Study on the application of enzyme extracted from aspergillus oryzae soluble solid content improvement of coffee

Abstract

The objective of this study was to investigate the optimal conditions for Aspergillus oryzae incubation in order to obtain the highest pectinase activity and then apply it into Robusta fermentation with various temperatures so as to achieve the highest soluble solid content. This research needed to be performed since pectin content in coffee cherries was the resistance affecting the extraction solute; therefore, a big waste of solute would still remain in coffee beans after brewing. The pectinase activity could be determined by DNS assay after running some factors of fungi incubation. The highest pectinase activity would be used in coffee fermentation which was 19.22 ± 0.78 U/ml. After coffee fermentation and some processes, coffee brew was tested for soluble solid content by refractometer. The highest soluble solid content was 3.75 ± 0.005 oBrix with respect to 35oC fermentation. Moreover, the product fermented by crude enzyme was also compared with that of being fermented by Viscozyme L – an expensive industrial enzyme. The product of Viscozyme L gave the result of 4.00 ± 0.008 oBrix that was a little higher than product of crude enzyme. The contribution of this study is applied in pilot scale and further studies. Keywords: Aspergillus oryzae, coffee fermentation, soluble solid content, pectinase activity