College of Food Science and Engineering, Northwest A&F University, Yangling, No. 22 Xinong Road, Yangling District, Xianyang, 712100, Shaanxi, China.
Bioprocess Biosyst Eng. 2022 Jul;45(7):1175-1188. doi: 10.1007/s00449-022-02734-8. Epub 2022 May 26.
Kvass is a popular low-alcohol beverage produced by the natural fermentation of dark rye bread or malt with complex microbial flora. However, few pieces of research focus on the microflora of traditional bread kvass, and the industrial kvass based on malt concentrate has some disadvantages, including the lack of viable probiotics and containing multiple artificial additives. Therefore, in the present study, based on the different homemade traditional bread kvass, the predominant species including Lacticaseibacillus paracasei, Acetobacter pasteurianus, and Saccharomyces cerevisiae were screened and identified. In addition, barley malt was used instead of bread for kvass production, and the co-fermentation conditions with three different strains were optimized as wort concentration of 7.4°Brix, cell ratio of 2/2/1 (S. cerevisiae/L. paracasei/A. pasteurianus), inoculum amount of 8%, fermentation temperature of 29.5 °C and fermentation time of 24.6 h. Moreover, the physicochemical (pH, total soluble solids, color, and alcohol content) and probiotic (microorganisms counting and antioxidant activity) properties of the barley malt kvass prepared at optimal conditions were symmetrically evaluated. Besides, compared with the commercial kvass products, the produced barley malt kvass exhibited better taste and more desirable antioxidant activity, and also maintained around 6-7 log CFU/mL of viable probiotic microorganisms during a week of storage. The present study not only enriched the biological resource of the traditional kvass, but also promoted the development of the kvass as a live-bacteria beverage.
克瓦斯是一种流行的低酒精饮料，由黑麦面包或麦芽的自然发酵与复杂的微生物菌群制成。然而，很少有研究关注传统面包克瓦斯的微生物菌群，而基于麦芽浓缩物的工业克瓦斯存在一些缺点，包括缺乏有活力的益生菌和含有多种人工添加剂。因此，在本研究中，基于不同的自制传统面包克瓦斯，筛选并鉴定了主要的发酵菌，包括副干酪乳杆菌、巴氏醋杆菌和酿酒酵母。此外，用大麦麦芽代替面包来生产克瓦斯，并优化了三种不同菌株的共发酵条件，麦汁浓度为 7.4°Brix，细胞比例为 2/2/1（酿酒酵母/副干酪乳杆菌/巴氏醋杆菌），接种量为 8%，发酵温度为 29.5°C，发酵时间为 24.6 h。此外，还对称地评估了最佳条件下制备的大麦麦芽克瓦斯的理化（pH 值、总可溶固形物、颜色和酒精含量）和益生菌（微生物计数和抗氧化活性）特性。此外，与商业克瓦斯产品相比，所生产的大麦麦芽克瓦斯具有更好的口感和更理想的抗氧化活性，并且在一周的储存期内，仍能保持约 6-7 对数 CFU/mL 的有活力益生菌微生物。本研究不仅丰富了传统克瓦斯的生物资源，还促进了活菌饮料克瓦斯的发展。
