Current Practice and Future Directions of Application of Puffed/Extruded Technologies in Food

A special issue of Foods (ISSN 2304-8158). This special issue belongs to the section "Food Engineering and Technology".

Deadline for manuscript submissions: closed (10 March 2023) | Viewed by 39438

Special Issue Editors

College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, China
Interests: rheological properties and interaction of protein; polysaccharide; starch and cellulose in food
Special Issues, Collections and Topics in MDPI journals
Department of Engineering, China Agricultural University, Beijing, China
Interests: extrusion process; puffing; grains; drying; food extrusion technology; numerical simulation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The development of new food products obtained by extrusion processing has increased in recent years. As a highly versatile, productive, low cost, and low energy cost mechanical process, extrusion is considered as the multiple unit operations which contained mixing, shearing, plasticizing, melting, cooking, denaturation, fragmentation, and texturization to produce a wide variety of food products, such as ready-to-eat foods, and enhance the nutritional quality in the food industry.

The physical and chemical property changes to the material involve complex changes in the food matrix, phytochemical composition and organoleptic properties, such as texture, colour and flavour, due to the influence of high temperature, high pressure, and high shear during extrusion process.  These changes are related to extrusion parameters, such as processing temperature, processing speed, and feed moisture, also the characteristics of raw materials. This Special Issue aims to focus on the variation of extrusion puffing and texturizing technologies to improve the nutritional, functional and acceptability of food, and the effect of pre-treatment methods and numerical simulation is also taken into consideration.

Dr. Lijun Wang
Dr. Min Wu
Guest Editors

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Keywords

  • extrusion
  • puffing
  • extrusion texture
  • extrusion parameters
  • low/high moisture extrusion
  • single-screw/twin-screw extruder
  • numerical simulation
  • functional properties
  • physicochemical and structural properties
  • rheology property

Published Papers (18 papers)

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Research

17 pages, 3183 KiB  
Article
Acid-Mediated Formation of Soybean Isolate Protein Emulsion Gels with Soybean Oil as an Active Component
by Chonghao Bi, Tong Zhou, Zeyuan Wu and Zhigang Huang
Foods 2023, 12(9), 1754; https://doi.org/10.3390/foods12091754 - 23 Apr 2023
Cited by 1 | Viewed by 1158
Abstract
In this study, the effect of soybean oil concentration on the rheology, water-holding capacity, and thermal stability of acid-mediated soy protein isolate (SPI) emulsion gels was investigated. The microstructure was analyzed and interpreted by CLSM and SEM observations. The results showed that the [...] Read more.
In this study, the effect of soybean oil concentration on the rheology, water-holding capacity, and thermal stability of acid-mediated soy protein isolate (SPI) emulsion gels was investigated. The microstructure was analyzed and interpreted by CLSM and SEM observations. The results showed that the addition of soybean oil improved the elastic properties of the acid-mediated SPI emulsion gels. The storage modulus increased from 330 Pa (2% soybean oil concentration) to 545 Pa (8% soybean oil concentration) with a significant increase (p < 0.05). The increase in soybean oil concentration resulted in more SPI-coated oil droplets acting as active particles, enhancing the gel network. The acid-mediated SPI emulsion gels became more disordered as the soybean oil concentration increased, with the fractal dimension increasing from 2.92 (2%) to 2.95 (8%). The rheological properties, thermal analysis, and microstructure of 6% SPI gel and acid-mediated SPI emulsion gels with 2% to 8% soybean oil concentration were compared. The acid-mediated SPI emulsion gels with soybean oil as the active filler showed improved gel properties, greater thermal stability, and a homogeneous network structure compared to the acid-mediated SPI emulsion gels. Full article
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13 pages, 2491 KiB  
Article
A Strategy for Rapid Acquisition of the β-D-Fructofuranosidase Gene through Chemical Synthesis and New Function of Its Encoded Enzyme to Improve Gel Properties during Yogurt Processing
by Zhou Chen, Yimei Shen and Jiangqi Xu
Foods 2023, 12(8), 1704; https://doi.org/10.3390/foods12081704 - 19 Apr 2023
Cited by 1 | Viewed by 1062
Abstract
A chemical gene synthesis strategy was developed in order to obtain β-D-fructofuranosidase, and a novel gene, AlFFase3, was characterized from Aspergillus luchuensis and expressed in Escherichia coli. The recombinant protein was purified, showing a molecular mass of 68.0 kDa on SDS-PAGE, and [...] Read more.
