Functional enhancement of goat milk kefir through Syzygium cumini polyphenol enrichment

Aim: To evaluate the effects of Syzygium cumini extract on selected physicochemical, microbiological, and bioactive properties of goat milk kefir. Methods: Goat milk kefir was supplemented with varying concentrations of S. cumini extract and analyzed for physicochemical parameters, antioxidant activity, lactic acid bacteria (LAB) viability, amino acid composition, fatty acid profile, and microstructure. Multivariate analysis was applied to assess relationships among quality attributes. Results: The addition of S. cumini extract influenced several quality parameters of kefir. The treatments showed increased antioxidant activity and, for the 2.0% extract, higher LAB counts than the control. Modifications in protein, fat, amino acid, and fatty acid profiles were also observed. In addition, extract supplementation significantly affected protein content, antioxidant capacity, and color parameters, while viscosity showed only numerical variation. Principal component analysis indicated that kefir samples with 1.5% and 2.0% extract were associated with a distinct set of physicochemical and functional properties. Conclusions: The incorporation of S. cumini extract may contribute to modifications in the physicochemical and biofunctional characteristics of goat milk kefir. These findings suggest its potential application as a natural ingredient in fermented dairy products; however, further studies are recommended to confirm its functional and shelf-life implications.