Pectinases production using an exotic caatinga passion fruit waste and wheat bran as a substrate for clarification of grape juice

Abstract

Caatinga passion fruit waste (CPFW):Wheat bran has shown reliable performance for enzyme production. However, the mixture of wheat bran and CPFW may provide all nutrient sources needed by Aspergillus niger for pectinase generation. This work investigates the production of pectinolytic enzymes using a substrate composed of CPFW:Wheat bran using Aspergillus niger FSDE16 via semi-solid-state fermentation (SSSF). A blend of wheat bran:CPFW (1:1, g/g) with 60% moisture content was inoculated with 106 spores/mL for 144 h. Substrates were fermented using the 7 combinations of temperature (25–75 °C) and pH (3–6) dispose in an experimental design. Upon the completion of fermentation, all analyses were conducted including the enzymatic production, optimal activity, and enzymatic thermostability. Afterwards, grape juice clarification was conducted, and the clarified juice was evaluated considering viscosity reduction, yield increase, turbidity reduction, yield increase, colour, and phenolic profile. Results demonstrate that enzyme stability was achieved within the temperature range of 30–40 °C, with optimal activity recorded at 50 °C (42.7 U/g). The application of crude enzymatic extract in grape juice clarification led to an increase of yield (>280%), and a viscosity (>80%) and turbidity (>98%) reduction. The clarification treatment revealed a significant increase in the phenolic compounds evaluated, except epicatechin gallate, Pro-B2, and resveratrol, which reduced their concentrations. The clarification resulted in a colour intensity reduction. This study underscores the potential of using food waste for enzyme production, presenting a sustainable approach with implications for cost reduction and waste management in the food industry.