A chemical gene synthesis strategy was developed in order to obtain β-D-fructofuranosidase, and a novel gene, AlFFase3, was characterized from Aspergillus luchuensis and expressed in Escherichia coli. The recombinant protein was purified, showing a molecular mass of 68.0 kDa on SDS-PAGE, and displaying a specific activity towards sucrose of up to 771.2 U mg−1, indicating its exceptional enzymatic capacity. AlFFase3 exhibited stability between pH 5.5 and 7.5, with maximal activity at pH 6.5 and 40 °C. Impressively, AlFFase3, as a soluble protein, was resistant to digestion by various common proteases, including Flavourzyme, acidic protease, pepsin, neutral protease, Proteinase K, alkaline proteinase, and trypsin. AlFFase3 also demonstrated significant transfructosylation activity, with a yield of various fructooligosaccharides up to 67%, higher than almost all other reports. Furthermore, we demonstrated that the addition of AlFFase3 enhanced the growth of probiotics in yogurt, thereby increasing its nutritional value. AlFFase3 also improved the formation of yogurt gel, reducing the gel formation time and lowering the elasticity while increasing its viscosity, thereby improving the palatability of yogurt and reducing production costs. Full article
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13 pages, 1066 KiB  
Article
Kidney Bean Substitution Ameliorates the Nutritional Quality of Extruded Purple Sweet Potatoes: Evaluation of Chemical Composition, Glycemic Index, and Antioxidant Capacity
by Eny Palupi, Nira Delina, Naufal M. Nurdin, Hana F. Navratilova, Rimbawan Rimbawan and Ahmad Sulaeman
Foods 2023, 12(7), 1525; https://doi.org/10.3390/foods12071525 - 04 Apr 2023
Cited by 3 | Viewed by 2857
Abstract
The extrusion process may influence the nutritional profiles of carbohydrate-rich food ingredients, including the glycemic index (GI) and antioxidant capacity. This study aimed to evaluate the nutritional profile of extruded purple sweet potato (EPSP) substituted with kidney bean flour (KBF) (0, 30, and [...] Read more.
The extrusion process may influence the nutritional profiles of carbohydrate-rich food ingredients, including the glycemic index (GI) and antioxidant capacity. This study aimed to evaluate the nutritional profile of extruded purple sweet potato (EPSP) substituted with kidney bean flour (KBF) (0, 30, and 40%). These foods were further characterized by their proximate composition, resistant starch, polyphenols, GI, and antioxidant capacities. The 40% KBF substitution enhanced the protein and fiber contents of the EPSP by up to 8% and 6%, respectively. Moreover, it also revealed that EPSP with 40% KBF substitution had a low-GI category (53.1), while the 0 and 30% substitution levels had a high-GI category, i.e., 77.4 and 74.7, respectively. However, the extrusion processing reduced the anthocyanin content and antioxidant capacity of purple sweet potato flour containing 40% KBF by 48% and 19%, respectively. There was a significant relationship between the GI values of proteins, fats, and fibers (p < 0.05). The insignificant effect of resistant starch and phenol contents on GI value was recorded due to the low concentrations of those components. KBF substitution could ameliorate the profile of protein, fiber, and GI, but not for antioxidant capacity. The other innovative processes for preserving antioxidant capacity might improve the product quality. Full article
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17 pages, 4756 KiB  
Article
The Impact of High-Pressure Homogenization and Thermal Processing on the Functional Properties of De-Fatted Chickpea Flour Dispersion
by Zhigang Huang, Jiayi Zhang, Guoliang Zhang, Fei Gao and Chonghao Bi
Foods 2023, 12(7), 1513; https://doi.org/10.3390/foods12071513 - 03 Apr 2023
Cited by 1 | Viewed by 1132
Abstract
Defatted chickpea flour (DCF), a rich source of protein and starch, is frequently utilized in the food industry. Two crucial methods of modifying food materials are high-pressure homogenization (HPH) and heat treatment (HT). This study investigates the effect of co-treatment (HPH-HT) on the [...] Read more.
