Fermentation of red pitahaya extracts using spp. and for reduction of sugar content and concentration of betacyanin content.

Unlabelled: A study was conducted to concentrate the betacyanin in red pitahaya extracts by removing the coexisting sugars by fermentation. Four lactic acid bacteria (, , and ) and a yeast species () were screened to determine their efficiency to reduce sugar content in red pitahaya extracts for concentration of their betacyanin content. A reduction of sugar content (19.8-56.4%) and increase in the yield of betacyanins were observed in all extracts as compared to the control, which was not innoculated with any microorganisms after 1 day of fermentation. The lowest total sugar content (26.40 g/L) was observed in extracts fermented by . Extracts fermented by also showed greater numbers of microbial cells (10.75 log CFU/mL) and a lower pH value (3.54) compared to those (6.89-8.48 log CFU/mL and pH 4.64-5.42) of the spp. after 1 day of fermentation. An optimization step using response surface methodology (RSM) was then conducted using Temperature, time and agitation speed were found to have a significant effect on the total sugar content and BC of concentrated betacyanins from red pitahaya, while the yield of betacyanins was significantly influenced by temperature and agitation speed.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05116-2.