Analyzing ethanol accumulation in different kombucha tea brands during storage: relationship between storage and ethanol production
Chhay, James (author)
School of Health Sciences (author)
© James Chhay, 2020. All rights reserved. No part of this work covered by the copyright heron may be reproduced or used in any form or by any means – graphics, electronic, or mechanical including photocopying, taping, or information storage and retrieval systems – without written permission of the author.
Background Kombucha tea is a fermented tea beverage that is mainly consumed for its associated-health benefits. These associated-health benefits may range from detoxifying the body to cancer treating. However, there is little to no scientific evidence that suggests that they work on humans. Similarly, kombucha tea is also prone to post-fermentation. This presents possible ethanol production and accumulation within the tea after packaging which can pose a possible health risk to susceptible population if not properly labelled or controlled. This study will investigate if there is any post-ethanol accumulation in commercially produced kombucha tea products under various storage conditions. Methods The ethanol concentration of 3 different kombucha tea brands (i.e.: Pure+, Health-Ade, and RISE) at various storage conditions (i.e.: no storage, refrigeration, and room temperature) were analyzed using GC-FID to determine post-ethanol accumulation. In addition, NCSS software was used to conduct a statistical analysis on the data to determine whether the 3 different kombucha tea brands exceeded the ethanol regulatory limit and whether the ethanol accumulation was dependent on storage temperatures. Results The mean ethanol concentration for Pure+, Health-Ade, and RISE after refrigeration for 3 weeks were 0.722%, 0.696%, and 0.050% relatively which all showed a slight decrease in ethanol compared to their baseline ethanol levels (i.e.: no storage). Similarly, Pure+, Health-Ade, and RISE mean ethanol concentration after room temperature storage were 1.766%, 1.285%, and 0.794% relatively which indicates ethanol accumulation. Statistical analysis showed that there is a significant difference between room temperature storage and the other 2 storage conditions (i.e.: no storage and refrigeration). Also, only Pure+ and Health-Ade under room temperature storage showed a statistically significant mean ethanol concentration above the regulatory limit. Conclusion Results suggests that room temperature storage of Pure+, Health-Ade, and RISE for 3 weeks increased the ethanol levels significantly while refrigerating them will decrease the ethanol levels slightly which can minimize any potential post-fermentation process from happening. Furthermore, only Pure+ and Health-Ade under room temperature storage for 3 weeks were over the 1% ABV regulatory limit. Lastly, the data obtained from this study can be used to develop guidelines and policies in regulating kombucha tea manufacturers and in educating the public and other regulatory agencies on the matter.
Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology 2020.