Investigation of phenolic and volatile compounds changes during vinegar production using spontaneous fermentation of different prickly pear (Opuntia ficus-indica)-based matrices

In the current study, prickly pear vinegar (PPV) was spontaneously produced by surface culture using different matrices. The influence of prickly pear (PP) peel and the addition of sucrose on the evolution of both phenolic and volatile compounds during the fermentation process has been investigated. The main findings showed that produced PPV samples had a high number of functional compounds since 116 individual volatile compounds belonging to different chemical families and 20 phenolic compounds have been identified. To study the effect of matrix (juice or vinegar), PP fruit variety (red/yellow), PP peel (presence/ absence), and sugar addition (with/ without) on phenolic and volatile compounds, data were submitted to statistical analysis (analysis of variance, principal component analysis and cluster analysis). Results showed that the use or not of PP peel in the PPV production process was the variable with the most influence on the phenolic composition of the samples. In the case of volatile compounds and taking into account all samples (juice and vinegar), the two main factors affecting the volatile composition were the matrix (juice or vinegar) and the peel (presence or absence) (p < 0.05). However, sugar addition had no significant effect on the analyzed data.