【作者】 John Owusu；

【导师】 马海乐；

【作者基本信息】 江苏大学 ， Food Science and Engineering， 2013， 博士

【摘要】 摘要：近些年来,水果和蔬菜的消费量之大,引起了广泛关注。这可能是因为,研究报告表明冠状动脉心脏病,糖尿病,白内障和不同类型的癌症等发病情况与果蔬的消费状况呈现反比关系。番茄是世界上消费最多的蔬菜品种之一,是类胡萝卜素,番茄红素等的主要来源,具有较强的抗氧化作用。并且番茄中还含有较高的β胡萝卜素,维生素C,维生素E,黄酮类和酚类物质。新鲜番茄的含水量约95%,极易变质,因此仅可以保藏几个星期。为了延长其保质期,必须对番茄进行处理。本研究为利用bayanus, BV818型酿酒酵母将番茄加工成番茄酒。将新鲜番茄的pH分别调整为4.11,3.40和3.20,在15和20℃进行酒精发酵,将在此三个pH水平下生产的番茄酒被指定为酒A和酒B。该研究的目的是监测番茄发酵情况,确定番茄酒的物理化学性质,评估的番茄酒中的生物活性成分及其抗氧化活性物质,建立番茄酒陈化过程中的颜色变化模型,比较不同时间的陈化番茄酒与利用33kHz超声波处理酒的质量关系,评定番茄酒生产过程中的挥发性化合物成分和感官性状。发酵动力学研究表明,20℃发酵比15℃发酵下糖分消耗量更多,前者发酵历时12天,而后者为17天。番茄酒(酒B)在两个发酵温度下,pH为3.20时发酵产生乙醇的速率最低,不太适合酵母活性,因此调整pH为4.20。发酵温度和pH值对发酵后的番茄酒的理化性质有显著影响(P<0.05)。番茄酒的浓度与pH值,发酵温度,乙醇含量和挥发性酸度之间没有显著性影响。番茄酒的乙醇含量介于8.15-9.25(%V/V),挥发性酸含量范围为0.0360.057克/升,此值在番茄酒最小允许量值以下。瓶中陈化90天之后,20℃发酵的番茄酒的物理化学性质在不同储藏温度下有显著差异(P<0.05),15℃发酵的番茄酒大多数理化性质在不同的储藏温度下差异不显著。此外,在90天陈化期间,对番茄酒物理化学指标进行多变量分析,并且不同发酵温度下,依据不同储藏温度将番茄酒进一步分类。一般而言,番茄酒在20℃下发酵的生物活性成分含量显著高于15℃下发酵(P<0.05)。另外,番茄酒在20℃下发酵的抗氧化活性,降低能耗和DPPH自由基清除率等显著高于15℃下发酵(P<0.05)。即使最具生物活性的成分含量,番茄酒B20显着高于其他番茄酒,Control20在降低能耗和总抗氧化活性显著高于Wine20。存储温度对番茄酒陈化过程中生物活性物质含量有显著影响(P<0.05)。番茄酒B15和C20存储于15℃条件下具有最高的总抗氧化活性值(P<0.05),番茄酒A20存储于15℃条件下具有最佳的降低能耗值(P<0.05),番茄酒C20存储于10℃和15℃下具有最佳的DPPH自由基清除率值(P<0.05)番茄酒陈化过程中,颜色参数L*,A*, B*, C*, H*和△E*变化对二次模型和线性模型进行拟合选择最佳模型,其中决定系数(R2),根均方误差(RMSE)残差平方和(RSS)和卡方(CS)作为选择标准。番茄酒二.次模型对于几乎所有的颜色参数具有最高的R2,最低的RSS, RMSE,和CS,因此此模型认为能够最好的描述番茄酒陈化过程中颜色变化。a*的变化与番茄酒中p胡萝卜素和番茄红素含量显著相关(P<0.05)。然而,b*的变化与羟基指标显著相关。通过对陈化过程树形图聚类分析表明,b*值变化与β-胡萝卜素含量相关,a*与番茄红素和花色素苷含量相关,L*与番茄酒发酵pH值相关。一般来说,储存于15℃的番茄酒的L*,a*,b*和C*值显著高于(P<0.05)存储于10℃条件下。通过对番茄酒超声处理和存储于瓶中陈化酒的理化指标表明,超声波处理的番茄酒与瓶中陈化酒有类似的理化性质。然而,大多数超声波处理番茄酒的生物活性物质含量比瓶中陈化酒显着提高(P<0.05),并且两者的抗氧化性能先类似。主成分分析(PCA)结果表明,番茄酒A和酒B发酵于15和20℃下的瓶中陈化酒的各项指标,与超声波处理酒相类似。瓶中陈化酒的△E*值显著高于(P<0.05)超声波处理的番茄酒,瓶中陈化酒的颜色比未经处理酒有显著差异。固相微萃取(SPME)技术被用于测定番茄酒中挥发性化合物,并通过气相色谱-质谱(GC-MS)和NIST库来确定挥发性化合物。挥发性化合物通过使用1-丙醇作为内标物方法获得。在番茄酒中总共有171种芳香类化合物被检出。由31种醇类,82种酯类,23种脂肪酸,19个羰基,4种呋喃,7种含硫化合物,4种萜烯类物质,和1种其他物质组成。总共有32种挥发性化合物的气味活性值大于1(OAV),而在15℃下发酵番茄酒的OAV大于1的有25种挥发性化合物,在20℃下发酵番茄酒含有29种挥发性化合物。挥发性化合物OAV大于1的成分主要为,辛酸乙酯,已酸乙酯,乙酸异戊酯,特异性香气物质。在15和20℃发酵后,辛酸乙酯,乙酸乙酯,乙酸异戊酯等香气成分分别占到全球番茄酒香气的96.12-98.44%和91.0494.81%。在15℃条件下发酵,分别在10℃和15℃条件下陈化后番茄酒的这三种化合物的分别占到97.72-98.07%和97.68-98.11%,然而,在20℃条件下发酵,在10℃和15℃条件下陈化番茄酒的这三种化合物的分别为94.89.95.66%及94.29-96.08%。发酵温度和pH值对番茄酒的挥发性化合物的组成和含量有显著性影响(P<0.05)。此外存储温度对番茄酒的挥发性成分和含量也影响较显著(P<0.05)。番茄酒生产质量合格的评级范围为4.7-5.5,规模化为7。番茄酒C15在15℃下发酵的番茄酒有最高的综合值,但在20℃下发酵的番茄酒,A10和B10被评为最佳。未来的研究方向应该对不同的酵母菌株生产番茄酒的条件血糖浓度,pH值,温度接种量进行优化实验,以及对不同的发酵条件最终番茄渣中番茄红素残留含量的影响,将此番茄红素提取并微胶囊化添加到番茄酒中。更多还原

【Abstract】 The consumption of fruits and vegetables has received much attention in recent times. This is probably because reports have indicated that there is an inverse relationship between their consumption and coronary heart diseases, diabetics, cataracts, different types of cancers, etc. Tomato is one of the most consumed vegetables in the world and a major source of the carotenoid, lycopene known to be the most efficient quencher of singlet oxygen. It is also a good source of p-carotene, vitamin C, vitamin E, flavonoids and phenolics. Fresh tomato contains about95%water and this makes it susceptible to spoilage and can therefore be kept for a few weeks. In order to extend its shelf life tomato has to be processed. In this study tomato was processed into wine using the yeast Saccharomyces bayanus, BV818. The original tomato must pH of4.11was adjusted to two other pH levels3.40and3.20and alcoholic fermentation was carried out at15and20℃, and the wines produced from the three pH levels were designated as