in a significant (p < 0.05) increase in the TPC content and antioxidant properties. The use of composite flours contributed to a significant increase in hardness (at 6% mushroom powder) and a change in color parameters, with lower whiteness and a greater ΔE recorded for cookies with A. bisporus lyophilisate. In the sensory evaluation, the samples enriched with P. ostreatus powder received higher scores compared with control samples, while the cookies with A. bisporus flour were evaluated lower than the control.

1. Introduction

Cookies as snacks are popular among consumers for many reasons. A wide selection of shapes and sizes, high digestibility, high energy value, relatively low production costs, convenience, and long shelf life contribute to their popularity [1]. As stated in the report “Production and distribution of confectionery. Bittersweet prospects for the industry” [2], regarding data from 2015–2021, confectionery production in the European Union is highly concentrated in six countries: Germany, Italy, France, the Netherlands, Belgium, and Spain, providing a total of 80% of the value of manufactured products. Poland is in seventh place in this ranking. This sector is quite an important part of the domestic food industry, accounting for almost 6% of its total production in 2021. In the Polish confectionery industry, cookies account for approximately 40% of the total production value.

Shortbread cookies are made from dough by combining flour, fat, and sugar. Additional ingredients that can be used include eggs or yolks, cream, flavors, potato flour, and chemical leavening agents. The best quality shortbread cookies are obtained by maintaining the weight proportions between flour, fat, and sugar of 3:2:1 [3]. The best choice for the production of cookies is soft white wheat flour, with weak gluten, which ensures a tender bite, a higher spread ratio, and a uniform surface structure [4]. However, white flour compared with whole grain flour has reduced content of ingredients such as fiber, lysine, B-group vitamins, and major and trace elements [5]. Partial or complete replacement of the base flour with another flour substitute (e.g., mushroom powders [6], pulse flour [7], fruit waste powders [8]) on the one hand improves the nutritional composition of blended flour, but on the other hand contributes to modifying the technological quality of flours and final products.

Consumer behavior stimulates food producers to design products with improved nutritional composition. The number of nutritional claims such as “source of”, “rich in”, “light”, and health benefits is increasing [9,10]. Despite the availability of products with such claims, taste and cost of purchase are still the most important factors for consumers [10]. Modifying the composition of popular food products, e.g., cookies, in order to improve their nutritional or health-promoting value should not result in excessive increases in production costs and the final price. Mushrooms are cheap to produce because they can be grown indoors, they produce higher yields in a short time, and waste is often used for their cultivation [11,12]. The great advantage of cultivated mushrooms is their year-round availability. The popularity of mushrooms, their production, and consumption are constantly growing. Poland is a significant producer of this raw material in Europe. Cultivation is focused primarily on two species of mushrooms: Agaricus bisporus and Pleurotus ostreatus. The mentioned species are also the most frequently consumed and cultivated in the world, with A. bisporus taking first place [11,13].

Edible mushrooms are a raw material with a low fat content and at the same time a large amount of protein, fiber, ash, vitamins, sterols, and polyphenols [11,14,15,16,17]. The presence of a large group of mycochemicals contributes to the numerous health-promoting properties of mushrooms [18]. The appreciated taste and flavor of mushrooms as well as the chemical composition that determines their nutritional value and numerous health benefits encourage scientists to use this raw material as a functional food and for the design of functional foods. Mushrooms have been studied for their use as meat [19], fat [20], salt [19,20], or flour replacements [14,21,22]. Mushrooms have been used as a food additive in various forms, e.g., fresh or after thermal treatment [19], in the form of powders after drying and grinding [14,23,24], as water extracts [25], or polysaccharide fractions [26]. Preparing mushrooms as a flour substitute involves drying them using various methods [14,27,28] and then grinding the dried mushrooms into powder. Some aspects of using mushroom powder as a flour replacement are describe in an earlier article [14]. The base flour most often replaced with mushroom powder is wheat flour. Mushrooms have been studied as a substitute for flour in pasta production [29] and baked goods such as bread [14,30], cakes [31], cookies [22,24,27], and breadsticks [32]. Enriching these products with mushrooms contributed to obtaining products with an increased content of fiber [24,29], B vitamins, and vitamin D [14] or with a higher content of polyphenols [6,14,22]; however, the products were usually darker [14,21,22] and characterized by lower specific volume and higher hardness [14]. The presence of mushroom flour also resulted in a lower glycemic index of final products [29]. Mushroom powders have also been used in gluten-free formulas [33].

Mushrooms are a raw material rich in many major and trace elements [11] and may be an important source of these in the human diet. For adult Poles, the recommended dietary allowance (RDA) for various major elements is for calcium (Ca), 1000 mg/day; for magnesium (Mg), 310–400 mg/day; for iron (Fe), 10–18 mg/day. In turn, the RDA for trace elements is in the case of zinc (Zn), 8–11 mg/day; copper (Cu), 0.9 mg/day; selenium (Se), 55 mg/day; and manganese (Mn), 1.8–2.3 mg/day [34]. In the European population, the average dietary intakes of selected elements in adults during the day are Ca from 598 mg [35] to 1374 mg [36], Mg from 232 mg to 439 mg [37], Fe from 9.4 mg to 17.9 mg [38], Zn from 8–14 mg [39], Cu from 1.15–2.07 mg [40], Se from 31–65.6 µg [41], and Mn from 2 mg to 6 mg [42]. Mushrooms, compared with most vegetables, contain a larger amount of phosphorus (P) and potassium (K), and a relatively high content of Mg and Se [43]. However, mushrooms also can bind lead (Pb) or cadmium (Cd) and may constitute nutritional hazards [44]. Therefore, it is important to monitor the amount of these heavy metals in the mushroom biomass. The maximum permitted content of Cd and Pb in three species of mushrooms cultivated by producers, i.e., button mushrooms, oyster mushrooms, and shiitake (Lentinula edodes) is 0.15–0.2 mg Cd and 0.3 mg Pb per 1 kg of fresh weight [45]. With an average 90% water content in mushrooms, the amounts of these elements in dry weight should not exceed 1.5–2 mg Cd and 3 mg Pb on a dry weight basis [44].

The aim of the present research was to estimate the impact of using lyophilisates from white button mushrooms and oyster mushrooms as partial wheat flour substitutes (2%, 4%, 6% w/w) on the functional properties of the obtained blended flours as well as on physical parameters, basic nutritional composition, mineral content, selected health-promoting properties, and sensory evaluation of shortbread cookies prepared from these composite flours.

2. Materials and Methods

2.1. Mushroom Powder Preparation

Two mushroom species, white button mushrooms (Agaricus bisporus (Lange) Sing.) and oyster mushrooms (Pleurotus ostreatus (Jacq.) P. Kumm.), were obtained directly from the mushroom producer and processed within 24 h of harvesting. The raw materials were stored under refrigerated conditions prior to the treatments. The moisture content was 92.19% and 90.51% on a wet weight basis for button mushrooms and oyster mushrooms, respectively. The first stages of mushroom processing included washing and cutting into slices (3–4 mm). After freezing (−80 °C; 24 h), the raw material was dried (72 h) in a lyophilizer (Christ Alpha 1-2 LD plus, Germany). The obtained lyophilisates were ground (8000 rpm, 4 min) into flour in a laboratory mill (Retsch GM200, Retsch GmbH, Haan, Germany). Subsequently, the powders were sifted with a 0.25 mm sieve. The obtained powders were applied as a partial substitute for base flour in shortbread cookies.

2.2. Making the Shortbread Cookies

The ingredients from which the shortbread cookies (control samples) were prepared were as follows: 360 g of wheat flour (GoodMills Polska Sp. z o.o., Plony Natury, type 450), 240 g of butter (Mlekovita, 82% fat), 100 g of powdered sugar (Pfeifer & Langen Marketing Sp. z o.o., Diamant), and 40 g of yolk (Agrowita Sp. z o.o., Moja Kurka). To obtain other versions of cookies, the wheat flour was partially substituted for powdered lyophilisates (2%, 4%, 6% w/w). The dough was prepared using a Thermomix TM6 device (Vorwerk Elektrowerke GmbH & Co. KG, Wuppertal, Germany). First, the flour and sugar were mixed for 2 min. Then, the dough was mixed for another 3 min after adding the butter and next the yolk. The dough was left for 1 h at 4 °C to rest. Next, 5 mm thick sheets of dough were formed, from which round cookies were cut using stainless steel molds (Ø 70 mm). The shortbread cookies were baked (190 °C; 9 min) in a ChefTop oven (Unox, Cadoneghe, Italy). Before further analyses, the cookies were left to cool at a temperature of 20 ± 2 °C and then stored in a plastic container.

The samples of obtained cookies (Figure 1) were marked as follows: control—cookies with 100% wheat flour; Ab2—cookies with 2% A. bisporus lyophilisate as a flour substitute; Ab4—cookies with 4% A. bisporus lyophilisate as a flour substitute; Ab6—cookies with 6% A. bisporus lyophilisate as a flour substitute; Po2—cookies with 2% P. ostreatus lyophilisate as a flour substitute; Po4—cookies with 4% P. ostreatus lyophilisate as a flour substitute; Po6—cookies with 6% P. ostreatus lyophilisate as a flour substitute.

