响应面法优化风味米曲制备工艺

用异常维克汉逊酵母（Wickerhamomyces anomalus）、扣囊复膜酵母（Saccharomycopsis fibuligera）、克鲁维毕赤酵母（Pichia kudriazevii）、酿酒酵母（Saccharomyces cerevisiae）制备复配酵母,与纯种米根霉菌共培养制备风味米曲,采用单因素试验及响应面法优化制曲工艺。并以市售小曲为对照,对风味米曲进行了质量指标检测与半固态发酵制备米香型白酒验证。结果表明,最优制备工艺为酵母接种量1.0%,培养时间73 h,培养温度30 ℃。在此优化条件下,试饭的酯含量为3.65 g/L。最优工艺制备的风味米曲水分含量为10.58%,糖化力为423.77 U/g,发酵力为2.24 g/（g·72 h）。经半固态法实际酿酒后,酒体总酯含量达到了6.87 g/L,总酸含量与感官评分分别为1.63 g/L、92分,具备米香型白酒典型风格,且风味明显提升。     

酱香风味酵母抽提物的制备

添加香料、酱曲精进行酵母自溶制备抽提物,试验了温度、pH值、酱曲精加入量对酵母细胞自溶的影响。结果表明,当温度60℃、pH值6．5、加入酱曲精0．4%(酵母干重计)自溶24h效果较好,得浓厚酱香风味酵母抽提物。     

酵母抽提物对酱油种曲培养的促进作用及工艺优化研究

以酵母抽提物为促进剂,对酱油种曲培养的工艺进行优化,结果为:酵母抽提物1.30%,润水量100%,温度32℃,时间68 h,在优化条件下,孢子种曲孢子数可达13.18×10<'9>个/克干重,比对照组提高了54.88%,且孢子更为健壮.温度对种曲孢子数的影响显著,影响顺序为温度>酵母抽提物>润水量>时间.     

曲酸生产菌种的分离筛选与发酵条件研究

从土壤中分离出一株曲酸产量较高的米曲霉(Aspergillusoryzan)菌株,对该菌株的发酵条件进行了初步研究。结果表明,该菌株在淀粉8%、酵母膏0.2%、MgSO4·7H2O0.05%、K2HPO40.1%、pH6.0的培养基中,28℃恒温摇床振荡培养6d,摇瓶发酵液曲酸含量为41.2mg/mL。     

异常威克汉逊酵母的麸曲制作工艺优化

从大曲中分离得到一株产香酵母w2,将其应用在麸曲的制作中,对酵母麸曲原料配比和制曲工艺条件进行优化。试验表明,以酵母活菌总数为评价指标,酵母麸曲的最佳原料配比为:麸皮10 g、鲜酒糟5.6 g、玉米粉4.2 g。采用正交设计试验法进行酵母麸曲制曲工艺条件优化,得到酵母麸曲的最佳培养条件为:水分40%,培养时间18 h,培养温度30℃。将优化后所得的酵母麸曲应用于清香型小曲白酒工艺中,于糖化后24 h以2%的接种量可使乙酸乙酯含量增加3倍,总酯含量增加2倍。     

响应面法优化黄酒高温糖化酒母制作条件的研究

以酿酒酵母ALA01为材料对大酒母制作时物料添加量进行优化研究。利用Plackett-Burman设计筛选出麦芽、纯种曲和米浆水添加量是影响酒母质量的显著性因素,采用响应面Box-Behnken试验设计建立3个因素的二次多项式回归方程模型。优化结果显示,酵母数最佳参数是麦芽24.11 g/kg、纯种曲25.00 g/kg、米浆水324.70 g/kg,出芽率最佳参数是麦芽23.68 g/kg、纯种曲21.14 g/kg、米浆水328.56 g/kg,在各自最佳参数下,实际酵母数和出芽率分别达到2.35亿/mL和24.8%。利用酵母数最佳参数扩大培养时,酵母数达到2.37亿/mL,出芽率达到24.9%。     

