Enrichment of green table olives by natural anthocyanins during fermentation

The aim of this study is the enrichment of green table olives with anthocyanins by using beetroot and black carrot in the fermentation media and to improve functional properties of fermented olives. For this purpose, a full factorial design was constructed by considering the fermentation time, vegetable type and vegetable concentration as processing factors. The changes in the chemical and microbiological properties of both olive and brine samples were monitored. During fermentation, while phenolic components of olives were transferred to the brine, the anthocyanins originating from the black carrot and beetroot diffused into both olive and brine samples. The total monomeric anthocyanin content of fermented olives containing 20% percent of black carrot and beetroot was 149.87 and 154.05 mg/kg respectively. Moreover, the color of olives turned as fermentation progressed. Both ANOVA results (p < 0.05) and PCA model (R2 = 0.99; Q2 = 0.93) confirmed that reaction time is most important factor for the fermentation process. The sensorial analysis results indicated that the olives fermented with 20% vegetable for 10 days had been highly scored by panelists.

The online version contains supplementary material available at 10.1007/s13197-023-05751-x.