Kim Da-Hee, Cho Won-Young, Yeon Su-Jung, Choi Sung-Hee, Lee Chi-Ho
Department of Food Science and Biotechnology of Animal Resources, Konkuk University, Seoul 05029, Korea.
Division of Food Technology and Aquatic Life Medical Sciences, Sunmoon University, Chungnam 31460, Korea.
Food Sci Anim Resour. 2019 Oct;39(5):792-803. doi: 10.5851/kosfa.2019.e69. Epub 2019 Oct 31.
The supplementation with natural ingredients that are rich in polyphenols could improve the quality and functionality of yogurt. Lotus leaf (LL) are abundant in phenolic compounds. We aimed to investigate the effects of LL powder on the quality properties, total phenolic content (TPC), and antioxidant activity of yogurt. Yogurt was supplemented with four different concentrations (0%, 0.2%, 0.5%, and 1%) of LL powder and evaluated for 14 d refrigerated storage. During storage, the titratable acidity (TA) of all LL yogurt groups was higher than that of the control (p<0.05). The L* and a* values decreased by LL addition to the yogurts, while the b* values increased. All LL yogurt groups indicated better viscosity than that of control, and among them, 0.2% LL yogurts had the highest viscosity without significant decrease until the end of the storage duration. The addition of LL into yogurt enhanced the water-holding capacity (WHC) by at least 1.5-fold than that of control for the entire storage duration. The TPC of yogurts gradually increased with the addition of LL (p<0.05) and continued to increase during storage; the 1% LL yogurt at 14 d showed the highest value of 61.94±1.68 μg GAE/g. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and reducing power of the yogurts were also significantly enhanced with increasing LL concentrations (p<0.05). These results suggest that lotus leaf may be useful as a natural ingredient for improving the quality and antioxidant activity of yogurt.
补充富含多酚的天然成分可以提高酸奶的品质和功能。荷叶富含酚类化合物。我们旨在研究荷叶粉对酸奶品质特性、总酚含量（TPC）和抗氧化活性的影响。在酸奶中添加四种不同浓度（0%、0.2%、0.5%和1%）的荷叶粉，并在冷藏条件下储存14天进行评估。在储存期间，所有添加荷叶的酸奶组的可滴定酸度（TA）均高于对照组（p<0.05）。添加荷叶后，酸奶的L值和a值降低，而b*值升高。所有添加荷叶的酸奶组的粘度均优于对照组，其中，0.2%荷叶酸奶的粘度最高，在储存期结束前无显著下降。在整个储存期间，向酸奶中添加荷叶可使持水能力（WHC）提高至少1.5倍。酸奶的TPC随着荷叶的添加而逐渐增加（p<0.05），并在储存期间持续增加；14天时，1%荷叶酸奶的TPC最高，为61.94±1.68μg GAE/g。随着荷叶浓度的增加，酸奶的DPPH（2,2-二苯基-1-苦基肼）自由基清除活性和还原能力也显著增强（p<0.05）。这些结果表明，荷叶可能是一种用于改善酸奶品质和抗氧化活性的天然成分。
