Utilization of coffee skin fiber as potential source of reducing sugar by means on enzymatic hydrolysis

Coffee spent ground is a primary by-product obtained during soluble coffee processing and potential to be utilized as a high value product due to its protein content. The quite popular effort to utilize protein-contained material is to process it to hydrolysate which also possess antioxidant activity. This research was aimed to study the possibility of protein and antioxidative compound from coffee spent ground by means of enzymatic hydrolysis using crude papain enzymes. Crude papain was used in different concentration ranged from 2, 4 and 6% to incubate the coffee spent grounds for 2, 3, and 4 hours and  then analyzed for its protein content and its antioxidant activity, whereas response surface methodology was employed to study the tendency of the effect of incubation time and enzymes concentration towards hydrolysis results. The result showed that the use of crude papain was effective to liberate the protein and antioxidant compound the coffee spent ground with its optimum condition utilized 6% of enzyme and 2 hours incubation time. At mentioned condition, it could extract up to 67.38% of the protein of the coffee spent ground and its hydrolysate possessed relatively high antioxidant activity.