Pectin-rich Banana Peel Varieties: A Low-cost Biomass for Pectinase Production by Aspergillus flavus in Solid-state Fermentation and its Effect on the Clarification of Orange Juice

Abstract

A total of five pectin-rich banana peels, including those of two Musa paradisiaca cultivars (nendran and kadali) and three Musa acuminata varieties (matti, palayankodan, and robusta), were used for pectinase production by Aspergillus flavus via solid-state fermentation (SSF). Comparative analysis revealed highest pectin content in the palayankodan peel (18.09 ± 0.29%). The palayankodan peel variety presented 135 ± 2.2 U/gds pectinase activity in SSF using A. flavus, whereas robusta peels presented 108 ± 1.9 U/gds pectinase activity in SSF. A one-factor-at-a-time experiment was performed, and the variables moisture, pH, and fermentation period affected enzyme production. A central composite design was used to optimize pectinase production in SSF via three prominent variables (moisture content, pH, and fermentation period). The experimental result was statistically significant (p<0.01), and twofold enzyme production was achieved. The crude pectinase was extracted from the fermented medium and used as a clarifying agent. The pectinase-treated orange juice presented a decreased turbidity compared to the untreated control. The amount of total sugar and total suspended solids was reduced, whereas the total pH increased. Therefore, the A. flavus strain can be utilized for large-scale production of pectinase, which could meet the growing industry demands.