Rahmani Fatemeh, Gandomi Hassan, Noori Negin, Faraki Azita, Farzaneh Melika
Department of Food Hygiene Faculty of Veterinary Medicine University of Tehran Tehran Iran.
Department of Food Science and Technology Shahr-e-Qods Branch Islamic Azad University Tehran Iran.
Food Sci Nutr. 2021 Aug 5;9(10):5536-5545. doi: 10.1002/fsn3.2512. eCollection 2021 Oct.
In this study, the effect of aqueous extract of green tea on the viability of probiotic bacteria including and and the sensory and physicochemical and functional properties of synbiotic yogurt was investigated during 4 weeks of storage. and . counts did not significantly change in yogurt containing 0.5% and 1% of the extract during storage. Also, the addition of the extract to yogurt highly increased the phenolic compounds, since the amount of phenolic compounds in yogurt containing 0.5% and 1% extract was 660 and 1,123 mg gallic acid/kg, respectively. In addition, a significant increase in the antioxidant activity of yogurt containing green tea extract was observed in comparison with the control. The amount of antioxidant activity increased during 4 weeks of storage, which reached to 4,193 and 7,337 mg BHT eq./kg in probiotic yogurt containing 0.5% and 1% extract, respectively. The acidity increased during 4 weeks of storage, while the pH decreased. Addition of the extract significantly increased the acidity of probiotic yogurt compared with the control ( < .05). In addition, in all studied groups, an increase in syneresis was observed during the study, and the syneresis was greater in yogurt containing aqueous extract of green tea, compared with the control group. Although adding the green tea extract to probiotic yogurt impaired taste, texture, and appearance compared with the plain yogurt, the overall acceptability of these samples was yet above the acceptable level. In conclusion, the results of the study showed that the addition of aqueous extract of green tea increased the antioxidant properties and the amount of phenolic compounds in yogurt, while the viability of probiotic bacteria was not changed. Therefore, the simultaneous use of green tea extract and probiotics in yogurt is recommended as an effective functional food formulation.
在本研究中，考察了绿茶水提取物对包括[具体益生菌名称1]和[具体益生菌名称2]在内的益生菌活力以及合生元酸奶的感官、理化和功能特性在4周储存期内的影响。[具体益生菌名称1]和[具体益生菌名称2]的计数在含有0.5%和1%提取物的酸奶储存期间没有显著变化。此外，向酸奶中添加提取物显著增加了酚类化合物的含量，因为含有0.5%和1%提取物的酸奶中酚类化合物的含量分别为660和1123毫克没食子酸/千克。此外，与对照组相比，含有绿茶提取物的酸奶的抗氧化活性显著增加。抗氧化活性在4周储存期内增加，在含有0.5%和1%提取物的益生菌酸奶中分别达到4193和7337毫克丁基羟基甲苯当量/千克。酸度在4周储存期内增加，而pH值下降。与对照组相比，添加提取物显著增加了益生菌酸奶的酸度（P<0.05）。此外，在所有研究组中，在研究期间均观察到乳清析出增加，并且与对照组相比，含有绿茶水提取物的酸奶中乳清析出更多。尽管与原味酸奶相比，向益生菌酸奶中添加绿茶提取物会损害其口感、质地和外观，但这些样品的总体可接受性仍高于可接受水平。总之，研究结果表明，添加绿茶水提取物可提高酸奶的抗氧化性能和酚类化合物含量，而益生菌的活力未发生变化。因此，建议在酸奶中同时使用绿茶提取物和益生菌作为一种有效的功能性食品配方。
