Research on factors affecting the extractability of antioxidant compounds from coffee husks abstract

Abstract

Coffee husks is a typical by-product in the coffee bean industry. This by-product has a high biological activity, but recently in Vietnam, it has been used as fuel, fertilizer, and substrate for mushroom cultivation. This study aims to identify conditions for extracting polyphenol from ripe robusta coffee husks from Dăklak province. Factors affecting the extraction process are pH, temperature, coffee husks : solvent ratio, and time. The obtaining data showed that extracting at pH=4, 50^oC, with the solvent:coffee husks ratio = 7:1, during 1 hour would contribute the best results in terms of an extraction efficiency of soluble solids (33 %), the extraction efficiency of polyphenol (94 %), antioxidant activity according to DPPH assay (1959 ± 168 µM TE/ g dry matter of extracted solution) and FRAP assay (1976 ± 117 µM TE/ g dry matter of extracted solution). In addition, the extracted solution from the coffee husk is a potential source of polyphenol, as well as the antioxidant capacity that could be applied to future researches..