泡菜中植物乳杆菌的筛选及益生活性研究

从民间自制泡菜中筛选乳酸菌。根据菌落形态,革兰氏染色和溶钙透明圈,分离得到17株乳酸菌菌株,用16S r DNA测序鉴定分离菌株,并测试了其耐酸和耐胆盐能力。结果表明,筛选菌株中WHLP-01、WHLP-02、WHLP-03和WHPE-02四株菌株可以在p H=2.0的环境下生存2 h;WHLP-01与WHLP-02两株菌株可以在0.3%胆盐浓度下存活;其中菌株WHLP-01属植物乳杆菌,其对常见的8株致病菌均有明显的抑制效果和降胆固醇能力,可以作为微生态制剂的候选菌株深入研究。     

冬果梨果酒酵母的筛选及鉴定

以冬果梨作为富集培养基,对野生酵母菌株进行收集、分离,得到980株;采用TTC平板法、耐乙醇性能测定以及产乙醇性能测定共三级筛选,最终筛得一株可耐受18%vol乙醇、乙醇产量达7.79%vol、发酵过程中糖利用率92.75%的菌株L-0301。通过对筛选所得菌株L-0301的形态特征观察、26S rDNA D1/D2区序列分析方法对菌株进行分类鉴定,结果显示,菌株L-0301为酵母亚科酵母属酿酒酵母菌（Saccharomyces cerevisiae）。     

棉酚降解菌的筛选、鉴定及棉粕固态发酵效果研究

目的:筛选分离出棉酚降解菌株,研究其生长降解特性和对棉粕中棉酚脱毒效果,为深入研究微生物降解棉酚的机制提供依据。方法:从山东棉花产地采集土壤样本,以醋酸棉酚为唯一碳源,稀释涂布法分离筛选出一株具有棉酚降解能力的菌株,通过16S rRNA基因序列系统发育分析以及生理生化特征对菌株进行初步鉴定,确定菌属。用高效液相色谱测定其对棉酚的降解和棉粕固态发酵脱毒效果。结果:筛选到一株可以降解棉酚的细菌,命名为YL01,初步鉴定为拉乌尔菌属Raoultella sp.。该菌株除利用棉酚外,还可以邻苯二酚、原儿茶酸和对苯醌为唯一碳源生长。YL01在以棉酚为唯一碳源的无机盐液体培养基中生长10 d后,棉酚的降解率为48%;接种该菌株到棉粕中,通过固态发酵,8 d内棉粕中棉酚含量下降43%,蛋白含量增加10%。结论:本研究分离筛选到一株棉酚降解菌Raoultella sp. YL01,为进一步深入研究棉酚的微生物降解机制奠定了基础,其对运用生物处理技术消除棉粕中棉酚具有潜在的应用前景。     

利用96孔板和酿酒酵母生长圈复合筛选高产管囊酵母

野生酿酒酵母不能利用木糖作为碳源,但是可以利用乙醇作为碳源和能源。管囊酵母可以利用木糖生产乙醇。酿酒酵母可以利用管囊酵母生产的乙醇作为碳源。本研究将管囊酵母进行紫外诱变后,利用96孔板培养,选取OD值较高的孔进行酿酒酵母生长圈筛选。管囊酵母在木糖(5%)为唯一碳源的YNB培养基上生长并产生乙醇。产生的乙醇越多,指示菌酿酒酵母的生长圈相对越大。利用酿酒酵母生长圈法筛选的正变率为35.22%,筛出1株菌UV171,乙醇产量为10.7 g/L,比对照高25.9%,对菌株UV171进行稳定性实验,传至3代其产量稳定。     

果蔬酵素中优良酵母菌的分离、鉴定及耐受性研究

该研究采用传统培养分离技术从自然发酵的果蔬酵素中分离酵母菌,通过高糖、乙醇耐受性测定从中筛选优良菌株,采用形态观察、生理生化试验及分子生物学技术对其进行菌种鉴定,并对其低pH、高糖、乙醇及高温耐受性进行分析。结果表明,分离筛选得到一株优良酵母菌,编号为7-1-1,经鉴定,该菌株属于异常威克汉姆酵母（Wickerhamomyces anomalus）,其具有良好的耐受性,能在低pH（1.5）、高糖（900 g/L）的培养基上生长,可耐受体积分数为14%的乙醇和37 ℃的高温,可为果蔬发酵剂的开发奠定一定的基础。     

