| Rice bran insoluble dietary fiber has rough texture, it can not be broken down by the body’s digestive enzymes which inherent in food ingredients, adding carboxymethyl group change ability of water affinity to avoid the rough texture and achieve the effect of fat substitutes. In thwas paper, first rice bran was become as raw material, insoluble dietary fiber was extracted from rice bran, secondly, it was modified by adding carboxymethyl group so that it can achieve the effect of fat substitute, and then to study its properties. Finally, it was applied to cookies which instead of part of fat.Firstly, insoluble dietary fiber was extracted by enzymatic and chemical methods from rice bran, and then to study its properties. Best condition of extracting technology was confirmed. Content, reaction temperature, reaction time of a-alpha amylase of reswastanting high temperature respectively was 250 U/g,70℃,90min. Content, reaction temperature, reaction time of NaOH respectively was 0.5%,70℃,60min. Content of insoluble dietary fiber of rice bran was 29.31%. The water holding capacity of insoluble dietary fiber of rice bran was 2.74g/g, oil holding capacity was 3.25g/g, and the swelling power was 4.10mL/g.Fat substitute of rice bran dietary fiber was preparaed by adding carboxymethyl group. Best condition of extracting technology was confirmed. Adding amount of NaOH was 15g, the alkalization temperature is 25.9℃, alkalization time is 1.5h, adding content of chloroacetic acid was 16.27g, etherification time was 4.5h, etherification temperature was 69℃. Under these conditions, the substitution degree of carboxymethyl substitution of dietary fiber from rice bran dietary fiber was 1.2668. It can be seen from the infrared spectrum that the carboxymethyl substitution of fat substitution of dietary fiber of rice bran has already occurred. The properties of the pseudo plastic fluid were determined by rheological measurement of different substitution degree of fat substitute. Increasing the degree of substitution of carboxymethyl group in the sample of fat substitute can help to improve the simulation of fat property.The properties of fat substitute of rice bran dietary fiber were studied. Functional properties of fat substitutes were all greater than those of rice bran insoluble dietary fiber,and It is also with inulin as fat substitute. With the increase of fat substitute of rice bran dietary fiber, moisture absorption, water solubility and solubility, emulsification and emulsion stability, water holding capacity and oil holding capacity, swelling power gradually increased, the most properties is up to 49.94%,58.4% and 88.57%,24.36% and 127.6%,12.58g/g and 9.30g/g, 5.96mL/g, but also higher than inulin substitutes, generation of small molecule substances has increased, Particle surface becomes loose, soft and particle size distribution is not the same, the average particle size was smaller, the smallest average particle diameter of up to 5.37μm, the fat substitute particle size has achieved, and is smaller than the average particle size of inulin (8.93μm)alternative goods.Fat substitute of rice bran dietary fiber added into cookies, insteading of different amounts of butter, studying the physical and chemical properties, quality structure and sensory evaluation of cookies. When the fat substitution amount was 20%, the cookie physicochemical properties, individual structure parameters was similar with 0% replacement level (all butter), and can achieve a good replacement effect. Compared by sensory evaluation and all the butter, the sensory score of the cookies of 20% of the fat content is similar as 0% replacement level (all butter) and can generally accepted. Using Statistics V17.0 SPSS statistical analysis software analyzed the correlation between sensory evaluation and texture analysis. The hardness, adhesiveness, chewiness, crisp has significant correlation, the correlation coefficient is very high. Good sensory evaluation and analysis ability can be obtained by using texture parameters. |
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