Effects of Lotus (Nelumbo nucifera) Leaf on Qualityand Antioxidant Activity of Yogurt during Refrigerated Storage

摘要

The supplementation with natural ingredients that are rich in polyphenols couldimprove the quality and functionality of yogurt. Lotus leaf (LL) are abundant inphenolic compounds. We aimed to investigate the effects of LL powder on thequality properties, total phenolic content (TPC), and antioxidant activity ofyogurt. Yogurt was supplemented with four different concentrations (0%,0.2%, 0.5%, and 1%) of LL powder and evaluated for 14 drefrigerated storage. During storage, the titratable acidity (TA) of all LLyogurt 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 amongthem, 0.2% LL yogurts had the highest viscosity without significantdecrease until the end of the storage duration. The addition of LL into yogurtenhanced the water-holding capacity (WHC) by at least 1.5-fold than that ofcontrol for the entire storage duration. The TPC of yogurts gradually increasedwith 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±1.68μg GAE/g. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavengingactivity and reducing power of the yogurts were also significantly enhanced withincreasing LL concentrations (p<0.05). These results suggest that lotus leafmay be useful as a natural ingredient for improving the quality and antioxidantactivity of yogurt.