Control, Wine A and Wine B. The objectives of the study were to monitor tomato must fermentation, determine the physicochemical properties of the wines, assess the bioactive compound composition of the wines and their antioxidant activity, model the colour of the tomato wines during ageing, compare the quality of wines aged in bottles to those aged with ultrasound of33kHz frequency, and to assess the volatile compound composition and the sensory properties of the tomato wines produced.The fermentation dynamics study indicated that sugar consumption was more efficient in the fermentation conducted at20℃than at15℃, and fermentation lasted for12days in the former but17days in the latter. At both fermentation temperatures, the wine (Wine B) made with tomato must of pH3.20gave the lowest rate of ethanol production, therefore the adjusted pH level4.20was less suitable for yeast activity.Fermentation temperature and tomato must pH significantly influenced most physicochemical properties (P<0.05) of the tomato wines after fermentation. Among the parameters whose concentration in the tomato wines were not influenced significantly by tomato must pH and fermentation temperature were ethanol content and volatile acidity. The ethanol content of the wines ranged from8.15to9.25(%v/v). The volatile acidity was in the range0.036-0.057g/L, and was below the minimum permissible level in wines. After90days bottle ageing, while most physicochemical properties of the tomato wines made at20℃were significantly affected (P<0.05) by the storage temperature, the influence of storage temperature for most physicochemical properties was not significant for those made at15℃. Also at the end of the90days ageing period, multivariate analysis of the physicochemical data indicated that the tomato wine samples were differentiated from one another mainly on the basis of fermentation temperature followed by storage temperature.Generally, significantly higher (P<0.05) bioactive compound concentration was obtained for tomato wines made at20℃than those made at15℃. In addition, the antioxidant activity, reducing power and DPPH scavenging activity was generally significantly higher (P<0.05) for wines made at fermentation temperature20℃than15℃. Even though most bioactive compound concentration of Wine B20was significantly higher than the other wines, Contro120gave significantly higher reducing power and total antioxidant activity than Wine20. Storage temperature exerted statistical significant influence (P<0.05) on the content of most bioactive compounds of the tomato wines after ageing. Wines B15and C20stored at15℃gave the best total antioxidant activity value (P<0.05), Wine A20stored at10℃recorded the best reducing power value (P<0.05), and the best DPPH scavenging activity values (P<0.05) were given by wine C20aged at both10℃and15℃. During tomato wine ageing the quadratic and linear models were fitted to the colour parameters L*, a*, b*, C*, H*and△E*us^ng co-efficient of determination (R2), root mean square error (RMSE), residual sum of squares (RSS), and Chi-square (CS) as the criteria for best model selection. For almost all the colour parameters of the wines the quadratic model gave the highest R2, the lowest RSS, RMSE, and CS, and was therefore considered the best for describing the colour changes of the wines which took place during ageing. The changes in a*was significantly related to the β-carotene and the lycopene contents of the wines (P<0.05). However, changes in b*was much correlated with the β-hydroxycinnamic