Editorial

2 pages, 182 KiB

Open AccessEditorial

Processing and Technology of Dairy Products: A Special Issue

by Hilton Deeth and Phil Kelly

Foods 2020, 9(3), 272; https://doi.org/10.3390/foods9030272 - 03 Mar 2020

Cited by 1 | Viewed by 2056

When this Special Issue was launched, we cast the net widely in terms of the subject matter we considered suitable for the papers [...] Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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13 pages, 1503 KiB

Open AccessArticle

The Effect of Calcium, Citrate, and Urea on the Stability of Ultra-High Temperature Treated Milk: A Full Factorial Designed Study

by Maria A. Karlsson, Åse Lundh, Fredrik Innings, Annika Höjer, Malin Wikström and Maud Langton

Foods 2019, 8(9), 418; https://doi.org/10.3390/foods8090418 - 17 Sep 2019

Cited by 11 | Viewed by 5251

Abstract

The composition of raw milk is important for the stability of dairy products with a long shelf-life. Based on known historical changes in raw milk composition, the aim of this study was to get a better understanding of how possible future variations in [...] Read more.

The composition of raw milk is important for the stability of dairy products with a long shelf-life. Based on known historical changes in raw milk composition, the aim of this study was to get a better understanding of how possible future variations in milk composition may affect the stability of dairy products. The effects of elevated calcium, citrate, and urea levels on the stability of ultra-high temperature (UHT) treated milk stored for 52 weeks at 4, 20, 30, and 37 °C were investigated by a two-level full factorial designed study with fat separation, fat adhesion, sedimentation, color, pH, ethanol stability, and heat coagulation time as response variables. The results showed that elevated level of calcium lowered the pH, resulting in sedimentation and significantly decreased stability. Elevated level of citrate was associated with color, but the stability was not improved compared to the reference UHT milk. Elevated levels of urea or interaction terms had little effect on the stability of UHT milk. Storage conditions significantly affected the stability. In conclusion, to continue produce dairy products with high stability, the dairy industry should make sure the calcium content of raw milk is not too high and that storage of the final product is appropriate. Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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13 pages, 1613 KiB

Open AccessArticle

Exploring the Use of a Modified High-Temperature, Short-Time Continuous Heat Exchanger with Extended Holding Time (HTST-EHT) for Thermal Inactivation of Trypsin Following Selective Enzymatic Hydrolysis of the β-Lactoglobulin Fraction in Whey Protein Isolate

by Laura Sáez, Eoin Murphy, Richard J. FitzGerald and Phil Kelly

Foods 2019, 8(9), 367; https://doi.org/10.3390/foods8090367 - 26 Aug 2019

Cited by 6 | Viewed by 3214

Abstract

Tryptic hydrolysis of whey protein isolate under specific incubation conditions including a relatively high enzyme:substrate (E:S) ratio of 1:10 is known to preferentially hydrolyse β-lactoglobulin (β-LG), while retaining the other major whey protein fraction, i.e., α-lactalbumin (α-LA) mainly intact. An objective of the [...] Read more.

Tryptic hydrolysis of whey protein isolate under specific incubation conditions including a relatively high enzyme:substrate (E:S) ratio of 1:10 is known to preferentially hydrolyse β-lactoglobulin (β-LG), while retaining the other major whey protein fraction, i.e., α-lactalbumin (α-LA) mainly intact. An objective of the present work was to explore the effects of reducing E:S (1:10, 1:30, 1:50, 1:100) on the selective hydrolysis of β-LG by trypsin at pH 8.5 and 25 °C in a 5% (w/v) WPI solution during incubation periods ranging from 1 to 7 h. In addition, the use of a pilot-scale continuous high-temperature, short-time (HTST) heat exchanger with an extended holding time (EHT) of 5 min as a means of inactivating trypsin to terminate hydrolysis was compared with laboratory-based acidification to <pH 3 by the addition of HCl, and batch sample heating in a water bath at 85 °C. An E:S of 1:10 resulted in 100% and 30% of β-LG and α-LA hydrolysis, respectively, after 3 h, while an E:S reduction to 1:30 and 1:50 led >90% β-LG hydrolysis after respective incubation periods of 4 and 6 h, with <5% hydrolysis of α-LA in the case of 1:50. Continuous HTST-EHT treatment was shown to be an effective inactivation process allowing for the maintenance of substrate selectivity. However, HTST-EHT heating resulted in protein aggregation, which negatively impacts the downstream recovery of intact α-LA. An optimum E:S was determined to be 1:50, with an incubation time ranging from 3 h to 7 h leading to 90% β-LG hydrolysis and minimal degradation of α-LA. Alternative batch heating by means of a water bath to inactivate trypsin caused considerable digestion of α-LA, while acidification to <pH 3.0 restricted subsequent functional applications of the protein. Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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12 pages, 740 KiB

