Process Optimization for Amylase-mediated Juice Extraction from Soursop (Annona muricata)

Abstract

This study aimed to optimize the enzyme-assisted extraction of juice from soursop (Annona muricata) using α-amylase to improve juice yield and quality. Soursop is rich in bioactive compounds and has significant market potential, but conventional extraction methods often result in limited yield and suboptimal quality. Enzymatic extraction was explored as a solution, using Response Surface Methodology with a Box-Behnken Design to optimize three processing variables: α-amylase concentration (0–1.25%), incubation temperature (40–60 °C), and incubation time (30–240 minutes). Samples with 1:1 (w/w) pulp-to-water ratio were subjected to the different combinations of processing variables. A reduced quadratic model (R² = 0.99) significantly explained the variations in juice yield. The optimized conditions, with the use of 0.41% α-amylase incubated at 51.99 °C for 63.53 minutes, resulted in a maximum yield of 80.04%. Despite enzymatic and thermal treatment, antioxidant activity (DPPH, FRAP, ABTS) was effectively retained, and total phenolic content increased significantly. HPLC analysis confirmed elevated levels of individual phenolic compounds and detected resveratrol (0.27 mg/100 mL) in the optimized juice. The optimized extract also exhibited higher total soluble solids, increased titratable acidity, and noticeable color changes. These findings demonstrate the effectiveness of α-amylase treatment in enhancing juice extractability and bioactive compound retention, offering promising implications for functional beverage development.