Preparation Of Brown Rice Flour By Low Temperature Impact Mill And Its Application In Gluten-free Bread

About 1%of the world's population is allergic to gluten.At present,the only effective and safe treatment for patients with celiac disease is to follow a strict gluten-free diet for life,which leads to the timely recovery of the small intestinal mucosa.Bread is one of the staple foods of people,gluten-free bread prepared with brown rice flour is expected to make up for the nutritional imbalance of gluten-free bread because brown rice is rich in nutrients.However,brown rice products usually have a rough taste and poor palatability due to their high fiber content.Milling is one of the effective ways to improve the palatability of brown rice products.Therefore,the nutritional components and physicochemical properties of brown rice flour ground by low temperature impact mill(LTIM)was studied,and brown rice flour was applied the production of gluten-free bread.The results were as followed:1.In order to compare the effect of low temperature impact milling on the nutritional components and physicochemical properties of brown rice flours with the other two traditional milling methods(wet colloid milling and dry high-speed universal grinding),brown rice flours with the similar average particle size(D_4,3?57?m)were prepared.It was found that LTIM produced a fine flour with unimodal particle size distribution,and well retained non-starch nutrients.Especially,the phenolic content of flour prepared by LTIM was two times higher than that prepared by colloid mill.LTIM also led to less damaged starch content than high-speed universal grinder.The damaged starch content related well with the thermal and gel hydration properties.Interesting,comparing the particle size distribution before and after enzymolysis,it was found that LTIM could pulverize dietary fiber of brown rice efficiently.2.In order to investigate the quality of gluten-free bread made of brown rice flour prepared by low temperature impact mill,brown rice flour with average particle diameters of 418.67?m,269.33?m,113.67?m,65.67?m and 31.87?m were prepared.It was found that as the particle size of brown rice flour decreased,the starch structure was destroyed,the damaged starch content increased from 3.11%to 15.07%,and the relative starch crystallinity decreased from 29.97%to 21.94%.The interaction between the starch and water in the model dough and the matrix structures among the endosperm masses were enhanced as the particle size decreased,making the gluten-free dough more viscoelastic.However,dough made with finer flour was too sticky,which limited the expansion of dough.Gluten-free bread prepared with medium-sized(113.67?m)brown rice flour had favorable quality characterized by large specific volume(1.94cm³/m L),low hardness(11.59 N),numerous and homogeneous gas cells.