酵母菌发酵柑橘皮渣生产柠檬酸

以柑橘皮渣为原料,用酵母菌发酵生产柠檬酸,发酵液成分采用纸层层析进行鉴定,发酵液经过钙盐法处理获得柠檬酸固体。通过改变发酵温度、发酵时间、发酵液中甲醇添加量和发酵液中菌种添加量研究发酵最佳条件,根据L9（34）正交试验,最终确定酵母菌发酵柑橘皮渣生产柠檬酸的最佳条件为：发酵温度29℃,发酵时间108h,发酵液中添加8％的酵母活化液和2％的甲醇。     

浓香型白酒低产杂醇油酵母菌的筛选及特性研究

为降低白酒中杂醇油含量,从浓香型白酒生产大曲和糟醅中筛选低产杂醇油酵母菌。通过TTC培养基和乳酸培养基分离,再利用气相色谱进行产杂醇油能力分析,筛选出1株产酒能力强且低产杂醇油的酵母菌LJ-07,通过形态特征以及26S rDNA基因序列分析鉴定为酿酒酵母(Saccharomyces cerevisiae)。该菌的最适温度范围为25~30℃,最适pH6.5,且耐糖、耐乙醇性能较好。与常用的酿酒酵母菌相比,酵母菌LJ-07的杂醇油产量降低了23.53%,而产乙醇的能力持平,其他香气成分的产量几乎没有影响,该菌可用于浓香型白酒生产。     

糯米发酵炸糕酵母菌的分离鉴定及优势菌株筛选

为探究天津耳朵眼炸糕工业化纯种或混种发酵中的优势酵母菌株,以耳朵眼炸糕的沥水米浆和发酵面团为原料,首先采用米浆固体培养基划线分离纯化的方法,获得6株酵母菌。其次对其进行WL培养基菌落形态观察、个体形态显微镜观察、生理生化特征测定和18S rRNA基因序列分析,发现Y2、Y3菌株为酿酒酵母（Saccharomyces cerevisiae）,Y4为西文毕赤酵母（Pichia occidentalis）,Y7-1、Y7-2为矮小假丝酵母（Candida humilis）,Y8为溶磷白地霉（Galactomyces geotrichum）。最后测定各菌株的产气量、碳源利用率和菌体生长速度,结果显示Y2发酵产气快且产气量最大,发酵结束时发酵液中的残糖含量最低为16.33 mg,快速生长期的OD600为0.149。由此认为Y2菌株为糯米炸糕发酵生产的优势酵母菌,具有作为纯种发酵菌剂生产的潜力,为耳朵眼炸糕的品质控制和工业化生产提供了理论依据。     

Ferulic Acid Release and 4‐Vinylguaiacol Formation during Chinese Rice Wine Brewing and Fermentation

The release of ferulic acid (FA) and the subsequent enzymatic decarboxylation to 4‐vinylguaiacol (4‐VG) were nearly ubiquitous during the production of Chinese rice wine. To evaluate the release of FA and the transformation to 4‐VG, the levels of FA and 4‐VG were determined by high performance liquid chromatography (HPLC) and gas chromatography‐mass spectrum (GC‐MS), respectively. During rice wine brewing, the concentrations of FA and 4‐VG increased as fermentation time prolonged, with a rapid rise in days 1 to 5 of the main fermentation and followed by a slower rise from the 6th day post inoculation. FA and 4‐VG levels in mashes, fermented by yeast with wheat Qu, were significantly higher than those in mashes fermented by yeast using commercial enzyme additions. The release of FA from rice by wheat Qu involves an enzymatic release mechanism. The levels of FA and 4‐VG from rice flour by wheat Qu rose gradually during the first 24 h and then tended to stabilize. The capacity of yeasts to decarboxylate phenolic acids (Pof⁺ phenotype) was absent in most rice wine brewing yeasts. These results suggest that the production of FA and 4‐VG originated from materials in the wheat Qu rather than by the yeast during Chinese rice wine brewing and fermentation.     

新疆发酵驼乳中分解植酸盐酵母菌的筛选及鉴定

为发掘和保护新疆牧区传统发酵驼乳中潜在益生酵母菌资源,从新疆伊犁地区不同牧区采集12份传统发酵驼乳样品,通过酵母浸出粉胨葡萄糖（YPD）培养基分离酵母菌,通过富含植酸二钾的培养基初筛及降解植酸盐能力的测定从中筛选可降解植酸盐的酵母菌,通过形态观察、生理生化试验及5.8S rDNA ITS1/ITS4区域序列同源性分析进行菌种鉴定,并测定其耐酸及耐胆盐性能。结果表明,筛选出11株可分解植酸盐的酵母菌,鉴定8株为库德毕赤酵母（Pichia kudriavzevii）,2株为白地霉（Geotrichum candidum）,1株为乳酸克鲁维酵母（Kluyveromyces lactis）,其中库德毕赤酵母菌BJ9-12在模拟胃液和模拟肠液中的存活率分别为87.79%和81.50%,耐酸及耐胆盐性能较好,且培养48 h时分解植酸盐的透明圈直径达到3.45 cm,在发酵食品中具有良好的应用潜力。     

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.     