2.3. Basic Composition of Mushroom Powders, Wheat Flour and Shortbread Cookies

The basic components such as moisture, protein, fat, ash, and total dietary fiber of mushroom powders, wheat flour, and cookies were determined in accordance with American Association of Cereal Chemists (AACC) methods [46]. After subtracting the sum of these basic ingredients from 100, the amount of digestible carbohydrates was obtained. The factor 6.25 was used to estimate the amount of raw protein in flour and cookies [24], while in the case of mushrooms the factor 4.38 [43] was used due to the significant chitin content. Based on the amount of the basic components, the energy value was determined using following conversion factors per 1 g of nutrient: fat—9 kcal; protein and carbohydrates—4 kcal; dietary fiber—2 kcal [47].

2.4. Mineral Composition of Mushroom Powders, Flour and Shortbread Cookies

The content of 13 elements in wheat flour, mushroom powders, and shortbread cookies was determined. Three groups of elements were analyzed: (i) major essential elements (Ca, K, Mg, Na); (ii) essential trace elements (Cu, Fe, Mn, Ni, Zn, Se, Co); (iii) trace toxic elements (Pb, Cd), in accordance with the protocol by Kasprzyk et al. [48] with modifications. Before determining the elements, samples (0.5 g) were poured with 5 mL of HNO₃ and subjected to mineralization in a microwave oven (210 °C; 7 atmospheres). The obtained samples were diluted with demineralized water to 50 mL and then analyzed using flame atomic absorption spectrometry (AAS—Varian SpectrAA 280FS, Australia) for the amounts of the following elements: K, Na, Ca, Mg, Fe, Zn, Mn, Cu, or by inductively coupled plasma mass spectrometer (ICP Mass Spectrometer Varian MS-820 Belrose, Australia) for the amounts of such elements as Cd, Pb, Se, Co and Ni. The element content was expressed as mean values in mg/kg dw (n = 3).

2.5. Colour Measurement

The L*(brightness), a* (red/green value), and b* (blue/yellow value) color parameters of cookies, wheat flour, and mushroom powders were determined using a 3Color K9000Neo colorimeter (3Color, Narama, Poland). The measurement conditions used were as follows: D65 light source, observer—10° field of view; diaphragm measuring diameter—11 mm. In total, 15 measurements of color parameters were performed. Moreover, the browning index (BI) [49] was determined for all versions of the cookies, along with total color change (ΔE) [50] between cookies supplemented with mushroom powders and control cookies. The parameters ΔE and BI were calculated based on the equations below (Equations (1) and (2), respectively):

ΔE = [(L*_sample − L*_control)² + (a*_sample − a*_control)² + (b*_sample − b*_control)²]^½

(1)

BI = 100 − L*

(2)

2.6. Functional Properties of Mushroom Powder, Base Flour and Blended Flour

The bulk density (BD) was measured in accordance with the protocol by Okezie and Bello [51] with some modifications. A 50 mL cylinder was filled with 10 g of wheat flour and blended flour or 3 g of mushroom powders and then the volume was read. The BD value was expressed as the ratio of the mass of a given flour or lyophilisate to its volume (g/mL).

Swelling capacity (SC) was measured in accordance with the methodology given by Tosh and Yada [52] with minor modifications. In a 50 mL cylinder, 3 g of wheat flour and blended flour or 1 g of mushroom powder were mixed with distilled water, which was topped up to 30 mL. The mixture was vortexed for 1 min and left for 24 h at a temperature of 20 ± 2 °C. Then, the final volume (Vf) was read and SC was calculated according to Equation (3):

SC = Vf (mL)/Sample weight (g)

(3)

The water solubility index (WSI) was measured in accordance with the protocol by Zhang et al. [53] with modifications. A mixture of 0.5 g of wheat flour, mushroom powder, or blended flour (W1) and 25 mL of distilled water in a 50 mL falcon tube was incubated in a water bath (30 min, 80 °C). After cooling, the samples were centrifuged (5000× g; 20 min) (MPW-350R, Warsaw, Poland). The supernatant from the sediment was poured into a previously weighed vessel (W2) and dried (105 °C; 24 h). The mass of the obtained residue (W3) was weighed. The water solubility index was calculated according to Equation (4):

WSI (%) = (W3 (g) − W2 (g))/(W1 (g) × 100)

(4)

The WHC and OHC were determined in accordance with the method described by Tan et al. [54] with modifications. For this purpose, 100 mg of wheat flour and blended flour or 33 mg of mushroom powder (W1) was blended with 1.5 mL of distilled water or rapeseed oil in previously weighed 2 mL Eppendorf tubes (W2). The mixture was thoroughly vortexed for 1 min and left for 0.5 h at 20 ± 2 °C. Then, the samples were centrifuged for 20 min at 10,000× g (MPW-350R, Warsaw, Poland). The supernatant was carefully removed and the tubes with the contents were left upside down for 30 min to allow the remaining water and oil to drain and the obtained residue was weighed (W3). WHC and OHC were presented as the weight of water or oil bound by 1 g of sample. WHC and OHC were calculated according to Equation (5):

WHC (g^water/g) or OHC (g^oil/g) = (W3 (g) − W2 (g) − W1(g))/W1 (g)

(5)

2.7. Basic Properties of Cookies

The water activity (a_w) was determined at 25 °C using LabSwift-aw equipment (Novasina AG, Lachen, Switzerland). The measurements were taken 24 h after baking and keeping the cookies at room temperature. Prior to determination, the samples were stored in a plastic container. Measurements were taken three times for each version of the cookies, and a 3 g sample was used each time for a_w measurement.

For each version of the cookies, the average weight (g) was estimated, and the diameter (D) (mm) and thickness (T) (mm) were also evaluated using an electronic caliper. Based on these two parameters, the spread ratio (D/T) was calculated [55]. In total, 12 measurements were performed for each batch of cookies.

2.8. Cookies Texture

The texture of samples was analyzed with a TA.XTplusC Texture Analyser (Stable Micro Systems, Godalming, UK) within 24 h after baking. Before the measurements were taken, fragments with a diameter of 50 mm were cut out from the middle part of the cookies. Cookies was measured using a sharp cutting blade probe (type HDP/BS) at a pre-test speed of 1 mm/s, test speed of 3 mm/s, post-test speed of 10 mm/s. The data were analyzed using Exponent Connect 8.0 software (Stable Micro System Ltd., Surrey, UK). The cutting force was used as an indicator of cookies’ hardness (g). In total, 12 measurements were performed for each batch of cookies.

2.9. Total Phenolic Content (TPC) and Antioxidant Properties

2.9.1. Extraction Procedure

The extraction procedure was carried out in accordance with the protocol presented by Radzki et al. [15] with modifications. A laboratory mill (Retsch GM200, Retsch GmbH, Haan, Germany) was used for grinding the cookie samples. The obtained fine powders were sifted through a sieve (0.25 mm). Ten mL of ethanol (80% v/v) was mixed with samples of wheat flour and ground cookies (500 mg each) and 100 mg of mushroom powder. Extraction was performed in a water bath (80 °C; 180 rpm; 1 h). Next, the mixture was cooled and centrifuged (4200× g; 20 min) (MPW-350R, Warsaw, Poland). Extracts were prepared in triplicate for all samples.

2.9.2. Total Phenolic Content (TPC)

The TPC was quantified in accordance with the method described by Singleton and Rossi [9] and Dubost et al. [56] with some modifications. The ethanolic extracts (200 µL) were mixed with diluted (10:1) Folin and Ciocalteu reagent (800 µL). After 3 min, 1250 µL of 7% Na₂CO₃ was added, and the mixtures were left to stand for 0.5 h in the dark at 20 ± 2 °C. The absorbance was read at 725 nm (Helios Gamma, Thermo Fisher Scientific, Waltham, MA, USA) against a blank sample. The TPC was presented as gallic acid equivalent (GAE) per 1 g of dry weight (dw).

2.9.3. Antioxidant Activity

Measurement of ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) radical scavenging activity was conducted in accordance with the protocol by Re et al. [57]. Ethanolic extracts (100 µL) after mixing with ABTS + solution (1000 µL) were measured at 734 nm after 15 min of incubation. In turn, the ferric reducing antioxidant power (FRAP) measurement was carried out in accordance with the methodology presented by Benzie and Strain [58]. FRAP solution (1900 µL) was mixed with ethanolic extracts (100 µL) and, after incubation (37 °C; 15 min), the absorbance measurements were conducted at 593 nm. Antioxidant activity measured by ABTS and FRAP methods was expressed in µmol of trolox equivalent (TE) per 1 g of dw.

2.10. Dry Weight

The oven-drying method was used to determine the water content of samples by drying them at 105 °C for at least 24 h. Based on the water content, the dry weight was calculated (dw) [15].

2.11. Sensory Evaluation

Shortbread cookies were subjected to sensory evaluation by a panel of 25 untrained consumers aged 20 to 56 (14 women and 11 men). The assessment was conducted among employees and students at Life Sciences University in Lublin. Cookies (coded with a random 3-digit number) were served on white plates one day after production. A 9-point hedonic scale was used to estimate the degree of overall liking or disliking of different types of cookie, where 1 = dislike extremely, 5 = neither like nor dislike, 9 = like extremely). The following cookie attributes were assessed: appearance, color, aroma, taste, texture, and overall acceptability [59].

2.12. Statistical Analysis

The results were statistically analyzed (one-way ANOVA), comparing means via the Tukey test (p < 0.05). STATISTICA13.3 software (StatSoft, Cracow, Poland) was used for analyses. The results were expressed as mean values ± standard deviation (SD).

3. Results and Discussion

3.1. Basic Composition of Wheat Flour, Mushroom Powders, and Shortbread Cookies

Table 1. Basic composition of raw materials and shortbread cookies.

