| Peanut meal,as the main by-product of peanut oil processing,contains a lot of bioactive components,which has high nutritional and research value.Using beneficial bacteria to ferment peanut meal to extract bioactive substances,and then processing them into food additives and functional foods,which is beneficial to increase the added value of peanut meal.But at present,there is no report on the study of mixed bacteria,especially the fermentation of peanut meal by Bacillus natto and Monascus.This paper mainly uses the solid-state fermentation of peanut meal by the mixed bacteria of Bacillus natto and Monascus,makes full use of the advantages of the two bacteria,explore the best blending formula of the two strains to obtain peanut meal fermented products rich in nattokinase(NK),?-aminobutyric acid(GABA),cholesterol-lowering peptides,polysaccharides and other biologically active substances and extract and isolate these active substances.The simple and fast method provides a reference for the high-value utilization of peanut meal and the health care industry.The paper is divided into the following five parts:1.Production of nattokinase and ?-aminobutyric acid from peanut meal by solid-state fermentation with mixed bacteria.Purpose: to explore the optimal fermentation conditions for the production of nattokinase and ?-aminobutyric acid from peanut meal by solid-state fermentation with mixed bacteria;methods: the optimal fermentation conditions were studied by single factor experiment and orthogonal experiment;results: temperature 31 ?,time 46 h,feed water ratio 1:0.4 g/mL,strain ratio(Bacillus natto: Monascus)2:1,inoculation amount 6%,under this condition,the activity of NK in the fermentation product was 844.56±13.80 U/g,the content of GABA was 105.25±0.25 mg/g.2.Extraction and separation of cholesterol reducing peptide from peanut meal by solid-state fermentation with mixed bacteria.Purpose: to explore the extraction conditions and the optimal fermentation conditions of cholesterol lowering peptide from peanut meal fermentation products.;methods:(1)the extraction conditions of cholesterol lowering peptide from peanut meal were studied by acid extraction and alcohol precipitation;(2)the optimal fermentation conditions of cholesterol lowering peptidewere obtained by single factor and orthogonal test;results:(1)the optimal fermentation conditions were obtained by 0.10 mmol/L acid solution is the extraction solution of peanut meal fermentation product and the extraction solution is added with 50% ethanol solution of three times volume to remove impurities.Under this condition,the extraction amount of peanut meal polypeptide is the highest and the effect of polypeptide reducing cholesterol is the best.(2)The optimal fermentation conditions of cholesterol lowering peptide were: fermentation temperature 31?,time 46 h,strain ratio(Bacillus natto:Monascus)1:1,inoculation amount 6%.Under these conditions,the content of peanut meal polypeptide was 72.21±0.74 mg/g,the absorption rate of peanut meal polypeptide(3.5 mg/mL)to sodium cholate was 61.73%±2.82% and the absorption rate of sodium taurocholate was 52.45% ± 0.55%.The adsorption rate of 1 mg/m L peanut meal polypeptide to sodium cholate was 30.86% ± 1.65% and to sodium taurocholate was32.17%±1.44% after the treatment of artificial gastric juice and intestinal juice.It can be seen that peanut meal polypeptide still has good cholesterol lowering effect after the treatment of gastric juice and intestinal juice.3.Study on fermentation conditions of antioxidants in peanut meal.Purpose: to explore the optimal fermentation conditions for the solid-state fermentation of peanut meal with mixed bacteria to obtain antioxidants from peanut meal;method: the removal rate of hydroxyl radical(OH),the removal rate of 1,1-diphenyl-2-picrylhydrazine(DPPH)and the reducing power of iron ion of peanut meal fermented products were used as evaluation indexes.Factor experiment and orthogonal experiment to explore the effect of fermentation conditions on the antioxidant effect of peanut meal fermentation;results:peanut meal extract fermented under the conditions of temperature 31 ?,time 58 h,feed water ratio 1: 0.5 g/mL,strain ratio(Bacillus natto: Monascus)1: 3,inoculation amount6% has the highest anti-oxidation activity,the removal rate of ·OH is 88.41%±0.42%,the removal rate of ·DPPH is 68.50%±1.23% and the OD value of the reducing power of iron ion is 0.755±0.01.4.Study on the fermentation conditions of peanut meal polysaccharides.Objective:to explore the optimal fermentation conditions of peanut meal polysaccharides produced by the fermentation of peanut meal with Bacillus natto and Monascus mixed strains,and the extraction conditions of peanut meal polysaccharides extraction and to determine the antioxidant effect of peanut meal polysaccharides;method: hot water extraction,theethanol solution precipitation method was used to extract and isolate the peanut meal polysaccharides in the peanut meal fermentation;the fermentation temperature,time,feed-water ratio,strain ratio(Bacillus natto: Monascus),inoculation amount to peanut meal were examined by single factor experiment.The effect of peanut meal polysaccharide content in the fermentation,on this basis,orthogonal test was carried out to obtain the best fermentation conditions of peanut meal polysaccharide;through the removal rate of ·OH,the removal rate of ·DPPH and the reducing power of iron ion;explore the antioxidant effect of peanut meal polysaccharides;results: temperature 31 ?,time 70 h,feed-water ratio 1: 0.4 g/mL,strain ratio(Bacillus natto: Monascus)2: 1,inoculation amount 6%,peanut meal extract polysaccharide obtained by fermentation under this condition The content is 84.46 mg/g.Using three volumes of 90% ethanol solution to precipitate the fermentation broth resulted in the highest content of crude polysaccharides in peanut meal,with a yield of 90.04% ± 1.87%.The crude polysaccharide of peanut meal(100 mg/mL)obtained by alcohol precipitation has a clearance rate of 74.82%±1.59% for ·OH,60.00% ± 0.46% for ·DPPH,the OD value of the reducing power for iron ions is 0.42.5.Study on the extraction method of active ingredients of peanut meal fermented material.Objective: to explore the extraction and separation methods of nattokinase(NK),?-aminobutyric acid(GABA),cholesterol-lowering peptides,polysaccharides and other fermentation active substances,and to find a simple and rapid method to extract and separate these active substances;methods: by comparing the direct water extraction method,water extraction and acid adjustment for different pH values,and direct acid extraction method,explore the optimal extraction method for extracting the active ingredients of peanut meal;results: the fermented peanut meal is extracted with water and centrifuged;the residue can extract polysaccharides,and the supernatant is acidified to adjust the pH to 4.84 and then centrifuged;the nattokinase can be obtained from the precipitate and the supernatant is rich peanut meal polypeptide,?-aminobutyric acid and peanut meal antioxidant,the centrifugal supernatant is statically adsorbed by NKA-9macroporous resin,and peanut meal polypeptide can be isolated.Through this water extraction and acid precipitation column method,peanut meal polysaccharide(36.81±1.48 mg/g),nattokinase(NK activity is 678.04±3.19 U/g),?-aminobutyric acid can be isolated per gram of fermentation product(103.33 ± 0.72 mg/g)and peanut mealpolypeptide(35.05±0.58 mg/g). |
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