【作者】 董书阁；

【导师】 管斌；

【作者基本信息】 中国海洋大学 ， 水产品加工及贮藏工程， 2007， 硕士

【摘要】 随着苹果产量的增加和苹果产业的发展,提高苹果产业效益成为保持苹果产业稳定健康发展的关键,苹果加工新产品的开发是苹果产业增效的一条重要途径,苹果醋发酵产品有良好的市场前景。优质醋酸发酵产品的开发是稳定和促进市场发展的基础。本研究从苹果应用于生产优质醋酸发酵产品入手,围绕提高醋酸发酵效率及苹果醋风味质量这一核心,应用微生物基本分离方法,采用现代发酵新技术和化学分析技术,研究了苹果醋酿造技术。酒精发酵是苹果醋生产的前提。采用果粮混酿的方法生产酒精。选择了果酒酵母D1作为发酵菌株,确定了果粮比例为1:1,发酵初始总糖度为13%。通过单因素试验和响应面优化试验设计得出了最佳酒精发酵条件。添加适量的尿素和硫酸铵都能促进酵母产酒精。无机盐MgSO4和KH2PO4也都能促进酵母产酒精。最适添加量为:(NH4)2SO4:0.15%;KH2PO4:0.05%;MgSO4:0.1%。发酵终了酒精浓度为7.8%,发酵周期为108h。从醋醅和自然腐烂发酵的苹果中分离出两株醋酸菌,分别命名为DT-2和AD1。菌种鉴定菌株DT-2为攀膜醋杆菌,菌株AD1为弱氧化醋杆菌。并通过单因素试验和响应面优化实验设计确定了它们的最佳发酵条件。以酒精发酵结束后的酒精液为原料,以菌株DT-2为发酵菌株,酿制苹果醋。发酵液中含有一定量的还原糖有利于发酵产酸,但若糖含量较高则会抑制醋酸发酵产酸;同样较高的酒精浓度也会抑制醋酸发酵产酸。当发酵液酒精度为6%,糖度为0.8%时,苹果醋含酸量为5.36%,此时酒精转酸率最高。加入底酸乙酸会促进醋酸发酵产酸,加入量控制在0.5～1.5%比较合适。采用标准型通风发酵罐液体发酵生产苹果醋。果粮混酿酒精发酵,发酵终了酒精浓度为7.08%,发酵周期为36h;醋酸发酵终了总酸含量为5.63%,发酵周期为72h。用纯苹果汁酒精发酵,发酵终了酒精浓度为6.55%,发酵周期为4天。调整发酵液酒精浓度为3%,以醋酸菌AD1为试验菌株生产苹果醋饮料,发酵终了总酸含量为2.67%,发酵周期为7天。添加蔗糖、柠檬酸、乳酸钙可明显消除苹果醋饮料的刺激味,通过单因素试验和正交试验确定了苹果醋饮料的最佳配方:苹果醋饮料:100mL;蔗糖:12 g;柠檬酸:100mg;乳酸钙:150mg。采用双菌——菌株DT-2和菌株AD1发酵有利于提高苹果醋的风味和营养。最佳条件为接种比例为3:2、接种量为7%、接种次序为接种菌株DT-2 12h后接种菌株AD1。发酵终了总酸含量为4.70%,发酵周期为5天。更多还原

【Abstract】 The crux of maintaining the apple industry developing steadily and healthily is to enhance its benefit keeping pace with the increasing of apple quantity and the development of apple industry.New apple products development is an important way to raise the benefit. Now that the products of acetic acid fermentation have good market vista, the bases to stabilize and develop the market are the application of advanced techniques and the enhancement of its quality.Beginning with the application of apples to the production of apple acetic acid fermentation products, in the ways of basic microbial techniques, advanced fermentation and analysis techniques, the research works of apple vinegar brewing techniques and measures of enhancing acidification ability and flavor quality have been conducted.Because alcohol fermentation is the precondition for apple vinegar production,alcohol produced by using Fruit-Grain mixed fermentation was studied first.Wine Yeast D1 was selected as the starting yeast.It was determined that the optimum proportion of fruit-grain was 1:1 and primary total sugar was 13%. The optimum alcohol fermentation conditions were optimized by single factor test and by SAS software combined with the Plackett-Burman design and Response surface analysis method. Approp- riate Urea and Ammonium sulfate addition could advance the alcohol production .MgSO4 and KH2PO4 addition also could advance the alcohol production .The optimal addition was that (NH4)2SO4 0.15%;KH2PO4 0.05% and MgSO4 0.1%.The ultimate alcohol concentration was 7.8% and the fermentation cycle was 108h.Two strains of acetic bacteria were screened from vinegar grains and rotten apple,named DT-2 and AD1.Results of strain identification showed that the strain DT-2 was Ace.ascendens and the strain AD1 was Ace. Subxydans. The optimalfermentation conditions were optimized by single factor test and by SAS software combined with the Plackett-Burman design and Response surface analysis method.Then this research studied the brewing of apple vinegar by strain DT-2,using the alcohol from fermentation.The fermented broth containing some sugar benefited acidification,but higher sugar concentration can restrain acetic acid fermentation. Higher alcohol concentration can res- train acetic acid fermentation too.While the alcohol concentration was 6% and the sugar concentration was 0.8%,the acetic acid concentration was 5.36% and the acidification yield from alcohol was highest.Acetic acid addition can advance acidification and the optimal addition concentration was 0.5%～1.5%.Apple vinegar produced in 5L fermentor was also studied.The ultimate alcohol concentration was 7.08% in the fruit-grain mixed fermentation,and the fermentation cycle was 36h.The ultimate total acid concentration was 5.63% in vinegar fermentation,and the fermentation cycle was 72h.Furthermore pure apple juice for alcohol fermentation was studied,the ultimate alcohol concentration was 6.55%,and the fermentation cycle was 4 days.As for apple vinegar beverage production by the strain AD1,While the alcohol concentration was adjused to 3% in the fermentation broth,the ultimate acid concentration was 2.67%,and the fermentation cycle was 7 days.Adding cane sugar,citric and calcium lactate can remarkably eliminate the irritate taste of apple vinegar beverage.The optimal recipe of apple vinegar beverage determined by single factor test and orthogonal test was:apple vinegar beverage 100mL,cane sugar 12g,citric acid 100mg and calcium lactate 150mg.Finally this research showed the fermentation by two strains DT-2 and AD1 was beneficial to advance the flavor and nutrition of the apple vinegar.The optimal conditions were: the strains proportion DT-2 to AD1 3:2,the inoculate volume 7%,the inoculate sequence inoculating the strain DT-2,12h later inoculating the strain AD1.The ultimate total acid concentration was 4.70%,and the fermentation cycle was 5 days.更多还原