链霉菌 CSDX076次级代谢产物Pseurotin A的分离及结构鉴定

对从赤水丹霞山土壤样品中分离得到的链霉菌(Streptomyces sp.)CSDX076进行液体发酵。利用乙酸乙酯萃取,硅胶柱层析、薄层层析和反相中压柱层析对发酵液中的次级代谢产物进行分离、纯化;通过核磁共振法对纯化的分离产物进行结构鉴定。结果表明,该研究从链霉菌属中成功分离得到次级代谢产物Pseurotin A。采用滤纸片法对Pseurotin A进行抗菌活性测试,Pseurotin A对金黄色葡萄球菌具有抑制作用,其抑菌圈直径为5.0 mm。     

生香酵母筛选鉴定及其对辣椒酱发酵的影响

为了获得适用于辣椒酱发酵的生香酵母,从自然发酵辣椒酱中筛选优良菌种,并对菌种形态特征、生理生化特性、菌种发酵辣椒基料等进行了研究。经筛选,获得一株生香能力较强的菌株LA-Y09,该菌株被鉴定为鲁氏酵母（Saccharomyces rouxii）。菌种LA-Y09的最适生长温度为28 ℃,在NaCl质量分数为12%的培养基中仍有较高菌数,说明其具有良好的耐盐特性,在质量分数为8%的辣椒基料中能够生成多种呈现蜜香和果香的香气成分,使辣椒发酵醪香气得到明显提升。     

产GABA乳酸菌的筛选鉴定及其发酵条件研究

为了筛选得到一株高产γ-氨基丁酸(γ-aminobutyric acid,GABA)的乳酸菌,本研究选取传统发酵食品作为菌株来源,采用薄层层析法和高效液相色谱法对分离出的20株乳酸菌的GABA生产能力进行定性和定量分析,并对高产菌株进行种属鉴定及产GABA影响因素研究。结果表明:从传统发酵食品中分离得到一株GABA高产菌株14#,其发酵液中GABA含量为2.30 g/L,经菌落形态、生理生化特性以及16S rDNA基因序列分析鉴定该菌株为植物乳杆菌(Lactobacillus plantarum),研究其产GABA的影响因素并确定发酵优化条件为:MRS基础发酵培养基中以15 g/L的葡萄糖作为碳源,以10 g/L的酵母粉和15 g/L的牛肉膏作为复合氮源,添加1.5% L-谷氨酸钠,接种量为4%,初始pH为6.0,37 ℃静置培养48 h。优化后GABA含量可达9.12 g/L,比优化前产量(2.30 g/L)提高了近3倍。     

Formation of Volatile Sulfur-Containing Compounds by Saccharomyces cerevisiae in Soymilk Supplemented with L-methionine

The formation of volatile sulfur-containing flavor compounds from L-methionine catabolism by Saccharomyces cerevisiae EC-1118 was investigated in soymilk supplemented with this sulfur-containing amino acid with a focus on methionol (3-methylthio-1-propanol). Methionol produced from L-methionine metabolism of yeast in soymilk was extracted by solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). The effects of time (0 – 72 h), L-methionine concentration (0.05–0.20%), yeast extract concentration (0.00–0.30%), initial medium pH (4.5–6.9), and temperature (25–34°C) on the production of methionol were investigated. One-liter scale-up fermentation of soymilk by Saccharomyces cerevisiae EC-1118 was conducted for 48 h under static conditions with 0.15% of L-methionine, 0.10% of yeast extract, initial medium pH of 5.5, and temperature of 25°C, yielding 190 ppm of methionol. GC-olfactometry dilution analysis was conducted on extracts of the fermented soymilk, and no single compound was found to account for the overall odor perception. Methional (3-methylthio-1-propanal) and methionol were determined to be most potent odor-active compounds in the fermented soymilk. The fermented soy milk may serve as a complex sulfur flavor concentrate for applications in foods such as fermented soy products, enzyme-modified, and imitation cheeses.     

