Aroma profile of pilot plant-scale produced fruit vinegar using a thermotolerant Acetobacter pasteurianus strain isolated from Moroccan cactus

Abstract

In this study, new thermotolerant Acetobacter pasteurianus CV01 strain recently isolated from local product of Morocco has been investigated for its ability to perform efficient acetous fermentation at a large-scale. Firstly, the thermotolerance basis bioconversion of CV01 strain was compared to other mesophilic and thermotolerant acetic acid bacteria. Subsequently, CV01 strain was assessed for its ability to produce and tolerate high amount of acetic acid at optimal and thermal stress conditions in lab-scale bioreactor. It was found that the studied strain exhibited thermotolerant properties compared to reference strains and could withstand the increase in temperature during acetous fermentation in fermenter. Furthermore, gas chromatography-mass spectrometry (GC-MS) was used on the samples prepared with solid phase microextraction (SPME) to determine the volatile compounds of the pilot plant produced apple vinegar based on developed start-up and semi-continuous fermentation protocol. The operation strategy in the 500-L pilot plant scale acetator allowed achieving 7.3% (w/v) of final acetic acid concentration recording high yield and acetification rate. The aroma profile of experimentally produced vinegar was found different from that of the commercial reference one. According to the literature, the results obtained show that major volatile compounds found in pilot-plant produced apple vinegar are related to good aromatic note descriptors which could have a positive impact on the organoleptic quality of industrial vinegar. Consequently, it can be concluded that CV01 Acetobacter strain is well suited for large-scale production of high quality fruit vinegar.