Defatted chickpea flour (DCF), a rich source of protein and starch, is frequently utilized in the food industry. Two crucial methods of modifying food materials are high-pressure homogenization (HPH) and heat treatment (HT). This study investigates the effect of co-treatment (HPH-HT) on the particle size, rheological behavior, and thermal characteristics of DCF suspensions. The results indicate that both HPH and HT can result in a more uniform distribution of particle size in the suspensions. The effect of HPH on G′ was observed to be reductionary, whereas HT increased it. Nevertheless, the HPH-HT treatment further amplified G′ (notably in high-concentration DCF), which demonstrates that the solid properties of DCF are improved. The apparent viscosity of the suspensions increased with individual and combined treatments, with the HPH-HT treatment of DCF12% exhibiting the most significant increase (from 0.005 to 9.5 Pa·s). The rheological behavior of DCF8% with HPH-HT treatment was found to be comparable to that of DCF12% treated only with HT. In conclusion, HPH-HT treatment shows a synergistic impact of HPH and HT on the rheological properties of DCF suspensions, however, it has limited effect on the particle size distribution and freeze–thaw stability. Full article
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14 pages, 2812 KiB  
Article
Hot Air Impingement Drying Enhanced Drying Characteristics and Quality Attributes of Ophiopogonis Radix
by Zhian Zheng, Shanyu Wang, Chujie Zhang, Min Wu, Dezhou Cui, Xiaosong Fu, Lei Gao, Aichao Li, Qing Wei and Ziliang Liu
Foods 2023, 12(7), 1441; https://doi.org/10.3390/foods12071441 - 29 Mar 2023
Cited by 8 | Viewed by 1691
Abstract
The effects of drying temperature and air velocity on the drying characteristics, color, bioactive compounds, rehydration ratio, and microstructure of Ophiopogonis Radix during hot air impingement drying (HAID) were explored in the current study. The experimental results showed that the drying temperature and [...] Read more.
The effects of drying temperature and air velocity on the drying characteristics, color, bioactive compounds, rehydration ratio, and microstructure of Ophiopogonis Radix during hot air impingement drying (HAID) were explored in the current study. The experimental results showed that the drying temperature and air velocity had a significant impact on the drying characteristics and quality attributes of dried products except for the rehydration ratio. The drying time decreased from 720 to 240 min with the increase of drying temperature from 50 to 70 °C. Increasing the air velocity from 6 to 12 m/s enhanced the drying process of Ophiopogonis Radix, while the extension of air velocity to 15 m/s lowered the drying rate. The samples that were dried at a lower drying temperature obtained lower color difference. Properly increasing the drying temperature or air velocity could increase the total polysaccharide and flavonoid contents of dried products. Additionally, a back-propagation neural network (BPNN) model was developed to predict the moisture ratio of Ophiopogonis Radix during the drying process. The optimal BPNN with 3-11-1 topology were obtained to predict the moisture ratio of Ophiopogonis Radix during HAID and performed with an acceptable performance. Full article
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14 pages, 1305 KiB  
Article
Enhancing the Techno-Functionality of Pea Flour by Air Injection-Assisted Extrusion at Different Temperatures and Flour Particle Sizes
by Nasibeh Y. Sinaki, Jitendra Paliwal and Filiz Koksel
Foods 2023, 12(4), 889; https://doi.org/10.3390/foods12040889 - 19 Feb 2023
Cited by 4 | Viewed by 1713
Abstract
Industrial applications of pulses in various food products depend on pulse flour techno-functionality. To manipulate the techno-functional properties of yellow pea flour, the effects of flour particle size (small vs. large), extrusion temperature profile (120, 140 and 160 °C at the die) and [...] Read more.
Industrial applications of pulses in various food products depend on pulse flour techno-functionality. To manipulate the techno-functional properties of yellow pea flour, the effects of flour particle size (small vs. large), extrusion temperature profile (120, 140 and 160 °C at the die) and air injection pressure (0, 150 and 300 kPa) during extrusion cooking were investigated. Extrusion cooking caused the denaturation of proteins and gelatinization of starch in the flour, which induced changes in the techno-functionality of the extruded flour (i.e., increased water solubility, water binding capacity and cold viscosity and decreased emulsion capacity, emulsion stability, and trough and final viscosities). In general, the large particle size flour required less energy input to be extruded and had higher emulsion stability and trough and final viscosities compared to the small particle size flour. Overall, among all of the treatments studied, extrudates produced with air injection at 140 and 160 °C had higher emulsion capacity and emulsion stability, making them relatively better suited food ingredients for emulsified foods (e.g., sausages). The results indicated air injection’s potential as a novel extrusion technique combined with modification of flour particle size distribution and extrusion processing conditions to effectively manipulate product techno-functionality and broaden the applications of pulse flours in the food industry. Full article
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24 pages, 6089 KiB  
Article
A Systematical Rheological Study of Maize Kernel
by Shaoyang Sheng, Aimin Shi and Junjie Xing
Foods 2023, 12(4), 738; https://doi.org/10.3390/foods12040738 - 08 Feb 2023
Cited by 2 | Viewed by 1239
Abstract
In this study, the rheological behavior of maize kernel was systematically investigated using a dynamic mechanical analyzer. The loss in toughness caused by drying resulted in a downward shift in the relaxation curve and an upward shift in the creep curve. The long [...] Read more.
