Effect Of Flour Yield Accumulated Via Ash Content On Quality Of Wheat Flour

The quality of wheat flour is related to the development of national economy and human nutrition,health and safety.To solve the problems of overprocessing of wheat flour,serious loss of nutrients and poor adaptability during food processing,in this study,the flow rates of179 flour streams on the flour milling production line were measured and their ash contents were analyzed.Based on the ash content,wheat flour with different cumulative yield was prepared.The effect of cumulative flour yield of wheat flour(CFYWF)including the physicochemical,nutritional properties and safety of wheat flour,the rheological properties of dough,and the eating quality of steamed bread,fresh wet and dry noodles were investigated,which could provide a theoretical reference for the production of wheat flour with ideal processing,edible and nutritional quality.The main results were as follows:(1)With the increase of CFYWF,the change trend of damaged starch and moisture content of wheat flour was not obvious.And whiteness,L*value,b*value and setback showed a downward trend.With the increase of CFYWF,ash,fat,protein and bran star contents showed an upward trend,while peak viscosity tensile area,extension,dough fermentation height and air holding capacity showed a downward trend.Generally speaking,When the CFYWF was in the range of 55.1%-70.0%,the difference in the rheological properties of the dough were slight.When the CFYWF was in the range of 55.1%-76.4%,the physicochemical properties and dough rheological properties of wheat flour were better.When the CFYWF was over 77.9%,the physicochemical,mixing,stretching and fermentation rheological properties of wheat flour decreased significantly.(2)With the increase of CFYWF,the contents of phosphorus,potassium,magnesium,iron,copper,zinc,manganese,molybdenum,VB₁,VB₆,folic acid,dietary fiber,alkyl resorcinol and total amino acid,energy value,protein NRV(Nutrient Reference Value)and fat NRV showed an overall upward trend.And the loss rates of minerals,vitamins,dietary fiber and alkyl resorcinol gradually decreased.When the CFYWF was less than 75.0%,alkyl resorcinol,phosphorus,VB₂ and biotin were not detected,and the loss rates were relatively high.When the CFYWF was higher than 75.0%,the loss rates of minerals,vitamins,dietary fiber and alkyl resorcinol were decreased significantly.(3)When the increase of CFYWF,the contents of phytic acid,fatty acid,microorganism and polyphenol oxidase activity in wheat flour increased.When the CFYWF was higher than77.9%,the contents of phytic acid,fatty acid value,polyphenol oxidase activity and the total plate counts increased significantly,and the contents of heavy metals(arsenic and cadmium)also showed an increasing trend,but the increasing range was small.When the CFYWF was in the range of 55.1%-82.0%,the total plate counts in wheat flour were lower than the microbial standard limit of low bacteria wheat flour.Within this range,lead,chromium and mercury were not detected in wheat flour,and the pollutions levels of lead,cadmium,chromium,mercury and arsenic were far lower than the national limit,and the qualified rate was 100%.(4)When the CFYWF was in the range of 55.1%-70.0%,the eating quality of steamed bread,the specific volume and hardness of steamed bread changed slightly.With the CFYWF continued to increase,the specific volume of steamed bread decreased and the hardness increased significantly.When the CFYWF was in the range of 55.1%-76.4%,the sensory scores of steamed bread were higher and the overall quality was desirable.The higher the flour yield,the darker the color of fresh wet and dried noodles,which would affect the acceptability of consumers.In general,when the CFYWF was in the range of 55.1%-77.9%,the texture and tensile properties of fresh wet and dried noodles were better.With the increase of CFYWF,the sensory scores of fresh wet and dried noodles showed a significant downward trend.When the CFYWF was in the range of 55.1%-77.9%,the sensory scores were higher than 75,and the overall score of dried noodles was higher than fresh wet noodles,and its brightness was also higher.In general,the effect of flour yield on cooking quality of fresh wet noodles was more significant than dried noodles.There were significant differences in physicochemical,nutritional properties,safety of wheat flour with different CFYWF,as well as the eating quality of steamed bread,fresh wet and dried noodles.When the CFYWF was in the range of 55.1%-70.0%,there was no significant difference between the rheological properties of dough,but the contents of nutrition in wheat flour were lower,compared to whole wheat meal.When the CFYWF was in the range of 55.1%-76.4%,the quality of steamed bread was desirable.When the CFYWF was in the range of 55.1%-77.9%,the sensory scores of fresh wet and dried noodles were higher than 75.When the CFYWF was higher than 75.0%,the loss rates of nutrients in wheat flour decreased significantly.When the CFYWF was higher than 77.9%,the contents of nutrients in wheat flour were higher and the loss rates were lower,but the physicochemical properties were much worse,and the contents of risk factor increased significantly.When the CFYWF was too high,it would have adverse effects on the physicochemical properties and safety of wheat flour,as well as the eating quality of steamed bread,fresh wet and dried noodles,which was not conducive to the storage of wheat flour and the processing of flour products.However,when the CFYWF was low,the color of flour was white,but the nutrient loss rates were larger.Therefore,the proper processing precision should be maintained in the production practice.The CFYWF in the range of 75.0%-76.4%should be used to make steamed bread,and the CFYWF in the range of 75.0%-77.9%should be used to make fresh wet dried noodles,which could ensure the effective retention of nutrient components in the wheat and promote the full utilization of wheat resources.