Open AccessArticle

On the Use of Ultrafiltration or Microfiltration Polymeric Spiral-Wound Membranes for Cheesemilk Standardization: Impact on Process Efficiency

by Julien Chamberland, Dany Mercier-Bouchard, Iris Dussault-Chouinard, Scott Benoit, Alain Doyen, Michel Britten and Yves Pouliot

Foods 2019, 8(6), 198; https://doi.org/10.3390/foods8060198 - 08 Jun 2019

Cited by 11 | Viewed by 5398

Abstract

Ultrafiltration (UF) and microfiltration (MF) are widely-used technologies to standardize the protein content of cheesemilk. Our previous work demonstrated that protein retention of a 0.1-µm MF spiral-wound membrane (SWM) was lower, but close to that of a 10 kDa UF one. Considering that [...] Read more.

Ultrafiltration (UF) and microfiltration (MF) are widely-used technologies to standardize the protein content of cheesemilk. Our previous work demonstrated that protein retention of a 0.1-µm MF spiral-wound membrane (SWM) was lower, but close to that of a 10 kDa UF one. Considering that the permeability of MF membranes is expected to be higher than that of UF ones, it was hypothesized that the former could improve the efficiency of the cheesemaking process. Consequently, the objectives of this work were to compare 0.1-µm MF and 10 kDa UF spiral-wound membranes in terms of (1) hydraulic and separation performance, (2) energy consumption and fouling behavior, (3) cheesemaking efficiency of retentates enriched with cream, and (4) economic performance in virtual cheesemaking plants. This study confirmed the benefits of using MF spiral-wound membranes to reduce the specific energy consumption of the filtration process (lower hydraulic resistance and higher membrane permeability) and to enhance the technological performance of the cheesemaking process (higher vat yield, and protein and fat recoveries). However, considering the higher serum protein retention of the UF membrane and the low price of electricity in Canada, the UF scenario remained more profitable. It only becomes more efficient to substitute the 10 kDa UF SWM by the 0.1-μm MF when energy costs are substantially higher. Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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19 pages, 1768 KiB

Open AccessArticle

Ripening of Hard Cheese Produced from Milk Concentrated by Reverse Osmosis

by Anastassia Taivosalo, Tiina Kriščiunaite, Irina Stulova, Natalja Part, Julia Rosend, Aavo Sõrmus and Raivo Vilu

Foods 2019, 8(5), 165; https://doi.org/10.3390/foods8050165 - 15 May 2019

Cited by 5 | Viewed by 5213

Abstract

The application of reverse osmosis (RO) for preconcentration of milk (RO-milk) on farms can decrease the overall transportation costs of milk, increase the capacity of cheese production, and may be highly attractive from the cheese manufacturer’s viewpoint. In this study, an attempt was [...] Read more.

The application of reverse osmosis (RO) for preconcentration of milk (RO-milk) on farms can decrease the overall transportation costs of milk, increase the capacity of cheese production, and may be highly attractive from the cheese manufacturer’s viewpoint. In this study, an attempt was made to produce a hard cheese from RO-milk with a concentration factor of 1.9 (RO-cheese). Proteolysis, volatile profiles, and sensory properties were evaluated throughout six months of RO-cheese ripening. Moderate primary proteolysis took place during RO-cheese ripening: about 70% of α_s1-casein and 45% of β-casein were hydrolyzed by the end of cheese maturation. The total content of free amino acids (FAA) increased from 4.3 to 149.9 mmol kg⁻¹, with Lys, Pro, Glu, Leu, and γ-aminobutyric acid dominating in ripened cheese. In total, 42 volatile compounds were identified at different stages of maturation of RO-cheese; these compounds have previously been found in traditional Gouda-type and hard-type cheeses of prolonged maturation. Fresh RO-cheese was characterized by a milky and buttery flavor, whereas sweetness, saltiness, and umami flavor increased during ripening. Current results prove the feasibility of RO-milk for the production of hard cheese with acceptable sensory characteristics and may encourage further research and implementation of RO technology in cheese manufacture. Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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14 pages, 2443 KiB

Open AccessArticle

Salt Distribution in Raw Sheep Milk Cheese during Ripening and the Effect on Proteolysis and Lipolysis

by Olaia Estrada, Agustín Ariño and Teresa Juan

Foods 2019, 8(3), 100; https://doi.org/10.3390/foods8030100 - 17 Mar 2019

Cited by 15 | Viewed by 4778

Abstract

The salt distribution process in artisanal sheep cheese with an innovative shape of eight lobes was investigated. The cheese was subjected to two brining conditions: 24 h with brine at 16°Baumé and 12 h at 22°Baumé. The chemical composition (pH, water activity, dry [...] Read more.

