Extraction optimization and functional properties of corn germ meal albumin protein as a potential source of novel food ingredients

Application of Solid-State Fermentation for the Improving of Extruded Corn Dry-Milling By-Products and Their Protein Functional Properties

In this study, the effect of solid-state fermentation (SSF) with Lactobacillus sakei MI401 and Pediococcus acidilactici PA-2 strains on functional properties of extruded (130 °C; 25 rpm) corn-milling by-products (CMB) and their albumin, globulin, and prolamin fractions was evaluated in order to produce stabilized and functionalized food/feed stock. Extrusion resulted in a considerable reduction of microbial contamination of CMB by five log cycles, increased damaged starch, water-absorption capacity, and lowered protein and fat contents by 12.4% and 37%, respectively. The application of SSF for the extruded CMB have been shown to improve the water absorption, foaming, and emulsifying capacity of albumins and globulins and also increased the digestibility and free radical scavenging activity of prolamins. The essential amino acid content (EAA) in CMB and antioxidant activity of prolamins was lowered after extrusion but significantly increased after SSF. The combination of the abovementioned treatments can be confirmed as a prospective functionalization of CMB, capable of potentially enhancing its safety and improving nutritional, biochemical, and technological properties of proteins.

Heat treatment of quinoa (Chenopodium quinoa Willd.) albumin: Effect on structural, functional, and in vitro digestion properties

Quinoa seeds are rich in protein, polyphenols, phytosterols, and flavonoid substances, and excellent amino acid balance that has been revisited recently as a new food material showing potential applied in fitness and disease prevention. Heat treatment is one of the most effective strategies for improving the physiochemical characteristics of a protein. However, research examining the effects of temperature on quinoa albumin (QA) properties is limited. In this study, QA was subjected to thermal treatment (50, 60, 70, 80, 90, 100, and 121°C). SDS−PAGE revealed that QA is composed of several polypeptides in the 10−40 kDa range. Amino acid (AA) analysis showed that the branched-chain amino acids (BCAAs), negatively charged amino acid residues (NCAAs), and positively charged amino acids (PCAAs) contents of QA were more than double that of the FAO/WHO reference standard. Additionally, heating induced structural changes, including sulfhydryl-disulfide interchange and the exposure of hydrophobic groups. Scanning electron microscopy demonstrated that the albumin underwent denaturation, dissociation, and aggregation during heating. Moreover, moderate heat treatment (60, 70, and 80°C) remarkably improved the functional properties of QA, enhancing its solubility, water (oil) holding capacity, and emulsification and foaming characteristics. However, heating also reduced the in vitro digestibility of QA. Together, these results indicate that heat treatment can improve the structural and functional properties of QA. This information has important implications for optimizing quinoa protein production, and various products related to quinoa protein could be developed. which provides the gist of commercial applications of quinoa seeds for spreading out in the marketplace.