Amylose: Acetylation, Optimization, and Characterization.

Amylose, as a polymeric carbohydrate, is a very attractive raw material owing to its performances. However, the acetylation of amylose separated from high amylose corn starch (HACS) will be beneficial to further improve its functional characteristics so that acetylated amylose (AA) is able to be well applied for some special situations. In this work, we chiefly discuss the optimization of acetylation conditions by a response surface methodology, property, and characterization of AA. The experimental results indicated that the acetylation of amylose was affected by some factors, such as reaction temperature, reaction time, amount of acetic anhydride, and pH. The blue value of amylose was changed by acetylation. Maltese crosses on the separated amylose particles disappeared owing to the separation. The crystalline structure of HACS was C-type, whereas the structure of AA was the immediate between B- and V-type. The acetylation lowered the onset temperature, peak temperature, and end temperature of amylose, but raised its melting enthalpy. PRACTICAL APPLICATION: Although inherent functional diversity of starch extracted from different biological sources adds to the range of applications, acetylated amylose, as an additive, will be better control the consistency and texture of some foods, enhance the strength of edible films, and improve the slow-release of drugs. It will also provide options for extending the scope of desired functional characteristics.