降胆固醇霉菌TS406的鉴定与发酵条件的研究

以形态特征为依据,对具有降解胆固醇能力的霉菌TS406菌株进行鉴定,在此基础上,通过单因素实验,以胆固醇氧化酶活性和胆固醇降解率为指标,确定该菌株发酵培养的最适碳、氮源及其比例,并对发酵条件进行初步研究。结果表明,霉菌TS406属于青霉属真菌,其发酵培养的最适碳、氮源分别是淀粉和酵母粉,两者在培养基中的最适浓度均为1.5g/L。发酵培养的最佳条件是:培养液的初始pH为6.5,培养温度为28℃,接种量为3%,装液量为30mL/250L,胆固醇氧化酶的活性可以达到1420U/L,发酵培养2d后胆固醇的降解率为91.2%。     

Impact of two Williopsis yeast strains on the volatile composition of mango wine

The aim of the research was to study the volatile composition of mango wine fermented with two Williopsis yeast strains: Williopsis saturnus var. mrakii NCYC500 and W. staurnus var. suaveolens NCYC2586. Thirty terpenoids, twenty‐six esters, ten alcohols, nine acids, seven aldehydes and ketones, two ethers, two phenols and one sulphur compound were identified in the mango wine fermented with strain NCYC500, while twenty‐seven terpenoids, thirty esters, eleven alcohols, eight acids, eight aldehydes and ketones, three ethers, two phenols, one sulphur compound and one furan were detected in the mango wine fermented with the strain NCYC2586. The kinetic changes, final concentrations and odour activity values of major volatiles were compared between the two Williopsis yeast strains and also with other yeast reported in the literature. The results showed that Williopsis yeast strains NCYC500 and NCYC2586 were high producers of acetic acid and acetate esters, but low producers of medium‐ to long‐chain fatty acids and their corresponding ethyl esters. Unlike mango wine fermented with Saccharomyces cerevisiae, most terpenoids derived from mango juice were retained in the resultant mango wine fermented with the two Williopsis yeast strains, suggesting the mango wine could retain the aromatic hints of fresh mango.     

一株去除玉米赤霉烯酮酵母的初步研究

确定了一株具有玉米赤霉烯酮(ZEA)去除能力的菌株CLY01.CLY01酵母在添加了ZEA的培养基中进行发酵,采用HPLC法检测发酵醪中ZEA的浓度,发现该菌株发酵96h后,培养基中的ZEA浓度从3.893mg/L降低为0.125mg/L,ZEA去除率达到96.79%.该菌株具有高效去除玉米赤霉烯酮的能力.     

温度对浓香型白酒发酵的影响

为探讨温度对浓香型白酒发酵的影响,采用实验室模拟固态控温发酵方式,对发酵过程进行控温,监测糟醅理化指标、典型微生物数量变化、出坛糟醅主要挥发性风味物质。结果表明,高温发酵加快糟醅水分蒸发,酵母菌及霉菌数量快速减少,产酒生酸快,最终糟醅酒度偏低（1.52%vol）;中温和低温发酵好氧细菌及酵母数量较多,有利于持续产酒产酸,最终糟醅酒精度分别为2.98%vol、4.67%vol。高、中、低温发酵出坛糟醅中高级醇含量分别为7.74 mg/100 g、7.42 mg/100 g、9.72 mg/100 g。中、低温发酵糟醅中未检测出糠醛,高温发酵糟醅中糠醛含量为1.90 mg/100 g。高、中、低温发酵糟醅总酯含量分别为69.99 mg/100 g、109.12 mg/100 g、96.64 mg/100 g。主成分分析（PCA）结果显示,中温（30 ℃）发酵糟醅与对照窖池出池糟醅风味组分构成更为接近,可通过控制发酵温度生产特定基酒。     

甘肃河西走廊葡萄酒产区高产β-葡萄糖苷酶酵母菌株筛选

以甘肃河西走廊葡萄酒产区成熟葡萄浆果自然发酵过程中分离得到的115 株酵母菌株为出发菌株,采用对硝基苯基-β-D-吡喃葡萄糖苷为底物的平板初筛,摇瓶复筛,对高产β-葡萄糖苷酶酵母菌株进行WL营养培养基和赖氨酸培养基初步分类以及26S rDNA D1/D2区序列分析。结果表明：6 株酵母β-葡萄糖苷酶活性与商业酵母ICV-D254酶活性相似,酶活力可达（51.40±4.74） mU/mL,其中菌株QLFE、MQFEH-1、MQFSC-3、MQFEH-2和MQFSM-3为酿酒酵母属,菌株QLFE-4为梅奇酵母属,与分子鉴定结果一致。     

A fuzzy comprehensive evaluation for selecting yeast for cider making

In this article, we present a new approach in solving the problem of selecting proper and excellent cider yeast. Eight different yeast strains commonly used in the cider industry were selected for this experiment. Different ciders were fermented by the yeasts. Sensory evaluation was conducted first. Then, aroma components were identified by the headspace‐solid phase microextraction–gas chromatography–mass spectrometry. Their contents were determined using quantitative standards with known amounts of target components and 2‐octanol as internal standards. A model of fuzzy comprehensive evaluation was established and used to assess and rank the cider‐making attributes of all eight yeast strains. Saccharomyces cerevisiae F14 was selected out of the eight yeasts for the best cider. The results suggest that the method described in this article is more accurate and objective than conventional methods.     