Sample	Protein %	Fat %	Ash %	Carbohydrates %	Fiber %	Moisture %	Energy Value kcal/100 g
Raw materials
Ab powder	33.61 ± 0.31 C	3.20 ± 0.04 C	9.68 ± 0.02 C	15.82 ± 0.57 B	31.15 ± 0.14 B	6.54 ± 0.11 A	289 ± 1.27 B
Po powder	26.89 ± 1.06 B	2.75 ± 0.09 B	8.36 ± 0.08 B	7.86 ± 0.54 A	45.77 ± 0.7 C	8.37 ± 0.04 B	255 ± 0.35 A
Wheat flour	11 ± 0.2 A	1.2 ± 0.08 A	0.5 ± 0.02 A	71 ± 1.2 C	3.0 ± 0.2 A	13.3 ± 0.11 C	345 ± 2.71 C
Cookies
Control	6.21 ± 0.04 a	29.23 ± 0.13 a	0.21 ± 0.03 a	56.21 ± 0.29 d	2.80 ± 0.09 a	5.34 ± 0.07 b	518 ± 2.10 b
Ab2	6.67 ± 0.04 c	29.31 ± 0.07 a	0.34 ± 0.02 b	52.93 ± 0.07 b	5.67 ± 0.10 b	5.09 ± 0.00 b	513 ± 0.70 ab
Ab4	6.76 ± 0.03 c	29.46 ± 0.18 a	0.52 ± 0.03 b	53.23 ± 0.33 bc	5.91 ± 0.12 b	4.12 ± 0.03 a	517 ± 0.57 b
Ab6	7.20 ± 0.10 d	29.57 ± 0.17 a	0.64 ± 0.02 d	51.15 ± 0.33 a	6.87 ± 0.14 d	4.57 ± 0.02 a	513 ± 1.52 ab
Po2	6.45 ± 0.02 b	29.30 ± 0.20 a	0.28 ± 0.01 b	53.69 ± 0.26 c	5.91 ± 0.15 b	4.37 ± 0.09 a	516 ± 1.60 ab
Po4	6.75 ± 0.02 c	29.44 ± 0.32 a	0.38 ± 0.02 c	52.90 ± 0.26 b	6.43 ± 0.14 c	4.10 ± 0.16 a	516 ± 4.28 ab
Po6	6.78 ± 0.05 c	29.38 ± 0.13 a	0.50 ± 0.01 e	50.87 ± 0.19 a	8.02 ± 0.15 e	4.45 ± 0.22 a	511 ± 0.91 a

^A–C or ^a–e—the different letters in columns mean that there are significant differences between mean values (HSD Tukey’s test, p < 0.05, n = 3); Ab powder—A. bisporus powder; Po powder—P. ostreatus powder; control—cookies with 100% wheat flour; Ab2—cookies with 2% A. bisporus lyophilisate as a flour substitute; Ab4—cookies with 4% A. bisporus lyophilisate as a flour substitute; Ab6—cookies with 6% A. bisporus lyophilisate as a flour substitute; Po2—cookies with 2% P. ostreatus lyophilisate as a flour substitute; Po4—cookies with 4% P. ostreatus lyophilisate as a flour substitute; Po6—cookies with 6% P. ostreatus lyophilisate as a flour substitute.

presents the results for the basic composition of raw materials (mushroom powders and wheat flour) and shortbread cookies. Compared with wheat flour, mushroom lyophilisates contained significantly (p < 0.05) higher protein content (from 26.89% to 33.61%) and fat content (from 2.75% to 3.20%), 16–20 times more ash, and 10–15 times more fiber. The basic composition of mushroom powders used as a substitute for base flour translates into the composition of baked goods. The increasing content of mushroom flour from 0% to 6% contributed to a significant (p < 0.05) increase in the amount of protein, ash, and fiber in the cookies. The highest protein content was recorded in cookies with 6% button mushroom (7.20%) compared with the control cookies (6.21%). With 6% replacement of wheat flour, the amount of ash compared with the control cookies increased to more than double in the case of cookies supplemented with oyster mushrooms (0.5%) and to more than three times in the case of cookies with A. bisporus (0.64%). Cookies enriched with mushroom lyophilisates had a higher fiber content of from 5.67% (Ab2 cookies) to 8.02% (Po6 cookies) compared with control cookies (2.8%). A slight decrease in the amount of carbohydrates in products with mushrooms was recorded, and no significant differences were noticed in the amount of fat between the different versions of the cookies. The results presented in this work show that the highest moisture content was recorded in cookies with 100% wheat flour (5.34%) and cookies with 2% button mushroom powder (5.09%). The remaining versions of the cookies had significantly lower moisture content, from 4.10% to 4.57%.

The mushroom powders used for this research can be considered high-protein and high-fiber foods. According to European Union law [60], food that contains at least 3 g of fiber per 100 g or at least 1.5 g of fiber per 100 kcal may be called a “source of fiber”, while food containing at least 6 g of fiber per 100 g or at least at least 3 g of fiber per 100 kcal can be considered “high in fiber”. The same document specifies the possibility of using the claims “source of protein” and “high protein” in the cases of foods where at least 12% or 20% of the energy value of the food comes from protein.

Mushrooms are a raw material with a significant amount of fiber, minerals, and protein containing all essential amino acids, while being low in fat [43]. The amount of protein reported in A. bisporus ranges from 7% to 40.5% of dry weight, while in Pleurotus spp. it ranges from 7.6% to 37.04% [61,62]. The main component of mushrooms, apart from water, is carbohydrates, which include mono- and disaccharides, polyols, polysaccharides such as β-glucans, glycogen, and chitin [63]. The data for total carbohydrate content vary in the range from 50.9 to 74.0% in white button mushrooms and from 51.9% to 85.2% in oyster mushrooms [64]. Thanks to the significant presence of non-starch polysaccharides, mushrooms are a very good source of dietary fiber, i.e., carbohydrate polymers, which are not hydrolyzed by the endogenous enzymes in humans. Mushroom fiber is primarily the insoluble fraction of glucans and chitin and the fraction soluble in water, usually constituting less than 10% of dry matter [65]. The amount of total dietary fiber (TDF) in mushroom species and fruiting body parts varies. Synytsya et al. [66] reported that the TDF content in Pleurotus species was 34.5–63.1% in pilei and 38.9–64.8% in stems. Authors Nile and Park [67] reported that the TDF content of the 20 tested mushrooms ranged from 24% to 36% of dry matter, with A. bisporus containing 31% total dietary fiber. Mushrooms are low in fats, with linoleic acid making up 75% of the total fatty acids [68]. Kirbağ and Akyüz [69] reported that the fat content in A. bisporus and Pleurotus spp ranged from 0.5% to 1.3%, while Shbeeb et al. [68] reported fat content ranging from 2.5% in P. ostreatus to 3.1% in A. bisporus. The ash content in mushrooms is relatively high and ranges from 52.7 to 120 g/kg dw in selected cultivated species and from 55.3 to 232.8 g/kg dw in some wild-grown mushrooms [43].

The results presented by other authors show that partial replacement of wheat flour with powder from Pleurotus ostreatus [23], P. sajor-caju [27], P. albidus [21], Termitomyces robustus [70], Lentinula edodes [71], Calocybe indica [6], or Cordyceps militaris [22] results in an increase in the content of protein, dietary fiber, and ash and a decrease in fat and carbohydrates in cookies enriched with mushroom flour. Shams et al. [72] reported that replacing barley flour with Agaricus bisporus powder at an amount of 10–50% contributed to a decrease in the content of fiber and carbohydrates, which was due to the fact that barley flour is a better source of fiber than mushrooms. However, these samples had a higher protein and ash content than the control. Replacing sorghum flour with from 5% to 15% shiitake, black, and silver ear mushroom powder contributed to an increase in protein content only in the case of shiitake mushroom biscuits [24]. The protein content showed a decrease in the following order: shiitake mushroom flour (24.68 g/100 g) > sorghum flour (11.74 g/100 g) > black ear mushroom flour (10.92 g/100 g) > silver ear mushroom flour (10.88 g/100 g). However, mushroom flours had higher fiber content (from 38.46 to 76.78 g/100 g) than the base flour (11.50 g/100 g), which contributed to obtaining high-fiber biscuits.

3.2. Mineral Composition

The mineral composition of mushroom powders and base flour is summarized in

Table 2. Mineral composition of wheat flour and mushroom powders.

Element mg/kg dw	A. bisporus Powder	P. ostreatus Powder	Wheat Flour
Ca	320.14 ± 6.97 c	114.44 ± 4.15 a	234.91 ± 3.52 b
Mg	1044.99 ± 22.84 b	1062.48 ± 17.63 b	155.32 ± 8.73 a
K	1962.06 ± 54.20 b	15,758.11 ± 126.65 c	231.06 ± 10.47 a
Na	441.55 ± 10.07 b	85.37 ± 4.12 a	nd
Fe	34.58 ± 2.84 b	53.34 ± 2.29 c	6.86 ± 0.32 a
Zn	56.44 ± 1.91 b	51.44 ± 2.58 b	5.57 ± 0.25 a
Cu	36.13 ± 2.39 c	7.13 ± 0.09 b	1.89 ± 0.14 a
Mn	5.08 ± 0.03 c	4.42 ± 0.14 b	3.18 ± 0.07 a
Se	0.414 ± 0.007 b	0.115 ± 0.004 a	0.116 ± 0.005 a
Co	0.061 ± 0.003 a	0.059 ± 0.004 a	0.060 ± 0.001 a
Ni	0.184 ± 0.008 c	0.161 ± 0.007 b	0.127 ± 0.003 a
Pb	0.029 ± 0.006 a	0.042 ± 0.003 b	nd
Cd	0.038 ± 0.004 b	0.176 ± 0.002 c	0.017 ± 0.002 a

^a–c—different letters in a row mean that there are significant differences between mean values (HSD Tukey’s test, p < 0.05, n = 3); nd—not detected.

