Characteristics of some traditional Vietnamese starch-based rice wine fermentation starters (men)

In the Mekong Delta region of South-Vietnam, wine from purple glutinous rice is particularly interesting because of its sherry-like taste and flavour and its attractive brown-red colour. It is manufactured at home or by small cottage industries, using traditional solid-state starters (Men). With the objective of improving the knowledge about the functionality of traditional Men, this study deals with the properties and composition of 29 samples of Vietnamese commercial rice wine starters. We selected 6 rice wine starters for their superior ability to liquefy cooked rice, high ethanol accumulation, and production of attractive flavour and colour in the resulting wine. Ethanol contents reached 12 g/100 ml, a sweet alcoholic fragrance was noticed and the wine colour varied from red to lightly brown. Total mould, yeast and bacteria counts in Men were 3.4-6.0, 5.8-7.2 and 2.6-6.2 log CFU/g of dry weight sample, respectively. A total of 119 microbial strains, comprising 53 moulds, 51 yeasts and 15 bacteria, was isolated. Mould isolates with excellent functionality were identified as Amylomyces rouxii, Amylomyces aff. rouxii (an atypical form of A. rouxii), Rhizopus oligosporus and Rhizopus oryzae. Yeast isolates with excellent fermentation properties were all identified as Saccharomyces cerevisiae; other, less functional isolates were identified as Candida glabrata and Pichia anomala.     

Manufacture and Characterization of Gua-Nai: A New Dairy Food Produced with an Oriental-Type Culture

Gua-nai is a sweet-set gel produced from pasteurized whole or skim milk. The milk-clotting enzymes were elaborated from Chinese wine cake culture raised on steamed glutinous rice (sweet rice). The organisms involved were isolated and identified as Amylomyces rouxii, Rhizopus oryzae, Aspergillus oryzae, and a single yeast, Endomycopsis burtonii. These organisms were employed in the reconstitution of the wine cake culture using sweet rice flour as the medium. During the rice fermentation, a clear, effervescent, pale yellow liquid phase appeared exhibiting both proteolytic and milk-clotting activities and containing ethanol. Taxonomic studies of the mycoflora of the fermenting rice also revealed a gradual disappearance of the filamentous molds, leaving only the yeast in the medium at completion of fermentation. A consumer taste panel did not indicate significant differences between gua-nai made with commercial wine cake culture and that made with the culture reconstituted from isolated microorganisms.     

The microbial ecology of tape ketan fermentation

The growth of fungi, yeasts and bacteria was followed during the fermentation of tape ketan. The tape was prepared using samples of Indonesian ragi as inoculum. Fermentation was characterized by the dominant growth of Amylomyces rouxii and Candida pelliculosa (10(5)-10(7) cfu/g), and a lesser contribution from Saccharomyces cerevisiae. Hansenula anomala grew to a limited extent during some fermentations. Bacteria of the genera Bacillus and Acetobacter contributed also to the fermentation, producing populations up to 10(5) cfu/g. Ragi was the main source of microorganisms involved in the fermentation. Tape fermented by inoculating pure cultures of Amylomyces rouxii and the yeasts, either individually or as mixtures, was not of typical quality, indicating the importance of bacteria in the overall fermentation.     

甜酒酿发酵机理的初步研究

以糯米为原料制做甜酒酿,安琪甜酒曲的添加量为糯米重量的0.4％,发酵温度为30℃,发酵时间48h.研究表明甜酒酿制作过程中起糖化作用的糖化酶类主要是根霉菌在甜酒酿的发酵过程中产生的;甜酒酿的发酵过程是边糖化边发酵.发酵结束时甜酒酿的酸度(以乙酸计)为0.229g/(100g甜酒酿),乙醇含量为0.7％vol,pH值为3.75,甜酒酿中还原糖的含量为23.9％,较高的还原糖含量和较低的pH值有利于延长甜酒酿的保藏时间.     

酿造糯米酒优良根霉与酵母菌株的筛选

为开展纯菌种液态曲糯米酒酿造工艺研究,对九种传统糯米酒曲进行优良菌种筛选试验.经液化力、糖化力测试选取3种酒曲,从中分离纯化出9株根霉,对其进行糖化试验,筛选出一株30℃糖化70h产总糖(354.0g/L)、葡萄糖(153g/L)最高的根霉E-2.经产酒精能力测试选取4种酒曲,从中分离纯化出10株酵母,对其进行发酵力试验,筛选出一株30℃发酵80h产酒精量最大,发酵效率(92.9％)最高的酵母Y-1Y.     

