Obtaining Cornstarch Lactilado and Evaluation of Functional Properties of Modified Starches

The objective was to develop a new corn starch esterification technique using lactic acid, commonly found in nature, analyzing the change in its functional properties. For esterification and production of lactated starch (LA), a concentration of 2.5% w/w lactic acid was used at a temperature of 150ºC with a time interval of 0.5 to 7 hours of treatment. To evaluate and certify the effective chemical modification after treatment, analyzes were performed to quantify the percentage of lactyl formation in all samples during the heating times, degree of dextrinization, solubility, amylose, intrinsic viscosity, apparent viscosity and mass clarity.
Through the results of the physicochemical analysis it can be observed that the treatment was effective by the high percentage of lactile formation 0.94% to 3.85%. With increasing treatment time, an increase in equivalent dextrose (ED) ranged from 0.38% to 1.88%, solubility increased from 2.26% to 34.21%, and transmittance was another index that increased compared to native starch, from 1.8% reading with the lowest transmittance index to 82.1%. In the transmittance analysis it was observed that with 3 hours it is possible to produce esterified starch with resistance to retrogradation under cold storage condition, and in the analysis of the percentage of amylose reinforced the idea that the treatment was effective, as it resulted in a significant decrease of 22.36% in acidified starch without heat treatment to 12.58% in starch with 7 hours of heat treatment. Intrinsic viscosity dropped from 1.09% to 0.07%. Indicating high breakage of glycosidic bonds, the apparent viscosity also dropped in the three reading cycles, and in the native and acidified and dry starches, it was not possible to determine the viscosity degree because it was outside the maximum viscosity limit of the apparatus.