Wheat Quality Evaluation Of Shaanxi Guanzhong And Control Of Its Flour Products Color

253 wheat samples were taken as materials to investigate the wheat quality of Guanzhong area in recent years,and improve its color of flour products. The differences between different years and areas were analysised comprehensively. According to multivariate statistical analysis, the wheat quality evaluation indexes were divedied into 7 factors, and wheat samples were divedied into 3 categories. Took the main wheat cultivars in this area as subjects, the factors which have effect on the color of flour products were studied. And the control of flour products color were did. The results are as follows:(1)The main cultivar of Guanzhong area is Xiaoyan22, accout for 65.22% of the total samples. Next came Xinong series which contains Xinong979, Xinong88, Xinong889, accout for 20.55% of the total samples. Kernel quality and milling quality of the wheat from the year of 2008 and 2010 were better. The protein quality of Guanzhong area is good and stable. The processing quality of the wheat of Guanzhong area was gradually decreased year by year. The wheat kernel quality, milling quality, protein quality and farinograph parameters and extensograph parameters of Weinan region were better. The wheat kernel quality and milling quality of Xianyang region were worse, but the farinograph parameters and extensograph parameters were good. The wheat kernel quality, milling quality of Baoji region were good, but the protein quality, farinograph parameters and extensograph parameters were worse relatively. Conclusively, the main cultivars of Guanzhong area were medium-gluten wheat, lack of high-gluten and weak-gluten wheat, the quality is stable.(2)25 indexes of wheat quality properties can be compressed into seven common factors, namely protein quality factor, starch gelatinization factor, milling quanlity factor, protein content factor, flour processing accuracy factor,α- amylase activity factor and flour color-water absorption factor. The main indexes of wheat quality were selected by correlation structure analysis of the seven common factors, that are flour protein content, flour a* value, flour b* value, wet gluten content, sedimentation value, peak viscosity, setback, softening degree, valorimeter value, resistance, max resistance and energy. According to cluster analysis 253 wheat samples were divided into 3 categories. The characteristic of the wheat of first category was high protein content, poor flour color and poor farinograph parameters and extensograph parameters. The cultivars of the second category were Xinong series and Mianyang series. The characteristic of this category was low protein content and wet gluten content, good flour color and good processing quality. In the third category, the samples came from 2008 and 2009, most of them were Xiaoyan22, the quality was common.(3)There was significant difference between Xiaoyan22 and Xinong979 of the color indexes. The protein content and carotenoid content of Xiaoyan22 flour were higher, and the damaged starch content and PPO activity of Xinong979 flour were higher. The flour and its raw dough sheet color of Xinong979 flour was better than Xiaoyan22, but the cooked dough sheet of Xiaoyan22 was better than Xinong979. The color difference of raw dough sheet made from Xinong979 during storage is significantly higher than Xiaoyan 22. The protein content and the color of the flour were the main influence factors for flour product color, the a* value of flour products and the color difference of raw dough sheet during storage were affected by PPO activity.(4)Vitamin C, citric acid, phytic acid, L-cysteine and glutathione could improve the color of flour product. Took the L* value, a* value, b* value of dough sheet which storaged for 24 hours as indexes, the addition of the color regulator was Vitamin C 0.2%, citric acid 0.6%, phytic acid 1.0%, L-cysteine 0.4% .(5)The color regulator has significant effect on noodle and steamed bread, the L* value was increased, the a* value, b* value were decreased. But the color regulator has adverse effect on dough quality and taste quality of noodle and steamed bread. The effects on noodle shown as reducing the thickness of noodle, shorting cooking time, the ratio of broken noodle and the cooking loss were decreased. The hardness and adhesiveness were increased, the was no significant difference change of springness, cohesiveness and chewiness. But gumminess, breaking force and firmness were decreased. The effects on steamed bread shown as slightly lower specific volume, hardness, adhesiveness and gumminess were increased obviously.