【作者】 张欣；

【导师】 周慧；

【作者基本信息】 吉林大学 ， 生物工程（专业学位）， 2021， 硕士

【摘要】 黑果腺肋花楸果实是一种新兴小浆果,其含有大量多酚类物质,是天然的功能性食品原材料。然而,黑果腺肋花楸鲜果贮藏时间短、运输性能差、口感酸涩,使其极少的被应用,因此为了扩大黑果腺肋花楸的应用范围,对其的具体成分的研究就变得尤为重要。而已知黑果腺肋花楸中原花青素的含量是所有果蔬中最多的,且原花青素本身具有多种药理活性,例如:抗癌、抑菌、降低心血管等。因此本论文应用超声辅助低共熔溶剂来提取黑果腺肋花楸中的原花青素,并研究其抗氧化和抑菌活性。具体研究内容如下:1.低共熔溶剂提取黑果腺肋花楸原花青素制备氯化胆碱与丙二酸不同比例的低共熔溶剂,利用其来进行提取黑果腺肋花楸原花青素的工艺优化,得出的最佳工艺为:溶剂比例为氯化胆碱:丙二酸=1:1.2、溶剂的含水量为10%、料液比为1:15 g/m L、提取时间为40 min、提取温度为50℃、超声功率为200 w,提取原花青素的最高含量为63 mg/g。正交试验的结果显示最佳提取工艺与单因素实验基本一致。再利用70%酸性乙醇溶液进行对比验证,提取含量为23 mg/g,是低共熔溶剂提取含量的1/2,表明低共熔溶剂是一种很好的提取溶剂。最后利用DM130大孔树脂对粗提物进行纯化,所得纯化物中原花青素的含量为82.4%。2.黑果腺肋花楸原花青素的抗氧化活性实验考察了原花青素对DPPH、OH^-、O^2-、ABTS这四种自由基的清除能力和气总还原能力,以维生素C作对照试验。结果表明:浓度在0.1～4 mg/m L范围内原花青素对DPPH自由基的清除能力大于V_C,对OH^-自由基和ABTS自由基的清除能力与V_C基本一致,对O^2-自由基的清除能力小于V_C,其总还原能力大于V_C。3.黑果腺肋花楸原花青素的抑菌活性采用牛津杯法和微量肉汤稀释法对原花青素的抑菌性能进行定性和定量测定,并绘制了30%乙醇和原花青素对供试菌种在72 h内的生长抑制曲线。结果表明:原花青素对金黄色葡萄球菌的抑制作用强于大肠杆菌,而对青霉菌和黑曲霉菌没有抑制效果。金黄色葡萄球菌的MIC小于大肠杆菌。生长曲线表示MIC浓度下原花青素几乎完全抑制了金黄色葡萄球菌和大肠杆菌的生长。4.黑果腺肋花楸提取物在鲜切水果保鲜上的应用对纯化后的原花青素进行鲜切苹果保鲜实验的应用,结果表明,原花青素组鲜切苹果的失重率强于30%乙醇处理组和对照组。原花青素组的硬度和糖度与其他两组基本一致。从色差值可看出原花青素组的L*值低于其他两组,而C*高于其他两组。原花青素组的MDA含量显著低于其他两组。浓度为MIC的原花青素组中所含的细菌总数远小于其他两组。本论文利用低共熔溶剂借以超声辅助提取黑果腺肋花楸中的原花青素对比与乙醇,提取含量扩大一倍,经过DM130大孔树脂对粗体物进行纯化;然后对纯化物进行抗氧化和抑菌活性的研究,表明其具有强抗氧化和抑菌能力;最后将其应用于鲜切苹果的保鲜应用,表明其具有一定的保鲜作用。更多还原

