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

- Direct steam injection (DSI) processing improved functional properties of pea-rice protein isolate.
- Temperature and pH of DSI treatment had significant impacts on the functionality of protein blends.
- SDS-PAGE electrophoresis found disruption of high molecular weight aggregates.
- SH, SS bonds contents and Ho indicated changes in protein blends three-dimensional conformation.
- Amino acid analysis found no changes in the essential amino acid composition.

Direct steam injection (DSI) processing with pH adjustment was investigated to enhance the functionality of pea-rice 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 °C) and pH values (2 −1 1) 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 °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 m2/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.