Comparison of the Antioxidant and Sensorial Properties of Kvass Produced from Mountain Rye Bread with the Addition of Selected Plant Raw Materials.

Consumers' growing awareness of healthy nutrition results in an increase in demand for the production of beverages with health-promoting properties. An example of such a product is kvass produced in the fermentation process. This research aimed to determine the impact of plant additives on the antioxidant and sensorial properties of kvass made from bread based on mountain rye flour. The bread extract was fermented at different temperatures (28 and 34 °C). Additives of 3, 5, and 10% were used in the tests, which included black chokeberry juice and infusion, sea buckthorn fruit juice and infusion, and peppermint leaf infusion. A higher fermentation temperature in the production process resulted in an improvement in the organoleptic and antioxidant properties of the tested kvasses. The highest antioxidant activity was demonstrated by kvass with the addition of 10% black chokeberry juice (0.734 µmol Trolox g (ABTS), 4.90 µmol of Trolox g (DPPH)), and a peppermint leaf infusion (0.773 µmol Trolox g (ABTS), 4.71 µmol Trolox g (DPPH)). The conditions of kvass production and the type and amount of the additive influenced the selected physicochemical parameters of the obtained kvasses. The chromatographic analysis confirmed the content of 13 phenolic compounds in kvass with the addition of black chokeberry juice, which was 1.68-1.73 mg/100 mL of the finished product with a 10% share of the additive. The 11 phenolic compounds in kvass with the addition of peppermint infusion were confirmed for 7.65-6.86 mg/100 mL of the finished product with 10% of the additive. Kvass enriched with additives from black chokeberry fruit and peppermint leaves may be a promising new category of functional beverages with health-promoting properties resulting from the content of polyphenol compounds. It could be a better base for enrichment with raw materials that are richer in these compounds than pasteurized products.