Interaction of milk proteins with kiwifruit and mixed fruit polyphenols : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Food Innovation at Lincoln University

Abstract

The biofunctional properties of polyphenol along with the nutritional property of milk makes this system an excellent source of various health benefits. The structural and physiochemical properties of milk proteins facilitate their use as vehichles for bioactives. There is a growing demand for the delivery of antioxidants and its protection to ensure its bioavailability. Milk proteins are known to bind to polyphenols and protect them from the various harsh conditions within the stomach, till its released for absorption. Phenolic profiles of the Kiwifruit and fruit complex extracts showed predominant amounts of catechin, epicatechin and procyanidin B1 and B2, along with smaller amounts of other phenols such as caffeic acid, gallic acid, protocatechuic acid, syringic acid, rutin and quercetin. The HPLC extraction was carried out in various step using 70% acetone followed by 8% TCA precipitation. Addition of milk to theses extracts showed a decrease in antioxidant activity. However, extraction of polyphenols from the milk-polyphenols sytem did show considerable amounts of antioxidative property in coorelation with the amount of phenolics that were extracted. Loading efficiency studies revealed that almost 100% of the polyphenols were bound to the milk proteins.