In this study, the rheological behavior of maize kernel was systematically investigated using a dynamic mechanical analyzer. The loss in toughness caused by drying resulted in a downward shift in the relaxation curve and an upward shift in the creep curve. The long relaxation behavior became obvious when the temperature was above 45 °C, resulting from the weakening of hydrogen bonds with temperature. The maize kernel relaxed more rapidly at high temperatures, caused by a reduction in the cell wall viscosity and polysaccharide tangles. The Deborah numbers were all much smaller than one, suggesting that the Maxwell elements showed viscous behavior. Maize kernel, as a viscoelastic material, showed a dominant viscous property at high temperatures. The decline in β with increasing drying temperature indicated an increase in the width of the relaxation spectrum. A Hookean spring elastic portion made up the majority of the maize kernel creep strain. The order–disorder transformation zone of maize kernel was about 50–60 °C. Due to the complexity of maize kernel, the William–Landel–Ferry constants differed from the universal values; these constants should be ascertained through experiments. Time-temperature superposition was successfully used to describe the rheological behavior. The results show that maize kernel is a thermorheologically simple material. The data acquired in this study can be used for maize processing and storage. Full article
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15 pages, 2692 KiB  
Article
Sustainable Environmental Assessment of Waste-to-Energy Practices: Co-Pyrolysis of Food Waste and Discarded Meal Boxes
by Gang Li, Tenglun Yang, Wenbo Xiao, Jiahui Wu, Fuzhuo Xu, Lianliang Li, Fei Gao and Zhigang Huang
Foods 2022, 11(23), 3840; https://doi.org/10.3390/foods11233840 - 28 Nov 2022
Cited by 5 | Viewed by 1564
Abstract
The reuse of biomass waste is conducive to the recovery of resources and can solve the pollution problem caused by incineration and landfill. For this reason, the thermogravimetric analyzer (TGA) was used to study the pyrolysis of the mushroom sticks (MS) and discarded [...] Read more.
The reuse of biomass waste is conducive to the recovery of resources and can solve the pollution problem caused by incineration and landfill. For this reason, the thermogravimetric analyzer (TGA) was used to study the pyrolysis of the mushroom sticks (MS) and discarded meal boxes at different heating rates (10 °C·min−1, 20 °C·min−1, 30 °C·min−1). The statistical analysis showed that the factors of pyrolysis temperature and particle size had a greater effect, while the heating rate was significant. The TGA revealed that the maximum weight loss rate of the co-pyrolysis of MS and discarded meal boxes increased with the rise of the heating rate, the temperature at which the pyrolysis started and ended increased, and the thermal weight loss displayed a hysteresis phenomenon. By comparing the theoretical heat weight loss curves with the experimental curves, a synergistic effect of the co-pyrolysis process between MS and discarded meal boxes was demonstrated, and the co-pyrolysis process resulted in a reduction in the solid residue content of the products. The Coats-Redfern method was used to fit the pyrolysis process of MS and discarded meal boxes, which applied the first-order kinetic model to describe the main process of pyrolysis and obtained the reaction activation energy between 43 and 45 kJ·mol−1. The results indicated that co-pyrolysis of MS and discarded meal boxes could decrease the activation energy of the reaction, make the reaction easier, promote the degree of pyrolysis reaction, reduce the generation of pollutants, and provide a theoretical basis for the recycling and energy utilization of MS and discarded meal boxes. Full article
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15 pages, 2786 KiB  
Article
A Study of the Reliability and Accuracy of the Real-Time Detection of Forage Maize Quality Using a Home-Built Near-Infrared Spectrometer
by Fei Gao, Yuejing Zhang and Xian Liu
Foods 2022, 11(21), 3490; https://doi.org/10.3390/foods11213490 - 03 Nov 2022
Cited by 1 | Viewed by 1221
Abstract
The current study was conducted to explore the real-time detection capability of a home-built grating-type near-infrared (NIR) spectroscopy online system to determine forage maize quality. The factor parameters affecting the online NIR spectrum collection were analyzed, and the results indicated that the detection [...] Read more.
