Morphological Features and Physicochemical Properties of Starches from Six Wheat Varieties in Yuncheng, Shanxi Province

This study aimed to elucidate the differences and advantages among starches from various wheat varieties, providing scientific evidence for the selection and application of these wheat varieties in the Yuncheng region of Shanxi Province. Six kinds of specialty wheat starches were used to analyze the morphological features and physicochemical properties by scanning electron microscopy, fourier transform infrared spectrometer, X-ray diffractometer, differential scanning calorimeter and rapid visco analyser. The microstructure of starches included amylose content, amylopectin content, morphology, particle size, crystallinity and short-range ordering. The physicochemical properties included transparency, swelling, freeze-thaw stability, pasting properties, thermal properties and gel texture characteristics. The correlation between different factors was analyzed using pearson correlation coefficient. The results showed that the six wheat starches consisted of A and B starch granules, which belonged to the typical A-type crystal structure, with relative crystallinity ranging from 11.63% to 20.41%. The content of amylose ranged from 0.56% to 26.24%. There were significant differences in the parameters of granule size, crystallinity, pasting characteristics, freeze-thaw stability and gel texture characteristics of different starches (P<0.05). The 'Yunhei 161' starch had the smallest particle size, the highest degree of short-chain ordering, enthalpy (ΔH), transparency, freeze-thaw stability and swelling. This starch was easy to paste but not easy to regenerate. In terms of gel textural properties, hardness, elasticity and chewiness of 'Jiemai 23' starch were significantly higher than the other groups (P<0.05). Correlation analysis showed that the content of amylose was positively correlated with solubility, pasting temperature and setback, which negatively correlated with crystallinity and enthalpy. Correlations were also found between relative crystallinity, pasting temperature, solubility and setback. In conclusion, the structure and physicochemical properties of starch were differentiated by wheat varieties. 'Yunhe 161' and 'Jiemai 23' were two high quality wheat starches, which could provide a reference for starch industrial application.