. In turn,

Table 3. Mineral composition of shortbread cookies.

Element mg/kg dw	Cookies
	Control	Ab2	Ab4	Ab6	Po2	Po4	Po6
Ca	371.15 ± 13.79 a	373.52 ± 14.13 a	370.11 ± 10.12 a	378.13 ± 14.83 a	363.81 ± 13.64 a	363.11 ± 19.88 a	356.95 ± 13.66 a
Mg	112.09 ± 6.78 a	123.77 ± 3.73 ab	137.97 ± 6.96 bc	152.78 ± 8.04 c	119.78 ± 9.85 ab	127.65 ± 10.54 ab	142.00 ± 9.87 bc
K	81.52 ± 4.40 a	94.89 ± 5.60 a	100.46 ± 6.83 a	123.66 ± 11.68 a	203.14 ± 18.10 b	322.25 ± 28.04 c	408.79 ± 22.85 d
Na	nd	nd	nd	nd	nd	nd	nd
Fe	6.99 ± 0.13 a	7.37 ± 0.51 a	7.95 ± 0.46 abc	8.75 ± 0.34 bcd	7.82 ± 0.29 ab	8.88 ± 0.19 cd	9.69 ± 0.53 d
Zn	6.99 ± 0.08 a	8.33 ± 0.06 bc	9.40 ± 0.32 de	10.73 ± 0.46 f	7.97 ± 0.18 b	9.00 ± 0.43 cd	10.21 ± 0.49 ef
Cu	1.36 ± 0.05 a	1.83 ± 0.03 b	2.39 ± 0.10 c	2.83 ± 0.08 d	1.41 ± 0.03 a	1.46 ± 0.02 a	1.51 ± 0.09 a
Mn	1.64 ± 0.02 a	1.64 ± 0.05 a	1.63 ± 0.07 a	1.67 ± 0.07 a	1.60 ± 0.07 a	1.63 ± 0.04 a	1.67 ± 0.07 a
Se	0.103 ± 0.006 a	0.108 ± 0.007 a	0.111 ± 0.010 a	0.116 ± 0.014 a	0.102 ± 0.006 a	0.105 ± 0.005 a	0.114 ± 0.014 a
Co	0.051 ± 0.002 a	0.050 ± 0.004 a	0.052 ± 0.001 a	0.057 ± 0.005 a	0.053 ± 0.001 a	0.053 ± 0.003 a	0.055 ± 0.005 a
Ni	0.158 ± 0.006 a	0.160 ± 0.006 a	0.161 ± 0.008 a	0.163 ± 0.006 a	0.158 ± 0.006 a	0.155 ± 0.002 a	0.161 ± 0.007 a
Pb	nd	nd	nd	nd	nd	nd	nd
Cd	nd	nd	nd	nd	nd	nd	nd

^a–f—different letters in a row mean that there are significant differences between mean values (HSD Tukey’s test, p < 0.05, n = 3); nd—not detected; control—cookies with 100% wheat flour; Ab2—cookies with 2% A. bisporus lyophilisate as a flour substitute; Ab4—cookies with 4% A. bisporus lyophilisate as a flour substitute; Ab6—cookies with 6% A. bisporus lyophilisate as a flour substitute; Po2—cookies with 2% P. ostreatus lyophilisate as a flour substitute; Po4—cookies with 4% P. ostreatus lyophilisate as a flour substitute; Po6—cookies with 6% P. ostreatus lyophilisate as a flour substitute.

presents the mineral content of cookies enriched with mushroom flour. Compared with wheat flour, mushroom lyophilisates are characterized by significantly (p < 0.05) higher amounts of most of the analyzed elements: Mg, K, Na, Fe, Zn, Cu, Mn, and Ni. The content of toxic elements (Cd, Pb) in the mushroom powders is within the standards set by European Union regulations [45]. Similarly, Pb and Cd in the cookies were not recorded, nor was sodium (Na). There were no significant (p < 0.05) differences in the content of elements such as Ca, Mn, Se, Co, or Ni between the variants of the obtained cookies. Higher levels of Zn were recorded in all cookies with the addition of mushroom powders (from 7.97 to 10.73 mg/kg dw) compared with the control cookies (6.99 mg/kg dw). The use of lyophilisate from A. bisporus in amounts of 2–6% contributed to a significant increase in the Cu content in baked goods, in the range from 1.83 to 2.83 mg/kg dw, compared with the control (1.36 mg/kg dw). Inclusion of at least 2% dried oyster mushroom contributed to a more than twofold higher K content in the supplemented cookies (203.14 mg/kg dw) compared with the content of this element in the control samples (81.52 mg/kg dw). In cookies where part of the base flour was substituted with button and oyster mushroom powder from 4% to 6%, higher amounts of iron or magnesium were recorded.

The increase in most minerals in mushroom-enriched cookies was the result of the higher amounts of ash in the mushroom powders (Table 1). As shown by the results presented in other works, the addition of mushroom powder leads to an increase in the ash and element content in composite flours where the base is sweet potato and rice flour [73] or maize flour [74]. Rathore et al. [6] observed an increase in the amounts of ash and elements (Zn, Fe, K) in cookies where part of the wheat flour was replaced with Calocybe indica flour. Owheruo et al. [23] recorded a significant (p < 0.05) increase in the amounts of ash and elements such as Na, Ca, K, and Zn in cookies prepared from wheat flour with the addition of oyster mushroom flour. The authors suggested that the biscuits they obtained would be suitable for people on a low salt diet, because the biscuits had a low sodium to potassium ratio (below 1).

The amounts of individual elements in mushrooms are the result of many factors, including species, part of the fruiting body (e.g., cap, stipe), fungal lifestyle (e.g., saprotrophs), and type of growing medium [43,75]. According to the literature data [11,13,76], the amounts of major essential elements in cultivated mushrooms varied; in the case of Ca it was 860–1400 mg/kg dw and 190–1500 mg/kg dw; for K it was from 18,321–49,000 mg/kg dw and 21,840–51,000 mg/kg dw; for Mg it was from 1099–1480 mg/kg dw and 165–2300 mg/kg dw; and for Na it was from 240–957 mg/kg dw and 250–1440 mg/kg dw, for A. bisporus and P. ostreatus, respectively.

According to EU regulations [60,77], the condition for using the “source of mineral/s” nutritional claim is a content of at least 15% of the RDA of a given ingredient. In turn, the nutritional claim “high mineral/s” can only be used if the product contains at least twice the value of products marked as a “source of mineral/s”. Taking into account the moisture content of the mushroom powders used in our tests, it can be concluded that in the case of A. bisporus flour, the nutritional claims “source of Mg, Mn, and Se” and “high Fe, Zn, Cu” can be used, and in the case of oyster mushroom flour, the nutritional claims “source of Mg, Mn, Se, and K” and “high Fe, Zn, Cu” can be used.

3.3. Colour Measurements

Table 4. Color parameters of mushroom powders, wheat flour, and shortbread cookies.

Sample	Parameter
	L*	a*	b*	∆E	BI
Raw materials
A. bisporus powder	82.91 ± 0.21 A	1.47 ± 0.07 C	14.39 ± 0.22 B	-	-
P. ostreatus powder	87.25 ± 0.23 B	-0.86 ± 0.06 A	15.18 ± 0.34 C	-	-
Wheat flour	93.47 ± 0.18 C	0.36 ± 0.03 B	9.34 ± 0.17 A	-	-
Cookies
Control	77.39 ± 1.00 f	3.10 ± 0.47 a	26.50 ± 1.31 b	-	22.61 ± 1.00 a
Ab2	66.04 ± 1.00 c	5.25 ± 0.71 b	21.07 ± 1.00 a	12.92 ± 1.30 c	33.96 ± 1.00 d
Ab4	62.61 ± 0.71 b	6.19 ± 0.54 bc	21.73 ± 0.66 a	15.95 ± 1.01 d	37.39 ± 0.71 e
Ab6	60.97 ± 1.33 a	7.11 ± 0.75 d	21.88 ± 0.72 a	17.33 ± 1.71 d	39.03 ± 1.33 f
Po2	75.30 ± 1.27 e	5.37 ± 1.26 b	29.17 ± 1.41 c	4.63 ± 1.59 a	24.70 ± 1.27 b
Po4	74.66 ± 1.39 e	6.12 ± 1.17 bc	29.00 ± 1.30 c	5.15 ± 1.18 a	25.34 ± 1.39 b
Po6	72.11 ± 1.14 d	6.67 ± 1.09 cd	28.96 ± 1.06 c	7.05 ± 1.30 b	27.89 ± 1.14 c

L*—brightness; a*—red/green value; b*—blue/yellow value; ^A–C or ^a–f—the different letters in columns mean that there are significant differences between mean values (HSD Tukey’s test, p < 0.05, n = 15); ∆E—total colour change; BI—browning index; control—cookies with 100% wheat flour; Ab2—cookies with 2% A. bisporus lyophilisate as a flour substitute; Ab4—cookies with 4% A. bisporus lyophilisate as a flour substitute; Ab6—cookies with 6% A. bisporus lyophilisate as a flour substitute; Po2—cookies with 2% P. ostreatus lyophilisate as a flour substitute; Po4—cookies with 4% P. ostreatus lyophilisate as a flour substitute; Po6—cookies with 6% P. ostreatus lyophilisate as a flour substitute.

presents the L*, a*, b*, ∆E, and BI for the cookies and L*, a*, b* for wheat flour and mushroom lyophilisates. Color is one of the most important features influencing consumer acceptance of a product. In turn, the type of flour or substitute used has a significant impact on the color of the cookies. The values of all color parameters for raw materials (wheat flour and mushroom powders) were different. The lightness (L*) was the highest for wheat flour, and among the mushroom powders, the powder from freeze-dried oyster mushrooms (L* = 87.25) was much lighter than that from button mushrooms (L* = 82.91). In turn, regarding chromatic values, a higher share of green color was recorded for oyster mushroom powder (a* = −0.86), a higher share of red color (a* = 1.47) for button mushroom powder, and higher values of the b* parameter (from 14.39 to 15.18) for mushroom powders compared with wheat flour (b* = 9.34).

