Comparison of Wet Grinding Methods for Extraction of Sweet Potato Starch

The selection of an appropriate isolation method is crucial for scalable and cost-effective production of high-quality sweet potato starch, and this study presents a direct comparative evaluation to inform that choice. The study systematically evaluated the influence of four wet grinding methods, namely, distilled water (DW), sodium bisulfite (CM), centrifugation (CF), and sour-liquid (SL) processing on sweet potato starch yield, purity, and physicochemical properties. Starch yield ranged from 7.56% (CF) to 13.08% (DW), while purity varied from 66.55% (SL) to 89.33% (CM). The CM method, using sodium bisulfite, enhanced whiteness and purity by 19% compared to SL by effectively removing impurities, whereas the SL method, driven by microbial fermentation, resulted in increased protein (1.02%) and lipid (0.45%) retention, altering functionality. Amylose content varied from 15.46% (SL) to 27.80% (CM), influencing gelatinization temperature (61.3°C–72.6°C) and pasting properties. The CF method provided a balance between yield and purity, making it suitable for small-scale starch production. Microbial interactions in SL facilitated higher swelling power and solubility, enhancing its industrial applicability in biodegradable films and specialty starches. The findings underscore the importance of selecting appropriate extraction methods to optimize starch quality and functionality, contributing to more sustainable and efficient starch processing.