EFFECTS OF ENHANCEMENT METHODS ON THE EXTRACTION OF ANTHOCYANINS FROM REUTILIZED BORDÔ GRAPE SKINS

Bordô grapes (Vitis Vinifera Bordô) are extensively cultivated to produce full-bodied wine, rich in flavor and aroma. In winemaking, 20% of the processed grapes become waste, discarded as pomace. The discarded grape skin, as part of the pomace, is rich in phenolic compounds, such as anthocyanins, natural colorants with antioxidant capabilities. Extracting anthocyanins from grape skins reduces waste generation and ensures efficient utilization of raw materials. Therefore, it is necessary to evaluate methods that enhance anthocyanin extraction. The anthocyanin extraction methods employed included mechanical agitation, ultrasonic bath, and ultrasound. The aqueous extraction was formulated with 40% (w/w) grape skins in a solution acidified with citric acid (1%). The non-enhanced extract, obtained solely by macerating the skins in acidified water followed by resting, serves as the control. Extraction times of 5, 10, and 20 minutes were assessed for all three devices, with ultrasound tested at power levels of 200 and 300 watts. The efficiency of the enhancement method was determined by Total Anthocyanin Content (TAC), with results expressed in milligrams of cyanidin-3-glucoside per 100 grams of wet sample. Statistical analysis was performed using ANOVA and Tukey's Test, at a significance level of 0.05. The methods exhibited significant differences in anthocyanin extraction from grape skins, with values ranging between 432 and 689 mg/100g. The mechanical agitator showed the lowest anthocyanin content and did not differ significantly from the control. The highest anthocyanin content was achieved through ultrasonic extraction at 300 watts for 20 minutes. Ultrasound at 300 watts yielded higher anthocyanin contents at all tested times, with results surpassing those of the ultrasonic bath and magnetic stirrer by over 25% and 30%, respectively. Therefore, the use of ultrasound for efficient anthocyanin extraction is encouraged.