Traditional shortbread cookies are characterized by color ranging from yellow through golden to slightly brown. Control cookies were characterized by the highest value of the L* parameter (77.39). With the increase in the addition of mushroom lyophilisate, the value of this parameter was significantly lower, from 75.30 to 72.11 for cookies with P. ostreatus powder and from 66.04 to 60.97 for cookies with the addition of A. bisporus. An inverse relationship was noted for the a* parameter of enriched cookies, for which the value was significantly higher (from 5.25 to 6.67), while the value of the a* parameter of control cookies was 3.10. In turn, the highest yellowness (b* parameter) was recorded for cookies with the addition of oyster mushrooms, then for control cookies, and the lowest for cookies with button mushrooms.

Higher ΔE was noted for the cookies with A. bisporus (from 12.92 to 17.33) than those with P. ostreatus (from 4.63 to 7.05). A similar relationship was noted for the browning index. The lowest BI value was observed for cookies without mushrooms (22.61), cookies enriched with oyster mushrooms had a BI of 24.70 to 27.89, and the browning index of the cookies with A. bisporus ranged from 33.96 to 39.03.

The results presented in this article show that freeze-dried button mushrooms are darker than freeze-dried oyster mushrooms, even though fresh mushroom caps of the white variety are characterized by higher values of the L* parameter. The results presented by other researchers also confirm this. Examples of color parameter values for the caps of fresh white button mushrooms given in other reports include parameter L* ranging from 89.02 to 93.23, parameter a* ranging from 0.57 to 0.73, and parameter b* equal to 12.75 or 12.8 [78,79]. In turn, according to Kic [80], the caps of fresh oyster mushroom fruiting bodies are darker (L* = 75.94 and 78.09), while the other parameters range from −0.04 to −0.21 and from 12.29 to 13.05 for parameter a* and b*, respectively. According to other researchers, the color parameters of freeze-dried button mushrooms are as follows: parameter L* from 73.39 to 86.19, parameter a* from 0.89 to 1.66, and parameter b* from 10.22 to 15.29 [14,81]. In the case of freeze dried oyster mushrooms, the whiteness parameter L* ranged from 82.42 to 84.72, while the value of the chromatic coordinate a* ranged from −0.58 to 1.49, and for the chromatic coordinate b* it was 12.42 and 15.47 [82,83].

The color of dried mushrooms is influenced by many factors, including preliminary processing (e.g., washing, cutting) [84] and the drying method [85], as well as the parameters used [86]. During pre-treatment, the chemical composition (phenolic compounds, free amino acids) and the activity of oxidizing enzymes (e.g., peroxidase, polyphenol oxidase) contributes significantly to changing the color of the raw material [87]. A. bisporus are mushrooms with a high polyphenol content and high enzymatic activity [88]. The drying method also determines the color of the raw materials. When convective drying is used, the main role in the darkening of dried products is played primarily by Maillarad reactions [89], while in freeze drying, the enzymatic activity of raw materials [90] has a significant impact. According to Ucar and Karadag [83], the L* value of P. ostreatus increased after freeze-drying. This is confirmed by the results obtained, where the mushroom powder from white button mushrooms is clearly darker than that obtained from oyster mushrooms.

The effects of partial replacement of wheat [21,22], whole grain [91], barley [72] and sorghum [24] flour with mushroom powder on the color change of cookies have been observed by other researchers. Regardless of whether the basic flour was replaced by an amount of 1–5% [22] or even up to 100% [21] mushroom powder, the value of the L* parameter was lower compared with control cookies. Only cookies made from whole grain flour where 10% and 30% of the flour was replaced with dried oyster mushrooms showed a similar L* value [91], and cookies in which sorghum flour was replaced by 5%, 10%, or 15% silver ear mushroom powder had L* values that were significantly higher [24]. In the case of the chromatic coordinate a*, there was no significant effect of supplementation with dried Pleurotus albidus [21], and there was increase in the value of this parameter for cookies supplemented with Cordyceps militaris powder [22], while there was a decrease in the redness of cookies with the addition of P. ostreatus [91], shiitake, or black ear mushrooms [24] compared with the control. For the chromatic b* coordinate, an increase in the value was observed in the case of cookies supplemented with C. militaris [22], A. bisporus [72], or silver ear mushrooms [24] and a decrease in the yellowness of cookies supplemented with P. albidus [21], P. ostreatus [91], shiitake, or black ear mushrooms [24].

The change in the color of the surface of bakery products is the result of non-enzymatic browning reactions. i.e., Maillard reactions and caramelization, which result in the formation of colorful high-molecular compounds, caramels, and melanoidins [92]. Maillard reactions depend on the presence of reducing sugars, free amino acids, proteins, and nitrogen-containing compounds, while caramelization occurs as a result of the reaction of reducing sugars at appropriately high temperatures. These reactions occur more intensively with lower water content, i.e., mainly on the surface of bakery products, where water evaporates intensively [49].

3.4. Functional Properties of Mushroom Powder, Wheat Flour, and Blended Flours

Data regarding functional properties of mushroom powders, base flour, and blended flours are presented in

Table 5. Functional properties of mushroom powders, wheat flour, and blended flours.

Sample	Parameter
	BD (g/mL)	WHC (gwater/g)	OHC (goil/g)	SC (mL/g)	WSI (%)
Ab powder	0.10 ± 0.00 B	5.17 ± 0.26 A	5.44 ± 0.32 A	20.51 ± 0.48 B	42.13 ± 0.22 A
Po powder	0.08 ± 0.01 A	7.32 ± 0.36 B	7.29 ± 0.10 B	16.51 ± 0.41 A	54.06 ± 0.41 B
Wheat flour	0.76 ± 0.01 f	0.77 ± 0.02 a	0.68 ± 0.01 a	2.59 ± 0.08 ab	7.30 ± 0.17 a
WFAb2	0.70 ± 0.01 e	0.80 ± 0.01 a	0.76 ± 0.02 b	2.61 ± 0.04 ab	7.94 ± 0.26 ab
WFAb4	0.66 ± 0.01 d	0.83 ± 0.02 a	0.85 ± 0.02 c	2.70 ± 0.03 b	8.47 ± 0.13 b
WFAb6	0.63 ± 0.01 bc	0.87 ± 0.03 ab	0.95 ± 0.00 d	2.88 ± 0.04 c	9.80 ± 0.42 c
WFPo2	0.65 ± 0.02 cd	0.90 ± 0.06 ab	0.80 ± 0.03 bc	2.56 ± 0.04 a	7.91 ± 0.04 ab
WFPo4	0.62 ± 0.01 b	0.99 ± 0.10 bc	0.91 ± 0.02 d	2.61 ± 0.02 ab	10.10 ± 0.20 c
WFPo6	0.58 ± 0.01 a	1.07 ± 0.03 c	1.03 ± 0.03 e	2.98 ± 0.05 c	11.15 ± 0.32 d

BD—bulk density; WHC or OHC—water- or oil-holding capacity; SW—swelling capacity; WSI—water solubility index; ^A,B or ^a–f—different letters in columns mean that there are significant differences between mean values (HSD Tukey’s test; p < 0.05; n = 3); Ab—A. bisporus; Po—P. ostreatus; WFAb2—wheat flour with 2% addition of A. bisporus; WAb4—wheat flour with 4% addition of A. bisporus; WAb6—wheat flour with 6% addition of A. bisporus; WPo2—wheat flour with 2% addition of P. ostreatus; WPo4—wheat flour with 4% addition of P. ostreatus; WPo6—wheat flour with 6% addition of P. ostreatus.

. Functional properties reflect the complex interactions between compounds and the structure and physico-chemical properties of food ingredients in a given environment [59].

The BD is a parameter describing the expansion and porosity of flours [93]. Bulk density was significantly lower for mushroom powders (0.08–0.10 g/mL) than for wheat flour (0.76 g/mL). It is clear that replacing part of the wheat flour with mushroom lyophilisate results in a reduction in the BD value of composite flours (0.58–0.70 g/mL). Flour blends containing oyster mushroom powder had lower BD values than flours with button mushroom. BD value is affected by practical size [7] and moisture content [59]. Van Toan and Thu [71] obtained similar BD results for wheat flour (0.72 g/mL). In turn, the powder from shiitake mushrooms dried at 65 °C had a BD of 0.372 g/mL. In another publication, the authors reported that the bulk densities of mushroom powders were 0.22 g/mL and 0.28 g/mL for A. bisporus and P. ostreatus, respectively [17].

