Use of principal component analysis and cluster Aanalysis for differentiation of traditionally-manufactured vinegars based on phenolic and volatile profiles, and antioxidant activity

This study aimed to characterize twelve vinegar samples produced by the traditional method with the use of whole fruits and without any preservatives in terms of their physicochemical properties, total phenolic content (TPC), total flavonoid content (TFC), phenolic compound profiles, antioxidant activity (DPPH• scavenging activity, FRAP, CUPRAC), and volatile compositions, as well as their abilities to delay oxidation in mayonnaise. Types of raw material significantly affected all of the above parameters (p<0.05). Gallic acid, protocatechuic acid, and caffeic acid were detected as the major phenolic acids in all vinegar samples. Among, flavonoids, rutin, and kaempferol were also identified. The major volatiles belonged to acetic acid esters and alcohol groups, and isoamyl acetate was determined in all vinegar samples at changing ratios. The high positive correlation coefficient (r>0.70) was determined between DPPH• scavenging activity of vinegars and induction period of accelerating oxidation based on the OXITEST of mayonnaises produced with these vinegars. Vinegar types significantly affected the oxidative stability of mayonnaise (p<0.05). Furthermore, it was demonstrated that vinegar samples could be clearly discriminated by principal component and cluster analyses. This study suggests that fruit type should be considered as a crucial factor in the production of vinegars affecting not only sensory properties but also their physicochemical and bioactive properties.