The salt distribution process in artisanal sheep cheese with an innovative shape of eight lobes was investigated. The cheese was subjected to two brining conditions: 24 h with brine at 16°Baumé and 12 h at 22°Baumé. The chemical composition (pH, water activity, dry matter, fat, and protein content), proteolysis (nitrogen fractions and free amino acids), and lipolysis (free fatty acids) were evaluated in two sampling zones (internal and external) at 1, 15, 30, 60, 90, 120, 180, and 240 days of ripening. The whole cheese reached a homogeneous salt distribution at 180 days of ripening. Brining conditions did not have an influence on the rate of salt penetration, but on the final sodium chloride (NaCl) content. Cheese with higher salt content (3.0%) showed increased proteolysis and lipolysis as compared to cheese with lower salt content (2.2%). Proteolysis index and total free fatty acids did not differ significantly (p > 0.05) between internal and external zones of cheese. It is suggested that producers start marketing this artisanal cheese at 6 months of ripening, when it has uniform composition and salt distribution. Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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11 pages, 2173 KiB

Open AccessArticle

Proteolysis and Rheological Properties of Cream Cheese Made with a Plant-Derived Coagulant from Solanum elaeagnifolium

by Néstor Gutiérrez-Méndez, Alejandro Balderrama-Carmona, Socorro E. García-Sandoval, Pamela Ramírez-Vigil, Martha Y. Leal-Ramos and Antonio García-Triana

Foods 2019, 8(2), 44; https://doi.org/10.3390/foods8020044 - 30 Jan 2019

Cited by 25 | Viewed by 5940

Abstract

Cream cheese is a fresh acid-curd cheese with pH values of 4.5–4.8. Some manufacturers add a small volume of rennet at the beginning of milk fermentation to improve the texture of the cream cheese. However, there is no information about the effect that [...] Read more.

Cream cheese is a fresh acid-curd cheese with pH values of 4.5–4.8. Some manufacturers add a small volume of rennet at the beginning of milk fermentation to improve the texture of the cream cheese. However, there is no information about the effect that proteases other than chymosin-like plant-derived proteases may have on cream cheese manufacture. This work aimed to describe some proteolytic features of the protease extracted from fruits of Solanum elaeagnifolium Cavanilles and to assess the impact that this plant coagulant has on the viscoelastic properties of cream cheeses. Results showed that caseins were not hydrolyzed extensively by this plant-derived coagulant. In consequence, the ratio of milk clotting units (U) to proteolytic activity (U-Tyr) was higher (1184.4 U/U-Tyr) than reported for other plant proteases. The plant coagulant modified neither yield nor composition of cream cheeses, but viscoelastic properties did. Cream cheeses made with chymosin had a loss tangent value (tan δ = 0.257) higher than observed in cheeses made with 0.8 mL of plant-derived coagulant per liter (tan δ = 0.239). It is likely that casein fragments released by the plant-derived coagulant improve the interaction of protein during the formation of acid curds, leading to an increase in the viscoelastic properties of cream cheese. Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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15 pages, 459 KiB

Open AccessArticle

Effects of Apricot Fibre on the Physicochemical Characteristics, the Sensory Properties and Bacterial Viability of Nonfat Probiotic Yoghurts

by Oya Berkay Karaca, Nuray Güzeler, Hasan Tangüler, Kurban Yaşar and Mutlu Buket Akın

Foods 2019, 8(1), 33; https://doi.org/10.3390/foods8010033 - 18 Jan 2019

Cited by 15 | Viewed by 4317

Abstract

In this study, the physical, chemical, rheological, and microbiological characteristics and the sensory properties of nonfat probiotic yoghurt produced at two different concentrations of apricot fibre (1% and 2%, w/v) and three different types of probiotic culture (Lactobacillus ( [...] Read more.

In this study, the physical, chemical, rheological, and microbiological characteristics and the sensory properties of nonfat probiotic yoghurt produced at two different concentrations of apricot fibre (1% and 2%, w/v) and three different types of probiotic culture (Lactobacillus (L.) acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 (Bifidobacterium BB-12), and their mixtures) were investigated. As the fibre content increased, the rheological, structural, and sensory properties of probiotic yoghurt were negatively affected, while counts of L. delbrueckii subsp. bulgaricus, L. acidophilus LA-5, and Bifidobacterium BB-12 increased. When all the results were evaluated, the best results were obtained by using L. acidophilus LA-5 as probiotic culture and adding 1% (w/v) apricot fibre. Full article

(This article belongs to the Special Issue Processing and Technology of Dairy Products)

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