The highest water-holding capacity (WHC) was recorded for oyster mushroom (7.32 g/g) and A. bisporus lyophilisate (5.17 g/g). The high WHC values of mushroom powders also resulted in an increase in WHC for blended flours. However, significantly (p < 0.05) higher values were recorded for flour with 4% and 6% P. ostreatus (0.99 and 1.07 g/g, respectively) compared with wheat flour (0.77 g/g). Similar relationships are presented by other authors. Rathore et al. [6] reported that replacing wheat flour (WHC = 37.78%) with C. indica powder from 5% to 20% resulted in an increase in WHC from 41.74% to 54.69%. Tu et al. [24] reported that compared with sorghum flour, for which WHC was 2.04 g/g, powders from three mushroom species had higher WHC (11.63 g/g for black ear, 9.65 g/g for silver ear, and 3.76 g/g for shiitake mushroom). The water-holding capacity of composite flours with mushroom powders (5–15%) was significantly (p < 0.05) higher than that of the base flour. The authors noticed a positive correlation (p < 0.001) of WHC and the amount of soluble and insoluble fiber in mushroom powders. Higher water-holding capacity may be related to a higher polysaccharide content. This is confirmed by our research (Table 1), where a significantly higher fiber content was found in oyster mushrooms. Cornelia and Chandra [28] explain that the lower water-absorption properties of oven-dried oyster mushroom powder compared with sun and cabinet drying are the result of greater degradation of the fiber due to high temperature and too long a water-removal process. In addition to the high content of water-soluble polysaccharides [16], mushrooms are characterized by a high proportion of polar amino acids influencing hydrophilic interactions in the food matrix [17,94]. Rathore et al. [6] indicate that the increase in the water absorption of composite flour may result from the increase in the leaching and solubility of amylose and the destruction of the crystalline structure of starch. In addition to the chemical composition (amounts of polysaccharides and hydrophilic proteins) of the mushroom powder, the practical size of the powder also influences its water-holding capacity. The results of research by Heo et al. [95] show that the water-holding capacity of freeze-dried button mushroom powder decreases significantly (p < 0.05) with decreasing practical size.

The OHC of mushroom lyophilisates was significantly higher (5.44 g/g for button and 7.29 g/g for oyster mushrooms) than that of wheat flour (0.68 g/g). The increase in the content of mushroom lyophilisate in composite flours also contributed to an increase in the oil-holding capacity. The OHC of flours enriched with lyophilized mushrooms ranged from 0.76 g/g for flour with 2% A. bisporus to 1.03 for flour with 6% P. ostreatus. These results are similar to those presented in other articles. In the paper by Van Toan and Thu [71] the authors report that the OHC for wheat flour is 0.91 g/g, and replacing wheat flour in an amount from 5% to 15% with shitake mushroom flour contributed to an increase in the ability to retain oil from 0.925 g/g to 1.575 g/g. In another study [17], it was reported that A. bisporus and P. ostreatus powders had higher oil-holding capacity (548.3% and 462.6% respectively) compared with maize flour (297.2%), and replacing the base flour with mushroom powders by 10% up to 50% resulted in an increase in fat binding in composite flours (from 302.2% to 433.2%). The OHC is an important feature that can improve flavor and mouthfeel and enhance texture and product yield [96]. The main ingredients that contribute to fat-holding capacity are hydrophobic proteins [97]. Thermal processing of food leads to the exposure of a larger amount of non-polar amino acids in the protein side chains, which in turn results in a stronger bond of proteins with fats [98]. These protein–lipid interactions are attributed to the physical binding of fat molecules between proteins and non-covalent bonds, including hydrophobic, hydrogen, and electrostatic bonds [99]. OHC is particularly desirable in products with minced meat, in meat substitutes, gravies, and soups, and allows the storage time of bakery and confectionery products to be extended [96].

The swelling capacity (SC) describes the ability of the matrix to expand due to water absorption [95]. Data regarding swelling capacity (SC) are presented in Table 5. Higher values for the discussed parameter were found for freeze-dried A. bisporus (20.51 mL/g) and P. ostreatus (16.51 mL/g), while the SC for wheat flour was 2.59 mL/g. However, significantly (p < 0.05) higher SC values of blended flours were recorded only for the versions in which the base flour was replaced by 6% mushroom powder. According to Ishara et al. [17], SC for mushroom powder is 14.47 mL/g and 13.71 mL/g for button and oyster mushrooms, respectively. In turn, the SC for composite flours where 10 to 50% of maize flour was replaced with mushroom powder ranged from 12.3 mL/g to 12.97 mL/g, while the SC for 100% maize flour was 12.81 mL/g. The results presented in the next paper [95] show that the SC of freeze-dried A. bisporus depends on the practical size of the mushroom powder. The data show that coarse mushroom powder has a significantly (p < 0.05) higher SC (10.92 mL/g) compared with fine (SC = 8.20 mL/g) and superfine (SC = 3.13 mL/g) mushroom powders. The SC of flour is influenced by the amounts of proteins, starch, and fiber [100]. Ishara et al. [17] suggest that hydrating properties, including WHC and SC, are probably caused by the presence of fiber and a porous structure favoring the absorption, retention, and swelling of flour particles in water. This is confirmed by our research showing that mushroom powders have higher content of these compounds than wheat flour (Table 1).

The results of the WSI measurements of the samples are presented in Table 5. This parameter was higher for mushroom powders (42.13% for A. bisporus and 54.06% for P. ostreatus) compared with wheat flour (7.30%). For composite flours, WSI was significantly (p < 0.05) higher for flours with 4% or 6% addition of mushroom lyophilisates compared with the WSI of base flour, and the highest value for this parameter was recorded for blended flour with 6% addition of oyster mushrooms (11.15%). Determining the WSI values of mushroom powders and composite flours with the addition of mushrooms has been the subject of research by other authors. Ishara et al. [17] reported that the solubility index of button mushroom flour was 60.25% and that for oyster mushroom flour was 50.99%, and the WSI for mushroom-enriched flours increased with the increase in the amount of mushroom powder. Another work reported the solubility index values for mushroom powders to be 26.55 g/g, 5.26 g/g, and 8.39 g/g for Lentinula edodes, black, and silver ear mushrooms, respectively [71].

The presence of proteins and soluble dietary fiber is largely responsible for the hydrating properties of mushrooms, and a higher amount of these compounds results in a higher solubility index [101]. Mushrooms are an abundant source of complex carbohydrates, including chitin and the water-soluble polysaccharide fraction (WSP). The literature data indicate that the WSP content in fresh fruiting bodies of the oyster mushroom was 78.7 mg/g dw [16], while the amount of WSP in non-processed fruiting bodies of A. bisporus was 96.9 mg/d dw [102]. Moreover, A. bisporus lyophilisate had a higher protein content than oyster mushroom (Table 1). These data could explain the higher WSI value of the A. bisporus powder in our study. Kraithong et al. [93] indicate that a high solubility index suggests a large content of water-soluble ingredients that can form a suspension during hydrothermal treatment. In turn, the lowest WSI may indicate a high capacity to maintain food structures during such treatments.

The water solubility index (WSI) and other indicators, e.g., water-holding capacity (WHC), allow assessment of the material’s behavior in food matrices as a binder, stabilizer, and emulsifier, as well as a source of protein in dairy and baked goods, drinks, and meat products [103].

3.5. Basic Properties of Cookies

The effect of button and oyster mushroom powders on weight, thickness, diameter, and spread ratio of the shortbread cookies is given in

Table 6. Basic properties of shortbread cookies.

Sample	Parameter
	Weight (g)	Diameter (D) (mm)	Thickness (T) (mm)	Spread Ratio D/T	aw	Hardness (g)
Control	26.25 ± 0.96 a	73.27 ± 0.30 ab	7.92 ± 0.41 a	9.27 ± 0.47 ab	0.513 ± 0.01 e	569.78 ± 112.83 a
Ab2	26.46 ± 1.00 a	74.30 ± 0.99 bc	8.06 ± 0.35 a	9.24 ± 0.45 ab	0.482 ± 0.01 d	564.94 ± 120.02 a
Ab4	25.60 ± 0.79 a	74.32 ± 0.75 bc	7.78 ± 0.41 a	9.58 ± 0.43 b	0.445 ± 0.01 bc	613.04 ± 122.59 a
Ab6	25.93 ± 0.90 a	74.31 ± 0.74 bc	8.21 ± 0.28 a	9.06 ± 0.29 ab	0.463 ± 0.01 cd	797.24 ± 123.94 bc
Po2	25.44 ± 0.75 a	75.05 ± 0.78 c	7.83 ± 0.20 a	9.59 ± 0.31 b	0.437 ± 0.00 b	526.13 ± 79.35 a
Po4	25.43 ± 0.70 a	74.62 ± 1.24 bc	8.32 ± 0.12 a	8.97 ± 0.18 ab	0.404 ± 0.01 a	659.21 ± 116.87 ab
Po6	25.53 ± 0.87 a	72.76 ± 0.36 a	8.29 ± 0.44 a	8.80 ± 0.44 a	0.442 ± 0.01 bc	894.01 ± 138.43 c

^a–e the different letters in columns mean that there are significant differences between mean values (HSD Tukey’s test; p < 0.05); a_w—water activity; control—cookies with 100% wheat flour; Ab2—cookies with 2% A. bisporus lyophilisate as a flour substitute; Ab4—cookies with 4% A. bisporus lyophilisate as a flour substitute; Ab6—cookies with 6% A. bisporus lyophilisate as a flour substitute; Po2—cookies with 2% P. ostreatus lyophilisate as a flour substitute; Po4—cookies with 4% P. ostreatus lyophilisate as a flour substitute; Po6—cookies with 6% P. ostreatus lyophilisate as a flour substitute.