The current study was conducted to explore the real-time detection capability of a home-built grating-type near-infrared (NIR) spectroscopy online system to determine forage maize quality. The factor parameters affecting the online NIR spectrum collection were analyzed, and the results indicated that the detection optical path of 12 cm, conveyor speeds of 10 cm s−1, and number of scans of 32 were the optimal parameters. Choosing the crude protein and moisture of forage maize as quality indicators, the reliability of the home-built NIR online spectrometer was confirmed compared with other general research NIR instruments. In addition, an NIR online multivariate analysis model developed using the partial least squares (PLS) method for the prediction of forage maize quality was established, and the reliability, applicability, and stability of the NIR model were further discussed. The results illustrated that the home-built grating-type NIR online system performed satisfying and comparable accuracy and repeatability of the real-time prediction of forage maize quality. Full article
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14 pages, 802 KiB  
Article
Butterfly Pea Flower as a Novel Ingredient to Produce Antioxidant-Enriched Yellow Pea-Based Breakfast Cereals
by Ravinder Singh, Cheng-Chia Yu, Guan-Wei Chen, Ching-Hsueh Chen, Nasibeh Y. Sinaki, Jenshinn Lin and Filiz Koksel
Foods 2022, 11(21), 3447; https://doi.org/10.3390/foods11213447 - 30 Oct 2022
Cited by 5 | Viewed by 4547
Abstract
Butterfly pea flower (BP) is a rich source of bioactive components and can potentially be utilized to produce appealing, wholesome foods. Antioxidant and dietary fiber-enriched breakfast cereals were produced by extrusion cooking using blends of BP and yellow pea flour (YP). BP was [...] Read more.
Butterfly pea flower (BP) is a rich source of bioactive components and can potentially be utilized to produce appealing, wholesome foods. Antioxidant and dietary fiber-enriched breakfast cereals were produced by extrusion cooking using blends of BP and yellow pea flour (YP). BP was added to YP at 0%, 5% and 10% levels (w/w), respectively, and extruded at two temperature profiles with die temperatures of 130 and 150 °C. Incorporation of BP significantly (p < 0.05) improved the total phenolics content, antioxidant properties, and insoluble and total dietary fiber content of the extrudates, with 10% BP extrudates showing the highest values. At a die temperature of 150 °C, the extrudates had a higher expansion ratio, a lower dry hardness, and a higher dry crispiness as compared to those at 130 °C. The color of BP-incorporated extrudates was darker and bluer as compared to the no-BP extrudates. The 10% BP extrudates retained relatively more of their hardness, crispiness, and crunchiness after soaking, indicating a better bowl-life and, therefore, better suitability of this blend formula for breakfast cereal production. Overall, this research shows that healthier breakfast cereals with appealing color and relatively longer bowl-life can be produced using BP, making BP a potential novel ingredient for extrusion formulations. Full article
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18 pages, 3428 KiB  
Article
Artificial Neural Network Assisted Multiobjective Optimization of Postharvest Blanching and Drying of Blueberries
by Weipeng Zhang, Ke Wang and Chang Chen
Foods 2022, 11(21), 3347; https://doi.org/10.3390/foods11213347 - 25 Oct 2022
Cited by 7 | Viewed by 1480
Abstract
This study aimed to optimize the postharvest blanching and drying process of blueberries using high-humidity air impingement (HHAIB) and hot-air-assisted infrared (HAIR) heating. A novel pilot-scale hot-air-assisted carbon-fiber infrared (IR) blanching/drying system was developed. Fresh blueberries with an average diameter of 10~15 mm [...] Read more.
This study aimed to optimize the postharvest blanching and drying process of blueberries using high-humidity air impingement (HHAIB) and hot-air-assisted infrared (HAIR) heating. A novel pilot-scale hot-air-assisted carbon-fiber infrared (IR) blanching/drying system was developed. Fresh blueberries with an average diameter of 10~15 mm were first blanched with high-humidity air at 110 °C and 12 m/s velocity for different durations (30, 60, 90, and 120 s); subsequently, the preblanched blueberries were dried at different IR heating temperatures (50, 60, 70, 80, and 90 °C) and air velocities (0.01, 0.5, 1.5, and 2.5 m/s), following a factorial design. The drying time (DT), specific energy consumption (SEC), ascorbic acid content (VC), and rehydration capacity (RC) were determined as response variables. A three-layer feed-forward artificial neural network (ANN) model with a backpropagation algorithm was constructed to simulate the influence of blanching time, IR heating temperature, and air velocity on the four response variables by training on the experimental data. Objective functions for DT, SEC, VC, and RC that were developed by the ANN model were used for the simultaneous minimization of DT and SEC and maximization of VC and RC using a nondominated sorting genetic algorithm (NSGA II) to find the Pareto-optimal solutions. The optimal conditions were found to be 93 s of blanching, 89 °C IR heating, and a 1.2 m/s air velocity, which resulted in a drying time of 366.7 min, an SEC of 1.43 MJ/kg, a VC of 4.19 mg/100g, and an RC of 3.35. The predicted values from the ANN model agreed well with the experimental data under optimized conditions, with a low relative deviation value of 1.43–3.08%. The findings from this study provide guidance to improve the processing efficiency, product quality, and sustainability of blueberry postharvest processes. The ANN-assisted optimization approach developed in this study also sets a foundation for the smart control of processing systems of blueberries and similar commodities. Full article
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19 pages, 8831 KiB  
Article
Qualitative and Quantitative Correlation of Microstructural Properties and In Vitro Glucose Adsorption and Diffusion Behaviors of Pea Insoluble Dietary Fiber Induced by Ultrafine Grinding
by Lingyi Li, Jianfu Liu, Yang Zhang, Qian Wang and Jinrong Wang
Foods 2022, 11(18), 2814; https://doi.org/10.3390/foods11182814 - 13 Sep 2022
Cited by 6 | Viewed by 1731
Abstract
Ultrafine grinding is an important pretreatment to achieve the physical modification of dietary fiber. In this study, ultrafine grinding treatments were performed for different times to give pea insoluble dietary fiber (PIDF) samples with varied particle sizes (D50). The correlations [...] Read more.