A RAPID SPECTROPHOTOMETRIC METHOD TO DETERMINE ESTERASE ACTIVITY OF YEAST CELLS IN AN AQUEOUS MEDIUM

A new rapid method to determine the total esterase enzymatic activity of yeast cells is proposed. In a sodium phosphate buffer a β-naphthol synthetic ester is hydrolized by cells, and the released β-naphthol is coupled with a diazonium salt (Fast Garnet GBC) in the presence of sodium dodecyl sulfate. The whole procedure is carried out in an aqueous buffer medium, and the resulting azo dye is directly evaluated by absorbance measurement at 524 nm. The analytical results from different assays were adjusted to a fixed cell concentration with a statistical procedure. The method shows good repeatability, reproducibility and detectability, and it requires simple equipment and instruments. It is therefore suitable both for routine analysis, as industrial yeast strain screening, and for yeast physiological studies, in order to improve the aromatic quality of fermented drinks.     

一株产香酵母菌的筛选及应用于发酵馒头的研究

采用嗅闻法和总酯滴定法从老酵子中分离筛选产香菌株,通过形态学观察及分子生物学技术对其进行鉴定,并对其生长条件进行研究,最后,采用气相色谱-质谱（GC-MS）法测定添加产香酵母发酵馒头和未添加产香酵母发酵馒头中挥发性成分。结果表明,从老酵子中分离出一株产香菌株ZY-01,其发酵液总酯含量为355.2 mg/L,经鉴定菌株ZY-01为异常威克汉姆酵母（Wickerhamomyces anomalus）。菌株ZY-01的最优生长条件为：生长时间为28 h,温度28 ℃,pH值4.0。添加产香酵母发酵馒头和未添加产香酵母发酵馒头主要检测出16种、12种风味物质,添加产香酵母的馒头与未添加产香发酵的馒头相比,醇类、酯类物质含量分别增加11.27%、8.85%。     

Antioxidant Activities of Compounds Isolated from Fermented Broth of Zygosaccharomyces Rouxii

Previously, a sugar-tolerant strain of Zygosaccharomyces rouxii that had moderate antioxidant activity was isolated. In this investigation four active substances were isolated and their antioxidant activity was determined with different methods. The yeast strain (MAFF 237555) was cultured in yeast extract-malt extract (YM) medium, and the fermented broth was extracted with ethyl acetate. Dried solid extract was separated into neutral and acidic fractions. The neutral fraction was fractionated on a silica-gel column and purified on a Sephadex LH-20 column. The acidic fraction was recrystallized from acetone. The mother liquor was fractionated on two successive silica gel columns, followed by purification on a Sephadex column. The combined active aliquots were further purified on ODS and Phenyl high performance liquid chromatography (HPLC) columns, successively. The chemical structures of isolated substances were analyzed by electron ionization mass spectrometry (EIMS) and nuclear magnetic resonance (NMR) spectroscopy and were identified as tyrosol, succinic acid, vanillic acid and para-hydroxy benzoic acid. Using available commercial compounds, we determined the antioxidant activity of isolated substances with seven assay methods was determined and compared to natural and synthetic standard compounds. It was observed that the activity of each substance varied with the assay mode. No single substance could be identified as an all-round highly active antioxidant, which was also true with the standard compounds. The diverse activities suggested that Z. rouxii could be used as a source of wide-spectrum natural antioxidant.     

发酵法提取燕麦β-葡聚糖的初步探索

研究了发酵法对提取燕麦麸皮中的β-葡聚糖的影响,比较了发酵液中β-葡聚糖的含量。结果显示,4种酵母菌发酵后发酵液中β-葡聚糖含量都比未经过发酵的燕麦麸培养液中β-葡聚糖含量明显增加。采用酵母发酵的方法提取燕麦β-葡聚糖的最优发酵条件:发酵培养基在灭菌前加蛋白酶、淀粉酶和糖化酶共同处理,所用菌种为黄酒酵母,发酵时间控制在48h;摇床参数为170r/min,28℃。