Effects of moisture and temperature during grain storage on the functional properties and isoflavone profile of soy protein concentrate

Functional Foods from Black Rice (Oryza sativa L.): An Overview of the Influence of Drying, Storage, and Processing on Bioactive Molecules and Health-Promoting Effects

Black rice (Oryza sativa) stands out for its high content of bioactive compounds with functional properties that play an important role in health benefits. The phytochemical level is affected by industrial processing due to its instability to the hydrothermal process. Studies about the influence of industrial processing on the phytochemical profile of black-rice-based foods are still scarce. This study carried out a comprehensive review of the influence of industrial applications on the bioactive compounds in food products based on black rice and their health-promoting effects. Most industrial processes such as drying, storage, cooking, and extrusion affect phytochemical content and antioxidant capacity. Alternatively, technologies such as fermentation, UV-C irradiation, and sprouting can maintain or improve the phytochemical content in black rice products.

Effects of Packaging Materials on Structural and Simulated Digestive Characteristics of Walnut Protein during Accelerated Storage

Walnuts are rich in fat and proteins that become oxidized during the processing and storage conditions of their kernels. In this study, the effect of three packaging materials (e.g., polyethylene sealed packaging, polyamide/polyethylene vacuum packaging, and polyethylene terephthalate/aluminum foil/polyethylene vacuum packaging) were investigated on the oxidation, structural and digestive properties of walnut kernel proteins. Results showed that the amino acid content gradually decreased and carbonyl derivatives and dityrosine were formed during storage. The protein molecule structure became disordered as the α-helix decreased and the random coil increased. The endogenous fluorescence intensity decreased and the maximum fluorescence value was blue-shifted. After 15 days of storage, surface hydrophobicity decreased, while SDS-PAGE and HPLC indicated the formation of large protein aggregates, leading to a reduction in solubility. By simulating gastrointestinal digestion, we found that oxidation adversely affected the digestive properties of walnut protein isolate and protein digestibility was best for polyethylene terephthalate/aluminum foil/polyethylene vacuum packaging. The degree of protein oxidation in walnuts increased during storage, which showed that except for fat oxidation, the effect of protein oxidation on quality should be considered. The results of the study provided new ideas and methods for walnut quality control.

Effect of Storage Conditions on the Protein Composition and Structure of Peanuts

Peanuts are important oil crops and plant protein source. This study evaluated the influence of storage temperature (15, 25, and 35 °C) and time (0, 160, and 320 days) on the protein composition and the molecular structure of peanuts through sodium dodecyl sulfate polyacrylamide gel electrophoresis, particle size, total sulfhydryl (-SH) contents, nanostructural characterization, surface morphology microstructure, and spatial distribution of proteins and lipid analysis. Results showed that the basic subunits and disulfide contents of peanut protein were not affected by storage temperature and time. However, the -SH contents decreased significantly (P < 0.05) in all samples except the 15 °C/160 day storage group. The protein particle size and graininess increased when stored at 25 and 35 °C for 160 and 320 days, respectively; however, there was no significant change (P > 0.05) when stored at 15 °C. In addition, significant changes (P < 0.05) on the microscopic morphology and spatial distribution of protein and lipids were observed when stored at 25 and 35 °C for 320 days.

Environmentally Friendly Methods for Flavonoid Extraction from Plant Material: Impact of Their Operating Conditions on Yield and Antioxidant Properties

The flavonoids are compounds synthesized by plants, and they have properties such as antioxidant, anticancer, anti-inflammatory, and antibacterial, among others. One of the most important bioactive properties of flavonoids is their antioxidant effect. Synthetic antioxidants have side toxic effects whilst natural antioxidants, such as flavonoids from natural sources, have relatively low toxicity. Therefore, it is important to incorporate flavonoids derived from natural sources in several products such as foods, cosmetics, and drugs. For this reason, there is currently a need to extract flavonoids from plant resources. In this review are described the most important parameters involved in the extraction of flavonoids by unconventional methods such as ultrasound, pressurized liquid extraction, mechanochemical, high hydrostatic pressure, supercritical fluid, negative pressure cavitation, intensification of vaporization by decompression to the vacuum, microwave, infrared, pulsed electric field, high-voltage electrical discharges, and enzyme-assisted extraction. There are no unified operation conditions to achieve high yields and purity. Notwithstanding, progress has been achieved in the development of more advanced and environmentally friendly methods of extraction. Although in literature are found important advances, a complete understanding of the extraction process in each of the unconventional techniques is needed to determine the thermodynamic and kinetic mechanisms that govern each of the techniques.

