Sericultural & Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China; College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, 330045, China.
Sericultural & Agri-Food Research Institute, Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China.
J Dairy Sci. 2021 Dec;104(12):12403-12414. doi: 10.3168/jds.2020-20037. Epub 2021 Sep 14.
Adding functional ingredients is an important method to develop functional dairy products. Mulberry pomace (MPo), a byproduct of mulberry fruit processing, is rich in phenolic compounds and anthocyanins and can be served as the functional ingredient in functional dairy products. The aim of this work was to prepare a functional flavored yogurt by incorporating MPo into stirred yogurt and to investigate the effects of MPo on the physicochemical and textural properties of the product during cold storage. We supplemented MPo powder up to 3% (wt/wt) in fermented milk, and the changes in color, pH, titratable acidity (TA), total phenol content (TPC), total anthocyanin content (TAC), water-holding capacity, rheological behavior, texture, and microstructure of the functional flavored yogurt were monitored during storage under 4°C for 28 d. The MPo powder brought a pink to dark red color to the yogurt, decreased the lightness (L*) and yellow-blue color (b*) values, increased the red-green color (a*) values, decreased the pH value, and increased the contents of TA, TPC, and TAC in a dose-dependent manner. The addition of MPo at 1%, 2%, and 3% (wt/wt) significantly increased water-holding capacity, consistency, viscosity, and viscosity index, and reduced firmness of yogurt samples. Supplementation of MPo significantly reduced the pore spaces and channels inside the samples and improved microstructure of the functional yogurt. During the 28 d of cold storage, MPo-fortified yogurt samples kept relatively constant color, although their L*, a*, and b* showed a decreasing tendency. The pH of all yogurt samples gradually decreased with increasing of TA. Interestingly, TPC and TAC contents and the texture parameters of MPo-fortified yogurt increased gradually and continuously during the 28 d of cold storage. Mulberry pomace is beneficial to improve the physicochemical and textural properties of yogurt and has the potential as a natural stabilizer to be used in functional yogurt rich in phytochemicals.
添加功能性成分是开发功能性乳制品的重要方法。桑椹渣（MPo）是桑椹果实加工的副产物，富含酚类化合物和花青素，可作为功能性乳制品的功能性成分。本工作旨在通过将 MPo 掺入搅拌酸奶中来制备功能性调味酸奶，并研究 MPo 在冷藏过程中对产品理化性质和质构特性的影响。我们在发酵乳中补充 MPo 粉末高达 3%（wt/wt），并在 4°C 下储存 28 天期间监测功能性调味酸奶的颜色、pH 值、滴定酸度（TA）、总酚含量（TPC）、总花青素含量（TAC）、持水能力、流变行为、质地和微观结构的变化。MPo 粉末使酸奶呈现粉红色至暗红色，降低亮度（L*）和黄蓝色值（b*），增加红绿色值（a*），降低 pH 值，并以剂量依赖的方式增加 TA、TPC 和 TAC 的含量。添加 1%、2%和 3%（wt/wt）的 MPo 显著增加了酸奶样品的持水能力、稠度、粘度和粘度指数，并降低了其硬度。MPo 的添加显著减少了样品内部的孔隙和通道，并改善了功能性酸奶的微观结构。在 28 天的冷藏过程中，MPo 强化的酸奶样品的颜色保持相对稳定，尽管它们的 L*、a和 b呈下降趋势。所有酸奶样品的 pH 值均随 TA 的增加而逐渐降低。有趣的是，MPo 强化酸奶的 TPC 和 TAC 含量和质构参数在 28 天的冷藏过程中逐渐且持续增加。桑椹渣有利于改善酸奶的理化性质和质构特性，具有作为富含植物化学物质的功能性酸奶天然稳定剂的潜力。
