Parametric optimization of sweet potato‑based glucose syrup production and preservation: a response surface methodology approach

Abstract

Sweet potato is one of the largest sources of starch. Due to this fact, it can be utilized to obtain value-added products. This research aims at optimizing the operation parameters for sweet potato-based glucose syrup production and preservation. A maximum yield of starch isolated using distilled water was found to be 31.59%. The produced starch was then subjected to acidic hydrolysis to obtain glucose syrup with a dilute sulfuric acid concentration of (0.5, 1, and 1.5%) at temperatures (130, 140, and 150 °C) and time (25, 30, and 35 min). The total reducing sugar content of the hydrolysates was determined using the dinitro salicylic acid method and an optimum reducing sugar amounting to 242.3 g/L was found at 1.34% sulfuric acid concentration, 140.89 °C temperature, and 32.96 min. The moisture, dry matter, ash, density, viscosity, and pH of the product were found to be 26%, 74%, 0.26%, 1.37 g/mL, 5.63, and 4.9, respectively. Since glucose syrup has a short shelf-life during storage, potassium sorbate having concentrations of 0, 0.025, 0.05, 0.075, and 0.1% were studied for 60 days to sustain the shelf-life of glucose syrup. Potassium sorbate concentration 0.05% which is within the permitted level was identifed as a suitable preservative to retain the quality and extend the shelf-life of glucose syrup at room temperature