Ultrafine grinding is an important pretreatment to achieve the physical modification of dietary fiber. In this study, ultrafine grinding treatments were performed for different times to give pea insoluble dietary fiber (PIDF) samples with varied particle sizes (D50). The correlations and quantitative relationships between the microstructures of multi-scales PIDF and its in vitro glucose adsorption and diffusion behaviors were comprehensively evaluated. The results indicated that the specific surface area (SSA), pore volume (PV) and oxygen-to-carbon surface ratio (O/C) of PIDF were significantly increased by ultrafine grinding at the cellular scale, while D50 and cellulose crystallinity (CrI) were significantly decreased. These changes significantly improved the glucose adsorption capacity (GAC) of PIDF. The order of importance of microstructural changes on GAC was O/C > PV > SSA > CrI > D50. GAC showed positive exponential relationships with SSA, PV, and O/C and showed a negative linear relationship with CrI. The ability to retard glucose diffusion increased significantly with decreased fiber particle size because of improved adsorption and interception of glucose and the dense physical barrier effect of PIDF. The quantitative equation of maximum glucose dialysis retardation index was GDRImax = −1.65 ln(D50) + 16.82 ln(GAC) − 68.22 (R2 = 0.99). The results could provide theoretical support for quantitative and targeted intervention of dietary fiber structure for blood glucose control. Full article
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11 pages, 1557 KiB  
Article
Effects of Multiscale Mechanical Pulverization on the Physicochemical and Functional Properties of Black Tea
by Yang Zhang, Weihua Xiao and Lujia Han
Foods 2022, 11(17), 2651; https://doi.org/10.3390/foods11172651 - 01 Sep 2022
Viewed by 1355
Abstract
Black tea leaves were pulverized at an organ-scale (~mm), tissue-scale (500–100 μm) and cell-scale (<50–10 μm) to investigate their physicochemical and functional properties. The results showed that cell-scale powders exhibited a bright brown color compared with organ- or tissue-scale powders with the highest [...] Read more.
Black tea leaves were pulverized at an organ-scale (~mm), tissue-scale (500–100 μm) and cell-scale (<50–10 μm) to investigate their physicochemical and functional properties. The results showed that cell-scale powders exhibited a bright brown color compared with organ- or tissue-scale powders with the highest total color difference (∆E) of 39.63 and an L value of 55.78. There was no obvious difference in the oil-holding capacity (OHC) of the organ- and tissue-scale powders (3.71–3.74 g/g), while the OHC increased significantly to 4.08 g/g in cell-scale powders. The soluble dietary fiber (SDF) content of cell-scale powders increased remarkably to 10.41%, indicating a potential application as a high-SDF food. Further, cell-scale pulverization of black tea enhanced its DPPH scavenging activity and ferric-ion-reducing antioxidant power (FRAP). However, the polyphenol content (13.18–13.88%) and the protein content (27.63–28.09%), as well as the Pb2+ adsorption capacity (1.97–1.99 mg/g) were not affected by multiscale pulverizations. The mean particle size (D50) correlated linearly with tap density (TD), color parameters of L and b, SDF content, DPPH scavenging activity and FRAP. The results indicate that black tea powders pulverized at a cell-scale can be used as a soluble fiber-rich functional food additive with a bright color, enhanced OHC and antioxidant capacity. Full article
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27 pages, 5111 KiB  
Article
Effect of Combined Infrared and Hot Air Drying Strategies on the Quality of Chrysanthemum (Chrysanthemum morifolium Ramat.) Cakes: Drying Behavior, Aroma Profiles and Phenolic Compounds
by Huihuang Xu, Min Wu, Yong Wang, Wenguang Wei, Dongyu Sun, Dong Li, Zhian Zheng and Fei Gao
Foods 2022, 11(15), 2240; https://doi.org/10.3390/foods11152240 - 27 Jul 2022
Cited by 19 | Viewed by 2650
Abstract
Chrysanthemum (Chrysanthemum morifolium Ramat.) is a seasonal plant with high medicinal and aesthetic value, and drying is an effective practice to enhance its storability after harvesting. The effects of hot air drying (HAD), combined infrared and hot air drying (IR-HAD), and sequential [...] Read more.