基于柑橘的多酵母协同发酵料酒的制备

为研究开发新风味调味料酒,本文采用具有特有风味品质的柑橘作为主体原料,分析了柑橘果肉汁和柑橘皮汁对酿酒酵母、鲁氏酵母和球拟酵母发酵的影响,优化了初始碳源和氮源条件,建立了多酵母协同混合发酵料酒的新技术。在添加160 g葡萄糖和10 g酵母浸粉的1000 mL全柑橘肉汁(去皮榨汁)中,发酵初期添加2%酿酒酵母,隔24 h添加2%球拟酵母,并在第48 h加入2%鲁氏酵母。在此最适条件下30 ℃静置发酵168 h后,所制备的柑橘料酒中乙醇和乳酸的浓度分别为145.00和0.11 mg/mL。本文为柑橘料酒产品的开发奠定了基础。     

Bioethanol production from rice straw by a sequential use of Saccharomyces cerevisiae and Pichia stipitis with heat inactivation of Saccharomyces cerevisiae cells prior to xylose fermentation

In order to establish an efficient bioethanol production system from rice straw, a new strategy to ferment the mixture of glucose and xylose by a sequential application of Saccharomyces cerevisiae and Pichia stipitis was developed, in which heat inactivation of S. cerevisiae cells before addition of P. stipitis was employed. The results showed that heating at 50°C for 6h was sufficient to give high xylose fermentation efficiency. By application of the inactivation process, 85% of the theoretical yield was achieved in the fermentation of the synthetic medium. At the same time, the xylitol production was reduced by 42.4% of the control process. In the simultaneous saccharification and fermentation of the lime-pretreated and CO(2)-neutralized rice straw, the inactivation of S. cerevisiae cells enabled the full conversion of glucose and xylose within 80 h. Finally, 21.1g/l of ethanol was produced from 10% (w/w) of pretreated rice straw and the ethanol yield of rice straw reached 72.5% of the theoretical yield. This process is expected to be useful for the ethanol production from lignocellulosic materials in the regions where large-scale application of recombinant microorganisms was restricted.     

Fermentation and microflora of plaa-som, a thai fermented fish product prepared with different salt concentrations

Plaa-som is a Thai fermented fish product prepared from snakehead fish, salt, palm syrup and sometimes roasted rice. We studied the effects of different salt concentrations on decrease in pH and on microflora composition during fermentation. Two low-salt batches were prepared, containing 6% and 7% salt (w/w) as well as two high-salt batches, containing 9% and 11% salt. pH decreased rapidly from 6 to 4.5 in low-salt batches, whereas in high-salt batches, a slow or no decrease in pH was found. Lactic acid bacteria (LAB) and yeasts were isolated as the dominant microorganisms during fermentation. LAB counts increased to 10(8)-10(9) cfu g(-1) and yeast counts to 10(7)-5 x 10(7) cfu g(-1) in all batches, except in the 11% salt batch, where counts were 1-2 log lower. Phenotypic tests, ITS-PCR, carbohydrate fermentations and 16S rRNA gene sequencing identified LAB isolates as Pediococcus pentosaceus, Lactobacillus alimentarius/farciminis, Weisella confusa, L. plantarum and Lactococcus garviae. The latter species was only isolated from high-salt batches. Phenotypic characteristics, ITS-PCR and carbohydrate assimilation identified 95% of the yeasts as Zygosaccharomyces rouxii. It is concluded that the fermentation of plaa-som is delayed by a salt-level of 9% due to an inhibition of LAB growth. The growth of Z. rouxii has no influence on the fermentation rate, but may contribute positively to the flavour development of the product.     

烧酒曲中扣囊复膜酵母的分离及鉴定

为了筛选1株可用于纯菌种酿造糯米酒的酵母菌,将烧酒曲稀释涂布在淀粉培养基(YPS)平板上培养,得到1株产淀粉酶酵母菌(YW12)。通过形态学、生理生化特征和18S rDNA、ITS区序列分析鉴定,YW12为扣囊复膜酵母(Saccharomycopsis fibuligera)。YW12在YPS液体培养基中28℃培养4 d,用Yoo改良法测其粗酶液的淀粉酶活力为49.8 U/mL。YW12在糯米糖化液(含175 g/L葡萄糖)中28℃发酵3 d的酒精度为5.63%(v/v)。YW12既能同化淀粉又能发酵产生酒精,具有用于纯菌种酿造糯米酒的潜力。     

Microbial diversity of traditional Vietnamese alcohol fermentation starters (banh men) as determined by PCR-mediated DGGE

