Resumen
In this study, different concentrations of the inducer (pectin) and the carbon source (glucose) were evaluated as components of the culture medium for the production of pectinases by Aspergillus niger. Furthermore, it evaluated the stability of the enzymes produced with respect to the temperature and the enzyme extract produced was tested for the clarification of strawberry juice. The highest pectinolytic activity (68 U/g) was obtained at a concentration of 6% (w/w) of pectin in the absence of glucose in the medium. Pectinases activity has shown high stability at 20 °C and 30 °C while a gradual decrease of activity was observed when the temperature rose. A reduction of about 50% of the total pectinases activity was measured at 50 °C after 60 min of exposure. The experimental enzymatic extract was compared with a high-quality commercial product for the clarification of strawberry juice. Similar data were obtained for turbidity and viscosity reduction. The enzymatic treatment led to a reduction of about 60% in the turbidity and 40% in the viscosity of the juice. After the enzymatic treatment, the total phenolic compounds, total anthocyanins, and antioxidant activity were preserved. The results obtained in the present work indicate the potential of the enzymes produced for using in fruit processing.