金沙窖酒酒醅中产香酵母分离与鉴定

从金沙窖酒的酒醅、大曲及环境中筛选得到一株产香酵母FBKL2.0011,将其用于实验室模拟酒厂发酵蒸酒,通过感官评定及气质联用（GC-MS）对酒样挥发性物质进行分析,共检测出43种香气组分.并通过对其个体形态特征、生理生化试验及分子生物学分析,初步鉴定为酵母属（Saccharomyces）.     

The occurrence and growth of yeasts in dairy products

Yeasts were isolated, identified and enumerated from 161 samples of retail dairy products. Highest yeast populations (up to 10⁶–10⁷ cells/g) were found in yogurt and cheese samples while lower counts occurred in samples of pasteurized milk, cream, butter and ice cream. Candida famata, Kluyveromyces marxianus, Candida diffluens and Rhodotorula glutinis were the most frequency isolated species. The growth of these and other species was demonstrated during the refrigerated storage of cream, butter and cheese samples and by their inoculation and incubation in milk and yogurt samples. The predominance and growth species was probably related to their production of protein and fat hydrolysing enzymes and the ability to grow at 5°C.     

The interaction between yeasts and bacteria in dairy environments

The general environment from which raw dairy products originate and the microbiological quality of the products in its processed state inevitably admit yeast growth and spoilage. Only part of the primary microflora survives under the selective pressures exerted by the intrinsic and extrinsic biotic factors present, processing procedures and preservatives. Yeasts that possess the proper physiological attributes to counteract the specific ecological determinants will be favored. Eventually, a particular yeast community will develop, and if the environmental factors permit, this characteristic yeast community will result in a specific association contributing positively or negatively to the final product. The association that develops between yeasts and bacteria is governed by specific key properties selecting for a few predominant yeasts. These yeasts may either stimulate or inhibit normal bacterial growth. The extent to which interaction between yeasts and bacteria contribute to the final product is discussed.     

葡萄酒厂空气中酒香酵母的快速检测与鉴定

酒香酵母一直被看成是葡萄酒的有害菌,通过空气传播.本文介绍了酒香酵母的代谢特性及利用PNA快速检测与鉴定酒厂空气中酒香酵母的方法,以期为酒厂及科研部门提供一些信息.     

Algae,bacteria, and yeasts as food or feed

The use of algae, bacteria, and yeasts as food for man or feed for animals has been the subject of considerable discussion in both the scientific and technological literature and in the popular press in recent years. This interest has arisen largely as a result of the need for additional food supplies in chronic food‐shortage areas of the world and for food for life‐support of astronauts on extended space missions. We direct out attention here to the most recent literature and attempt to analyze the current status of the use of these microorganisms for either food or feed with projections to possible applications in the future.     

Effect of variety, vintage and winery on the prediction by visible and near infrared spectroscopy of the concentration of glycosylated compounds (G-G) in white grape juice

The use of visible (Vis) and near infrared (NIR) spectroscopy was explored as a rapid, simple and low cost measurement of the concentration of total glycosylated compounds in white grape juice. The effects of variety (Chardonnay, Riesling and Sauvignon Blanc), winery and vintage (2004 to 2006) on the Vis-NIR spectra were also examined. Juice samples from South Australian wineries were scanned in transmittance mode on a FOSS NIRSystems6500 instrument and subjected to laboratory analyses for the measurement of the concentration of total glycosylated compounds (G-G), total soluble solids (TSS), pH and total phenolics (TP). Partial least squares (PLS) regression method was used to relate the G-G reference data to the Vis-NIR spectra. For all samples, PLS regression resulted in a coefficient of determination in calibration ( R ²_cal) and standard error of cross validation (SECV) of 0.82 and 49.15 μM, respectively. Splitting the sample set by variety, winery or vintage improved the PLS calibrations for the variety sets. The results show that Vis-NIR spectroscopy has potential for use as a rapid, semi-quantitative technique to predict G-G concentration in white grape juices as 'low', 'medium' or 'high'. This method will be valuable when taking decisions at the winery during vintage to allocate juices according to their aroma potential. Further studies are in progress to validate the robustness and accuracy of the calibration models.     