Effect of Drying Temperatures on the Peanut Quality during Hot Air Drying

Peanuts are usually with high moisture after harvest and must be dried to prevent mildew. Hot air drying is the most commonly used method for peanut drying. The purpose of this study was to evaluate the drying temperatures on the peanut qualities. In this paper, fresh peanuts were dried with solar radiation (control group) and hot air at 35-60°C until the moisture content of peanut reduced below 10%. The physical (texture, damaged percentage of red testa and breakage percentage of peanut kernel), physiological (germination) and biochemical (the contents of vitamin E and aflatoxin B₁; acidity values, iodine values, peroxide values and fatty acid composition of peanut oil; solubility, emulsifying, foaming, water-holding capacity and oil-binding capacity of peanut protein) properties of peanut kernel were determined under different drying conditions (solar radiation, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C). The results showed that hot air temperatures had obvious influences on peanut qualities. The damaged percentage of red testa and breakage percentage of peanut kernel increased remarkably when the drying temperatures were above 45°C. Meanwhile, when drying temperatures were more than 45°C, the acid value and peroxide value of the extracted oil increased significantly. Furthermore, some properties exhibited prominent changes when the temperatures were higher than 50°C, such as hardness, brittleness, germination percentage, and the Vitamin E content of peanut kernel. In addition, the research results revealed that hot air can increase hydrophobicity of peanut protein and affect the functional properties of peanut protein. Therefore, it could be concluded that peanut should be dried by hot air below 45°C for quality maintenance. It also provided reference to choose suitable drying temperatures based on the final use of peanut.

Effects of refrigeration on biochemical, digestibility, and technological parameters of carioca beans during storage

The objective of this study was to evaluate the effects of grain moisture, temperature, and storage time on biochemical, digestibility, and technological parameters of carioca beans. The grains were stored at 16.7% and 13.8% of moisture at 12, 20, 28, and 36°C for 240 days. It was observed that a reduction in the storage temperature maintained the germination and vigor of the grains. The temperature of 36°C causes between 3.81% and 4.52% reduction in weight of a thousand grains and significant darkening. Carioca beans stored at 36°C exhibited hard-to-cook (HTC) defect at 80 days and increases in hardness after 240 days. The best digestibility indexes of carioca beans were obtained with refrigerated storage. The refrigerated storage (12°C) provides the best preservability of the grains throughout the storage, verified by the parameters biochemical, digestibility, and technological parameters. PRACTICAL APPLICATIONS: Carioca beans are among the most consumed beans in Brazil and their quality for consumption is directly influenced by storage conditions that alter color, nutritional value, bioactive, and cooking properties. Thus, this study seeks to present a practical and viable solution for stockist of bean grains, so that they can store these grains for long periods, maintaining the quality standards for commercialization. In addition, this technology allows the stockist to identify the best time for commercialization of the carioca beans, which has high added value.

Changes in Phenolic Acid and Isoflavone Contents during Soybean Drying and Storage

The changes in phenolic acid and isoflavone profile of soybean genotypes ( Nidera 5909 RR and BMX Força RR) dried at different temperatures and stored for 12 months were investigated. In both cultivars, there was a reduction of the germination capacity and an increase of fungal incidence with the increase of drying temperature and storage time. Multivariate analysis of phenolic acids allowed for the differentiation among treatments. Cultivar Nidera 5909 RR, dried at 110 °C, showed an interaction with characters of greater relevance for differentiation, being influenced by the increase of bound coumaric, and syringic, and free-hydroxybenzoic, syringic, and coumaric acids. Multivariate analysis of isoflavones showed a strong affinity of the aglycone isoflavones (genistein, glycitein, and daidzein) within the Nidera 5909 RR cultivar at all drying temperatures and with BMX Força RR cultivar at the highest temperatures. These results indicate that the release and interconversion of isoflavone malonyl-β-glucosides and β-glucosides into aglycone forms are simultaneous reactions during storage.