Analytical evaluation of current starch methods used in the international sugar industry: Part I

• Only the USDA Starch Research method accurately solubilized corn starch.
• All of the starch methods quantified potato starch; ICUMSA GS1-17 was the best.
• Use of a potato starch standard curve over-estimated starch concentrations.
• Method sensitivity was affected by I2 reagents, wavelength, and starch standard.

Several analytical starch methods exist in the international sugar industry to mitigate starch-related processing challenges and assess the quality of traded end-products. These methods use iodometric chemistry, mostly potato starch standards, and utilize similar solubilization strategies, but had not been comprehensively compared. In this study, industrial starch methods were compared to the USDA Starch Research method using simulated raw sugars. Type of starch standard, solubilization approach, iodometric reagents, and wavelength detection affected total starch determination in simulated raw sugars. Simulated sugars containing potato starch were more accurately detected by the industrial methods, whereas those containing corn starch, a better model for sugarcane starch, were only accurately measured by the USDA Starch Research method. Use of a potato starch standard curve over-estimated starch concentrations. Among the variables studied, starch standard, solubilization approach, and wavelength detection affected the sensitivity, accuracy/precision, and limited the detection/quantification of the current industry starch methods the most.