新疆酿酒葡萄表皮乳酸菌的分离鉴定及耐受性分析

以新疆酿酒葡萄表皮为原料,经分离、鉴定和耐受性分析,筛选适合新疆葡萄发酵的乳酸菌。结果表明,使用MRS培养基从新疆酿酒葡萄表皮中共分离纯化出37株乳酸菌,主要分为4类。通过形态观察及16S rDNA基因序列分析,其中菌株axb81、axb80、axb79均被鉴定为柠檬明串珠菌（Leuconostoc citreum）,菌株axb74被鉴定为乳酸乳球菌乳酸亚种（Lactococcus lactis subsp. lactis）。菌株axb74和axb79的pH、乙醇、SO2、盐的耐受性分析结果表明,菌株axb74最高耐受12%乙醇、pH 3.5、80 mg/L SO2、8%氯化钠,菌株axb79最高耐受11%乙醇、pH 3.0、80 mg/L SO2、9%氯化钠。     

传统发酵豆腐酸浆中高产酸乳酸菌的分离鉴定及特性分析

该研究从采集于全国具有代表性的6大豆腐产地的7种豆腐酸浆老汤中分离筛选各样品中高产酸乳酸菌,通过形态观察及分子生物学技术对其进行鉴定,并对其产酸特性、耐酸特性及耐盐特性进行研究。结果表明,分离筛选到7株产酸性能优良的乳酸菌,并鉴定菌株L2-03、L3-01、L6-07与L7-01为玉米乳杆菌（Lactobacillus zeae）,菌株L1-02、L8-03与L10-01为副干酪乳杆菌（Lactobacillus paracasei）。除菌株L6-07外,6株乳酸菌均能产草酸、酒石酸、丙酮酸、乳酸、乙酸、富马酸及琥珀酸共7种有机酸,其中乙酸与乳酸为主要有机酸。产酸能力方面,菌株L6-07产酸量最高,达25.69 g/L,产酸能力最强;耐酸性方面,菌株L6-07在pH 2.5的酸性条件下仍能保持生长,耐酸性最好;耐盐性方面,菌株L1-02在5%NaCl条件下表现出较强的耐受性,耐盐性最强,菌株L6-07次之。     

发酵木糖产酒精酵母菌的初步研究

采用稀释平板法及划线分离法从自然环境中筛选获得120株形态特征不尽相同的酵母菌,然后通过发酵木糖、葡萄糖试验获得6株能利用木糖为唯一碳源生长的酵母菌株,其中有1株分解木糖产乙醇能力较佳,其发酵条件为:96r/min摇瓶发酵、温度为30℃、木糖浓度为3.0%时木糖转化率最高达7.1%。     

白酒黄水中纤维素降解菌的分离鉴定及产酶活性研究

为拓展纤维素降解菌资源,以羧甲基纤维素钠（CMC-Na）为唯一碳源作初筛培养基,从浓香型白酒发酵副产物黄水中分离得到18株具有产纤维素酶能力的菌株进行纯培养。形态学、生理生化和系统发育鉴定结果显示,菌株XH01、XH04、XH05、XH18为Bacillus cereus,菌株XH34为Bacillus circulans,菌株SW01、SW05为Bacillus megaterium,菌株SW02为Bacillus endophyticus,菌株SW03、SW04为Bacillus simplex,菌株SW09、SW13为Bacillus bataviensis。菌株ZL08为Penicillium camemberti,菌株ZL13为Aspergillus fumigatus,菌株ZL04和ZL25为Penicillium chrysogenum,菌株ZL15和ZL17为Alternaria tenuissima。利用二硝基水杨酸法对菌株发酵液纤维素酶活进行研究,结果表明,菌株SW02的产酶活性较高,其羧甲基纤维素酶活为153.36 U/mL,β-葡萄糖苷酶活为126.00 U/mL,微晶纤维素酶活为17.64 U/mL,滤纸酶活为30.48 U/mL。     

