Physicochemical Properties of Rice Bran Hydrolysate Prepared in a Pilot Scale Process and Its Application in Milk Tablets

Abstract

The objectives of this study were to produce rice bran hydrolysate (RBH) in a pilot-scale process and determine its physicochemical properties including chemical compositions, α-amino contents, molecular weight (MW) distribution and antioxidant activities. The results found that RBH contained a crude protein of 16.14 %, α-amino contents of 51.56 mg Leucine Eq./g RBH, ABTS radical scavenging activity of 20.17 mg Trolox Eq./g RBH, and FRAP value of 5.77 mg Trolox Eq./g RBH. The major peak of MW peptides of RBH was 753 - 6,088 Da (50.81 %). RBH in various levels (0 - 2.0 %) was supplemented in milk tablets. Physicochemical properties, and sensory evaluation (9-point hedonic scale) of all milk tablets were then determined. The result indicated that the milk tablets with 2.0 % RBH (MT_2%RBH) contained higher antioxidant activities than the others, however, the overall acceptability score of all milk tablets was not significantly different (p ≥ 0.05). MT_2 %RBH was selected for further development by adding 2.0 % cocoa (MT_2%RBHC) and 2.0 % vanilla powder (MT_2%RBHV). The MT_2%RBHC containing higher antioxidant activities and sensory attributes score than the others was further selected for microbiological qualities, consumer and purchase tests (n = 300). It was found that MT_2%RBHC was accepted by 300 people, with an overall acceptability score of 7.16 (Like moderately), and its microbiological qualities, including total bacteria, total yeast and mold and Escherichia coli did not exceed the standard limits. These results suggested that RBH produced in the pilot-scale process has a potential as nutritive and antioxidative supplementation in milk tablets. HIGHLIGHTS Rice bran hydrolysate (RBH) has a potential for production in a pilot-scale process The major peak of molecular weight (MW) peptides of RBH was 753 - 6,088 Da (50.81 %) RBH has a potential as antioxidative supplementation in milk tablets Cocoa milk tablets supplemented with RBH were accepted by 300 panelists Microbiological qualities of milk tablet did not exceed the standard limits GRAPHICAL ABSTRACT