【Abstract】 The fruit of Sorbus melanocarpa is a new small berry,which contains a lot of polyphenols and is a natural functional food raw material.However,the fresh fruit of Sorbus melanocarpa has short storage time,poor transportation performance,and astringent taste,so that it is rarely used.Therefore,in order to expand the application range of Sorbus melanocarpa,the research on its specific components has changed.It is especially important.It is known that the content of proanthocyanidins in Sorbus melanocarpa is the most among all fruits and vegetables,and proanthocyanidins themselves have a variety of pharmacological activities,such as anti-cancer,antibacterial,and cardiovascular reduction.Therefore,this thesis uses ultrasound-assisted eutectic solvent to extract proanthocyanidins from Sorbus melanocarpa,and study its antioxidant and antibacterial activities.The specific research content is as follows:1.Extraction of Proanthocyanidins from Sorbus melanocarpa by eutectic solventPrepare eutectic solvents with different ratios of choline chloride and malonic acid,and use them to optimize the process of extracting proanthocyanidins from S.melanocarpa.The best process is:the solvent ratio is choline chloride:C Diacid=1:1.2,the water content of the solvent is 10%,the material-to-liquid ratio is 1:15 g/m L,the extraction time is 40 min,the extraction temperature is 50℃,the ultrasonic power is200 w,and the highest content of extracted proanthocyanidins is 63 mg/g.The results of the orthogonal experiment showed that the optimal extraction process was basically the same as the single factor experiment.Using 70%acidic ethanol solution for comparative verification,the extraction content is 23 mg/g,which is 1/2 of the extraction content of the eutectic solvent,indicating that the eutectic solvent is a good extraction solvent.Finally,DM130 macroporous resin was used to purify the crude extract,and the content of proanthocyanidin in the purified product was 82.4%.2.Antioxidant activity of Proanthocyanidins from Sorbus melanocarpaThe experiment investigated the scavenging ability of proanthocyanidins on DPPH,OH^-,O^2-,ABTS these four kinds of free radicals and the total gas reduction ability,and vitamin C was used as a control experiment.The results show that the scavenging ability of proanthocyanidins on DPPH free radicals is greater than that of V_C in the concentration range of 0.1～4 mg/m L,the scavenging ability of OH^-and ABTS free radicals is basically the same as that of V_C,and the scavenging ability of O^2-free radicals is less.V_C,its total reduction ability is greater than V_C.3.Antibacterial activity of Proanthocyanidins from Sorbus melanocarpaThe bacteriostatic properties of proanthocyanidins were determined qualitatively and quantitatively by the Oxford cup method and the micro broth dilution method,and the growth inhibition curve of 30%ethanol and proanthocyanidins on the tested strains within 72 h was drawn.The results showed that the inhibitory effect of proanthocyanidins on S.aureus was stronger than that of E.coli,but had no inhibitory effect on Penicillium and A.niger.The MIC of S.aureus is smaller than that of E.coli.The growth curve indicated that proanthocyanidins almost completely inhibited the growth of S.aureus and E.coli at the MIC concentration.4.Application of extract of Sorbus melanocarpa in the preservation of fresh-cut fruitsThe purified proanthocyanidins were applied in fresh-cut apple preservation experiments.The results showed that the weight loss rate of fresh-cut apples in the proanthocyanidin group was stronger than that of the 30%ethanol treatment group and the blank group.The hardness and sugar content of the proanthocyanidin group were basically the same as those of the other two groups.From the color difference value,it can be seen that the L*value of the proanthocyanidin group is lower than the other two groups,while the C*value is higher than the other two groups.The MDA content of the procyanidin group was significantly lower than the other two groups.The total number of bacteria contained in the MIC procyanidin group was much smaller than the other two groups.This thesis uses a eutectic solvent to extract proanthocyanidins from Sorbus melanocarpa by ultrasonic assisted extraction.Compared with ethanol,the extracted content is doubled.The crude product is purified by DM130 macroporous resin;then the purified product is subjected to antioxidant and the study of antibacterial activity shows that it has strong anti-oxidation and antibacterial ability;finally,its application in the preservation of fresh-cut apples shows that it has a certain preservation effect.更多还原