可降解咖啡碱菌株的筛选与鉴定

目的：筛选能够降解咖啡碱的细菌,以期在该毒素的生物脱毒中得到应用。方法：以咖啡碱作为唯一碳源和氮源进行咖啡碱降解菌株的初筛,之后将初筛的10 株菌通过液体培养基咖啡碱降解实验最终筛选出降解能力最强的1 株菌。结果：筛选出的HZ-1 菌株在48h 即可将咖啡碱完全降解,对目标菌株细胞形态、生理生化以及16SrDNA 进行鉴定,确定该菌株为Pseudomonas lutea,属于假单胞菌属。结论：利用咖啡碱作为唯一碳源和氮源从土壤中筛选出降解咖啡碱良好的菌株,为脱除咖啡碱提供了微生物菌种,填补了国内空白。     

Screening of cider yeasts for sparkling cider production (Champenoise method)

A total of 350 colonies isolated from a cider cellar in Asturias (Spain) were identified by rDNA ITS-RFLP restriction analysis. Saccharomyces spp. strains were characterized by mitochondrial DNA (mtDNA) restriction analysis. Fifty-four different Saccharomyces spp. strains were identified and tested to ascertain their capacity to carry out secondary fermentation of sparkling ciders. The screening of yeasts to determine their principal enological characteristics (tolerance to ethanol, production of volatile acidity and hydrogen sulphide) was accomplished by means of rapid, non-expensive assays (plate agar). As a result, 13 (24%) of the 54 initial Saccharomyces spp. yeast strains were eliminated. The technological properties assessed were flocculation capacity, ethanol and sulphite tolerance, and production of major volatiles. Ten Saccharomyces cerevisiae strains were characterized as true flocculants; all of these strains were able to grow in ethanolic medium and in the presence of 200mg/l of sulphite. Applying cluster analysis to the production of amyl alcohols, isobutanol, propanol and 2-phenylethanol, the strains were classified in two natural groups. Two flocculent yeast strains referred to as 3' and 50', representative of the each statistical group, were selected together with two reference strains (Saccharomyces bayanus C6 and S. cerevisiae Levuline CHP) to elaborate four sparkling ciders by the Champenoise method. The analysis of variance (p<0.01) among ciders revealed that glycerol, acetaldehyde, ethyl acetate, methanol, propanol, i-butanol and 2-phenylethanol were significantly influenced by the secondary yeast strain. The results of sensory analysis indicated that all the sparkling ciders were scored as good. No significant differences among sparkling ciders were found for odour attributes and taste intensity.     

Apple Aminoacid Profile and Yeast Strains in the Formation of Fusel Alcohols and Esters in Cider Production

The amino acid profile in dessert apple must and its effect on the synthesis of fusel alcohols and esters in cider were established by instrumental analysis. The amino acid profile was performed in nine apple musts. Two apple musts with high (>150 mg/L) and low (<75 mg/L) nitrogen content, and four enological yeast strains, were used in cider fermentation. The aspartic acid, asparagine and glutamic acid amino acids were the majority in all the apple juices, representing 57.10% to 81.95%. These three amino acids provided a high consumption (>90%) during fermentation in all the ciders. Principal component analysis (PCA) explained 81.42% of data variability and the separation of three groups for the analyzed samples was verified. The ciders manufactured with low nitrogen content showed sluggish fermentation and around 50% less content of volatile compounds (independent of the yeast strain used), which were mainly 3‐methyl‐1‐butanol (isoamyl alcohol) and esters. However, in the presence of amino acids (asparagine, aspartic acid, glutamic acid and alanine) there was a greater differentiation between the yeasts in the production of fusel alcohols and ethyl esters. High contents of these aminoacids in dessert apple musts are essential for the production of fusel alcohols and most of esters by aromatic yeasts during cider fermentation.     

