| Chenopodium quinoa Willd.,Commonly known as quinoa,was the staple of indigenous people in the Andes,and as an alternative source of food in other areas.China introduced to Tibet in 1987,followed by Shanxi,Qinghai and other places.Quinoa,"nutrition gold" said,nutrient value was rich.Quinoa contained a lot of saponins,especially in quinoa seed coat.The experimental materials purchased from Shanxi Huaqing quinoa wheat product development Limited.The basic nutrient contents of quinoa seeds,quinoa seed coat and quinoa hulls were analyzed and compared.The extraction,purification and bioactivity analysis(including in vitro antioxidant analysis and inhibition of bacterial experiment)of saponins from quinoa seed coat were studied.And provide the theoretical basis for the comprehensive processing and utilization of quinoa seed coat.Nutritional composition(water,ash,protein,crude fat)of quinoa seeds,seed coat and wheat shell were determined by GB method.The samples were treated with vanillin-perchloric acid-glacial acetic acid color method,and the saponin content was determined by ultraviolet-visible spectrophotometer.Determination of fatty acids in samples by Gas Chromatography(GC).Analysis of its nutrient composition showed: the protein content,crude fat and saponin content of quinoa seed were higher,the nutritive value was abundant when the nutritional composition of quinoa seed was the second.Quinoa wheat shell mineral content was higher,the other nutrient content was lower.Fatty acid composition analysis showed that the content of fatty acids contained in the samples was about the same,and the content of linoleic acid was the highest,the content of unsaturated fatty acids(UFA)in seeds,shells and shells was above 80%.The content of UFA in coat was the highest,and the percentage of saturated fatty acid(SFA)in quinoa seed was the lowest.The ultrasonic extraction of saponins from Chenopodium quinoa bran was optimized with the combined use of single-factor method and response surface method based on Box-Behnken design.Results showed that optimumconditions were as follows: liquid-solid ratio 39:1 mL/g,ethanol volume fraction 74%,ultrasonic time 33 min.Under the above optimized conditions,saponins extraction rate in quinoa bran was 23.371 mg/g.The crude saponin of quinoa bran was extracted by 80% ethanol.And then extracted with petroleum ether-ethyl acetate-n-butanol.The samples were purified by High-speed Countercurrent Chromatography(HSCCC)and optimized conditions were obtained by changed the acetic acid content,rotational speed and flow rate in the system of n-butanol-water as the basic solvent system.The results showed that the separation and purification were the best under the condition of rotation speed of 750 r/min,flow rate of 1.5mL/min and solvent system of n-butanol:water:acetic acid of 1:1:0.05.The antioxidant activities of the extracted saponins were evaluated by1,1-diphenyl-2-trinitrophenylhydrazine(DPPH),·OH and O2-· radical scavenging and Fe3+ reducing power assays.Inhibition of E.coli,S.aureus and B.subtilis activity was determined by plate counting.The results of antioxidant experiments showed that the saponins of quinoa had significant antioxidant activity and dose-dependent relationship with saponin concentration.Compared with the positive control Vc,quinoa coat of saponins was stronger,O2-· scavenging power was low,·OH and DPPH free radical scavenging power was slightly lower than Vc.Bacteriostatic experiments show that quinoa seed coat saponins have the ability to inhibit E.coli,S.Aureus and B.Subtilis,while the most sensitive to E.Coli.Under the action of concentrated hydrochloric acid 110 ℃,saponin hydrolysis into aglycone and sugar chain,then the concentrated hydrolyzate ingredients identified.Determination of saponin content in quinoa coat by HPLC.The results show that the quinoa seed coat contains mukurosigenin and oleanolic acid. |
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