| Present status of the major strong-gluten wheat quality in China was analyzed based on the wheat quality testing results of 2003-2005 by the Cereal Quality Supervision and Testing Center (CQSTC), the Ministry of Agriculture. On the basis of the analysis, three experiments, i.e. effect of the Bulher experimental mills on wheat flour quality, characteristics of wheat flour from different milling streams and effect of blending flour on improvement of bread-baking quality, were carried out. 1) In the Bulher mills' experiment, three different kinds of wheat were milled with 5 Bulher experimental mills that were selected from 5 different laboratories. The purpose of this experiment was to study the influence of Buhler mills on wheat flour quality and to provide information of for calibration of wheat milling procedure. 2) In the different milling streams' experiment, 6 Chinese strong-gluten wheat cultivars were milled with the Bulher mill of CQSTC ant the flour at different streams were collected to study the difference and varying regulation in flour quality characteristics of different milling streams and blending flours which were mixed by different milling streams. 3) In the experiment of blending flour on improvement of bread-baking quality, eight wheat cultivars were selected for flour blending in pairs. There were sixteen flour-blended combinations in total. Mixed flours were formed in the proportion of four in each combination. Protein quality, dough rheological properties and bread-baking quality were analyzed in order to study the change of quality characters of flour mixed by different wheat cultivars.1. In all tested samples, there were respectively 98, 155 and 152 ones which their stabilities amounted to 7min in 2003, 2004 and 2005.The average of their loaf volume were respectively 753cm~3, 753cm~3 and 766cm~3. According to National Standard, there were 7, 24 and 39 cultivars in 2003, 2004 and 2005 reaching strong gluten wheat (GCP≥14%, St≥7min, TW≥770g/l, LS≥80). The coefficient of variation of stability and developing time (55.94% and 51.18%) were higher in all traits, while the CV of test weight, flour yield and water absorption (2.57%, 3.30% and 4,69%) were lower. The three years' average of energy of area, extensibility, maximum resistance and loaf volume of strong gluten wheat in China were 106.4cm~2, 156.7mm, 485.7BU and 754.4 cm~3.Close relations with loaf volume in turn were protein content ( r=0.587, p<0.01) , wet gluten (r=0.496, p<0.01) , extensibility (r=0.477, p<0.01), energy of area (r=0.333, p<0.01), sedimentation value (r=0.300, p<0.01), developing time (r=0.277,p<0.01)and stability (r=0.184,p<0.01).2. Wheat flour quality was significantly affected by different mills. With regard to flour yield, ash content, damaged starch, water absorption and extensibility, there were significantly difference (p<0.05) in three kinds of wheat flour among different mills; With regard to flour crude protein and wet gluten content, there were no appreciable difference in three kinds of wheat flour among different mills; With regard to stability, energy of area, and maximum resistance, there were remarkably difference (p<0.05) in Shiluan 02-1 and Xinmai 18 flour among different mills, while there were no appreciable difference in Zhengmai 004 flour among different mills.3. Both cultivar and milling stream played an important role in improving wheat flour quality. Based on the analysis of variance, there were appreciable difference (p<0.01) in physical and chemical characteristics, dough rheological properties and bread-baking quality among milling streams, while most of the wheat flour quality were also significant difference (p<0.01 or p<0.05) among cultivars. Percentage of the mutation sum square of milling streams shared higher ratio of the total SS for all quality attributes.Flour quality traits of different milling streams differed significantly (p<0.05) and varied regularly among wheat cultivars. The protein content, wet-gluten content, stability, energy of area, extensibility, maximum resistance and bread-baking quality in break streams were superior to those in reduction streams. Compared with straight-run flour, the bread-baking quality of flour which is mixed with 1 st reduction stream and 1st, 2nd, and 3rd break streams was the best.4. Both combination and proportion of blending flour had significant effects on improving quality. Based on the analysis of variance, all of the quality traits were significantly (p<0.01) affected by blending combination. Most of the wheat flour quality traits except maximum resistance were also significantly (p<0.01 or p<0.05) affected by blending proportion. The improving effects among flour blending proportion were irregular. Percentage of the mutation sum square of combination share the higher ratio of the total SS for all quality attributes.Protein quality, dough rheological properties and bread-baking quality of blending flour from different wheat cultivars all changed. But there were no great changes in physical and chemical characteristics of blending flour, while there were significant change in dough properties and bread-baking quality.
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