【作者】 李拥军；

【导师】 孙远明；

【作者基本信息】 华南农业大学 ， 食品科学， 2019， 博士

【摘要】 为提高茶叶利用率,扩大其用途,有必要对茶叶进行深加工研究。茶酒是以茶叶为原料,经发酵或配制等工艺生产的低度酒,目前市场品种较少,且多为配制型。本论文选择广东单丛（枞）茶为原料发酵生产茶酒,对茶酒的发酵菌种筛选驯化、发酵工艺、成分分析及功能活性评价进行了研究。主要研究内容及结果如下:1.单丛茶酒发酵工艺。首先将酿酒酵母在不同配比茶汁麦芽汁培养基中培养,筛选出耐茶汁环境最强的驯化菌株,然后用⁶⁰Coγ射线诱变并筛选出长势最优的茶酒酵母T-5,最后将其连续10代发酵含糖茶汁,发现该菌株遗传稳定性良好。进而在单因素试验的基础上,采用U₁₅（3¹×5²）均匀试验考察酵母接种量、发酵温度及发酵液初始p H三因素对发酵液糖度、茶酒感官评价指标的影响,最终确定酵母接种量3.1%、发酵温度21℃、发酵液初始p H 3.3时,茶酒感官评分最高。本茶酒低温稳定性良好,酒精度为8.35%vol。2.单丛茶酒的成分分析。采用HPLC法检测分析了单丛茶酒中5种主要儿茶素组分GA、EC、ECG、EGC、EGCG含量的变化。结果表明,单丛茶汁发酵制备成茶酒后,各儿茶素组分含量虽有下降,但茶酒中仍含有较多儿茶素,尤其是抗氧化活性最强的EGC和EGCG含量非常高,分别占原茶汁中相应组分的78.27%和78.95%。分别通过溶剂萃取和顶空气化收集香气成分,采用GC-MS法分析鉴定茶酒中香气成分。结果表明,二氯甲烷萃取的样品共鉴定出58种成分,顶空气化获得的样品共鉴定出34种成分。两种方法获得的香气成分中,种类最多的都是酯类,且含量最高的均为正己酸乙酯。3.单丛茶酒的功能活性研究。（1）体外抗氧化活性。通过测定还原能力、清除自由基能力以及ORAC,对单丛茶酒的体外抗氧化活性进行了评价。结果表明,单丛茶酒还原能力高于等量的0.1 mg/m L抗坏血酸。除O₂^-·外,单丛茶酒清除DPPH·、ABTS·、·OH自由基能力明显强于等量的0.1 mg/m L抗坏血酸。单丛茶酒ORAC相当于Trolox ORAC的6.2倍。可见单丛茶酒具有良好的体外抗氧化活性。（2）抗疲劳活性。小鼠灌胃单丛茶酒后的力竭游泳时间显著延长,力竭游泳结束后,测得小鼠生化指标LA、MDA及BUN均有下降,而LDH、肝糖原及肌糖原均有提高,说明灌胃适量单丛茶酒有利于改善小鼠机体性能,延长小鼠运动时间,具有良好的抗疲劳活性。（3）对蛋用鸡抗氧化及其品质的影响。日粮中添加单丛茶酒可使鸡血清MDA含量下降,说明饲喂适量单丛茶酒有利于抑制血脂过氧化。蛋黄中MDA含量显著降低,表明日粮添加适量单丛茶酒后蛋黄脂质的氧化程度减弱,抗氧化能力增强。另外,鸡肉滴水损失和剪切力均显著降低,表明单丛茶酒可提高鸡肉嫩度。综上可知,通过筛选驯化的酵母菌株发酵制得的单丛茶酒是一种富含儿茶素（约占原茶汁儿茶素总量78.5%）的低度酒,具有良好的抗氧化和抗疲劳活性。在蛋用鸡基础日粮中添加单丛茶酒,还可提高鸡血清和蛋黄的抗氧化能力,改善蛋、肉品质。更多还原

