Study On The Rheological Properties Of Grain Bread Lfour And The Bread Process Optimization

With the deep knowledge of health functions the grains, coarse grains food hasbecome increasingly popular with people. However, the traditional coarse grain always beused as the single grain material, which don’t contain gluten and have a poor digestion andabsorption, as a result, they affect the body’s absorption of proteins, salts and some traceelements. Therefore, it’s a priority to carry out the deep processing of food grains. In thispaper, the rheological properties of the grains powder were studied, necessary improverwere optimized and the grain bread process were investigated, in order to make thenutritional grain bread for the modern people.In consideration of cereal nutritional complementarities and preparation technology,the oat flour, buckwheat flour, corn flour, glutinous rice flour and sweet potatostarch were chosen as materials for the production of grain bread powder. Based onthe nutrition analysis and China food composition tables, the grain bread powderformulation was designed with the linear programming by the Excel program. The formulaof the grain bread powder was the oat flour15%, buckwheat flour5%, corn flour5%,glutinous rice flour5%, sweet potato starch4%, and bread powder66%. The siltycharacteristic of the above grain bread powder was that water absorption of58.4%, theform time3.9min, the stable time4.7min, and the silty index56.Based on the single factor experiment, the wheat gluten, sodium stearoyl lactylate(SSL), xanthan gum and guar gum were determined as the grain bread flour qualityimprover. By response surface analysis, with the composite score for the response values,the improver formulation was that wheat gluten3.77%, SSL0.35%, xanthan gum1.08%and guar gum0.35%. The stable time of the group that added the compositeimprovers rosed to14.2min, silty index rosed to192, the composite score rosedfrom0.32to0.8.Its theological properties had a large degree of improvement.Based on the single-factor experiment, the amount of sugar, salt and yeast was chosento do orthogonal optimization experiments. The best grain bread recipe aboutaccessories were that the amount of sugar20%, salt1.2%and yeast2.4%.On thebasis of single-factor test, the mixing time, fermentation time and baking time were chosento do orthogonal optimization experiments. The best grain bread process parameters were that mixing time for25min, two time fermentation for3.5h and baking timefor20min. The hardness and elasticity of this bread was5998.06g and0.89. In addition,the bread had a soft texture, smooth mouth feel and light flavour of coarse grains.The hardness of the product increased, the elasticity reduced as the storage timeincreases. And its shelf life was longer than the ordinary bread. The pH and acidity of thebread showed consistency during about15days at the room temperature at the sealedcondition. The comparison of the scanning electron micrographs of the bread productsobtained in laboratory and commercially available showed that the grain bread produced bylaboratory was continuous and uniform but the surface was rough and unsmooth. Thecommercially ordinary bread was fine, but their stomata was smaller than grain bread. Themicroscopic structure was basically the same in laboratory derived and the commerciallyavailable.