Abstract

Coffee husks (CHs) is a high biological activity by-product of the coffee bean industry, but currently, in Vietnam, it has not been used properly in the food industry. This study was conducted to investigate the combined cellulolytic and pectinolytic enzymes to increase the polyphenol extractability of coffee husks. The red ripe Robusta coffee cherries from Dăklak province, Vietnam were blanched, peeled and the coffee husks was then extracted. The effects of pectinase content (from 0 to 800 U/gCHs), cellulase content (from 0 to 800 U/gCHs), pH (from 3.0 to 5.0), temperature (from 40◦C to 60◦C), CHs: solvent ratio (from 1: 6 to 1:12) and extracted time (from 60 minutes to 120 minutes) on soluble solid content (SSC), total polyphenol content (TPC) and antioxidant activity were investigated. The appropriate conditions for the treatment were pectinase dosage of 600 U/gCHs, cellulase dosage of 400 U/gCHs, pH 4.0, temperature 50◦C, CHs:soluble ratio = 1:10 and incubation time of 60 min under which the SSC, TPC and antioxidant activity of extract were highest by 60.60.4 g/100g dry weight of CHs, 200.5 gGAE /100g dry weight of CHs, 1.5 +/- 0.1 mMTE/g dry weight of extract (according to DPPH assay) and 1.5 +/- 0.1 mMTE/g dry weight of extract (according to DPPH assay). From this result, it can be seen that the extracted solution from coffee husk is a potential source for the production of soft drinks with high antioxidant activity.