【Abstract】 In order to improve the utilization rate of tea and expand its application,it is necessary to carry out deep processing research on tea.Tea wine is a low-alcohol content wine produced by a process such as fermentation or formulation using tea as raw material.However,there are few tea wine products on the market at present,and most of them are formulated tea wines.In this work,Dancong tea from Guangdong was selected as the raw material for the tea wine fermentation.The strain selection and domestication,fermentation process,composition analysis,and functional activity of tea wine were studied.The main contents and results were as follows:1.Fermentation process of Dancong tea wine.Firstly,Saccharomyces cerevisiae was cultured in different ratios of tea juice-wort media,and the strongest domesticated strains resistant to tea juice were selected.Then,the acclimated strain was mutagenized by⁶⁰Coγ-rays,and the strain with the best growth conditions named tea wine yeast T-5 was screened.Finally,the sugary tea juice was fermented for 10 consecutive generations with tea wine yeast T-5,and the strain was found to have good genetic stability.Furthermore,based on the single factor test,U₁₅（3¹×5²）uniform test was used to investigate the effects of three factors:yeast inoculum,fermentation temperature,and initial p H of the fermentation broth on the sugar content of the fermentation broth and the sensory evaluation indicators of tea wine.It was finally determined that when the yeast inoculum was 3.1%,the fermentation temperature was 21℃,and the initial p H of the fermentation broth was 3.3,the tea wine had the highest sensory score.Dancong tea wine had good low temperature stability and its alcohol content of the wine was 8.35%vol.2.Composition analysis of Dancong tea wine.The contents of five main catechin components including GA,EC,ECG,EGC and EGCG in Dancong tea wine were analyzed using HPLC method.The results showed that the content of catechins decreased after the fermentation of tea juice into tea wine,but tea wine still contained more catechins,especially EGC and EGCG contents with the strongest antioxidant activity are very high.They accounted for 78.27%and 78.95%of the corresponding components in the original tea juice,respectively.The aroma components were collected by solvent extraction and headspace respectively,and then analysed and identified using GC-MS.The results showed that a total of 58 components were identified by GC-MS analysis of the samples extracted with dichloromethane,and 34 components were identified by GC-MS analysis of the samples obtained by headspace gasification.Among the tea aroma components obtained by the two methods,the most common types are esters,and the content of ethyl hexanoate is the highest.3.Functional activity research of Dancong tea wine.（1）in vitro Antioxidant activity.The in vitro antioxidant activity of Dancong tea wine was evaluated by measuring the reduction ability,free radical scavenging ability,and oxygen radical absorbance capacity（ORAC）of Dancong tea wine.The results showed that the reducing ability of Dancong tea wine was higher than the equivalent amount of 0.1 mg/m L ascorbic acid.Dancong tea wine had strong ability to remove free radicals including DPPH·,ABTS·,·OH andO₂^-·.Except forO₂^-·,the abilities of the tea wine to clear other three free radicals were significantly stronger than the equivalent amount of 0.1 mg/m L ascorbic acid.The ORAC of Dancong tea wine was equivalent to 6.2 times that of Trolox.It can be seen that Dancong tea wine has good in vitro antioxidant activity.（2）Anti-fatigue activity.The exhaustive swimming time of mice after oral administration of Dancong tea wine was significantly prolonged.After the exhaustive swimming experiment,the biochemical indexes of mice such as LA,MDA and BUN were all decreased,while LDH,hepatic glycogen and muscle glycogen were all increased,indicating that the appropriate amount of Dancong tea wine was beneficial to improve the body performance of mice,prolong the movement time of mice and has good anti-fatigue activity.（3）Effects on antioxidation and quality of egg chickens.The addition of Dancong tea wine in the chicken diet can decrease the serum MDA content of the chicken,which indicated that feeding appropriate amount of Dancong tea wine was beneficial to inhibit lipid peroxidation.The MDA content in egg yolk was significantly reduced,indicating that the degree of oxidation of egg yolk lipids was weakened and the antioxidant capacity of egg yolk were enhanced after adding a proper amount of Dancong tea wine to the diet.In addition,the drip loss and shearing force of the chickens were significantly reduced,indicating that Dancong tea wine can improve the tenderness of the chicken.In summary,Dancong tea wine fermented by selected and domesticated yeast strain is a low-alcohol content wine rich in catechins（around 78.5%of the total tea catechins）,and has good antioxidant and anti-fatigue activities.Adding Dancong tea wine to egg chicken diet can also enhance the antioxidant capacity of chicken serum and egg yolk,and improve the quality of eggs and meat.更多还原