Development of vinegar obtained from lemon juice: Optimization and chemical characterization of the process

Abstract

A research on the production of lemon vinegar directly from lemon juice was conducted. For the alcoholic fermentation, two different strains of Saccharomyces cerevisiae, as well as two types of cultures (submerged culture and yeasts immobilized in alginate beads) were used. A microbiological control was also implemented during this stage. Acetic fermentation variables were optimized for a semi-continuous process. The whole process was monitored by means of volatile (SBSE/GC-MS), polyphenolic composition (UPLC-DAD), and sensory analysis was also conducted for the optimization procedure. The best conditions for alcoholic fermentation were obtained when Saccharomyces cerevisiae var. bayanus strain was used under a submerged culture, where a content of 13.53 mL ethanol/100 mL of wine was obtained. With regards to acetic fermentation, the use of an unloading volume of 33.33% of the total volume produced lemon vinegar in 20–24 h with an acidity of 13.29 g/100 mL of vinegar (expressed as acetic acid). The chemical monitoring of the process demonstrated that the majority of volatile compounds and polyphenols studied decreased during alcoholic and acetic fermentations. Multivariate statistical analysis such as principal component analysis allowed the classification of the samples according to the matrix (juice, wine and vinegar).