Oxidative stability of Pickering Emulsions Stabilized with Microgel Particles Obtained by Protein-Polyphenol Complexation

Nowadays, natural stabilization strategies used in the food industry to increase the shelf life of products and reduce oxidative degradation have gained great importance. Protein-polyphenol Pickering emulsion is a type of emulsion in which protein particles and polyphenols are used to stabilize oil droplets in water. In this study, primary and secondary oxidation products were determined in emulsions subjected to auto- and photo-oxidation to determine the oxidative stability of protein-polyphenol interactions through Pickering emulsions. In addition, the effect of enrichment of emulsion samples with antioxidant vitamin D and α-tocopherol (vitamin E) on oxidative stability was investigated. In this study, vitamin-free samples were accepted as control group. Whey protein isolate (WPI) microgels containing tannic acid (TA) or oxidized tannic acid (OTA) at 0.1, 1, 2 and 3% were produced. Pickering emulsions were produced using the obtained microgels and linseed oil, which is rich in Omega-3 fatty acids and has very low oxidative stability. The droplet sizes of the emulsions varied between 149 and 169 nm and particle charges between -42.65 and -48.03 mV. According to the data obtained during the auto-oxidation process, it was observed that the stability increased in direct proportion to the increase in polyphenol concentration. It was determined that vitamin D had a positive effect on the increase in the oxidative stability of the emulsion samples, but the addition of vitamin E showed prooxidant activity at high temperatures. In all samples with and without antioxidants, the rate of formation of oxidation products in photo-oxidation was slower than auto-oxidation and vitamin D had a higher photo-oxidative stability than vitamin E. The results of our study show that Pickering emulsions with high oxidative stability can be successfully produced using protein-polyphenol microgels stabilized for the transport of bioactive components.