engleski

Optimizing acidity and extraction time for polyphenolic recovery and antioxidant capacity in grape pomace skin extracts with response surface methodology approach

Objectives were to evaluate and optimize single and cumulative influences of extraction times (30, 45, 60 min) and acidity (0, 0.5, 1% of HCl) on quantities of total polyphenols (TP), hydroxycinnamic acids (HCA) and antioxidant capacity (AC) extracted from red grape skin pomace extracts (Vitis vinifera, cv. Merlot). Increasing time and acidity increased TP, HCA and AC. Highest quantities of TP, HCA and AC were at 1% HCl and between 45 and 60 min. Time had little influence on amounts of polyphenols without HCl. For most of extraction times, AC followed similar trends as studied polyphenols. AC remained constant between 30 and 45 min for low concentrations of HCl. Calculated optimal extraction conditions for: HCA57.93 mg/g dry pomace, t560 min, HCl50.84% ; TP599.99 mg/g dry pomace, t560 min, HCl50.79% ; DPPH52, 055.75 mg/ 100g were t560 min and HCl50.77%. All variables (TP, HCA and AC) strongly increased as a function of each other. Constructed mathematical models retained these relations.

total flavonoids ; proanthocyanidins ; anthocyanins ; flavonols ; optimal extraction acidity/time ; grape pomace skin extracts

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