X-Ray and FT-IR Research on Staling Characteristics of Potato Cake

Abstract:

The staling characteristics of potato cake during storage（1，24，72，120，168 h） were studied by X-ray diffraction and Fourier transform infrared spectroscopy，additionally，with Texture Analyzer and Color Difference Meter，effects of staling on cake quality（texture and color ） were studied. The results manifested that through the X-ray of the potato cake，after 1 h of storage，peaks at around 2θ of 12.5° and 20° arised，namely the amorphous peak of cereal starch and V-type structure which was the helical complex formed by amylose and fatty acids，after 120 h of storage，peaks at around 2θ of 17° showed up which was caused by B-type structure formed by amylopectin starch. The fourier transform infrared spectroscopy of cake samples showed major peaks at around 925，995，1 025，1 047，1 079，1 155 and 1 243 cm^{-1，the IR absorbance bands at 1 025 and 1 047 cm-1 was the amorphous starch and crystalline starch respectively，the band intensity ratio at 1047 and 1 025 cm-1 illustrated the order degree of starch，the higher the ratio was，the higher the order degree was. Potato cake had lower X-ray diffraction and IR absorbance bands intensity as well as（1 047/1 025） cm-1 ratio than ordinary cake during storage，suggesting that its staling rate was lower than that of ordinary cake. Aging will lead to cake hardness，chewiness，gumminess， a* and b* values increased，cohesiveness and L* values decreased，making the cake lack of lustre，taste rough with the deterioration of flavor.}