Optimisation of enzymatic treatment of avocado (Persea americana Mill) juice using response surface methodology (RSM)

Abstract

The high viscosity and pectin content of tropical fruits have been a persistent issue in the fruit juice industry. Enzymatic treatment using pectinolytic enzymes has emerged as an effective method to improve juice yield and enhance the functional attributes. This study aimed to optimise the enzymatic treatment of avocado pulp to improve juice yield, antioxidant activity, and total phenolic content (TPC). A second-order central composite design using Response Surface Methodology (RSM) was employed to evaluate the effects of varying enzyme concentrations (1.3 - 1.7 % v.w-1), incubation times (82 - 98 min), and avocado pulp-to-water ratios (1:2.16 - 1:3.8) at a constant temperature of 50°C. The models developed for all responses demonstrated a high coefficient of determination (R2>0.95), indicating good model reliability. Statistical analysis revealed significant (p<0.05) effects of all independent variables on the response. The optimal conditions for enzymatic treatment of avocado pulp were 1.45 % v.w-1 enzyme concentration, 94.01 min incubation time, and 1:3.5 avocado pulp-to-water ratio. Under these optimal conditions, the predicted values for juice yield, antioxidant activity, and TPC were 93.47 %, 84.38 %, and 53.79 mg GAE.mL-1, respectively. These findings support the effectiveness of pectinolytic enzymes to improve the physicochemical and functional properties of avocado juice.