Abstract

Effects of Chitosan on retrogradation properties of wheat starch

Author(s): Li Xing-Ke, Liu Fang-Li, Wei Song-Li, Zhang Hua

Starch retrogradation could increase foodÂ’s hardness and reduce foodÂ’s digestion rate, which had bad influence on the food quality. Chitosan is the only natural cationic polysaccharide which could inhibit starch retrogradation. The effects of chitosan on retrogradation properties of wheat starch were studied and the possible influence mechanism of chitosan on wheat starch was investigated by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) in the paper. Results showed that iodine blue value increased while gel strength of wheat starch decreased with increasing chitosan content. Meanwhile the gelatinization temperature, retrogradation enthalpy and retrogradation rate of wheat starch reduced slightly from 62.71 to 55.85℃, 4.68J/g to 2.41J/g and 54.47% to 19.87% respectively. Distinctive differences between wheat starch gels without or with chitosan were observed. Furthermore the intensity of a peak close to 16.9° of wheat starch samples with chitosan were decreased and narrowed compared with the native starch, indicating the disappearance of the typical B-pattern, which implied that chitosan could retard the recrystallization or the retrogradation behavior of gelatinized starch. After blended with chitosan, the stretching vibration peak of hydroxyl of wheat starch shifted from 3427.78 to 3419.65, which indicated more hydrogen bonds formed between chitosan and wheat starch