Chemical Properties, Antioxidant Activities and Sensory Evaluation of Berry Vinegar

Abstract

This study was carried out to examine the chemical properties, antioxidant activities and sensory scores of berry vinegar produced from 4 berry species, namely Morus alba L. (Mulberry), Vaccinium macrocarpon L. (Cranberry), Rubus idaeus L. (Rasberry), and Rubus laciniatus L. (Blackberry). Berry vinegars were produced via a 2-stage (alcoholic and acetous) fermentation process. The initial soluble solid contents in the berry juice were adjusted to 22 ºBrix before the fermentation. Alcoholic fermentation was conducted using Saccharomyces cerevisiae as the inoculant while Acetobacter pasteurianus was used for acetous fermentation. As observed for all samples during the alcoholic fermentation the levels of soluble solids decreased continuously and the levels of alcohol were found to increase at the end of fermentation process. Notably, the wine produced from ‘Blackberry’ species exhibited the highest levels of alcohol (11.73 %) while those produced from ‘Mulberry’ exhibited the highest levels of antioxidant activity (60.85 %). Similar results were observed for all samples during the acetous fermentation, in which the levels of alcohol dropped continuously and the levels of acetic acid were noted to elevate at the end of the fermentation process. The highest levels of acetic acid (5.01 %) was detected in the vinegars produced from ‘Cranberry’ species while those produced form ‘Raspberry’ species exhibited the highest levels of antioxidant activity (74.43 %). Sensory evaluation based on the 9-point hedonic scales showed that the vinegars produced from ‘Mulberry’ species displayed the highest overall acceptability with an average score of 7.27, equivalent to the hedonic scale of 9, which indicated the moderately pleasant levels of the vinegar preference of the consumers.