Interactions between yeasts and bacteria in the smear surface-ripened cheeses

Sufu or furu is a fermented soybean product originating in China. It is a cheese-like product with a spreadable creamy consistency and a pronounced flavour. Sufu is a popular side dish consumed mainly with breakfast rice or steamed bread. It has a long history and written records date back to the Wei Dynasty (220-265 AD). Sufu is made by fungal solid state fermentation of tofu (soybean curd) followed by aging in brine containing salt and alcohol. The present review is based on scientific data published in Chinese and international sources. Several types of sufu can be distinguished, according to processing method or according to colour and flavour. Choice of processing can result in mould fermented sufu, naturally fermented sufu, bacterial fermented sufu, or enzymatically ripened sufu. Depending on the choice of dressing mixture, red, white or grey sufu may be obtained. The stages of the process are discussed and include the preparation of tofu, the preparation of pehtze, salting and ripening. Fungal starters include Actinomucor spp., Mucor spp. and Rhizopus spp. The chemical composition is discussed with particular reference to the proximate composition, the amino acid content and profile, as well as the volatile flavour components of various types of sufu.     

盐渍青菜真菌菌群结构DGGE分析及酵母菌分离鉴定

盐渍青菜又称酸菜,是制作川菜及其调味品的一种非常重要的食品原料,对其菌群结构的研究与功能微生物的分离可以为工业化生产提供理论依据。采用变性梯度凝胶电泳技术(denatured gradient gel electrophoresis,DGGE)对不同盐渍青菜样品的真菌菌群结构进行了分析,结果表明,随着盐渍时间的延长,优势条带数量逐渐增多,真菌以酵母菌为主。4个主要的优势条带分别与假丝酵母属(Candida)、德巴氏酵母属(Debaryomyces)、接合酵母属(Zygosaccharomyces)的菌株相似。从盐渍青菜样品中分离得到10株酵母菌,通过分子生物学鉴定为汉逊德巴利酵母(Debaryomyces hansenii)、酿酒酵母(Saccharomyces cerevisiae)、鲁氏接合酵母(Zygosaccharomyces rouxii)。PCR-DGGE技术对盐渍青菜菌群结构的解析不依赖培养,方法简便快捷,能够直观准确地分析盐渍青菜的真菌菌群结构。     

具有共生关系的乳酸菌和酵母菌的筛选

对分离自酸马奶酒中的9株乳酸菌和8株酵母菌存在共生作用的菌株进行筛选。分别于各自培养基中加入相应的代谢产物,以等量的生理盐水作为对照,测定其稳定期的浊度值和干重值。结果表明:乳酸菌的代谢产物促进的酵母菌生长有12个组合,而接近一半的酵母菌代谢产物对乳酸菌有促进作用。有7个组合的乳酸菌和酵母菌存在共生作用。结论是7个共生组合分别是:LAB2YST4、LAB4YST2、LAB5YST2、LAB7YST2、LAB7YST4、LAB8YST2、LAB9YST2。7个组合中酵母菌YST2和除LAB2外其余的乳酸菌均存在不同程度的共生,共生原因还待进一步研究。     

Metabolite production of yeasts on a strawberry-agar during storage at 7 degrees C in air and low oxygen atmosphere

Changes of different quality factors of strawberries have been described until now from a physiological point of view. Possible effects on quality caused by yeast proliferation have not been described. To elucidate the metabolic activity of yeasts (i.e. Debaryomyces melissophilus, Rhodotorula glutinis, Cryptococcus laurentii), isolated from strawberries, they were inoculated on a simulation medium of strawberries (strawberry-agar). Their activity was measured by analysing and correlating microbiological counts, metabolite concentration in the headspace as well as in the medium, and sugar consumption. The isolated yeasts from strawberries could grow on the strawberry-agar, both under air conditions and modified atmosphere (MA) conditions. The maximum count for the yeasts reached 7.5-8.5 log cfu cm(-2) (air conditions) and 5.6-6.4 log cfu cm(-2) (MA conditions). Production or consumption of a number of compounds could be detected when microbial counts reached levels between 4.7 log cfu cm(-2) and 8.5 log cfu cm(-2) depending on species and atmospheric conditions. A range of volatile organic compounds, produced by the yeasts, was detected: acetone, ethyl acetate, ethanol, isopropyl acetate, ethyl butyrate, 1-propanol, 2-methyl-1-propanol, 1-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 1-hexanol and hexyl acetate. These compounds are able to influence the sensory properties of strawberries. A simultaneous decrease in sugar concentrations (sucrose, glucose, fructose) was observed. When ethanol reached high concentrations, ethyl acetate and ethyl butyrate were produced. This production can be attributed to a detoxification of ethanol by yeasts. The fermentative metabolism of yeasts during aerobic conditions could be explained by the Crabtree effect. As the detected volatile organic compounds produced by yeasts are also found in fresh strawberries, it can be concluded that these compounds are produced both by microbiological and physiological processes.     

