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

Area of Science:

• Food Science
• Protein Chemistry
• Biotechnology

Background:

• Pea and rice protein isolates (PR) are valuable plant-based protein sources.
• Enhancing the functional properties of PR blends is crucial for food applications.
• Direct steam injection (DSI) is a potential method for protein modification.

Purpose of the Study:

• To investigate the effect of direct steam injection (DSI) with pH adjustment on the functionality of pea-rice protein isolate blends (PR).
• To determine the optimal DSI processing conditions (temperature and pH) for enhancing PR functionality.
• To assess the impact of DSI on the nutritional quality, specifically available lysine content.

Main Methods:

• Pea and rice protein isolates (2:1 ratio) were prepared as 5% (w/w) slurries.
• Slurries were treated using direct steam injection (DSI) across temperatures of 66–107°C and pH values of 2–11.
• Treated PR blends were freeze-dried to obtain dry powders for analysis.

Main Results:

• Optimal DSI processing conditions were identified as 107°C and pH 11, based on protein solubility.
• Significant increases in protein solubility (3% to 41% at pH 7), emulsifying activity index (5.9 to 52.5 m²/g), foam stability (68.2% to 82.8%), and oil holding capacity (1.8 to 4.9 g/g) were observed (P<0.05).
• Available lysine content in the PR blend was not significantly reduced (P>0.05) by the DSI treatment.

Conclusions:

• Direct steam injection (DSI) processing effectively enhances the functional properties of pea-rice protein isolate blends.
• Optimal DSI conditions (107°C, pH 11) improve solubility, emulsification, foam stability, and oil holding capacity.
• DSI is a viable method for modifying plant-based protein functionality without compromising essential amino acid content.