Preparation Of A Bitter Almond Kernel Prolamin Based Hypoglycemic Peptide Drink

In recent years,the number of patients with diabetes is increasing year by year.Currently,acarbose and other drugs exist on the market,but there are many problems such as high price and various side effects.Therefore,it is of great significance to develop new natural hypoglycemic drugs.In this paper,we prepare?-glucosidase inhibitory peptide(AGIP)and?-amylase inhibitory peptide(AAIP)with hypoglycemic activity by enzymolysis of amygdalin(BAKG),and prepare a beverage with hypoglycemic activity containing AGIP and AAIP.The main results are as follows:(1)Crude protein was extracted from bitter almond by alkaline solution and precipitated with acid.Four fractions of protein,namely,albumin,globulin,prolamin and glutelin,were extracted by Osborne grading method,and the purity,yield,nutrient composition and isoelectric points of the above four protein fractions and total crude protein were determined.Finally,based on amino acid composition and fluorescence spectrosopic characteristics,the protein fractions with potential and high content of hypoglycemic peptides were screened out.The results showed that the high content of hypoglycemic amino acid fragment in BAKG mainly occurred in BAKG,so BAKG was selected as the raw material to prepare the hypoglycemic peptides.(2)Using BAKG as raw material,?-glucosidase inhibition rate,?-amylase inhibition rate and degree of hydrolysis as indexes,the appropriate protease was screened.Response surface methodology was used to optimize the process,and the proteolysis of BAKG for producing?-glucosidase and?-amylase inhibitory peptides was optimized.Finally,the effects of temperature,p H and simulated gastrointestinal digestion on the activities of?-glucosidase inhibitory peptide(AGIP)and?-amylase inhibitory peptide(AAIP)were studied.The optimal conditions of AGIP enzymatic hydrolysis was as follows:substrate concentration 4.0%(W/V),enzyme dosage 6000 U/g,55?,p H 7.0,6 h,which gives a peptide solution with an IC₅₀value of 17.66 mg/m L.The optimum conditions of AAIP was as follows:substrate concentration 6.0%(W/V),enzyme dosage 6000 U/g,50?,p H 6.0,6 h,which gives a peptide solution with an IC₅₀value 7.79 mg/m L.AGIP and AAIP showed high retention rate of activity under high temperatures,strong acid/alkali or simulated gastrointestinal tract digestion.(3)AGIP and AAIP were used to prepare hypoglycemic drinks via factorial and orthogonal experiments,and the resulting hypoglycemic drinks shows good taste and high stability.The results showed that the contents of sodium alginate was 2 mg/m L.The optimal levels of citric acid,xylitol,stevioside,and?-cyclodextrin were 15 mg/m L,8 mg/m L,0.4 mg/m L,and 0.4 mg/m L,respectively.