Studies On The Extraction And Efficacy Characteristics Of Water-soluble Dietary Fiber From Rice Bran

The utilization of rice bran is mainly concentrated in the feed,its rich nutrition resources such as dietary fiber are obviously ignored.In this study,the water-soluble dietary fiber(SDF)was extracted by ultrasonics-enzymatic method from rice bran.The physics-chemical characteristics and function feature of the product were measured and analyzed,the inhibition of escherichia coli and staphylococcus aureus and the proliferation effect of bifidobacterium was further discussed.The purpose of this study is to provide theoretical basis for the exploitation of high-quality SDF and make full use of resources from rice bran.The main results of this study were as follows:Based on the single experiment,the optimal extraction solution of SDF was optimized by Box-Behnken experiment design and surface analysis with the response value of extraction yield.At last,the results showed that enzyme amount had the greatest impact on the extraction of SDF,followed by liquid-solid ratio of rice bran and ultrasonic time,and ultrasonic power affected least.The optimum extraction conditions were enzyme amount 5.3%,liquid-solid ratio 1:24 g/mL,extraction time 5 min,and ultrasonic power 415 W.Under this condition,the theory value of the extraction rate of SDF was 9.22%,the actual operation of the experiment turned out to be 9.36%.The results of physics-chemical characteristics showed that the hydraulic of SDF is 3.16±0.15 g/g,the oil force is 0.99±0.08 g/g,swelling property was 1.39±1.39 mL/g,combined with the hydraulic 4.18+0.10 g/g.It has been shown from the study that SDF has cation exchange capacity and the solubility of SDF is proportional to the temperature.The analysis of Fourier infrared spectrum showed that SDF from rice bran has the characteristics of the infrared spectrum of polysaccharide.The result of scanning electron microscopy(SEM)showed that the SDF has different morphology with raw materials,the shape is irregular fragments made by a few particles.There are a lot of honeycomb holes that may lead to good solubility of SDF when taken by high multiple scanning surface.The results show that oxidation resistance increased with the concentration of the SDF and obvious rising trend,the free radical clearance rate in ABTS.+ system reached 37.13%,its iron reduction capacity is a tendency for 0.719 mmol/L of FeSO4 with the concentration of 10mg/mL.The experimental results of antimicrobial properties showed that SDF from rice bran has inhibiting effect on escherichia coli and staphylococcus aureus with the bacteriostatic zone of 12.55 mm and 8.95 mm respectively.The test of MIC of staphylococcus aureus is 100 mg/mL.The growth-promoting action of SDF on Bifidobacterium was studied by on vitro assay.The results show that SDF is an effective growth-promoting factor of Bifidobacterium.The antimicrobial properties of dietary fiber may provide foundation for the utilization and research of water-soluble dietary fiber from rice bran.