General application of Raman spectroscopy for the determination of level of acetylation in modified starches

A method using Raman spectroscopy was recently developed for the determinat ion of the degree of acetylation in modified wheat starch. In this article, we show that the method can be generalized to a wide range of starches of different botanical origin and amylose content. Calibration sets were used to develop regression equations for 11 types of acetylated starches, includ ing cereal (rice, maize, wheat) and noncereal (potato and sweetpotato) sour ces. The calibration lines were then used to predict the level of acetylati on of starch samples with unknown level of acetylation using their Raman sp ectra. In each case, R-2 > 0.98 for linear regression of Raman vs. titrimet ric determination of acetylation. The Raman-based calibration curves allow fast and nondestructive determination of the degree of acetylation for diff erent types of starches.