Study On The Correlations Between Protein And Starch Compositions And Eating Quality In Rice

This paper studied the correlations between eating quality and starch and protein contents with 21 group rice as materials, which harvested from Tianjin, Heilongjiang province and Hainan province, through conventional chemical analysis and sensory evaluation. The results showed that the sensory score of cooked rice grown in north China ranged from 66.6 to 82.11, while that of cooked rice grown in Hainan area from 64.23 to 79.99. There is a significant difference of taste quality between them(P<0.05). Chemical analysis showed that rice grown in Hainan region had higher protein content than that grown in north China (P<0.01). The protein contents of rice grown in north China were 6.23% to 8.99%, while those of rice grown in Hainan province were 6.78% to 11.19%, suggesting that for the same varieties of rice, high temperature is conducive to protein accumulation. Rice grown in north China had higher amysole content than the rice grown in Hainan region(P<0.01). The amylose contents in rice were 15.39% to 20.23% in north China and 14.68% to 19.34% in Hainan. Both protein content and amylose content presented a significant negative correlation with sensory score, higher protein and amylase contents mean poorer eating quality. However, the rice of R42 variety grown in Hainan had a better eating quality and higher protein content than that in north China. After milling, the loss of the protein was the least, and after germination, γ-aminobutyric acid content was the highest, which was 75.17 mg/100g. It can be seen that this kind of rice is a high-quality varieties and worthy of development.It was shown from the experiment of viscosity determine of rice using Rapid Visco Analyser (RVA) that there was negative correlation between the sensory evaluation value and the eigenstate of viscosity and significantly negative correlation between sensory evaluation value and hot paste viscosity. Highlighted on the solubility, albumin, globulin, gliadin and glutenin of rice were extracted and assayed. Glutenin content of rice grown in north China was higher than that grown in Hainan. A negative correlation was found between sensory evaluation value and the four protein, especially a significantly negative correlation was found between sensory evaluation value and the gliadin. It can be found from the path analysis that the smell of rice and amylose content had the greatest direct impact on the eating quality of rice in different regions.Observed by Scanning Electron Microscope (SEM), there were no obvious differences for the size, shape and arrangement of endosperm cell of the rice grown in different regions. The gelatinization of starch of the rice with good eating quality was good after cooking, with the endosperm cell structure completely invisible. γ-aminobutyric acid in rice germ was determined by the HPLC method with automatic pre-column derivation and UV detection and the result showed that γ-aminobutyric acid of the rice grown in Hainan was higher than that in the North.