绿衣观音土曲培养过程中微生物及酶系的动态变化

通过对绿衣观音土曲中微生物总数进行平板计数以及相关酶类进行跟踪检测,并结合分子生物学方法对分离获得的菌株进行鉴定,分析绿衣观音土曲培养过程中微生物及相关酶类的变化规律。结果表明,观音土曲培养过程中细菌数量最多,霉菌最少。酵母数量呈逐步上升趋势,培养后期数量达到峰值;细菌数量先上升后下降,在培养中期数量达到峰值;霉菌数量在培养后期最多。共分离鉴定出酵母8种、霉菌7种、好氧细菌7种和乳酸菌5种,酵母分别是酿酒酵母、异常威克汉姆酵母、库德里阿兹威毕赤酵母和扣囊复膜酵母等;霉菌主要为曲霉属、米根霉和毛霉等;细菌以芽孢杆菌和乳杆菌为主。糖化酶酶活最高,其次为淀粉酶,酸性蛋白酶酶活最低,3种酶活力均呈先下降后上升的趋势。     

曲坯含水量对机压包包曲品质的动态影响

为了确定机压"包包曲"适宜的曲坯含水量,在其他条件不变的情况下,采用单因素实验设计方法,研究曲坯含水量分别为37%、38%、39%、40%对大曲培养过程中品质的影响.实验结果表明:曲坯含水量对机压"包包曲"培养过程中酸度、糖化力、发酵力、霉菌数、酵母数、芽孢杆菌数等均有不同程度的影响,对新曲的感官品质也有一定的影响:最适曲坯含水量为39%.     

种曲工艺参数优化及其在酱油生产中的应用

为了确定种曲机培养种曲的最佳工艺条件,以中科3.951米曲霉菌种为研究对象,以孢子数为种曲质量评价指标,研究培养条件与种曲质量的关系。单因素和正交试验结果显示:风量对种曲质量的影响最大,补水量和酵母抽提物的用量次之,润水量的影响相对较小。100kg种曲机培养种曲的最优条件为:润水量110%,风量2m3/h,补水量70L/罐,酵母抽提物用量2.5%。最优条件下种曲孢子数可达100亿个/g(以干基计)以上,改善了酱油品质。     

应用PCR-DGGE方法研究甜酒曲中真菌多样性

提取6种甜酒酒曲的总DNA,利用真菌18S rRNA基因片段的通用引物NS1、Fung-GC,采用变性梯度凝胶电泳（PCR-DGGE）方法,进行不同甜酒酒曲中真菌多样性的分析。结果表明,6种甜酒酒曲中共分离出3属真菌和不可培养真菌,湖南韶山的甜酒曲中主要是扣囊复膜酵母属和根霉属的菌株;湖南湘潭甜酒曲中的真菌为酿酒酵母属、扣囊复膜酵母属和根霉属;湖南祁东、福建福州和浙江丽水甜酒曲中的真菌均为酿酒酵母属、扣囊复膜酵母属、根霉属和不可培养真菌;浙江兰溪甜酒曲中的真菌为根霉属和不可培养真菌。在传统的酒曲中的真菌主要是酿酒酵母属和扣囊复膜酵母属,此外不可培养真菌在甜酒酒曲中也起到非常重要的作用。     

糖化发酵剂对黄酒中高级醇含量的影响

文中分别对麦曲添加量、酵母菌种、接种量等3个工艺条件对黄酒发酵过程中高级醇积累的影响进行了研究。以麦曲为糖化剂,28℃主发酵5d,15℃后发酵15d,发酵结束后气相色谱外标法测定酒样中的高级醇。实验结果表明,当麦曲添加量在原料米重的4%～8%这一范围内,酒样中高级醇的含量随着麦曲添加量的增加而增加;在接种量0.8×107个/mL～1.2×107个/mL这一范围内,酒样中的高级醇含量随着接种量的增加而增加;菌种对于酒样中高级醇含量的影响较大,在所考察的4种菌种中以AS2.1392黄酒酵母作为发酵剂的酒样中的高级醇含量最少。     