Chrysanthemum (Chrysanthemum morifolium Ramat.) is a seasonal plant with high medicinal and aesthetic value, and drying is an effective practice to enhance its storability after harvesting. The effects of hot air drying (HAD), combined infrared and hot air drying (IR-HAD), and sequential IR-HAD and HAD (IR-HAD + HAD) on the drying behavior, color, shrinkage, aroma profiles, phenolic compounds, and microstructure of chrysanthemum cakes were studied. Results showed that the increasing temperature resulted in a decrease in drying time and an increase in drying rate and moisture diffusivity. The Logarithmic and Page models exhibited superior fit in describing the dehydration process. Among the three drying strategies, IR-HAD was more effective in reducing energy consumption, improving shrinkage, water holding capacity, water binding capacity and cellular microstructure, while IR-HAD + HAD showed better inhibitory effect on color deterioration. Furthermore, gas chromatography–mass spectrometry (GC-MS) analysis revealed that different drying strategies dramatically influenced the aroma profiles in samples, and IR-HAD obtained the highest concentration of volatiles. The results of ultra-performance liquid chromatography (UPLC) indicated that the introduction of infrared radiation contributed to increasing the contents of chlorogenic acid, luteolin, total phenolic and flavonoid. These suggested that IR-HAD was a promising technique for drying medicinal chrysanthemum. Full article
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20 pages, 8313 KiB  
Article
Twin-Screw Extrusion of Oat: Evolutions of Rheological Behavior, Thermal Properties and Structures of Extruded Oat in Different Extrusion Zones
by Chengyi Zhou, Min Wu, Dongyu Sun, Wenguang Wei, Haoze Yu and Tong Zhang
Foods 2022, 11(15), 2206; https://doi.org/10.3390/foods11152206 - 25 Jul 2022
Cited by 11 | Viewed by 2140
Abstract
Further investigation of material properties during the extrusion process is essential to achieve precise control of the quality of the extrudate. Whole oat flour was used to produce low moisture puffed samples by a twin-screw extruder. X-ray diffraction (XRD), Scanning electron microscopy (SEM), [...] Read more.
Further investigation of material properties during the extrusion process is essential to achieve precise control of the quality of the extrudate. Whole oat flour was used to produce low moisture puffed samples by a twin-screw extruder. X-ray diffraction (XRD), Scanning electron microscopy (SEM), infrared spectroscopy (FTIR), thermal analysis, and rheological experiments were used to deeply characterize changes in the structure and cross-linking of oats in different extrusion zones. Results indicated that the melting region was the main region that changed oat starch, including the major transformation of oat starch crystal morphology and the significant decrease of enthalpy representing the starch pasting peak in the differential scanning calorimeter (DSC) pattern (p < 0.05). Moreover, the unstable structure of the protein increased in the barrel and then decreased significantly (p < 0.05) after being extruded through the die head. The viscosity of oats increased in the cooking zone but decreased after the melting zone. A transformation occurred from elastic-dominant behavior to viscoelastic-dominant behavior for oats in the melting zone and after being extruded. This study provides further theoretical support for the research of the change of materials during extrusion and the development of oat-based food. Full article
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12 pages, 3462 KiB  
Article
High-Moisture Extrusion of Mixed Proteins from Soy and Surimi: Effect of Protein Gelling Properties on the Product Quality
by Yujie Zhang, Jinchuang Zhang, Qiongling Chen, Ning He and Qiang Wang
Foods 2022, 11(10), 1397; https://doi.org/10.3390/foods11101397 - 12 May 2022
Cited by 11 | Viewed by 3193
Abstract
The high-moisture extrusion of proteins from plant and animal sources should be a new way for developing alternative protein products with meat-like texture. The protein gelling properties are considered an important factor for the meat-like texture formation during the high-moisture extrusion processing. In [...] Read more.