YEAST STRAIN AND KINETIC ASPECTS OF THE FORMATION OF FLAVOUR COMPONENTS IN CIDER

An apple juice was fermented at 8°C using twelve strains of Saccharomyces uvarum. Glucose, fructose, malic and L-lactic acids, isobutanol, 2,3 butanediol, isoamyl alcohol, ethyl acetate and titratable acidity were determined and monitored in the course of fermentation. It was observed that yeast strains differed from one another mainly in fermentation rates. When components were determined in ciders of the same remaining fructose concentration, rather than after the same fermentation time, the only significant effect of the yeast strain was on the amounts of glucose and ethanol in sweeter cider (fructose 34 g/litre), or on the amounts of glucose, acetic acid, isobutanol and amyl alcohols in dryer ciders (fructose 17 g/litre). A sensory analysis showed that standard deviations of concentrations of remaining or formed components in ciders fermented by different yeast strains, was sufficient to be detected by the taste panel. Added glucose in this range of concentration (1.5 g/litre) in cider reduced the perception of sourness while the addition of acetic acid (0.3 g/litre) reduced the perception of the scented flavour. Added Isobutnol (6 mg/litre) reduced the perception of sweetness. No significant effect of added isoamyl alcohol (30 mg/litre) could be detected. Chemical determinations were correlated by means of regression equations derived from earlier work with some organoleptic characteristics. No anticipated effect of the yeast strain could be detected on any studied flavour characteristic. It is concluded that in ciders of the same attenuation, the effect if it does exist, of the S.uvarum strain isolated from ciders, must be low.     

Sulphite binding in ciders

Summary The extent of sulphite binding was measured in commercial ciders, and experimentally observed binding curves were compared with theoretically derived curves based on assessment of the levels of individual sulphite binding compounds determined in the ciders. Subsequently, experimental ciders were fermented under various controlled conditions using nine different strains of cider yeasts. The results indicated considerable differences both in the levels of sulphite binding compounds produced, and in the ability of different yeast strains to produce SO₂ in the cider. Juice concentration and the presence of cloud in juice had little or no effect on sulphite binding. Other factors which affected sulphite binding included the type and condition of juice (especially the effect of pectinase treatment) and, in some instances, the use of added yeast nutrients. Significant sulphite binding was also attributable to unaccountable components, probably derived from poor quality fruit, which were present in the apple juice prior to fermentation.     

Addition of fumaric acid and sodium benzoate as an alternative method to achieve a 5-log reduction of Escherichia coli O157:H7 populations in apple cider

A study was conducted to develop a preservative treatment capable of the Food and Drug Administration-mandated 5-log reduction of Escherichia coli O157:H7 populations in apple cider. Unpreserved apple cider was treated with generally recognized as safe acidulants and preservatives before inoculation with E. coli O157:H7 in test tubes and subjected to mild heat treatments (25, 35, and 45 degrees C) followed by refrigerated storage (4 degrees C). Fumaric acid had significant (P < 0.05) bactericidal effect when added to cider at 0.10% (wt/vol) and adjusted to pH 3.3, but citric and malic acid had no effect. Strong linear correlation (R2 = 0.96) between increasing undissociated fumaric acid concentrations and increasing log reductions of E. coli O157:H7 in apple cider indicated the undissociated acid to be the bactericidal form. The treatment that achieved the 5-log reduction in three commercial ciders was the addition of fumaric acid (0.15%, wt/vol) and sodium benzoate (0.05%, wt/vol) followed by holding at 25 degrees C for 6 h before 24 h of refrigeration at 4 degrees C. Subsequent experiments revealed that the same preservatives added to cider in flasks resulted in a more than 5-log reduction in less than 5 and 2 h when held at 25 and 35 degrees C, respectively. The treatment also significantly (P < 0.05) reduced total aerobic counts in commercial ciders to populations less than those of pasteurized and raw ciders from the same source (after 5 and 21 days of refrigerated storage at 4 degrees C, respectively). Sensory evaluation of the same ciders revealed that consumers found the preservative-treated cider to be acceptable.     

