Structure,retrogradation and digestibility of waxy corn starch modified by a GtfC enzyme from Geobacillus sp.12AMOR1  

作　　者：Xiaolei Li Yong Wang Siyu Mu Xiangqing Ji Cheng Zeng Dingkuan Yang Liyuan Dai Cuicui Duan Dan Li 

机构地区：[1]Key Laboratory of Agro-products Processing Technology,Education Department of Jilin Province,Changchun University,6543 Weixing Road,Changchun,130022,People’s Republic of China [2]Key Laboratory of Human Health Status Identification and Function Enhancement,Department of Science and Technology of Jilin Province,Changchun University,6543 Weixing Road,Changchun,130022,People’s Republic of China

出　　处：《Food Bioscience》2022年第2期282-290,共9页食品生物科学（英文）

基　　金：This work was sponsored in part by National Natural Science Foundation of China(NSFC-31671801,31371749);the key R&D program(21ZGN38)from Changchun science and technology bureau,the special project of industrial independent innovation capability(2020C036-7)from Jilin provincial development and reform commission;the science and technology research planning project(JJKH20220609KJ)from Jilin provincial department of education;the scholar climbing project(ZKP202006 and ZKP202016)from Changchun University.

摘　　要：To lower the retrogradation and digestibility of waxy corn starch for different food applications,a novel thermostable GtfC type 4,6-α-glucanotransferase without N-and C-terminals(GsGtfC)from Geobacillus sp.12AMOR1 was used.Waxy corn starch of 50 g/L was incubated with GsGtfC of 40-100 U/g substrate at 65℃and pH 5.5 for 1 h.Its molecular weight,iodine affinity,XRD crystallinity,and FTIR ratio of heights of bands at 1047 and 1022 cm^(-1) decreased,but ratio of DP<6 to DP≥25 branches and degree of branching increased.GsGtfC cleavedα-1,4-glycosidic bonds and inducedα-1,6-branching points to produce reuteran-likes polymers,which is different from Exiguobacterium sibiricum GtfC enzyme cleavingα-1,4-glycosidic bonds and synthesizing consecutiveα-1,6-glycosidic bonds to produce isomalto/malto-oligosaccharides.GsGtfC modified waxy corn starch had significantly lower DSC retrogradation enthalpies during the storage at 4℃for 3-14 days and significantly lower released glucose during the incubation with mammalian mucosalα-glucosidase at 37℃for 10-360 min.GsGtfC at 100 U/g substrate increased slowly digestible portion from 11.07%to 24.11%.

关 键 词：Waxy corn starch STRUCTURE RETROGRADATION DIGESTIBILITY GtfC 4 6-α-glucanotransferase 

分 类 号：O63[理学—高分子化学]