The Studies On Preparation Of Germinated Cowpea Flour And Application In The Steamed Bread

Germination has been regarded as an effective technology for enriching the functionfactor-aminobutyric acid. The process optimization of germinated cowpea to enrichment of-aminobutyric acid and different drying methods on the content of-aminobutyric acidwere studied by the Response Surface Method;Meanwhile the flour quality and steamed breadcharacter were used to study the effect of adding the germinated cowpea flour(the bestgermination condition)-at eight different additive levels to wheat flour.In addition, theinfluence of different enzyme preparation on the steamed bread character of composite flouradding germinated cowpea flour of10%.The main research results of the paper are as follows:1. The optimal process conditions of enrichment of-aminobutyric acid were:the pH ofsoaking solution at3.89,soaking time at25h,germination time at25h,germination temperatureat31℃,the content of-aminobutyric acid could achieve as high as115.79mg/100g;Theinfluence order of the four factors to the content of-aminobutyric acid was: pH of soakingsolution> germination time>soaking time>germination temperature.2. The optimal process conditions of hot air drying was: temperature at45℃and time at8h; The optimal process conditions of vacuum drying was: temperature at40℃and time at6h; The optimal process conditions of combination of hot-air and microwave dryingwas:microwave power at350W,time at6min and hot-air temperature at45℃,hot-air time at3h;The impaction to the content of-aminobutyric acid was minimum and the shortest timewas needed,when the combination of hot-air and microwave drying was selected.3. The ash and gluten index of composite flour had grown with increased the additiveamount of germinated cowpea flour,while falling number,wet gluten content,sedimentationvalue and whiteness had declined differently;The results of farinograph properties studieswere showed that the flour added with cowpea flour resulted in higher values for waterabsorption,while increased the dough stable time and decreased tensile energy gradually;Theresults of gelatinization characteristics showed:peak viscosity,final viscosity and lowestviscosity declined at varying degrees on the whole.4. The H value and the color L of steamed bread showed a trend of increasing beforereducing with increased the additive amount of germinated cowpea flour,while a increasedand b had not changed significantly,H value was highest than others when the amount was 2%;They had no negative impacts on the steamed bread,when the amount below2%. Theresults of TPA showed the hardness and cohesive were icreased by the addition of thegerminated cowpea flour.And the correlation analysis indicated that there were significantcorrelation between the bacic physical and chemical index,water absorption,tensileenergy,extension and gelatinization characteristics and steamed bread quality.5. The optimal adding scheme of three kinds of enzymes was:xylanase10ppm,glucolase7ppm,lipase5ppm; The influence order of the three enzymes to the sensoryevaluation of steamed bread was: xylanase> glucolase> lipase;The sensory evalution ofsteamed bread was effected significantly by xylanase,not glucolase and lipase.