Study On Factors Influcing Wheat Flour And Dough Sheet

222wheat samples collected from Henan, Shandong, Jiangsu, Shaanxi, Ningxia, Xinjiang,Inner Mongolia were milled into flour samples. Made dough sheet with there wheat floursamples and measured quality indexes of wheat and dough sheet. Relationships between colorand other indexes of wheat flour and dough sheet were analyzed. polyphenol oxidase activityin wheat flour was measured under different action conditions to fix method of measuringpolyphenol oxidase in wheat flour. The relationships between polyphenol oxidase andother indexes of wheat flour were analyzed（1） Wheat flour color of ten provinces: wheat flour L*of Hebei province was higher thanother provinces and Sichuan province lower than other areas; wheat flour a*of Henan andXinjiang was higher than other areas; wheat flour b*of Sichuan province was lower. L*and a*of dough sheet escalatedand droped separately with the storage time longer; b*of dough sheetescalates with time when the storage time was between0h and2h, but droped with time whenthe storage time was longer.（2） There was significant correlation relationship between color of wheat flour and doughsheet and wheat volume weight, wheat hardness index, wheat flour moisture content,polyphenol oxidase activity, ash content, flour extraction, crude protein, crude starch, brokenstarch, wet gluten content, falling number.（3） There was significant correlation relationship between the dough sheet color changein storage time and broken starch, flour extraction, ash content and polyphenol oxidase activityof wheat flour.（4） Dough sheet L*was in significant or very significant correlation with extensographarea, resistance at constant extension, maximum resistance and extension ratio of wheat flour,as dough sheet b*was in significant or very significant negative correlation with theseindexes.（5） Dough sheet malleability and toughness was in significant correlation with color ofwheat flour and dough sheet and color variation; color of wheat flour and dough sheet hadimportant effect on sensory evaluation.（6） Polyphenol oxidase activity of222wheat flour samples was between4and15min^-1g^-1, and polyphenol oxidase of wheat flour samples of Shanxi was higher, whileNingxia’s was lower. Polypeheol oxidase was in very significant correlation with flourextraction,soften of dough and crude protein, and was in very significant negative correlation with gluten index, sedimentation value, stable time, extensograph area, resistance at constantextension, maximum resistance and extension ratio. It was conjecture that polyphenol oxidasewas in negative correlation with gluten strength, but need to prove by more research.