| Bamboo shoot shell (BSS) is a plenty biomass resource with low costs, which has been discarded without any utilization. It is a waste of natural resource and a threat to the environment. BSS is rich in dietary fiber, which could be a resource for dietary fiber production. In this paper, using BSS as raw material, bamboo shoot shell dietary fiber (BSSD) was extracted by composite enzymes method, whose process parameters were optimized by response surface. The physicochemical properties of BSSD were studied, and then the hypoglycemic and hypolipidemic effects of BSSD were analyzed.(1) Taking bamboo shoot (Leleba oldhami Nakal) shells as raw materials, based on the results of single factor experiment, response surface method was applied to optimize the parameters of composite enzymes (cellulase, neutral protease, alpha amylase) method for the extraction of soluble dietary fiber (SDF). The optimal parameters are:ratio of solid to liquid of 1:24 (g/mL), enzyme dosage of 0.7%, hydrolysis time of 1.6 h, temperature of 40 ℃. Finally, the extraction rate of SDF was 8.674% and the extraction rate of IDF was 56.21%.(2) The analysis results showed that the BSS was rich in dietary fiber and protein, and the total dietary fiber (TDF) and protein content were 62.59% and 13.6%, respectively. The results showed that both IDF (insoluble dietary fiber) and TDF have significant water retention capacity (WRC) and water swelling capacity (WSC) and oil retention capacity (ORC), which were 9.16 g/g,6.90 ml/g and 4.74 g/g for IDF and 10.97 g/g、7.10 ml/g、5.76 g/g for TDF. Using the vitro experiment, NO2-,glucose and cholesterol absorption abilities of SDF, IDF and TDF were determined. IDF had higher NO2- adsorption ability compared to SDF and TDF. The glucose adsorption abilities were different (TDF>IDF>SDF), and the adsorption ability of TDF for 0.83 mmoL/L glucose reached to 24.79 μmoL·g-1. The values of pH had significant effects on the cholesterol absorption abilities of three kinds of dietary fiber, and SDF has higher ability than IDF and TDF when pH was 2. SDF, IDF, TDF and acarbose exhibited various inhibition effects of alpha glucosidase:acarbose>TDF>IDF> SDF. Moreover, the inhibition effects on alpha amylase:SDF≥acarbose>TDF>IDF. The results of glucose dialysis retardation index showed that the inhibitory effects of three kinds of dietary fiber on glucose:TDF>SDF>IDF. The viscosity:IDF>TDF >SDF. Finally, through compared the capacity of TDF with different ratio of SDF and IDF on cholesterol adsorption and inhibiting alpha glucosidase and alpha amylase activity, the research results showed that when the ratio of SDF and IDF was 1:3,TDF exhibited the greatest cholesterol absorption capacity and the highest inhibition effect on alpha glucosidase and alpha amylase activity.(3) In this experiment, the type Ⅱ diabetic mice model was induced by streptozotocin (STZ) injection combined with high-sugar and high-fat diet. Using the group treated with dimethylbiguanide as positive control, the hypoglycemic effects of BSSD on the diabetes mice were determined by the results of body weight, fasting blood glucose, oral glucose tolerance, four indicators of blood lipid (TC, TG, LDL-C, HDL-C), serum insulin levels. The results showed that three kinds of dietary fiber could significantly ameliorate the blood glucose and lipid metabolism disorderly situation of type Ⅱ diabetic mice. Especially, fasting blood glucose of TDF (1:3) group mice decreased to 7.40 mmol/L, serum insulin levels were 6.30 mIU/L higher than the model group’s. Compared with model group, TC, TG and LDL-C decreased by 29.26%,21.51% and 29.26%, respectively, while there was 23.17% increase in HDL-C. Those effects of BSSD had no significant difference with positive control group’s (p> 0.05), indicating that TDF (1:3) has potential auxiliary hypoglycemic effect.(4) Taken model group mice as control, the hypolipidemic effects of BSSD on high-fat diet induced hyperlipidemia mice model were studied. The indexes including mice feeding and body weight, four indicators of blood lipid (TC, TG, LDL-C, HDL-C), atherosclerosis index (AI), liver coefficient (LI%) were tested during 21 days. The results showed that the three kinds of dietary fiber can significantly improved the lipid metabolism disorderly situation of hyperlipidemia mice. Especially, compared with model group, the body weight of TDF (1:3) group mice decreased by 8.81%, the TC, TG, LDL-C, AI and LI decreased by 31.53%,21.35%,31.53%, 74.24% and 30.02% respectively, and there was 37.6% increase in HDL-C. Those effects above had significant difference with the model group’s (p<0.01), indicating that TDF (1:3) has the good auxiliary hypolipidemia effects. |
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