Variation in antioxidant capacities in common variant teas and spiced teas

Abstract

Traditionally, spices are added to black tea for flavoring but possess health benefits as well which derived from antioxidant polyphenols. Assessments on the polyphenol content and antioxidant activities were conducted to evaluate the variation of spiced tea from the common variants. Principal component analysis (PCA) was employed to identify the variation pattern and significant variables for monitoring purposes. A total of 23 selected commercial tea from different variant that comprised of spiced black tea (SBT, n=6), black tea (BT, n=6), green tea (GT, n=6) and Jasmine green tea (JGT, n=5) were analyzed for their polyphenol content (phenolic, flavonoid, and tannin), the DPPH scavenging capacities, ferric reducing antioxidant power (FRAP) capacities and oxygen radical absorbance capacity (ORAC) and the data obtained were analyzed by PCA. SBTs were found to be relatively comparable to regular BTs, GTs, but lower than JGTs in their antioxidant activities and polyphenol content. Tannins significantly contributed to the antioxidant activities of scavenging and reducing capacities (r2 > 0.8, p < 0.05). This suggests that tannin content accompanied with DPPH scavenging and FRAP reducing capacities assessments of tea samples are gratified for further quality monitoring. From this evaluation, the addition of spices to tea did not give a significant increase in their antioxidant capacity. Further in vivo studies may benefit the knowledge on both bioactive components in their synergistic effect.