Evaluation of Residual Starch Determination Methods for Dried Distillers' Grains with Solubles (DDGS).

摘要

A co-product of ethanol production is known as dried distillers’ grains with solubles (DDGS). DDGS contains residual starch that escaped hydrolysis under ideal conditions during ethanol production; therefore, residual starch in DDGS is expected to include enzyme-resistant starch. Common starch analysis methods involve enzymatic or chemical hydrolysis, but these methods may be unable to access resistant starch leading to an underestimation of the residual starch in DDGS. This study used several enzymatic starch analysis methods, with or without chemical pre-treatment, in an attempt to find an appropriate methodology for the measurement of residual starch in DDGS. Alternatively, an acid hydrolysis method that is commonly used by industry was also attempted for comparison. It was determined that the addition of a chemical solubilization step prior to enzymatic hydrolysis was necessary to access resistant starch present in DDGS samples. Chemical hydrolysis using dilute acid vastly overestimated the amount of residual starch in DDGS.