.

Differences in the values of parameters such as weight and thickness were not significant (p < 0.05). In the case of the next parameter, diameter, it was found that replacing wheat flour with button mushroom powder slightly increased the diameter of the cookies, but the use of A. bisporus lyophilisate in an amount from 2% to 6% had no significant effect. In turn, substituting wheat flour with freeze-dried oyster mushroom contributed to a significant change in the diameter of the cookies. It was observed that with a larger amount of oyster mushroom lyophilisate, the diameter of the supplemented cookies decreased; however, the addition of 2% freeze-dried oyster mushroom resulted in a larger diameter of the cookies (75.05 mm), and the addition of 6% oyster mushroom lyophilisate caused a decrease in diameter (72.76 mm) compared with cookies without mushrooms (D = 73.27 mm).

The spread ratio parameter describes the shape and quality of cookies [72]. The discussed parameter of the samples ranged from 8.80 (for the Po6 sample) to 9.59 (for the Po2 sample), however, no significant (p < 0.05) differences were noted between the results.

Chen et al. [22] reported that using dried C. militaris in amounts of 1%, 3%, and 5% instead of wheat flour, the supplemented cookies had similar diameter, thickness, and spread ratio compared with the control cookies, but the weights of cookies with 3% or 5% mushrooms were significantly lower than the control cookies. Rathore et al. [6] write that the addition of Calocybe indica in an amount of 5–20% to the cookies had no significant effect on the weight. However, it was found that with the increase in the mushroom powder content, the thickness increased significantly, while opposite tendencies were observed for the diameter and spread factor. The addition of A. bisporus to barley flour cookies in an amount from 10% to 50% resulted in significant increases in diameter and weight of samples, with 20% or more addition of mushroom flour producing a decrease in the thickness value and spread ratio; however, no significant difference was found for these two parameters (p ≤ 0.05) [72].

The results regarding water activity (a_w) are presented in Table 6. This parameter corresponded to moisture content (Table 1). The highest a_w values were noted for the control sample (a_w = 0.513) and cookies with 2% A. bisporus (a_w = 0.482), and the lowest for cookies with 4% P. ostreatus powder (a_w = 0.404); however, an increasing tendency was observed for cookies with 4% and 6% mushroom. Water activity and moisture content are crucial in the determination of the quality, acceptability, and storage stability of bakery products with high content of sugar and fat. Typical cookies have low water activity and low final moisture content (1–5%), which guarantees a long shelf life [27,104]. Food with a_w below 0.6 is considered microbiologically stable. However, a drop in a_w below 0.2 results in accelerated fat oxidation reactions [104].

Shams et al. [72] reported that cookies based on barley flour were characterized by comparatively low a_w value (0.402) and moisture content (3.81%), while cookies in which 10% to 50% of barley flour was replaced with A. bisporus powder were characterized by significantly higher water activity and moisture content. Substitution of wheat flour with C. militaris powder from 1% to 5% resulted in a slight increase in moisture content, from 6.45% for control cookies to 6.70% for cookies with 5% C. militaris flour, but no significant differences were found for this parameter [22]. In turn, Rathore et al. [6] reported that wheat cookies supplemented with C. indica (from 5% to 20%) had moisture content ranging from 5.5% to 4.8%, with the highest moisture content in control cookies (5.5%).

The hardness of the control samples was 569.78 g (Table 6). In turn, the value of this parameter for cookies enriched with mushrooms ranged from 564.94 g for cookies with the addition of 2% button mushroom lyophilisate to 894.01 g for cookies with the addition of 6% P. ostreatus powder. Replacing 4% or 6% base flour with mushroom lyophilisate resulted in an increase in the hardness of the cookies, but significantly (p < 0.05) higher values compared with the control sample were recorded only for cookies with 6% addition of mushroom lyophilisates. The influence of the addition of mushroom flours to base flours on the hardness of cookies has been analyzed by other researchers. Shams et al. [72] reported that a decrease was recorded in the hardness of barley cookies enriched with A. bisporus lyophilisate in an amount of 10–50%. Control cookies exhibited the maximum peak force (24.75 N), while for cookies enriched with mushroom powder, a decreasing trend was found for hardness, from 21.35 N to 14.31 N. Cornelia and Chandra [28] report that the increase in the hardness of cookies with the addition of P. ostreatus in an amount of 25–35% was the result of the increase in the protein content. However, this parameter also depended on the kind of fat used and on the method of drying mushrooms in the procedure of preparing the mushroom flour. In another work [22], when replacing wheat flour in cookies with C. militaris powder in amounts of 1%, 3%, or 5%, a slight decrease in hardness was observed. The hardness of the basic cookies was 3.75 N, and for the supplemented cookies from 3.24 N to 3.17 N, but the differences were not significant (p < 0.05). Chen et al. [22] suggest that the lower hardness values may be a result of disruption of the gluten network by the addition of C. militaris powder. Rathore et al. [6] noted an increasing trend in the hardness of wheat cookies with the addition of C. indica powder. The hardness increased from 23.14 N for the control cookies to 43.18 N for the cookies with the highest content (20%) of mushroom powder. However, there was no significant (p < 0.05) difference between the hardness of control cookies and those containing 5% mushroom powder. The authors explain the increase in this parameter by the presence of a larger amount of fiber in the C. indica powder, which could have disturbed the protein–starch interaction and changed the texture of the cookies. Tu et al. [24] reported that the change in the hardness of sorghum cookies, in which the flour was partially replaced by black ear, silver ear, and shiitake mushroom powder, was the result of a change in fiber, protein, and water content. Replacing 5% to 15% of sorghum flour with L. edodes or black ear mushroom powder significantly (p < 0.05) increased the hardness of the cookies, while no such effect was found in the case of silver ear mushroom powder. The authors emphasize the occurrence of positive correlations (p < 0.01) between hardness and insoluble dietary fiber, protein, and moisture content. Research shows that the hardness of biscuits increases gradually with increasing protein and gluten content [105]. However, gluten may play a secondary role in determining the texture of cookies [106]. It is possible to obtain gluten-free cookies, e.g., based on sorghum [24] or legume flour [101]. It is suggested that the texture of cookies depends mainly on starch gelatinization and sugar crystallization and not on the protein/starch structure [107]. Dietary fiber interacts physically with starch, acting as a coating or capsule that protects the starch granules from gelatinization and digestion [108]. This confirms the results presented in this paper. The significantly higher hardness of Ab6 and Po6 samples may be the result of a higher amount of fiber compared with cookies made from 100% wheat flour (Table 1). The hardness of cookies is influenced by interaction of many components of the food matrix, including primarily starch granules and other compounds: proteins/gluten, fiber, sugar, fat, and water [109].

3.6. Total Phenolic Content (TPC) and Antioxidant Properties

The TPC and antioxidant activities of the wheat flour, mushroom lyophilisates, and shortbread cookies enriched with button and oyster mushroom powders are presented in Figure 2.

Wheat flour and bakery products based on it are characterized by a low content of total polyphenols and low antioxidant properties [110,111,112]. The results presented in this work also confirm this. Wheat flour was characterized by the lowest content of TPC (0.47 mg GAE/g dw) as well as the lowest antioxidant properties compared with mushroom powders, with an almost four-fold higher content of polyphenols and higher antioxidant properties recorded for freeze-dried A. bisporus than in P. ostreatus. As expected, the increase in the addition of mushroom flour contributed to a significant (p < 0.05) increase in the TPC and antioxidant properties of shortbread cookies; however, no significant difference was observed between the amount of TPC in control cookies (0.21 mg GAE/g dw) and that in cookies with 2% addition of P. ostreatus (0.26 mg GAE/g dw), nor between levels of antioxidant properties measured via the ABTS method for control cookies and cookies with 2% addition of button or oyster mushroom powders.

A. bisporus and P. ostreatus are good sources of phenolic compounds and other antioxidants [76,102,113]. In a previous study [14], the content of total polyphenols in ethanolic extracts from A. bisporus was recorded at the level of 10.44 mg GAE/g dw. Smolskaitė et al. [114] reported that, depending on the type of solvent, the TPC values in extracts of button and oyster mushrooms were in the ranges of 4.21–4.64 and 4.26–5.67 mg GAE/g, respectively. Palacios et al. [115] reported that in methanol extracts of several tested mushroom species, the button mushroom, after Boletus edulis, had the highest polyphenol content, while the oyster mushroom had lower phenolic concentrations.