index. At the end of the ageing process cluster analysis using a dendrogram indicated that the b*value was related to the β-carotene content, a*was related to lycopene and anthocyanin, and L*was related to the pH of the wines. Generally, the wines stored at15℃gave significantly higher L*, a*, b*and C*values (P<0.05) than those stored at10℃.The results on the comparative study of ultrasonic and bottle ageing indicated that the ultrasonic treated wines were of comparable physicochemical properties to the bottle aged ones. However, though most bioactive compounds concentration of ultrasonic treated wines were significantly enhanced (P<0.05) than that of bottle aged samples, the two were of comparable antioxidant properties. The principal component analysis (PCA) results indicated that wines A and B made at both15and20℃and treated with the ultrasound were likely to have much more similar properties as the bottle aged wines. Significantly higher△E*(P<0.05) was obtained for most wines aged in bottles than the ultrasonic treated wines, and the colour of the bottle aged samples could be perceived to be much different from the untreated samples.The solid phase micro extraction (SPME) technique was used for the extraction of volatile compounds from tomato wine and the volatile compounds were identified using Gas chromatography-Mass spectrometry (GC-MS) and the NIST Library. The concentration of the volatile compounds was obtained through the use of1-propanol as an internal standard. In all a total of171volatile compounds were identified in the tomato wines, and this was made up of31higher alcohols,82esters,23fatty acids,19carbonyls,4furans,7sulphur-containing compounds,4terpenes, and1other (eucalyptus). There were a total of32volatile compounds which recorded odour activity values (OAV) greater than1, and while the tomato wines made at15℃had25volatile compounds of OAV greater than1, wines made at20℃gave29volatile compounds. Out of the volatile compounds which had OAV greater than1, ethyl octanoate, ethyl hexanoate and isoamyl acetate with characteristic fruity fragrances were the major contributors to the overall aroma of the tomato wines. After fermentation at15and20℃, the joint relative odour contribution (ROC) of ethyl octanoate, ethyl hexanoate, and isoamyl acetate to the global aroma of the tomato wines produced was96.12-98.44%and91.04-94.81respectively. After ageing the ROC of these three compounds were97.72-98.07and97.68-98.11%for wines made at15℃and stored at10and15℃respectively. However, for those made at20℃and stored at10and15℃, the respective ROC values were94.89-95.66and94.29-96.08%. Fermentation temperature and tomato must pH significantly influenced (P<0.05) the volatile compound composition and concentration of the tomato wines produced. In addition storage temperature also affected the volatile composition and concentration of the tomato wines significantly (P<0.05). Tomato wines of acceptable quality was produced from tomato with rating in the range4.7to5.5on a scale of7. Wine C15recorded the highest overall acceptability among wines made at15℃, but for those made at20℃, Wines A10and B10were rated the best.The futre study should consider the tilization of a different strain of yeast in tomato wine production; optimization of sugar concentration, pH, temperature and inoculums size; and finally the effect of different fermentation conditions on lycopene content of tomato residue and the extraction of lycopene from this residue to be microencapsulated into the tomato wine.更多还原