Desenvolvimento de leite fermentado de kefir com leite de cabra adicionado de luteína e suco concentrado de cana

Abstract

The growing interest in functional foods has stimulated the development of products that combine nutritional value with bioactive properties. In this context, kefir stands out as a fermented beverage obtained from a symbiotic consortium of lactic acid bacteria and yeasts, which has been associated with several health benefits. The present study aimed to develop and characterize fermented kefir beverages produced with goat milk and supplemented with lutein, evaluating the effect of different sweetening agents (crystal sugar and concentrated sugarcane juice) on the physicochemical, microbiological, and antioxidant properties of the formulations. Three formulations were prepared: a control formulation (without sweetener), a formulation containing 10% crystal sugar, and a formulation containing 10% concentrated sugarcane juice. The beverages were evaluated for proximate composition, pH, titratable acidity, instrumental color (L*, a*, and b*), water-holding capacity, syneresis, total phenolic compounds, antioxidant activity by ABTS and DPPH assays, and microbiological quality. The results showed significant differences (p < 0.05) among formulations for several physicochemical and technological parameters. The beverage containing concentrated sugarcane juice exhibited higher water-holding capacity and lower syneresis, indicating greater structural stability of the product matrix. In addition, this formulation showed the highest levels of total phenolic compounds and the greatest antioxidant activity in both ABTS and DPPH assays. Microbiological analyses indicated compliance with standards for lactic acid bacteria and absence of coliforms, while yeast counts were lower than the reference limits established in the legislation. The results indicate that the use of concentrated sugarcane juice may contribute to improving the technological and antioxidant properties of goat milk kefir beverages, demonstrating potential for the development of fermented dairy products with functional attributes.