Our results regarding the increase in TPC and the antioxidant properties of cookies enriched with mushroom powders are in agreement with the results presented in other articles. Enrichment with C. militaris powder positively affected the TPC and antioxidant activity (FRAP, DPPH and ABTS assay) of cookies with 1%, 3%, and 5% mushroom powder but there was no significant difference between the control and cookies with 1% C. militaris [22]. Rathore et al. [6] reported that in cookies in which wheat flour was replaced with C. indica powder in amounts from 5% to 20%, significantly (p < 0.05) higher content of polyphenols and flavonoids was noted, and the highest values observed were 17.53 mg GAE/g dw and 0.42 µg quercetin/g dw for cookies with 20% C. indica, while for the control sample, 6.26 mg GAE/g dw and 0.14 µg quercetin/g dw were recorded, respectively. The authors also observed an increasing trend in the level of antioxidant activity according to DPPH and FRAP assays for cookies with increasing content of C. indica powder. In another study [31], replacing barley flour with A. bisporus flour (from 10% to 50%) significantly increased the amount of TPC (from 53.36 to 71.12 mg GAE/g, respectively) compared with control cookies (49.23 mg GAE/g). In the same work, it was reported that cookies with a higher content of mushroom powder were characterized by higher DPPH scavenging activity and reducing power.

The increase in the TPC of mushroom-enriched cookies may be the result of the presence of the mushroom fiber, which limits the release of bound phenolic compounds [72]. Polyphenolic compounds tend to bind with polysaccharides, which largely affects the antioxidant properties of the polysaccharide fraction of mushrooms [116]. In turn, Han and Koh [117] write that thermal processing of food results in both the release of insoluble bound polyphenols and the breakdown of polyphenols under the influence of high temperature. The rise in antioxidant activity in bakery products enriched with mushroom powder may be the result not only of larger amounts of antioxidant compounds such as polyphenols or flavonoids present in greater amounts in mushrooms than in the base flour but also the presence other antioxidants like high-molecular brown pigments—melnoidins—formed in the Maillard reaction during the baking process [72].

3.7. Sensory Evaluation

The results of the sensory evaluation of shortbread cookies are presented in Figure 3.

Appearance was the least differentiated parameter according to the panelists (Figure 1 and Figure 3). The average number of points for the appearance of shortbread cookies ranged from 7.0 (for Ab4 and Ab6 cookies) to 7.3 (for Po2 cookies). This is confirmed by the results for basic cookie parameters such as weight, thickness, and spread ratio, which also varied only slightly (Table 6). Modification of the basic recipe consisting of replacing part of the wheat flour with freeze-dried mushrooms had a greater impact on other attributes in the sensory evaluation of cookies. The base cookies had an average value of 7.5 for the color attribute. Lower scores for color were recorded for all versions of the cookies with button mushrooms (6.0 for Ab2, 5.0 for Ab4 and Ab6) and cookies with 6% oyster mushrooms (7.0). In turn, the colors of cookies with 2% or 4% freeze-dried oyster mushrooms were rated the highest (8.2 and 7.6, respectively). Taking into account the results of color parameters (Table 4), it can be seen that the cookies with A. bisporus, rated lowest by the panelists in terms of color, were also characterized by the lowest values of the L* parameter and the highest ΔE and BI. In turn, the highest-rated cookies with 2% P. ostreatus were characterized by the lowest ΔE, a slightly lower value of the L* parameter, and a slightly higher BI value, and were more yellow and red in comparison with the control samples. The aroma of the control cookies and all versions of the cookies with P. ostreatus powder were evaluated similarly (8.0). In turn, the aroma of cookies with button mushrooms was assessed in the range from 7.0 (Ab6) to 7.2 (Ab2, Ab4). Cookies with oyster mushroom obtained higher taste scores, from 8.0 (for Po4 and Po6) to 8.5 (for Po2) compared with the control cookies (7.5). The texture of the shortbread cookies was rated as follows: Po2 (7.2) > Ab4 (6.6) > control, Ab2, Po2 (6.5) > Ab6 (6.2) > Po6 (6.1) samples. Taking into account the hardness results (Table 6), the lowest texture scores in the sensory evaluation are consistent with the highest averages for hardness in the case of cookies with 6% mushroom powder. Higher notes for overall acceptability were recorded for cookies with the addition of oyster mushrooms (from 7.3 for Po6 to 8.0 for Po2) compared with the notes for control cookies (7.2). In turn, cookies with button mushroom powder had the lowest scores, from 6.0 (Ab6) to 6.5 (Ab2).

The results presented by other authors regarding sensory evaluation show that the degree of acceptance of cookies enriched with mushroom powders depends on the species of mushrooms and the amount of added mushroom flour. According to Chen et al. [22], replacing base flour with C. militaris powder at an amount of 1% had no significant effect on all analyzed attributes relative to the control. A larger addition of mushroom powder (3% and 5%) lowered the color assessment by the panel. The odor and taste of samples with 1% and 3% C. militaris were rated higher than those of the control cookies. In turn, cookies with 5% mushroom powder added had too strong a taste and odor, which resulted in lower scores for these attributes. Cookies with 3% C. militaris received the highest notes for the following attributes: overall acceptability, taste, odor, and texture. Another study [27] analyzed the results of sensory evaluation on a 7-point scale for biscuits enriched with Pleurotus sajor-caju powder in amounts of 4%, 8%, and 12%. Biscuits with 4% mushroom flour received the highest marks for aroma, color, flavor and overall acceptance. The authors reported that biscuits with 4% P. sajor-caju had a milder flavour, lighter color, finer texture, and were comparable to the control biscuits. In turn, cookies with 12% P. sajor-caju, according to the evaluators, had an unattractive texture, color that was too dark, and flavor that was too intense. The authors emphasized that despite the highest scores being achieved by cookies with 4% mushroom powder, cookies with 8% P. saju-caju were also acceptable in terms of appearance, crispiness, flavor, and overall acceptance. The results of the sensory evaluation on a 9-point scale presented by Van Toan and Thu [71] show that the addition of 5% shiitake flour can positively affect the improvement of the attributes (color, taste, aroma, crispiness, and overall impression) of cookies compared with basic cookies. The lowest scores were given to cookies with a maximum of 15% mushroom flour. Although addition of 5%, 10%, or 15% L. edodes flour was acceptable to consumers, the authors recommended the addition of 5%. Replacing the basic flour with a larger amount of mushroom flour may also have a positive impact on significantly higher scores for selected attributes in the 9-point assessment, as presented by Baltacıoğlu et al. [91] in their work. Among biscuits enriched with 10%, 20% or 30% P. ostreatus powder, biscuits with 10% mushroom flour were characterized by the highest scores for color, homogeneity and size of pores, odor, and overall acceptability. The versions of cookies with 20% or 30% added P. ostreatus powder received lower scores.

In sensory evaluation, attributes such as taste or aroma are determined by the presence of compounds such as free and soluble sugars, sugar alcohols, organic acids, free amino acids, and 5′-nucleotides [63,118]. For example, the high content of free sugars and sugar alcohols may increase the perception of the moderately sweet taste of mushrooms [119]. As Mau writes [118], mannitol contributes most to the sweet taste, but the predominant taste and flavor of mushrooms is umami. According to the data collected and described by Jiang et al. [120], the button mushroom is characterized by a sweet, umami, and typical mushroom flavor, while a sour, astringent, and bitter flavor is typical of oyster mushrooms. Mau [118] suggests that due to the presence of monosodium glutamate-like (MSG-like) components, mushrooms go well with meat, seafood, soups, and cooked vegetables, but they cannot improve the taste of fruit, juices, desserts, or cooked cereals. According to the same publication, the level of monosodium glutamate equivalent was higher in A. bisporus (114%) than in P. ostreatus (48.0%), taking into account dry weight. Selli et al. [121] reported that thermal treatment is an important factor for odorants in mushrooms. High temperature contributes to the evaporation of compounds and the formation of aroma precursors, mainly through non-enzymatic browning reactions.

4. Conclusions

A. bisporus and P. ostreatus lyophilisates were characterized by higher amounts of basic nutrients, polyphenol compounds, elements (K, Mg, Na, Fe, Zn, Cu, Ni) compared with wheat flour. At the same time, the content of Pb and Cd was below the maximum safe limits set by EU regulations. The use of the lyophilisates as a partial substitute (2–6%) for wheat flour in shortbread cookies contributed to a significant (p < 0.05) increase in the amounts of selected elements, protein, and ash in all versions of the cookies. Moreover, samples with fiber above 3 g/100 g (Ab2, Ab4, Po2) and above 6 g/100 g (Ab6, Po4, Po6) were obtained, which would allow the use of “source of/high in fiber” nutrition claims.

The results presented in this study show that substituting a small amount (2–6%) of wheat flour with mushroom lyophilisates affects the functional properties of composite flours as well as the finished products. The values of the functional parameters of blended flours compared with the base flour were significantly (p < 0.05) lower for BD and higher for OHC for all blended flour versions, higher for WSI for flours with the addition of 4–6% mushroom powders, and higher for WHC for flours with 4% and 6% addition of oyster mushroom lyophilisate. The values of basic parameters of cookies such as weight, thickness, and spread ratio of enriched cookies did not differ statistically (p < 0.05) from the control samples. In turn, the values of the a_w parameter were lower. With the increase in the addition of mushroom lyophilisate, the L* value was significantly lower, while the value of the parameter a* (redness) increased. Higher ΔE and BI were recorded for the cookies with A. bisporus. Cookies with 6% mushroom powders (Ab6, Po6) were characterized by significantly higher hardness. The results of the sensory evaluation clearly indicate that among the analyzed versions of the cookies, the highest scores were given to samples with the addition of oyster mushroom, while the lowest scores were given to cookies with the addition of button mushrooms.

To sum up, the blending of wheat flour with oyster mushroom lyophilisate up to 6% seems to be a compromise between obtaining products with improved nutritional composition and maintaining sensory quality and acceptance by consumers.