Formulation of black soybean yogurt and evaluation of changes in the bioactive profile and other compositional aspects during fermentation and storage.

Black soybean is known for its antioxidant and anti-inflammatory properties that help prevent several degenerative diseases, but in the Western diet, it is poorly used, despite the interest in foods rich in bioactive compounds. This study aimed to formulate a black soybean yogurt (BSY) fermented by a probiotic culture of L. acidophilus and evaluate the nutritional and bioactive profiles, the total antioxidant capacity, and complementary parameters during fermentation and storage for one month. We also evaluated the potential for acceptance by Rio de Janeiro consumers (n = 103). The final BSY water content was 92.8%. The dry matter contained 50.2% protein, 20.1% lipid, 5.9% ashes, 23.8% carbohydrates, and other constituents, including 1% sucrose, 5.9% α-galactosides, 26.9 mg/100 g anthocyanins (mainly cyanidin-3-glucoside), 140.5mg/100 g isoflavones (mainly genistin and daidzin). Titratable acidity was 0.44% and pH 4.5. In the sensory test, 12% sucrose and fruit extracts (strawberry, prune, and grape) were added individually to the product to evaluate the acceptability. The sweetened strawberry extract offered the highest acceptability, with a 7.6 score in a nine-point hedonic scale, against a 5.6 of the sweetened control with no fruit extract. Furthermore, all products scored well in the clusters with assessors who consumed soy products often and daily (total n = 26), with the strawberry-flavored one scoring, on average, 8 or 9. One month storage at 8 ± 2 °C caused a 22% decrease in the anthocyanins content and no significant change in isoflavones, titratable acidity, and pH. Fermentation and the addition of a sweetened fruit extract proved to be promising tools to increase the consumption of black soy milk in the West.