| Germinated Brown Rice(GBR)is a brown rice product consisting of sprouts and endosperm with bran layer obtained by soaking whole brown rice in water until germination of the germ reaches a certain bud length(usually 0.5-1.0 mm).Rich in nutrients such as ?-aminobutyric acid(GABA),dietary fiber,ferulic acid,phenolic compounds,vitamins and essential minerals are mostly concentrated in the rice bran layer,therefore,germinated brown rice bran has special nutrition effect.The purpose of this study is to study the germination of brown rice bran polysaccharides,using different methods to extract the germinated brown rice bran polysaccharides,screening the best extraction methods and process conditions,and select the polysaccharide components were higher extraction rate of its separation Purification,preliminary identification of the structure and biological activity.(1)Ultrasonic assisted extraction,microwave-assisted extraction and complex enzyme assisted extraction method were used to optimize the extraction conditions of Germinated Brown Rice Bran Polysaccharides by single factor test and response surface methodology,and the best technological parameters were obtained.The optimum conditions of ultrasonic assisted extraction,ultrasonic power 140 W,liquid material ratio 14:1(mL/g),ultrasonic time of 76 min,the extraction rate was 2.85%;the optimum conditions of microwave assisted extraction were: microwave power 604 W,liquid material ratio of 24:1(mL/g),microwave time 3.83 min,the extraction rate of 2.82%;the best conditions composite enzyme assisted extraction method for enzyme quantity is 0.3mg/mL,enzymolysis temperature is 35.5,pH is 7,the enzymatic hydrolysis time was 50 min,the extraction rate of polysaccharide was 1.48%.(2)The starch of germinated brown rice bran polysaccharide was removed by?-amylase and glucoamylase,and its protein was removed by TCA.Six kinds of polysaccharides were isolated by DEAE-52 Cellulose chromatography and Sephadex G-200 gel filtration chromatography.Five kinds of polysaccharides with high purity were obtained by HPGCP.The purity of GBRP-? The molecular weights of GBRP-?,GBRP-?,GBRP-? and GBRP-? were 10237D?6008D?4619D?3764D and 3574 D,respectively.All of them were small molecule polysaccharides.After monosaccharide analysis,GBRP-?was mainly composed of D-Man,D-Glu,D-Dal,L-Ara and D-Fuc;GBRP-?,GBRP-? and GBRP-? are mainly composed of D-Glu,D-Dal and L-Ara;GBRP-? mainly consists of D-Glu,D-Dal,L-Ara and D-Fuc.The infrared detection results showed that the 5 polysaccharides had the characteristic peaks of polysaccharide,GBRP-III,GBRP-IV and GBRP-V were ?-D-pyranose,and GBRP-II was beta conformation polysaccharide.(3)The biological activity of the isolated and purified germinated brown rice bran polysaccharide as raw material was studied.The reducibility,inhibition of lipid peroxidation and DPPH ·,ABTS · scavenging ability as an index to study the antioxidant activity of the germinated brown rice bran polysaccharide similar to the reduction of each component,the maximum absorbance value of 0.371 ± 0.04;GBRP-? And GBRP-? on ABTS · clearance rate higher than 95%;GBRP-? and GBRP-? scavenging capacity of DPPH above 70%;inhibition of lipid peroxidation is weak,only GBRP-? its inhibitory capacity Over 50%,indicating that the germinated brown rice rice bran polysaccharides have good antioxidant activity under high dose conditions.(4)the germinated brown rice bran polysaccharides effect on gastric cancer cells(SGC7901),colon cancer cells(HT29),breast adenocarcinoma cells(MCF-7),NCI-H460 and HepG2.The polysaccharide fraction has a good dose-response relationship with the inhibition rate of all the cancer cells,and the inhibition rate of all the cancer cells is in the range of 22-45 %.The high dose of polysaccharide on cancer cells has a certain degree of toxicity,of which,GBRP-? on the inhibition of various tumor cells is weak;GBRP-? on HT-29 and HepG2 inhibition was more obvious;GBRP-? HT-29 the most inhibitory effect. |
PDF Full Text Request