Study Of Plant Probiotic Matrix Ingredients Rich In ?-aminobutyric Acid

Elderly and frail people usually have weak gastrointestinal function.It is necessary to develop a digestible and absorbable product.In addition to basic nutrients such as carbohydrate,plant-based substrates are also rich in antioxidant ingredients and dietary fiber.The matrix is composed with quinoa and highland barley,which having protein,balanced amino acid ratio and a variety of biologically active ingredients.During germination,quinoa and highland barley produced protease and amylase.Then used these enzymes to hydrolyzing protein,starch and other substances into amino acids,oligosaccharides,etc.The study is to obtain self-enzymatic hydrolysate of quinoa and highland barley hydrolysates(QHB-H)which is beneficial to the growth of lactic acid bacteria and are rich in nutrients,provided a balanced and comprehensive new plant-based substrate for the growth of probiotics.Firstly,analysed the germination conditions of quinoa and highland barley(?-amylase activity and GABA as indicators).The research showed that after quinoa and barley germinated,the activity of?-amylase and the content of GABA was greatly incresed.The best germination condition for quinoa was soaked for 2 h and germinated at 25?for 24 h,the GABA content and?-amylase activity reach 105.8 U/g and 91.35 mg/100g respectively;the best germination condition for highland barley was soaked for 9 h and germinated at 25?for36 h,the GABA content and?-amylase activity reached 150.9 U/g and 99.67 mg/100g respectively.Secondly,the enzyme produced by the quinoa and highland barley was used to hydrolyzed quinoa and barley substrate to obtain a nutrient-rich enzymatic hydrolysis product.It was suitable for the growth of probiotics.The best enzymatic hydrolysis conditions was enzymatic hydrolysis temperature at 55?,enzymatic hydrolysis time in 4 h,enzymatic hydrolysis solid-liquid ratio 1:3.The content of amino nitrogen prepared under the optimal enzymatic hydrolysis conditions was 0.15 g/100m L,and the content of reducing sugar is 98.18 mg/100m L.All 8 tested strains can grow well in QHB-H,and after fermentation viable bacteria can reach the order of 10⁸-10⁹ cfu/m L.One of the strains,Lactobacillus plantarum 567,grows 24hours and then enters stable phase,viable cell count can reach 1.89×10⁹ cfu/m L.After refrigerating at 4°C for 84 days,viable bacteria can still reach 2.66×109 cfu/g,and the GABA content was 199.1 mg/100g.Furthermore,to obtain a QHB-H matrix with high GABA content,some solutions was proposed.Firstly,external environmental stress was applied during germination process,and finally selected Na Cl-Ca Cl₂combined stress.After the stress,GABA content of quinoa was131.6±1.5876 mg/100g,and the GABA content of highland barley was 139.2±0.9761 mg/100g.Increased by 1.44 and 1.40 times respectively;added L-MSG in the germination process and enzymatic hydrolysis process to select the best addition stage,and finally selected the enzymatic hydrolysis stage.When addition amount is 1.5 g/L,the GABA content reaches 279.9 mg/100g.This article also studied some nutritional characteristics of QHB-H,and analyzed the main nutritional components during preparation process.The results showed that QHB-H was rich in amino acids,peptides,reducing sugars,polyphenols and flavonoids,and had good free radical scavenging ability,and also rich in biologically active ingredient GABA.After enzymatic hydrolysis,soluble protein content reached 3.748±0.0045 mg/g;panose content was0.25 mg/g.After fermentation soluble protein content was 3.355±0.0007 mg/g;the content of isomaltose was 5.72 mg/g,the content of panose was 1.42 mg/g.After enzymatic hydrolysis and fermentation,most of soluble protein was converted into oligopeptides and amino(89.90%),and the free amino acid content was about 200 mg/100g;total phenols and total flavonoids content was 155 mg/100g DW,11.97 mg/100g DW,respectively.The content of?-aminobutyric acid can reach about 300 mg/100g.QHB-H also has good free radical scavenging ability.After enzymatic hydrolysis and fermentation,the free radical scavenging ability of ABTS and DPPH are 38.05%and 64.21%,respectively.