Physicochemical and microbiological stability of fermented dairy beverages added with red rice extract

Abstract Fermented dairy beverages added with red rice extract and whey were the developed, physicochemical and microbiological properties were evaluated. A central composite rotatable design was applied, using nine treatments with three replicates. The pH indicated that the beverages could be consumed without the addition of preservative for up to 28 days of storage. The beverages are characterized as partially skimmed, with high protein content, zinc, manganese and copper levels, similar potassium and iron levels and low sodium, magnesium and calcium levels, if compared to the recommended daily index. The absence of pathogens and numbers of viable lactic acid bacteria above the established minimum level were observed. The physicochemical parameters were evaluated by ANOVA and PCA, grouping the beverages into four groups according to their physicochemical properties and three groups according to mineral levels. It is suggested that the most adequate treatments contain between 20 and 34% of red rice extract and from 26 to 54% of whey because of their lower copper contents.

摘要：本研究开发了添加红曲提取物与乳清的发酵乳饮料，并对其理化特性及微生物学特性开展了评价。本研究采用中心复合旋转设计（central composite rotatable design），设置9组处理，每组设3次重复。pH值检测结果表明，该饮料在贮藏28天内无需添加防腐剂即可安全饮用。该饮料属于半脱脂产品，其蛋白质、锌、锰及铜含量较高，钾与铁含量与推荐每日摄入量标准相近，钠、镁及钙含量则低于推荐每日摄入量标准。检测未检出致病菌，且活菌乳酸菌数量达到并超过既定最低限值。通过方差分析（ANOVA）与主成分分析（PCA）对理化参数进行分析，可依据理化特性将受试饮料划分为4组，依据矿物质含量划分为3组。研究表明，最优处理组的红曲提取物添加量应控制在20%~34%之间，乳清添加量应控制在26%~54%之间，因其铜含量更低。