Occurrence of the killer character in yeasts associated with Spanish wine production

The occurrence of neutral, sensitive or killer phenotypes in 270 oenological yeast strains belonging to 18 species was studied. Strains were isolated from a total of 54 samples representing spontaneous fermentations at 11 wineries of the three Madrid viticultural areas (Arganda, Navalcarnero and San Martı́n de Valdeiglesias). The percentage of strains with the killer phenotype was 42·6% but this percentage varied during the fermentation: 18·8% in must, 50·0% in the middle and 58·8% by late fermentation. The highest frequency of the killer phenotype occurred in the species Saccharomyces cerevisiae (86·9%). Killer activity for this species was shown to result from toxins in the K₂ and K₃ groups.     

具有共生关系的乳酸菌和酵母菌的筛选

对分离自酸马奶酒中的9株乳酸菌和8株酵母菌存在共生作用的菌株进行筛选。分别于各自培养基中加入相应的代谢产物,以等量的生理盐水作为对照,测定其稳定期的浊度值和干重值。结果表明:乳酸菌的代谢产物促进的酵母菌生长有12个组合,而接近一半的酵母菌代谢产物对乳酸菌有促进作用。有7个组合的乳酸菌和酵母菌存在共生作用。结论是7个共生组合分别是:LAB2YST4、LAB4YST2、LAB5YST2、LAB7YST2、LAB7YST4、LAB8YST2、LAB9YST2。7个组合中酵母菌YST2和除LAB2外其余的乳酸菌均存在不同程度的共生,共生原因还待进一步研究。      

Biodiversity of yeasts, lactic acid bacteria and acetic acid bacteria in the fermentation of "Shanxi aged vinegar", a traditional Chinese vinegar

Shanxi aged vinegar is a famous traditional Chinese vinegar made from several kinds of cereal by spontaneous solid-state fermentation techniques. In order to get a comprehensive understanding of culturable microorganism’s diversity present in its fermentation, the indigenous microorganisms including 47 yeast isolates, 28 lactic acid bacteria isolates and 58 acetic acid bacteria isolates were recovered in different fermenting time and characterized based on a combination of phenotypic and genotypic approaches including inter-delta/PCR, PCR-RFLP, ERIC/PCR analysis, as well as 16S rRNA and 26S rRNA partial gene sequencing. In the alcoholic fermentation, the dominant yeast species Saccharomyces (S.) cerevisiae (96%) exhibited low phenotypic and genotypic diversity among the isolates, while Lactobacillus (Lb.) fermentum together with Lb. plantarum, Lb. buchneri, Lb. casei, Pediococcus (P.) acidilactici, P. pentosaceus and Weissella confusa were predominated in the bacterial population at the same stage. Acetobacter (A.) pasteurianus showing great variety both in genotypic and phenotypic tests was the dominant species (76%) in the acetic acid fermentation stage, while the other acetic acid bacteria species including A. senegalensis, A. indonesiensis, A. malorum and A. orientalis, as well as Gluconobacter (G.) oxydans were detected at initial point of alcoholic and acetic acid fermentation stage respectively.     

Lactic acid bacteria and yeasts associated with spontaneous fermentations during the production of sour cassava starch in Brazil

Sour cassava starch is a traditional fermented food used in the preparation of fried foods and baked goods such as traditional cheese breads in Brazil. Thirty samples of sour cassava starch were collected from two factories in the state of Minas Gerais. The samples were examined for the presence of lactic acid bacteria, yeasts, mesophilic microorganisms, Bacillus cereus and faecal coliforms. Lactic acid bacteria and yeasts isolates were identified by biochemical tests, and the identities were confirmed by molecular methods. Lactobacillus plantarum and Lactobacillus fermentum were the prevalent lactic acid bacteria in product from both factories, at numbers between 6.0 and 9.0 log cfu g(-)(1). Lactobacillus perolans and Lactobacillus brevis were minor fractions of the population. Galactomyces geothricum and Issatchenkia sp. were the prevalent yeasts at numbers of 5.0 log cfu g(-)(1). A species similar to Candida ethanolica was frequently isolated from one factory. Mesophilic bacteria and amylolytic microorganisms were recovered in high numbers at all stages of the fermentation. B. cereus was found at low numbers in product at both factories. The spontaneous fermentations associated with the production of sour cassava starch involve a few species of lactic acid bacteria at high numbers and a variety of yeasts at relatively low numbers.     

