RESPONSE SURFACE METHODOLOGY ANALYSIS OF POLYPHENOL RECOVERY FROM ARTICHOKE WASTE

Large amounts of a solid waste consisting mainly of outer bracts and stems are produced from the industrial processing of artichokes. In this study, the recovery of polyphenols from the two waste components was investigated. Extraction experiments were carried outby an environmentally friendly procedure using aqueous ethanol as solvent. The total polyphenol content, expressed as mg of GAE per g of dry weight, was 10.23±0.68 mg/g for bracts and 16.36±0.85 mg/g for stems. To evaluate the effect of Temperature (T), Extraction time (E) and liquid-to-solid Ratio (R) on the extraction yields, a central composite design coupled with response surface methodology was used. Under the best conditions (T = 50°C, E = 110.4 min and R = 20 mL g-1), extraction yields between 90 and 93% were obtained. Statistical analysis of the data showed that E was the most influential factor, followed by T and R. Simplified polynomial models were developed to describe the effect of individual factors and their interactions on the extraction yield of polyphenols. Overall, the results of this study support the potential of using artichoke waste as a source of natural phenolic antioxidants and give useful directions on how to improve recovery by proper selection of extraction conditions.