title: Oil as reaction medium for glycation, oxidation, denaturation, and aggregation of whey protein systems of low water activity.
abstract: Whey protein isolate (WPI)-oil (75:25) and WPI-oil-(glucose-fructose) (45:15:40) as models of high-protein systems containing either olive (OO) or sunflower oil (SO) were stored at 20 or 40 °C to investigate component interactions. The indicators of protein oxidation (carbonyl content) and aggregation (total sulfhydryl content) and heats of protein denaturation and aggregation were investigated. Highest levels of disulfide bonding and carbonyls in WPI-OO formed during the first 2 weeks of storage concomitantly with enhanced protein aggregation. WPI-OO and WPI-SO systems (prestorage) showed increased protein denaturation temperature. The WPI proteins showed higher heat sensitivity with OO or SO at 40 °C, and the system with OO showed preaggregated protein as found from decreased heats of protein aggregation. OO or SO in WPI-oil-(glucose-fructose) systems reduced heats of protein aggregation. Lipid oxidation products and nonenzymatic browning reactions in glucose-fructose-containing systems decreased the solubility of solids and increased protein aggregation, hydrophobicity, and hardening of structure.
authors.affiliation: School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Naritchaya
authors.initials: N
authors.lastname: Potes
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Kerry
authors.forename: Yrjö H
authors.initials: YH
authors.lastname: Roos
mesh_terms: D061353:Food Storage; D006031:Glycosylation; D008894:Milk Proteins / Q000737:chemistry*; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010938:Plant Oils / Q000737:chemistry*; D050050:Protein Carbonylation; D011489:Protein Denaturation; D055550:Protein Stability; D012995:Solubility; D000074242:Sunflower Oil; D013696:Temperature; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000069463:Olive Oil; D010938:Plant Oils; D000074242:Sunflower Oil; D000067816:Whey Proteins