Biotransformation of Chickpea Flour Using Submerged Fermentation with Aspergillus oryzae to Enhance Protein Functionality and Proximate Composition

Presenter: Nicholle Kirsten Limsico Tan

Faculty Sponsor: Lutz Grossmann

School: UMass Amherst

Research Area: Biochemistry and Molecular Biology

Session: Poster Session 3, 1:15 PM - 2:00 PM, 165, D9

ABSTRACT

Fermentation is a promising strategy to enhance the functional, sensory, and nutritional properties of legume substrates. Specifically, filamentous fungi are recognized for producing a wide range of metabolites and various enzymes that facilitate the hydrolysis of complex macromolecules such as proteins, lipids, and carbohydrates. This study investigates the effect of fermentation time of Aspergillus oryzae biomass produced under submerged fermentation (SmF) with chickpeas as substrates. The fermentation occurred in a 5 L benchtop bioreactor that controlled for pH (pH 5), temperature (30 °C), and agitation (180 rpm) for 3 and 6 day periods. The soluble and insoluble fractions were analyzed independently to evaluate compositional and structural changes. Both fermentation periods showed increased protein yield, with SDS-PAGE analysis showing a reduction in higher-molecular-weight proteins and formation of smaller-sized peptides. Lipid and starch concentrations decreased, accompanied by an increase in D-glucose concentrations. Trypsin inhibitor proteins decreased in the pellet fractions but increased in the supernatant fractions, suggesting protease activity releasing bound forms of inhibitor proteins. The surface charge of the pellet fraction increased with longer fermentation time, whereas the supernatant fraction exhibited minimal changes. Protein solubility in the fermented pellet fraction was negligible, while fermented supernatant fractions showed increased solubility at higher pH values. Overall, fermentation resulted in significant changes in the protein structure, proximate composition, antinutritional compounds, solubility, and surface charge. These findings emphasize the importance of how fermentation parameters can be strategically adjusted to drive specific compositional and functional changes in the chickpea substrate.

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