Tavakoli Maryam, Habibi Najafi Mohammad B, Mohebbi Mohebbat
Department of Food Science and Technology, Faculty of Agriculture, Ferdowsi University of Mashhad, P. O. Box 91775-1163, Mashhad, Iran.
Heliyon. 2019 Feb 3;5(2):e01204. doi: 10.1016/j.heliyon.2019.e01204. eCollection 2019 Feb.
In this study, the effects of milk fat content (0%, 2% and 3.5%) and starter culture (autochthonous or commercial) on physicochemical properties, degree of proteolysis, antioxidant activity and viability of , within 21 days storage of probiotic yogurt at 5 ± 1 °C were investigated. Statistical analysis showed that the type of starter culture had a significant effect (P < 0.05) on proteolysis and antioxidant activity, in such a way that both of them were increased until the 14 day of storage but they decreased after this period. Similarly, the pH value of all samples decreased during storage time. It ranged from 3.84-4.34 and 4.18-4.43 for yogurt samples made by autochthonous and commercial starter culture, respectively. According to the results, the survival of decreased during storage time (P < 0.05), although it stood at recommended levels for health effects (at least 10 cfu/ml in traditional yogurt). Milk fat content did not have significant effect on the survival of probiotic organisms (P < 0/05).
在本研究中，研究了乳脂肪含量（0%、2%和3.5%）和发酵剂（本地的或商业的）对益生菌酸奶在5±1℃下储存21天内的理化性质、蛋白水解程度、抗氧化活性和益生菌活力的影响。统计分析表明，发酵剂类型对蛋白水解和抗氧化活性有显著影响（P<0.05），两者在储存至第14天时均有所增加，但在此之后下降。同样，所有样品的pH值在储存期间均下降。由本地发酵剂和商业发酵剂制作的酸奶样品的pH值范围分别为3.84 - 4.34和4.18 - 4.43。根据结果，益生菌在储存期间的存活率下降（P<0.05），尽管其仍处于对健康有益的推荐水平（传统酸奶中至少10 cfu/ml）。乳脂肪含量对益生菌的存活率没有显著影响（P<0.05）。