马奶酒发酵剂用菌种的筛选研究

采用乳酸菌联合酵母的发酵方法,制备一种新型马奶酒并为工业化生产马奶酒提供新型发酵剂。通过考察8%酵母菌（F1）、6%酵母菌联合2%嗜酸乳杆菌（F2）、6%酵母菌联合2%瑞士乳杆菌（F3）、6%酵母菌联合1%嗜酸乳杆菌及1%瑞士乳杆菌（F4）以上四种发酵菌种配比,以酒精度、酸度、感官品质为考察指标,开发适合马奶酒工业化生产的优良发酵剂。结果表明,当采用6%酵母菌联合1%嗜酸乳杆菌及1%瑞士乳杆菌（F4）的发酵方式时,马奶酒酒精度为1.39%vol,马奶酒酸度为90 °T,感官评分为91分,且马奶酒香醇可口、组织均匀,适于大众饮用;因此6%酵母菌联合1%嗜酸乳杆菌及1%瑞士乳杆菌,可作为工业化生产马奶酒所用的发酵剂。     

Exploiting heterozygosity in industrial yeasts to create new and improved baker's yeasts

The main aim of the work was to utilize heterozygosity of industrial yeast strains to construct new baker's yeast strains. Commercial baker's yeast strain ALKO 743, its more ethanol tolerant descendant ALKO 554 selected initially for growth over 300 generations in increasing ethanol concentrations in a glucose medium, and ALKO 3460 from an old domestic sour dough starter were used as starting strains. Isolated meiotic segregants of the strains were characterized genetically for sporulation ability and mating type, and the ploidy was determined physically. Heterozygosity of the segregant strains was estimated by a variety of molecular characterizations and fermentation and growth assays. The results showed wide heterozygosity and that the segregants were clustered into subgroups. This clustering was used for choosing distantly or closely related partners for strain construction crosses. Intrastrain hybrids made with segregants of ALKO 743 showed 16–24% hybrid vigour or heterosis. Interstrain hybrids with segregants of ALKO 743 and ALKO 3460 showed a wide variety of characteristics but also clear heterosis of 27–31% effects as assayed by lean and sugar dough raising. Distiller's yeast ALKO 554 turned out to be a diploid genetic segregant and not just a more ethanol tolerant mutant of the tetraploid parent strain ALKO 743.     

米发糕的双菌发酵剂工艺研究

以早籼米为原料,利用酵母茵和乳酸茵复配制成米发糕的专用发酵剂,研究两种茵的培养及比例对米发糕品质的影响,确定适宜的工艺配方.结果表明:采用马铃薯培养基对酵母茵进行培养和增茵;采用麦芽浸汁粉培养基对乳杆菌进行培养和增茵;将茵悬液按数量比为酵母菌∶乳酸菌=107∶107进行混合后浓缩至6.5％,加入8.5％米粉,0.3％白糖和0.15％单甘酯,混匀于32℃下热风干燥至含水量为13％.发酵剂贮藏一段时间后制作的米发糕品质略有下降.     

酒曲中生香酵母的分离及生理生化鉴定

从酒曲中筛选出11株生香酵母,并对其形态及生理生化特性进行研究,确定其种属。筛出菌后进行发酵测发酵液中总酯含量,选出高产优质菌株。在11株产酯酵母中,产酯最高的菌株是X7,其发酵液总酯含量达到1.78 g/L。     

Impact of yeast starter formulations on the production of volatile compounds during wine fermentation

The most diffused starter formulation in winemaking is actually represented by active dry yeast (ADY). Spray‐drying has been reported as an appropriate preservation method for yeast and other micro‐organisms. Despite the numerous advantages of this method, the high air temperatures used can negatively affect cell viability and the fermentative performance of dried cells. In the present study, 11 wine S. cerevisiae strains (both indigenous and commercial) were submitted to spray‐drying; different process conditions were tested in order to select the conditions allowing the highest strain survival. The strains exhibited high variability for tolerance to spray‐drying treatment. Selected strains were tested in fermentation at laboratory scale in different formulations (free fresh cells, free dried cells, immobilized fresh cells and immobilized dried cells), in order to assess the influence of starter formulation on fermentative fitness of strains and aromatic quality of wine. The analysis of volatile fraction in the experimental wines produced by selected strains in different formulations allowed identification of > 50 aromatic compounds (alcohols, esters, ketones, aldehydes and terpenes). The results obtained showed that the starter formulation significantly influenced the content of volatile compounds. In particular, the wines obtained by strains in dried forms (as both free and immobilized cells) contained higher numbers of volatile compounds than wines obtained from fresh cells. Copyright © 2014 John Wiley & Sons, Ltd.     

