| Blueberry is the most abundant type of nutrients in the genus Bilberry.It has a unique flavor and is rich in active substances such as anthocyanins and has strong antioxidant capacity.It is listed as one of the human health foods by the International Food and Agriculture Organization because of its unique nutritional value and health care function.In this experiment,the active components of wild blueberries were analyzed,and the extraction and purification process of anthocyanins in blueberries was studied to determine the optimal extraction and purification process,and the stability and functionality of anthocyanins were studied.The fermentation process of high alcohol blueberry wine was optimized by single factor and response surface test.At the same time,the changes of organic acid and volatile flavor substances in blueberry wine fermentation process were explored.The main results are as follows:1.Determination of the active ingredients in wild blueberries,the results showed that the total sugar content of wild blueberries was 12.46±0.49%,the total acid content was 2.37±0.16g/kg,the crude fat content was 3.47±0.12g/100g,and the protein content was 0.76±0.21g/100g,ash content is 1.02±0.08g/100g,organic acid is mainly malic acid,pyroglutamic acid,oxalic acid,tartaric acid,total phenol,total ketone,anthocyanin and VC active ingredients are respectively 112.69±5.68mg/g,10.76±0.17mg/g,974.9±5.73mg/100g,24.37±0.63mg/100g,the active ingredients were higher than commercially available artificially planted blueberries.2.The best way to extract blueberry anthocyanins was to use the microwave-ethanol method to treat raw blueberries.On the basis of single factor design,different material-liquid ratio,ethanol concentration,citric acid content,extraction time and microwave power were selected as independent variables to extract the content of blueberry anthocyanin as reference value,and orthogonal experiment optimization method was used to study each.The effect of variables on the extraction of blueberry anthocyanin.The results showed that the optimum conditions for the extraction of blueberry anthocyanins by microwave-ethanol method were:ratio of material to liquid 1:26,ethanol concentration 70%,citric acid content 0.9%,extraction time 34s,microwave power 350W,extraction process under optimal process.The content of chlorophyll was 885.7±5.64 mg/100g,and the extraction rate was 90.8%.3.By comparing the adsorption and analytical properties of four macroporous resins,HPD-100,DA-201,D101 and AB-8,AB-8 macroporous resin was used to purify blueberry anthocyanins.The adsorption and analytical results of AB-8 macroporous resin on crude extract of blueberry anthocyanin showed that the optimal purification conditions were as follows:concentrated extraction of anthocyanin crude extract at 50℃for 30min,adsorption equilibrium time 3h The adsorption temperature is 50℃,the sample pH 3.0,the sample concentration 2mg/mL,the sample flow rate 1mL/min,the analytical equilibrium time 3h,the eluent pH3.0,the elution liquid integral number 60%,and the eluent flow rate 1mL/min.The anthocyanin product obtained under the purification conditions was a black-purple powder,and the color price was 101.56,which was about 18 times that of the crude anthocyanin before purification.4.By studying the stability and DPPH·clearance and hydroxyl radical(OH·)scavenging ability of purified anthocyanins,it was found that blueberry anthocyanins were cyanotic under low pH,low temperature,dark and sodium benzoate.The retention rate of the element is high,and the Na+,Fe3+,and K+ions have little effect on the preservation rate of anthocyanins.The Cu2+,Zn2+,Ca2+,and Fe2+ ions have a great influence on the preservation rate of blueberry anthocyanins;DPPH·of blueberry anthocyanins The clearance rate and hydroxyl radical(OH·)scavenging ability were higher than that of ascorbic acid.5.Using wild blueberry as raw material,by studying the effects of different strains,ratio of material to liquid,inoculum amount,initial pH and fermentation temperature on blueberry wine,single factor analysis and Box-Behnken test were used to determine the most high-alcohol blueberry wine.Good process parameters.The results showed that the optimum process parameters were initial pH4.1,inoculum was 6.4%,and the main femmentation temperature was 26℃.The product obtained under this condition had rich fruit flavor,full mouthfeel,residual sugar 4.1+0.23Brix,pH4.02+0.31,the alcohol content was 16.5+0.2%,the total content of 9 organic acids was 20.56+0.37g/L,and the sensory score was 93.1±1.13.6.Three different yeast strains were fermented to produce blueberry wine,and the content of nine organic acids in the fermentation process was determined by HPLC.The results showed that there were significant differences in the content of nine organic acids in the fermentation process of different yeast strains,and the total content of nine organic acids in different stages of fermentation also showed different trends.At the end of pre-fermentation,the content of 9 organic acids in the blueberry wine fermented by the three strains was higher than that of the initial fermentation mash,and the highest GF3 was 6-7 times of the initial fermentation sputum,and T1 and FK3-2 were very close.It is about 3 times of the initial fermentation mash.At the end of post-fermentation,there was almost no difference in the content of organic acids in the wines fermented by T1 and FK3-2,while the content of organic acids in the GF3 fermented wine was the highest,more than twice that of the other two strains.At the end of fermentation,the content of 9 organic acids in the wine was higher than that in the initial fermentation mash,and both were lower than the content at the end of the main fermentation.7.At the end of post-fermentation,10,13,and 11 volatile flavor substances were detected from the fermented liquors of T1,FK3-2,and GF3,respectively.Among them,the total content of volatile flavor substances in GF3 was the highest.It is almost 3 times that of T1 wine and 1.3 times of FK3-2 wine.Compared with the flavor of post-fermentation period,the flavor content of post-fermentation period is high and the content is rich. |
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