Preparation Of Corn Hypoglycemic Active Peptide And Its Effect On Glucose And Lipid Metabolism In Diabetic Zebrafish

Diabetes is a metabolic disease that seriously threatens human health and life.Long-term use of synthetic drugs for the treatment of diabetes has certain side effects on the human body.Protein hydrolysates from food are easy to absorb and safe,which have potential value in developing functional products.In this paper,corn gluten meal was used as raw material to prepare corn hypoglycemic active peptides by double enzyme complex hydrolysis and ultrafiltration grading,and the structure of each component was analyzed.Then,zebrafish model was used to evaluate the hypoglycemic effect in vivo,aiming to provide a theoretical basis for the development of related health products of food-borne corn hypoglycemic functional active peptides.The main research contents and results are as follows:(1)Using hydrolysis degree and α-glucosidase inhibition rate as indexes,two proteases with good hypoglycemic effect were screened out from the four proteases,and the single factor test and orthogonal test were carried out respectively.The optimal enzymatic conditions are as follows: First,flavor protease was added(the optimal enzymolysis temperature was 50℃,p H 6.5,enzyme dosage was 5.5%(V/m),enzymolysis time was 4 h).Then adding alkaline protease(optimal temperature 50℃,p H 8.5,enzyme dosage 2%(V/m),reaction time 2 h)to complete the hydrolysis of corn protein hydrolysate α-glucosidase inhibition rate was the highest 81.38%.(2)The corn hypoglycemic active peptides were obtained by ultrafiltration of corn gluten hypoglycemic enzymolysis solution.The α-glucosidase inhibition rate and antioxidant activity of corn gluten hypoglycemic active peptides were analyzed after ultrafiltration,and the particle size distribution and structural changes were characterized.The results showed that the <1 k Da fraction had the highest α-glucosidase inhibition rate of 90.87%.The <1 k Da component also has high antioxidant activity,that is,the reducing power is as high as 0.181,the scavenging rate of hydroxyl radicals reaches 76.72%,and the scavenging rate of DPPH radicals reaches 52.56%.The results of dynamic light scattering showed that the average particle size of corn hypoglycemic active peptides decreased continuously with the ultrafiltration classification.The average particle size of the <1 k Da fraction was the smallest at 563.6 nm,and the distribution was the widest,and the distribution range was mainly concentrated in the range of 100-6000 nm.Fourier transform infrared spectroscopy results showed that the secondary structure of corn peptides of each component changed significantly.Compared with the >10 kda component,theβ-sheet content of the <1 kda component increased by 16.36%,while the β-turn content decreased by 20.68%.(3)Diabetic zebrafish were fed with different ultrafiltration components of zein hypoglycemic active peptides,and the effect of zein hypoglycemic active peptides on glucose and lipid metabolism in diabetic zebrafish was studied.The results showed that each component of zein hypoglycemic active peptides could significantly reduce the body mass index(BMI)of diabetic zebrafish,and improve blood glucose and lipid indexes.Among them,after the intervention of zein hypoglycemic active peptide with <1 k Da component,the glucose content of zebrafish in the diabetes model group was reduced from 0.662 mmol/L to 0.547 mmol/L,and the hypoglycemic effect was significant.At the same time,the content of total cholesterol,triglyceride and low-density lipoprotein decreased by 34.65%,28.82% and 26.62%,and high-density cholesterol increased by 96.67%,all of which were close to normal levels.The amino acid composition analysis of this component found that the contents of leucine and glutamic acid,which have the effect of regulating blood sugar,were 24.84% and 11.09%respectively.(4)Diabetic zebrafish were fed with corn hypoglycemic active peptides of <1k Da ultrafiltration fraction in different dose groups,and the effect of corn hypoglycemic active peptides on glucose and lipid indexes in diabetic zebrafish was evaluated by measuring zebrafish biochemical indexes.The results showed that both the low and high dose groups of corn hypoglycemic active peptides could improve the glucose level and were not affected by the dose.In the level of total cholesterol content,corn hypoglycemic active peptide has a significant effect on reducing cholesterol in diabetic zebrafish,and increasing the feeding dose can achieve an effect equivalent to that of acarbose.The triglyceride content and low density lipoprotein content of diabetic zebrafish fed with a high dose of corn hypoglycemic active peptide of <1 k Da component were significantly reduced by 19.18% and 37.74%,and the high density lipoprotein content was increased by 63.27%,and the Blood sugar has a significant effect.This study further identified the potential of corn as a raw material for the development of hypoglycemic products.