Use of response surface methodology to investigate the effects of processing conditions on sourdough wheat bread quality

Response surface methodology was used to investigate the influence of three factors, sourdough fermentation time, proof time and amount of yeast addition on the quality of sourdough wheat bread. Each predictor variable was tested at five levels. Sourdough fermentation times were 5, 11, 20, 29 and 35 h, yeast addition rates were 0.05, 0.75, 1.77, 2.80 and 3.50% (flour weight basis) and proof times were 16, 40, 75, 110 and 134 min. The performance of two different starter culture types, a mixed strain starter culture called Böcker Reinzucht–Sauerteig Weizen and a single strain starter culture of Lactobacillus brevis, was compared by separately completing the experimental design for each. Independently non-acidified control bread was prepared. A range of loaf quality parameters was determined including pH, total titratable acidity, loaf height, specific volume, crumb mean cell area and crumb hardness. Overall breads with better specific volume values were achieved with the use of sourdough relative to the control. Results indicated that maximum loaf specific volume was achieved when L. brevis sourdough was used particularly when it was used in conjunction with a high rate of yeast. Given a lower rate of yeast addition however, the mixed strain starter culture yielded better bread.     

双歧杆菌酸奶生产工艺的优化

通过研究婴儿双歧杆菌和长双歧杆菌在脱脂乳中的生长特性、影响其发酵的因素以及发酵方式 ,优化出双歧杆菌酸奶的最佳生产工艺。研究结果显示 ,选用长双歧杆菌制作酸奶时 ,在乳中添加 0 3 %酵母粉 ,低聚糖取代 10 %的蔗糖 ,接菌量为 10 % ;选用婴儿双歧杆菌制作酸奶时 ,在乳中添加 0 6%的酵母粉 ,以低聚糖取代 2 0 %的蔗糖 ,接菌量为 15 %。 3 9℃条件下发酵 ,然后再按 1∶1的比例与普通酸奶混合 ,所制得的酸奶在贮存期间 ,活菌数可达到10 8cfu/mL以上。     

野木瓜酵素发酵过程中活性成分的变化

本研究以贵州野木瓜为原料,采用三种优势菌群为不同的发酵剂制备野木瓜酵素,并分析不同发酵剂对其主要活性物质（总三萜、总黄酮、儿茶素、超氧歧化酶SOD）含量损耗的影响,结果表明：高效酒曲发酵结束后总三萜由6.79 mg/100 mL降低到5.71 mg/100 mL,降低了15.91%,总黄酮含量下降了40.00%,儿茶素含量下降了37.78%,SOD活性下降了56.32%;曲王发酵结束后总三萜含量下降了38.73%,总黄酮含量下降了58.82%,儿茶素含量下降35.56%,SOD活性下降了42.27%,变化显著（p<0.05）;甜酒曲发酵结束后总三萜升高0.74%,总黄酮含量下降15.89%,儿茶素含量下降0.11%,SOD活性下降了48.73%。综上可知,不同的发酵剂发酵后活性物质成分均有损耗,优势菌群不同,损耗程度有所差异,其中采用酵母菌、醋酸菌、乳酸菌复配而成的甜酒曲发酵结束后活性成分的衰减程度最低,因此,以酵母菌、醋酸菌、乳酸菌复配而成的发酵剂可应用于野木瓜酵素工业化生产中。     

产酒酵母的筛选鉴定及其在小曲中的应用

以采自川西南片区的10种曲样中分离出的18株酵母为研究对象,以产酒能力为主要指标,通过三级筛选得到一株优良产酒酵母Y-18,经分子鉴定确定其为酿酒酵母（Saccharomyces cerevisiae）。将其制作成纯种的酵母曲并和根霉曲进行复配试饭。结果表明,酵母Y-18在大米粉发酵培养基中的残糖含量最低,酒精度最高,分别为0.69 g/100 mL和10.3%vol;在60 g蒸熟大米中,添加酵母曲1.8 g、根霉曲0.5 g时,试饭酒精度最高（7.24%vol）、酸度适中、糖分最低。