The growth, properties and interactions of yeasts and bacteria associated with the maturation of Camembert and blue-veined cheeses

The growth of yeasts and bacteria were monitored during the maturation of Camembert and blue-veined cheese produced in Australia. Yeasts were prominent throughout maturation, growing to 10(5)-10(9)/g, depending on the manufacturer. Debaryomyces hansenii predominated, but there were lesser, inconsistent contributions from Yarrowia lipolytica. Of the non-lactic acid bacteria, Acinetobacter species were significant during the maturation of Camembert but not blue-veined cheeses, and grew to 10(6)-10(8) cfu/g. Staphylococcus and Micrococcus species were consistently isolated from the cheeses with Staphylococcus xylosus growing to 10(5)-10(9) cfu/g, depending on the product. Lactic acid bacteria (10(7)-10(9) cfu/g) were present throughout maturation but were not identified. Interactions between the various yeasts and bacterial isolates were examined. Several strains of D. hansenii exhibited killer activity but not against Y. lipolytica. None of the yeasts were antagonistic towards the bacteria but some strains of D. hansenii enhanced the growth of Y. lipolytica and S. xylosus. The yeast and bacterial isolates exhibited various degrees of extracellular proteolytic and lipolytic activities.     

Metabolites produced during fermentation of wine by mixed cultures of yeasts and lactic acid bacteria

Certain aspects of the interrelationship between associations of yeasts and lactic acid bacteria during the fermentation of grape must were studied. Action bySaccharomyces pastorianus gave rise to increased formation of keto acids and residual metabolites. Addition ofLactobacillus plantarum to the fermentation process may inhibit alcoholic fermentation and considerably increased the production of acetaldehyde andl(+) andd(–)lactic acids.

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Entstehung von Metaboliten bei der Fermentation von Wein durch Mischkulturen von Hefen und Milchsäurebakterien

Zusammenfassung Es wurden Wechselbeziehungen zwischen Hefen und Milchsäurebakterien während der Fermentation von Traubensaft untersucht.Saccharomyces pastorianus bewirkte ein Ansteigen der Ketosäurenproduktion und der Bildung von Rest-Metaboliten. Das Hinzufügen vonLactobacillus plantarum beim Gärungsprozess kann die alkoholische Gärung unterdrücken und hat die Produktion von Acetaldehyd sowie vonl(+)- undd(–)-Milchsäuren beträchtlich gesteigert.

     

The role of interaction between yeasts and lactic acid bacteria in African fermented milks: a review

Yeasts are present in indigenous African fermented milks in numbers up to log 8 cfu g(-1), together with a varied lactic acid bacteria (LAB) flora, and therefore potentially contribute to product characteristics. However, interaction between yeasts and LAB in these products has received little notice. In studies of indigenous fermented milk in Zimbabwe and Uganda, many samples contained more than one species of yeast, but Saccharomyces cerevisiae was most commonly isolated. Other frequent isolates were other species of Saccharomyces and several species of Candida. Most yeast isolates were lactose-negative but usually galactose-positive. Some strains assimilated lactate and citrate. The growth in milk of strains of yeasts and LAB, isolated from naturally soured milk in Zimbabwe, and their interaction when selected pairs of strains were grown together has been studied. Interactions were shown by the significantly different amounts of certain metabolites produced, such as acetaldehyde and malty aldehydes, when co-cultures were compared to pure cultures. Preliminary sensory acceptance tests did not show, however, that milks made from a co-culture with Candida kefyr and LAB were preferable to the pure LAB culture. Further work is still needed to elucidate the reactions that may be taking place in fermented milk between varying LAB and yeast populations. The potential for use as starter cultures depends on various aspects, including the final product being prepared. The role of other microorganisms in naturally fermented milk also needs to be studied.