Response Surface Methodological Approach for Scaling Up an Enzymatic Production of Sweet Potato Starch Syrup

Abstract

Sweet potato starch syrup can be utilized for various purposes in the food industry as a value-added product. Optimizing the glucose syrup production process and establishing a continuous sweet potato starch syrup production setup are essential steps toward making the process commercially viable. Notably, NASA has considered sweet potato syrup as a potential space food due to its nutritional richness and stability, highlighting its suitability to support astronaut performance in space environments. In this study, the effects of time, enzyme quantity, and temperature on degrees Brix and color properties of syrup were investigated. A central composite design was applied, generating a total of 27 experiments for the saccharification step. A significant quadratic model (p < 0.05) was obtained, predicting a maximum degrees Brix of 8.7 after saccharification and 68.8 after evaporation and an L∗ value of 58.1 under optimal conditions: a temperature of 61.4°C, a time of 5.3 h, and enzyme quantities of 226 and 321 μL for glucoamylase and pullulanase, respectively. These optimized saccharification conditions were validated, achieving an actual L∗ value of 69.39, degrees Brix of 7.3 after saccharification, and 64.3 after evaporation. This means that the saccharification time was reduced tremendously. When applied to a continuous scale-up production setup, the optimized conditions yielded an L∗ value of 67.54 and degrees Brix of 7.5 after saccharification and 64.9 after concentration. The study demonstrates that the developed process and models can be effectively applied to a continuous setup, indicating the feasibility of large-scale production. Overall, the production process of sweet potato starch syrup was improved significantly, with production time reduced substantially, supporting its potential as both an industrial and space-suited food source.