The high-moisture extrusion of proteins from plant and animal sources should be a new way for developing alternative protein products with meat-like texture. The protein gelling properties are considered an important factor for the meat-like texture formation during the high-moisture extrusion processing. In this study, the mixed protein gelling properties from soy protein isolate (SPI) and surimi at different ratios (90:10, 80:20, 70:30, 60:40 and 50:50) were investigated to relate to the high-moisture (70%) extruding product textural properties, correspondingly. Results showed that at SPI–surimi ratio 60:40, the heat-induced gelation time was clearly extended and the gel strength became much weaker. During the high-moisture extrusion processing, at SPI–surimi ratio 80:20, the extrudate showed the higher hardness, chewiness, gel strength and fibrous degree, while excessive surimi (more than 40%) in the blends would hinder the fibrous-oriented structure formation. It suggested that SPI may act as the continuous phase that is dispersed by surimi during the high-moisture extrusion processing. Interestingly, it was found that the gel strength of SPI–surimi blends was nonlinearly correlated with the specific mechanical energy (SME) and product textural properties. The study would be helpful for improving the textural properties of alternative protein products from soy and surimi. Full article
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15 pages, 2275 KiB  
Article
Study on Drying Control Strategy of White Radish Slice Based on Monitoring Medium Relative Humidity
by Dalong Jiang, Congcong Li and Zhian Zheng
Foods 2022, 11(9), 1197; https://doi.org/10.3390/foods11091197 - 20 Apr 2022
Cited by 2 | Viewed by 2003
Abstract
Enhancing the drying rate and dried products quality, as well as energy efficiency, is very tempting for the drying industry. Recently, a lot of investigations have illustrated that the drying temperature, air velocity, and sample thickness have significant influences on the drying process. [...] Read more.
Enhancing the drying rate and dried products quality, as well as energy efficiency, is very tempting for the drying industry. Recently, a lot of investigations have illustrated that the drying temperature, air velocity, and sample thickness have significant influences on the drying process. However, few investigations took into account the relative humidity (RH) as an important hot-air-drying parameter in the drying process. Therefore, in the current work, white radish slabs were used to explore the drying characteristics and quality under the drying condition of a constant RH, decreasing the RH step by step and decreasing RH automatically, together with a constant air velocity of 1 m·s−1 and a drying temperature of 60 °C. Compared to continuous dehumidification, the step-down RH process was conducive to the material center temperature rise in the early stage of drying. When the material central temperature was increased and then the RH was reduced, the drying rate was increased and the overall drying time was shortened. The automatic-down RH control drying process includes three dehumidification processes. The respective RH control values were 40%, 30%, and 20% and the respective durations were 180 min, 90 min, and 60 min. The comprehensive quality evaluation showed that the comprehensive score of the automatic-down RH control process at 60 °C was the highest, which was 0.85. The L* and b* values of the automatic-down RH control were 26.0 and 1.67, respectively, which were better than those of the step-down RH, constant 20% RH, and constant 40% RH. The maximum rehydration ratio was 3.96 under the automatic-down RH control condition, and the quality was good. The lowest energy consumption under the condition of the automatic-down RH control was 0.90 kW·h·kg−1. The present work contributes to a better understanding of the effect of the RH on the drying characteristics and quality of white radish slices, which is useful for enhancing the drying rate and dried products’ quality as well as energy efficiency. Full article
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18 pages, 3244 KiB  
Article
Effects of κ-Carrageenan and Guar Gum on the Rheological Properties and Microstructure of Phycocyanin Gel
by Yu-chen Lei, Xia Zhao, Dong Li, Li-jun Wang and Yong Wang
Foods 2022, 11(5), 734; https://doi.org/10.3390/foods11050734 - 02 Mar 2022
Cited by 15 | Viewed by 5308
Abstract
The effects of two polysaccharides on the performance and microstructure of phycocyanin gels were studied by choosing anionic polysaccharides (κ-carrageenan) and neutral polysaccharides (guar gum). The linear and nonlinear rheological properties and microstructure of the phycocyanin-polysaccharide composite gel were evaluated. The results show [...] Read more.
The effects of two polysaccharides on the performance and microstructure of phycocyanin gels were studied by choosing anionic polysaccharides (κ-carrageenan) and neutral polysaccharides (guar gum). The linear and nonlinear rheological properties and microstructure of the phycocyanin-polysaccharide composite gel were evaluated. The results show that both κ-carrageenan and guar gum can enhance the network structure of phycocyanin gel and weaken the frequency dependence. The sample with 0.4% κ-carrageenan has the highest gel strength. All samples exhibited Type I behavior (inter-cycling strain-thinning) and mainly elastic behavior. As the concentration of κ-carrageenan increases, hydrophobic interactions and disulfide bonds play an essential role in maintaining the three-dimensional structure of the gel. Too high a concentration of guar gum hinders the formation of protein disulfide bonds. This research can provide a theoretical basis for designing and developing new food products based on phycocyanin and different polysaccharides with ideal texture in the food industry. Full article
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