Physical and oxidative stability of emulsions stabilized with fractionated potato protein hydrolysates obtained from starch production byproduct: Use of bioinformatics and proteomics

Abstract

With the increasing demand for sustainable and functional proteins from alternative sources, it is necessary to use advanced proteomics and bioinformatics tools for more time and cost-efficient research. The identification and release of abundant proteins/peptides from plant-based sources has been gaining significant attention by the food industry in the last decade. Despite its low protein content (1–2%), the magnitude of proteins obtained from the starch industry (~240,000 tons/year) makes potatoes a highly relevant source as a plant-based protein. Previously, we have identified and validated abundant peptides with good emulsifying and antioxidant properties using bioinformatics and proteomics tools as well as in vitro model systems. Using data-driven targeted hydrolysis, we were able to release validated, functional peptides from the potato protein obtained from potato fruit juice, a protein rich by-product of potato starch production. This work focuses on fractionation of potato protein hydrolysates (PPH) obtained through such targeted hydrolysis using trypsin and subsequent fraction characterization. Unfractionated (PPH1) and membrane-fractionated (PPH2 as >10kDa, PPH3 as 10-5kDa, PPH4 as 5-0.8kDa and PPH5 as < 0.8kDa) PPH was characterized for emulsifying and antioxidant properties/potential. Pendant drop technique and dilatational rheology were applied for determining interfacial tension and viscoelasticity of the PPH fractions at the oil-water interface. PPH2 (>10kDa) showed higher decrease of oil-water interfacial tension. All fractions predominantly provided elastic, weak and easily stretchable interfaces. PPH2 provided more rigid interfacial layer than the other fractions. Radical scavenging and metal chelating activities of PPHs were also tested and the best activities were provided by fractions >5kDa. Furthermore, their ability to form physically and oxidatively stable 5% fish oil-in-water emulsions were investigated during 8-day storage and results generally showed that fractions >5kDa provided the best stability followed by the 5–0.8kDa fraction.