Effect of the type of acetic fermentation process on the chemical composition of prickly pear vinegar (Opuntia ficus-indica).

Abstract

BACKGROUND: In several countries, the cactus plant (Opuntia ficus-indica (L). Mill) knows renewed attention due to its ecological, socio-economic, and environmental role. In this study, prickly pear vinegar was produced employing two types of acetification processes: surface and submerged culture. Both acetification processes were performed at different temperatures (30 °C, 37 °C, 40 °C) by using two different species of thermo-tolerant acetic acid bacteria (Acetobacter malorum and Gluconobacter oxydans). Polyphenols and volatiles compounds analyzed by UPLC/DAD and SBSE-GC/MS, respectively, were considered as the main variables to determine the effect of the acetification process on the quality of the vinegar.

RESULTS: As a result, fifteen polyphenols and seventy volatile compounds were identified and quantified in the vinegar samples produced by both acetification processes. The results showed that the surface acetification method led to an increase in the concentration of phenolic components, which was higher than that in the submerged process. However, a significant increase of volatile compounds predominated by esters and acids was observed when submerged culture acetification was employed, whereas alcohols were predominant in surface culture vinegars. Moreover, the multivariate statistical analysis showed that the components that mostly contributed to the differentiation between all vinegar samples were the volatile compounds.

CONCLUSION: It has been proved that prickly pear vinegar could be successfully produced at higher temperatures than usual, by employing thermo-tolerant bacteria, and that the type of acetification method significantly affects the final quality of the vinegar produced. This article is protected by copyright. All rights reserved