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.

2,4-Alkadienal trapping by phenolics

“…Lipid oxidation is a common source of reactive carbonyls in foods (Bastos, Costa, & Pereira, 2017;Concepcion et al, 2018). Once formed, these compounds have a great relevance in food quality and safety because of their sensory properties (Rendon, Salva, & Bragagnolo, 2014), their ability to modify food macromolecules (Lorenzo, Pateiro, Fontan, & Carballo, 2014), and their tendency to produce nonenzymatic browning (Potes, Kerry, & Roos, 2013). Because they are electrophiles, these carbonyls react easily with the nucleophiles present in foods.…”

Effect of Storage Conditions on the Protein Composition and Structure of Peanuts

“…Actually, the active groups or oxidation products produced by lipid oxidation might interact with proteins and lead to protein decomposition or polymerization, which might damage the natural structure of proteins and even in turn affect their functional properties and nutritional value during storage. 15 − 17 However, only a few studies have focused on this aspect. It remained unclear at peanut protein oxidization and changing of their internal structures during storage.…”

Extensive dry heating-induced changes in physicochemical and immunological properties of whey proteins

“…Previous studies have reported that water content, temperature, heating time and pH are related to the formation of AGEs [21,57]. In this study, moisture (aw) and heating time were both found to significantly affect the production of AGEs and also the formation of sRAGE-binding ligands.…”

“…Aggregates and monomers of allergens may then get access to the intestinal immune system via different size-dependent pathways [56]. Therefore, it can be speculated that extensively heated allergen induced tolerance would be already initialized in the uptake process of allergens and the subsequent interactions with MLNs, which is considered as the major site of antigen loading and T-cell recognition [57]. [60]).…”

“…First, the effects of water activity and "pH" were evaluated. To extend this study, more factors, such as carbohydrate type, the presence of lipids [57], and other milk proteins (especially caseins) should be taken into account in the preparation of extensively heated allergens. Second, in chapter 3, …”