Milk protein and fat play different roles in affecting the bioavailability and the antioxidant activity of jujube juice phenolics in rats

Abstract

In this study, we intend to clarify the role that milk proteins and fat may play in affecting the bioavailability and the antioxidant activity of jujube juice phenolics. Three milk preparations-skimmed milk, milk fat, and whole milk were produced to represent milk protein, milk fat, and milk protein and fat together, respectively. The bioavailability of phenolics and the rat plasma antioxidant capacity were measured for 8 h after the consumption of jujube juice with and without milk preparations. The addition of skimmed milk to jujube juice resulted in significant changes in the plasma kinetics profile of phenolics, rather than affecting the overall absorption. Milk fat did not interact with jujube juice phenolics. However, when jujube juice was ingested with whole milk, a significant reduction of the bioavailability of phenolics and the maximum increase in plasma antioxidant capacity was observed. Moreover, a consistent increase in the median diameters of the emulsions indicated the formation of complexes of proteins, fat, and phenolics during digestion. The present study suggests that when ingested with jujube juice, milk proteins and fat play different roles in affecting the bioavailability and the antioxidant activity of jujube juice phenolics.