The diversity of fungi and bacteria associated with traditional Vietnamese alcohol fermentation starters (banh men) was investigated by PCR-mediated DGGE. From 52 starter samples, 13 species of fungi (including yeasts) and 23 species of bacteria were identified. The fungal composition of the starters was consistent with little variation among samples. It consisted of amylase producers (Rhizopus oryzae, R. microsporus, Absidia corymbifera, Amylomyces sp., Saccharomycopsis fibuligera), ethanol producers (Saccharomyces cerevisiae, Issatchenkia sp., Pichia anomala, Candida tropicalis, P. ranongensis, Clavispora lusitaniae), and (opportunistic) contaminants (Xeromyces bisporus, Botryobasidium subcoronatum). The bacterial microflora of starters was highly variable in species composition and dominated by lactic acid bacteria (LAB). The most frequent LAB were Pediococcus pentosaceus, Lactobacillus plantarum, L. brevis, Weissella confusa, and W. paramesenteroides. Species of amylase-producing Bacillus (Bacillus subtilis, B. circulans, B. amyloliquefaciens, B. sporothermodurans), acetic acid bacteria (Acetobacter orientalis, A. pasteurianus), and plant pathogens/environment contaminants (Burkholderia ubonensis, Ralstonia solanacearum, Pelomonas puraquae) were also detected. Fungal DGGE was found to be useful for evaluating starter type and starter quality. Moreover, in view of the high biological diversity of these substrates, bacterial DGGE may be useful in determining the identity of a starter. The constant occurrence of opportunistic contaminants highlights the need for careful examination of the role of individual components in starters.     

同时酶解发酵(SSF)转化造纸厂废细小纤维为酒精

<正> 发酵法生产酒精主要以糖蜜和淀粉质谷物为原料。从开辟新能源和解决环境污染考虑,以废纤维为原料生产酒精的研究近年来日益受到重视。主要有两种方法,一是用两类厌氧纤维素细菌直接发酵纤维废物为酒精;另为用纤维素酶酶解纤维素废物为葡萄糖后再经酵母发酵为酒精。前者方法较简单,但终产物中酒精所占的比例较低,后者遇到的困难主要是纤维素分解微生物和酵母菌发酵之间,所需条件不一。两类方法都是只适用于已经化学预处理脱去木质素的纤维材料,预处理费用高和同时伴有环境污染使此项技术至今还未能     

红曲黄酒传统酿造用曲中的微生物菌群及挥发性风味组分分析

采用固相微萃取-气相色谱-质谱联用技术对红曲和白曲中的挥发性风味组分进行分析鉴定,并利用主成分分析和正交偏最小二乘法判别分析模型确定不同酒曲中的特征香气成分,同时运用MiSeq高通量测序技术解析红曲和白曲中的微生物菌群结构。结果表明：从红曲和白曲中共检测出70?种挥发性成分,且红曲和白曲的挥发性风味组分存在显著差异;红曲中的优势微生物包括芽孢杆菌属、魏斯氏菌属、片球菌属、黑曲霉、紫红曲霉和黄曲霉等,而白曲中的优势微生物包括泛生菌属、肠杆菌属、魏斯氏菌属、酿酒酵母、少根根霉和印度毛霉等。研究结果为阐明红曲黄酒微生物的产香机理和提升红曲黄酒风味品质提供一定的理论依据。     

糯米甜酒曲根霉的筛选及强化曲的研究

选取5种不同地域、较为畅销的市售糯米甜酒曲,以酒曲酶活力为评价指标,筛选出优良糯米甜酒曲。将优良酒曲中霉菌进行分离纯化,制作纯种根霉曲,与酿酒酵母（Saccharomyces cerevisiae）不同比例混合复配制作强化曲。通过强化曲与市售酒曲的酒曲酶活力对比,并结合试制糯米甜酒的总糖、总酸、总酯、酒精度对比验证。结果表明,强化曲的最佳复配比例为：接种量为1%（其中根霉M9曲添加量0.90%,酿酒酵母添加量0.10%）。与市售甜酒曲相比,强化曲糖化力达796.5 U/g,提高14.8%;液化力达694.2 U/g,提高20.7%;试制糯米甜酒的总酯达0.78 g/L,提高168.9%;酒精度达12.1%vol,提高92.1%。经感官评价,强化曲酿制糯米甜酒口感醇甜、风味突出,感官评分为96分。     

