Characteristics And Structure Of Quinoa Starch And Its Effect On Type ? Diabetic Mice

Known as “golden grain”,quinoa has been thoroughly studied for its active ingredients such as vitamins,minerals,polyphenols,flavonoids,saponins,polysaccharides,peptides,ecdysone,etc.Many researchers are still exploring new activities ingredients,but starch,which accounts for 55% of them,has rarely been reported.In this paper,we studied the structure,characteristics and effects of quinoa starch on glucose metabolism,especially in comparison with common grains in terms of structure and properties,so as to provide a theoretical basis for its processing.The main research contents included the following four aspects.Determination of amylose and amylopectin content: Four commonly used determination methods were compared in terms of wavelength,accuracy,precision and recovery.A new method was established: mixed double standard,the detection wavelength of amylopectin was 638 nm and 430 nm,and the wavelength of amylopectin was 536 nm.The linear range of this method was 0~80?g/mL,the regression coefficients were 0.9984,0.9996,the recovery rates were 103.25~103.48%,94.85~94.52%,and the standard deviation of different starches was between 0.0013~0.52 and 0.11~1.54.The characteristics of quinoa starch: The starch gelatinization characteristics were determined by Brabender viscograph.Compared with other starches(153.5~1068BU),the setback value of quinoa starch was the lowest,97 BU,which showed that the anti-aging ability of quinoa starch was strong.The water-splitting rate was determined by repeated freezing and thawing at-18 °C.The results showed that the freeze-thaw stability of quinoa starch was general.The enzymatic hydrolysis of starch by ?-amylase at 0 min,20 min,1 h,3 h and 9 h showed the high enzyme sensitivity of quinoa starch.The swelling power of starches at different temperatures of 65 ° C,75 ° C,85 ° C and 95 ° C were measured,and it was found that the swelling power of quinoa starch and wheat starch were similar.The structure of quinoa starch: The morphology of quinoa starch granules was observed by scanning electron microscopy.Compared with common starch,the size of quinoa starch granules was the smallest(1~1.5?m),and the shape of quinoa starch granules was similar to that of rice starch,waxy rice starch and corn starch granules.X-ray diffraction measurement showed that the quinoa starch was C-type with a crystal form of V-type crystal,and the diffraction pattern was similar to that of tapioca starch;the relative crystallinity was calculated to be 45.82%,next to the crystallinity of waxy rice starch.By measuring the blue value(0.093),the maximum absorption wavelength(568)and analyzing the glucan gel chromatography,the results showed that the polymerization degree was high and had a high proportion of long and medium length branches in amylopectin.Digestive property in vitro of quinoa starch: The in vitro digestibility of starch was determined by the Englyst method,and the contents of rapidly digestible starch,slowly digestible starch and resistant starch in quinoa starch were 72.79%,6.84%,and 20.67%.By comparing and analyzing the processed raw and cooked starches,the resistant starch was further divided,and the ratio of raw starch granules and retrograded starch to starch was 10.19% and 20.67%,respectively.Effect of quinoa starch on type I diabetic mice: The mice model of type ? diabetes was fed with quinoa starch custom feed,and the results showed that quinoa starch could stabilize the body weight and improve the food utilization rate by comparing the body weight with the food intake.Fasting blood glucose,insulin tolerance test,oral glucose tolerance test and serum insulin test showed that there was no significant difference in hypoglycemic effect between quinoa starch diet group and positive control group,and it could effectively stabilize blood glucose.It could effectively inhibit the rapid rise of postmeal blood glucose and improve insulin resistance.By measuring the level of serum blood lipid,it was showed that quinoa starch could decrease the contents of triglyceride,total cholesterol and low density lipoprotein cholesterol,and increase the content of high density lipoprotein cholesterol.