Enhanced functionality of pea-rice protein isolate blends through direct steam injection processing

Direct steam injection (DSI) processing with pH adjustment was investigated to enhance the functionality of pearice protein isolate blends (PR). Protein slurries at concentration of 5% (w/w) of commercial pea and rice protein isolates in the ratio of 2:1 (w/w) across a range of steam temperatures (66-107 degrees C) and pH values (2-11) were studied. After DSI treatment, the PR were freeze-dried to obtain the final dry protein powder. Based on protein solubility profiles, the optimal DSI processing conditions were 107 degrees C and pH 11. Available lysine was not reduced (P > 0.05) in the blend. Solubility (from 3 to 41%, at pH 7), emulsifying activity index (from 5.9 to 52.5 m(2)/g), foam stability (from 68.2 to 82.8%), and oil holding capacity (from 1.8 to 4.9 g/g) values increased (P < 0.05) compared to the untreated PR. DSI can modify the functionality of PR without affecting the essential amino acid composition.