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。     

红曲黄酒酿造用曲及传统酿造过程中酵母菌的多样性研究

目的:探讨红曲黄酒酿造用曲中酵母菌多样性以及传统酿造过程中酵母菌菌群结构变化,为我国传统红曲黄酒中酵母菌资源的利用和对传统酿酒的有效控制及现代化酿酒新工艺的建立提供基础数据。方法:收集福建各地区的红曲黄酒酿造用曲20份,从中分离纯化出300株酵母菌,通过ITS1-5.8S-ITS2的PCR-RFLP指纹图谱对酵母菌进行分型,从各个分型类群中随机选取代表菌株,利用26S rDNA基因D1/D2区域序列分析进行分类鉴定;并采用PCR-RFLP快速分型鉴定技术分析红曲黄酒传统酿造过程中酵母菌菌群结构的变化。结果:从红曲黄酒酿造用酒曲中总共分离鉴定出12种类型酵母菌,其中扣囊复膜孢酵母(Saccharomycop-sis fibuligera)、酿酒酵母(Saccharomyces cerevisiae)和弗比恩毕赤酵母(Pichia fabianii)是酒曲中3种主要的酵母菌类型。红曲黄酒传统酿造过程酵母菌群的跟踪分析共鉴定出4种酵母菌,即酿酒酵母、扣囊复膜孢酵母、季也蒙毕赤酵母(Pichia guilliermondii)、粘性红圆酵母(Rhodotorula mucilaginosa)。在酿造前期扣囊复膜孢酵母是优势酵母菌,而在酿造的后期,酿酒酵母完全取代之成为优势菌。结论:红曲黄酒酿造用酒曲中的酵母菌具有丰富的生物多样性,红曲黄酒传统酿造过程酵母菌菌群结构处于动态变化,最终酿酒酵母成为酿造体系的优势酵母菌。     

不同基质浓度对酒精发酵的影响

研究了 1株酿酒酵母在清液发酵过程中不同基质浓度对发酵的影响。研究发现 ,在初糖质量分数 >15 %时 ,该酵母的生长开始受到抑制 ;在初糖质量分数为 3 5 %时 ,可达最大发酵酒精体积分数 16 5 %。将平均对基质菌体得率与初糖浓度进行关联 ,描述了基质与菌体生长之间的关系 ;而在葡萄糖质量分数≤ 15 %时 ,产物浓度与初糖浓度之间存在线性关系。     

嗜杀酵母Sa2发酵籼米小曲酒的工艺研究

该文对以籼米为原料,纯种根霉曲作糖化剂,嗜杀酵母(Sa2)曲作发酵剂的小曲酒的生产工艺进行了探讨,并对影响小曲酒的出酒率和品质的因素(糖化温度、糖化时间、纯种根霉曲添加量、嗜杀酵母曲添加量、加水量和发酵时间)作了研究.确定了籼米小曲酒发酵的最佳工艺条件:纯种根霉曲加曲量0.4％,糖化温度30℃,糖化时间1d,加水量120％,发酵时间4d,嗜杀酵母曲种加曲量0.8％.     

郫县豆瓣自然发酵过程中真菌群落的演替及黄曲霉毒素B1的消长

以四川省郫县豆瓣为研究对象,运用PCR-DGGE指纹图谱技术研究豆瓣自然发酵过程中真菌群落的演替,采用酶联免疫吸附法(ELISA)检测豆瓣样品中黄曲霉毒素B1(AFB1)含量。结果表明:郫县豆瓣自然发酵过程中的优势真菌有米曲霉(Aspergillus oryzae)、淀粉丝菌(Amylomyces rouxii)、米根霉(Rhizopus oryzae)、异常毕赤酵母(Pichiaanomala)、汉逊德巴利酵母(Debaryomyces hansenii)的近缘种,其中米曲霉是制曲阶段和发酵初期的优势真菌,淀粉丝菌和米根霉是制曲阶段的优势真菌,异常毕赤酵母和汉逊德巴利酵母是发酵初期的优势真菌。各发酵时间点样品的AFB1含量均低于国标(5μg/kg);在制曲和发酵初期阶段,AFB1的含量均不断增加,但在第14天后趋于稳定。因此,对AFB1的含量生物防治可重点集中在制曲阶段。     

利用微山湖水产品酿造米酒

以微山湖水产品莲藕、莲子为原料,用米酒酿造的传统方法,使用实验室筛选出的具有较优糖化力和发酵性能的根霉菌和酿酒酵母,进行纯种发酵,考察了原料配比、发酵温度及时间对品质的影响.实验得出,糯米:莲藕为1∶1,莲子为二者总量的4％,发酵温度28℃,发酵时间为5d.不仅为微山湖生物资源大规模被利用提供理论依据,而且还丰富了米酒市场.     

响应面优化北五味子米酒发酵工艺研究

以北五味子、大米为原料,以甜酒曲为糖化发酵剂,经混合发酵工艺,酿制北五味子米酒。在单因素试验基础上,选取北五味子果浆添加量、甜酒曲接种量、糖化时间、发酵时间为影响因素,以感官评分为响应值,进行响应面优化设计。结果表明,北五味子米酒最优的发酵工艺条件为北五味子果浆添加量16.3%、甜酒曲接种量2.2%,36 ℃糖化温度下发酵48.9 h,然后再于20 ℃继续发酵47.6 h。在此最佳工艺条件下,北五味子米酒中还原糖含量为11.94 g/100 g;酒精度为6.75%vol;总酸为0.86 g/100 g,感官评分为93.3分,北五味子米酒汤色呈现棕褐色,清澈透明,有典型的米酒发酵清香,酒味醇厚。