Analysis of the role of acidity and tea substrate on the inhibition of α-amylase by Kombucha
Mallory Dickmann, Rebecca Schneider, Samantha Armando, Katherine Seehusen, Patrick Hager, Michael J Strauss, Francis M Mann
Kombucha tea (KT) is an acidic, fermented, tea-based beverage associated with a variety of reported health benefits. Specifically, KT consumption has previously elicited hypoglycemic responses in alloxan-induced diabetic rats, implying KT consumption may alleviate symptoms of diabetes. One method by which KT may act as a hypoglycemic agent involves inhibition of digestive glucosidases, such as α-amylase. Indeed, KT demonstrated an IC50 of 0.16±0.06% (mL/U) during in vitro pancreatic amylase assay, while unfermented black tea failed to inhibit the enzyme. Inhibition of α-amylase by KT may be due to pH-dependent inactivation of the enzyme, biotransformation of tea catechins, or production of an inhibitory factor during fermentation. Production of tea-free kombucha (MT) allowed further analysis of the roles of tea catechins on the inhibitory capacity of the beverage. MT demonstrated a higher inhibitory dose than KT concentration at acidic pH (IC50 = 6.3±5.4% (mL/U)), but MT inhibitory activity was completely abrogated by pH adjustment. Conversely, the inhibitory capacity of pH adjusted KT was reduced less than 10-fold (IC50 = 1.2±0.23% (mL/U), however, complete inhibition was not achieved. Together these results support a role for both pH and biotransformation of tea compounds in the inhibitory mechanism of Kombucha tea on the enzyme α-amylase, however, de novo fermentative production of an α-amylase inhibitor is unlikely.
Keywords: acidity, black tea, diabetes, ph, rats
Citation: Dickmann M, Schneider R, Armando S, et al. Analysis of the role of acidity and tea substrate on the inhibitionof ?-amylase by Kombucha. J Nutr Food Technol. (2017);0(0): 1?5. DOI: 10.30881/jnfrt.0000
Study Mailing Address:
Francis Mann, 356 Greenquist Hall, University of Wisconsin-Parkside, Kenosha, WI 53141
Date Updated: March 28, 2020