Location: Small Grain and Food Crops Quality Research
Project Number: 3060-21650-002-047-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2023
End Date: Dec 31, 2024
Objective:
The long-term goal of this project is to develop a sustainable and scalable approach to produce a pea protein isolate with improved functionality and nutrition through the employment of a natural reaction and valorization of by-products. Specific objectives are: (1) Determine optimal conditions to produce glycated pea protein utilizing pea flour and pea fiber by-products; (2) Scale up the production of glycated pea protein isolates following identified optimal conditions; (3) Evaluate the structural, functional, and nutritional properties of the glycated pea protein isolates; and (4) Characterize the profile of the flavor compounds in the glycated protein samples and changes in flavor protein interactions.
Approach:
Pea flour will be used to produce pea protein isolate (PPI) in a pilot plant following a previously optimized pH extraction method. Pea hulls and pea inner fiber will be obtained and subjected to controlled enzymatic hydrolysis using cell wall enzymes in different mixtures. Fiber hydrolysates will be subjected to ultrafiltration to obtain two fractions, 3-10 kDa and 10-20 kDa, from each source of fiber, pea hulls and inner fiber. A total of four fiber fractions will be analyzed for chain-length distribution by high-performance anion-exchange chromatography with pulsed amperometric detection, as well as for their reducing power. The four fractions will be mixed individually with PPI in 4 different ratios (1:1, 2:1, 3:1, and 4:1) and incubated in a climate chamber at 49.0% relative humidity (RH) and 60 C for 12, 24, 36 and 48 hr to initiate a controlled and limited Maillard reaction. Extent of glycation will be assessed by monitoring changes in color, percent amine blockage, and protein and glycoprotein profiling. Conditions that result in limited and controlled Maillard-induced glycation, with no propagation to advanced stages will be selected for each of the fiber sources. Two hydrolyzed fiber sources will be used to glycate PPI under the selected glycation conditions. A mass balance study will be performed to assess the efficiency (target 80% protein purity) of the separation and the throughput. Glycated and non-glycated proteins, collectively referred to as partially glycated protein, will be collected and subjected to structural analysis including protein profiling, protein secondary structure distribution, intramolecular interactions, thermal denaturation, and surface properties. In addition, glycation sites will be determined using mass spectrometry. Functional properties including solubility, gelation, and emulsification will also be evaluated. Nutritional quality will also be assessed by monitoring changes in amino acid composition and in vitro digestibility. In addition, the impact of glycation on flavor development as well as flavor-protein interactions will be evaluated. Volatiles will be identified by gas chromatography coupled to mass spectrometry, using unsupervised chemometric tools to better understand the differences among the samples. Potential flavor-protein interactions will be assessed by monitoring volatile compounds disappearance/appearance upon glycation by comparison to various controls.
