Antioxidant activity stability and digestibility of protein from Se-enriched germinated brown rice

ABSTRACT The antioxidant activities of protein obtained from selenium-enriched germinated brown rice (Se-GBR) and germinated brown rice (GBR) were evaluated by measuring their ABTS∙+ radical scavenging activities and reducing power. Results showed that the antioxidant activity of the Se-GBR protein is higher than that of GBR under all treatment conditions. Heating improved the antioxidant activity of proteins. However, the addition of citric acid, metal ion and salt ion remarkably reduced the antioxidant activities of protein. The ABTS∙+ radical scavenging capacity under the conditions of light and sterilization were relatively stable, but the reduction capacity was remarkably reduced. Effects of different cooking methods (normal cooking, microwave cooking and high-pressure cooking) on protein contents, digestibility and interactions of Se-GBR and GBR were investigated. No significant change in protein content was observed after different cooking methods. However, high pressure and microwave cooking weakened the hydrophobic interactions of proteins, which led to the exposure of hydrophobic groups, as well as aggregates and precipitates of protein. Therefore, protein digestibility was decreased. The food processing methods should be considered to maintain the nutritional properties of Se-GBR and GBR proteins effectively.