YEAST STRAIN AND THE FORMATION OF FLAVOUR COMPONENTS IN CIDER

Two apple juices were fermented at 8°C and 18°C using thirteen strains of Saccharomyces uvarum. Glucose, fructose, malic, lactic, isobutanol, 2–3 butanediol, isoamyl alcohol, ethyl acetate and titratable acidity were determined in the two resulting experimental ciders. This data was correlated by means of multiple regression equations derived from earlier work with the following organoleptic characteristics: sweetness, sourness, fruity, scented, sharp and irritating flavours and a “global hedonic score” for overall acceptability. A significant effect of yeast strain could be detected on all component concentrations except ethanol, ethyl acetate, amyl alcohols and titratable acidity. The amounts of malic acid and titratable acidity found in cider depends mainly on the source of the juice. The anticipated effect of the source of the juice on sourness and on sharpness and fruity flavours is therefore significant. Yeast strain is also expected to have a significant effect on fruity and sharp flavours as well as on overall acceptability.     

不同原料苹果酒的酿造特性研究

以‘金世纪’单一苹果品种及‘金世纪’、‘嘎啦’、‘澳洲青苹’混合（1∶1∶1）苹果品种为原料酿造苹果酒,并对其进行理化指标、多酚物质、香气成分测定及感官品评。结果表明,两种苹果酒理化指标差异不显著（P＞0.05）;混合发酵苹果酒中的酚类物质总量（61.88 mg/L）显著高于单独发酵苹果酒（56.90 mg/L）（P＜0.05）,其中以原儿茶酸、儿茶素、原花青素、表儿茶素和绿原酸为主。香气主要以醇类和酯类物质为主,两种苹果酒中醇类物质含量分别为216.83 mg/L和78.85 mg/L;酯类以乙酸乙酯、乙酸丙酯、乳酸乙酯和乙酸己酯为主,前三者在混合发酵苹果酒中含量均显著高于单独发酵苹果酒（P＜0.05）,使其香气更加浓郁和复杂。混合发酵苹果酒在澄清度、回味、香气、风味平衡方面更好,但在色泽方面稍差。因此,混合苹果品种发酵更适合于苹果酒的酿造。     

Effect of processing treatments on the characteristics of juices and still ciders from Ontario‐grown apples

Recent interest in the commercial production of cider in Ontario, Canada revealed a lack of information on cider prepared from apples grown in North America. A study was conducted using locally grown culinary and dessert varieties of apples, since there is a lack of true cider varieties grown in Ontario. Four processing methods (treatments) were evaluated with respect to their effect on juice and cider characteristics; the chemical and microbiological characteristics of the juices and still ciders are reported. Sulphite addition to the juice at the time of juice extraction had no effect on the characteristics evaluated. Storage of fruits at 13 °C until they showed signs of shrivelling or senescence decreased juice yield and affected titratable acidity and pH levels of juices and ciders. Freezing fresh apples and thawing prior to processing produced juices that did not undergo keeving and had higher mould and yeast populations; methanol was present in juices and ciders from thawed apples. The significant effects of storage and freezing on apple juice characteristics should be taken into account when considering a delay in the processing of apples for cider production. © 2003 Society of Chemical Industry     

苹果酒中酚酸、黄烷-3-醇的检测

以小国光(Ralls)和富士(Fuji)及其所酿制的新鲜苹果酒为试验材料,采用反相高效液相色谱法测定分析苹果原汁、发酵中酒样和苹果成品酒中11种酚酸、5种黄烷-3-醇的含量。结果表明:苹果和苹果酒中存在4种酚酸(原儿茶酸、绿原酸、咖啡酸、对-香豆酸)、2种黄烷-3-醇(儿茶素和表儿茶素);不同品种的苹果原汁和苹果成品酒中酚类物质的含量都存在显著差异。其中,小国光苹果和小国光苹果酒中的酚类物质总含量较高;对于每个品种,绿原酸都是最主要的酚酸类物质,含量最高的黄烷-3-醇类物质都是表儿茶素。随着发酵过程的进行,苹果酒中酚类物质的含量有不同程度的增加。其增加趋势为S型曲线,即先平缓再较快再平缓。