Limited enzymatically hydrolyzed pea protein-inulin interactions in gel systems

Area of Science:

• Food Science
• Biochemistry
• Materials Science

Background:

• Protein-polysaccharide mixtures offer unique gel properties compared to single component gels.
• The functionality of plant proteins, like pea protein, is often inferior to animal proteins, limiting their food applications.
• Enzymatic hydrolysis and hydrocolloid addition are strategies to enhance protein functionality.

Purpose of the Study:

• To investigate the effect of limited enzymatic hydrolysis and inulin addition on the gelation properties of pea protein isolate.
• To determine the optimal conditions for enhancing the viscoelastic properties and network structure of pea protein-inulin gels.
• To elucidate the role of inulin in promoting protein-protein interactions and stabilizing the gel network.

Main Methods:

• Pea protein isolate dispersions were subjected to limited enzymatic hydrolysis using Alcalase® at varying times (0, 3, 6 min).
• Inulin was added at different ratios (0, 1:4, 2:4) relative to pea protein.
• Viscoelastic properties were assessed using amplitude and frequency sweeps, and gel microstructure was visualized via confocal laser scanning microscopy. Protein solubility was measured in urea and urea-Dithiothreitol solutions.

Main Results:

• Maximum gel strength (G' ~307 Pa) was achieved with 3-min hydrolysis and a 1:4 inulin to pea protein ratio.
• Hydrolysis for 3 min resulted in a dense gel network, while 6 min hydrolysis led to an open network, and 0 min hydrolysis showed large aggregates.
• Inulin promoted noncovalent bond formation (18% increased protein solubility in urea) and, with disulfide linkages, stabilized the gel structure.

Conclusions:

• Limited enzymatic hydrolysis (3 min) combined with a 1:4 inulin ratio significantly enhances pea protein gelation and structural integrity.
• Inulin plays a crucial role in promoting protein interactions and stabilizing the gel network through noncovalent and disulfide bonds.
• This study demonstrates a viable approach to improve the functionality of pea protein, making it more applicable in the food industry.