| The output of oranges in China is considerable,mainly for fresh consumption,and a few are processed into canned food,juice and other high value-added commodities.Orange peel is a by-product of orange processing,with a total annual output of about10 million tons.At present,there is less research on the comprehensive utilization of orange peel residue in China.Ninety percent of these orange peels are abandoned,leading to environmental pollution and waste of resources.Hesperidin is the main active ingredient in orange peel,which is of great extraction and utilization value,but its poor water solubility leads to its limited application,and must be molecularly modified to improve its solubility in order to broaden its application.Based on this,this paper firstly extracts hesperidin from orange peel by conventional extraction method and optimizes the extraction process parameters;then ferments hesperidin by inoculating different strains of bacteria into the enzymatic treatment of orange peel solution to obtain hesperidin enzyme,and screens the suitable compound strains by investigating the effect of fermentation of hesperidin into hesperidin by different strains of bacteria.Currently,there are few types of orange peel further processed products in the market,so the development of orange peel and kudzu complex enzymes is of great significance to the reuse of orange peel and can enrich the category of plant enzymes.The main research contents and results of this paper are :(1)The dried orange peel was chosen as the feedstock for hesperidin extraction by the alcohol-alkali extraction and acid precipitation methods.Alcohol-to-liquid ratio,alkali-to-liquid ratio,ethanol concentration,extraction temperature,and acid precipitation p H were chosen as the influencers of the single-factor experiment,and orthogonal experiments were conducted with the yield of hesperidin as the final index.The experimental results showed that,among the factors affecting the extraction rate of hesperidin,the effect of ethanol concentration was the most significant,followed by alcohol to material ratio,extraction temperature and alkali to material ratio;after screening,the most suitable processing process was derived as:The results showed that the main and secondary factors affecting hesperidin yield were as follows: The highest extraction rate was obtained with a stock ratio of 1:10 for orange peel powder to 70%ethanol and 1:8 for 0.5% Na OH solution,an extraction temperature of 70°C,an extraction time of 2 h and an acid analysis p H of 4.0.The yield of hesperidin was4.72%.(2)Select Lactobacillus acidophilus GIM1.321,Lactobacillus delbrueckii subsp.bularicus GIM1.155 and Lactiplantibacillus plantarun R4 and Saccharomyces ellipsoideus GIM2.105 were inoculated into the fermentation base of orange peel after enzymatic hydrolysis for fermentation,and the effects of lactic acid bacteria and yeast on physicochemical properties,antioxidant capacity in vitro and quality of main organic acids of orange peel fermentation base were studied.The results showed that all the four strains had good fermentation performance in the fermentation base of hesperidin,and had certain transformation ability to hesperidin.(3)Based on 17 indicators,including the number of viable bacteria,p H variation,total acid,reducing sugar variation,total phenol content,total flavonoids content,in vitro antioxidant capacity,major organic acid content,hesperidin and hesperitin contents of fermentation base materials of hesperidin and hesperidin fermented by different strains,a principal component analysis method was used to select suitable the strains for the fermentation of orange peel enzymes,and a comprehensive evaluation model was constructed.The results showed that Lactobacillus acidophilus GIM1.321,Lactiplantibacillus plantarun R4 and Lactobacillus delbrueckii subsp bularicus GIM1.155 were superior in terms of growth metabolism and functional effects,and the overall quality of the compound fermented enzymes was improved.(4)The prepared enzymatic hydrolysate of orange peel and pueraria were used as raw materials.Firstly,the optimal ratio of orange peel to pueraria and the combination of complex strains were selected through sensory evaluation for fermentation experiments.Second,the amount of inoculation of complex strains,fermentation time,fermentation temperature,and amount of sucrose addition were selected for single-factor experiments.Total phenol content and sensory assessment value were used as assessment indices for the orthogonal enzyme optimization experiment of the Orange pueraria complex.The results showed that the fermentation time had the most significant effect on the total phenolic content,followed by sucrose addition,lactobacillus complex inoculum and fermentation temperature,and the Lactobacillus complex inoculum had the most significant effect on the sensory evaluation value,followed by sucrose addition,fermentation temperature and fermentation time.Optimum process conditions achieved through optimisation: orange peel and a kudzu compounding ratio of 3:1,the amount of lactic acid bacteria inoculated,2.5%,the duration of the 7d fermentation,the fermentation temperature34℃ and the sucrose content 20%.The total phenolic content of the product was90.89±1.25 mg GAE/100 m L and the sensory score was 84.15±1.02 according to the optimized conditions.(5)The plant design of the 3000t/year fermented compound orange peel enzyme processing plant was carried out.The plant site selection,plant layout design,product and process demonstration,quality standard,equipment selection,engineering scheme,environmental protection treatment,material accounting,cost and profit estimation were analyzed and studied.The specific design plan includes the accounting of materials required for production,the selection and design calculation of major equipment used in production,and the estimation of water,electricity,consumption and other indicators to finally estimate the economic benefits of the plant.At the same time,the drawings were completed with the national and enterprise standards. |
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