发酵香肠中微生物和理化变化的研究

本文主要研究了在五组不同发酵剂作用下,在香肠的发酵和成熟过程中微生物指标和部分理化指标的变化情况,并做出了相应的分析和结论。结果表明,各类发酵微生物的生长都是先上升后下降的趋势,乳酸菌在混合发酵组的生长比在单一菌种组的生长更旺盛,球菌的生长也受乳酸菌的影响,两者表现出协同作用。     

传统发酵肉成熟过程中微生物菌群和理化性质变化

研究添加戊糖片球菌、木糖葡萄球菌（1∶1）复合发酵剂的发酵肉与自然发酵肉成熟过程中的微生物 菌群、理化性质及质构品质变化。结果表明：在成熟过程中,添加发酵剂的发酵肉（实验组）与自然发酵肉 （对照组）相比,酵母菌和肠肝菌数量无显著差异,而细菌菌落总数、乳酸菌、葡萄球菌数量均有显著差异 （P＜0.05）;且实验组发酵肉的最终pH值、水分含量、亚硝酸盐含量等理化指标均低于对照组,质构指标均优于 对照组;添加发酵剂的发酵肉在微生物菌群多样性和风味品质等方面均明显优于自然发酵肉。     

干酪乳杆菌和戊糖片球菌在发酵香肠中的作用研究

本研究对以干酪乳杆菌(Lactobacillus casei)和戊糖片球菌(Pediococcus pentosaceus)为发酵剂的发酵香肠在成熟过程中微生物和理化生化指标变化进行测定,通过与自然发酵和添加抑菌剂的香肠进行比较,确定两种乳酸菌均对发酵香肠成熟中活菌总数、乳酸菌总数有显著的增加作用,均能有效抑制发酵香肠中有害菌的生长,迅速降低香肠的pH、AW值,显著降低香肠中的亚硝酸盐残留量,更好的保障发酵香肠的安全性;干酪乳杆菌在抑制有害菌、降低香肠的pH值、AW值等方面的作用明显强于戊糖片球菌,更适合发酵香肠安全性的要求;发酵香肠的内源酶对其蛋白质和脂肪的变化起决定性作用。     

发酵剂对发酵香肠微生物变化的影响

利用从自然发酵香肠中优选出的两株微球菌C1S23、C3R10和乳酸菌11作为发酵剂用于发酵香肠制作,研究发酵香肠在成熟过程中微生物的变化情况,选出适用于生产的发酵剂。     

实验室制备活性乳酸菌饮料的工艺探讨

以普通全脂奶粉为原料,经巴氏消毒以后加入新鲜酸奶作为发酵剂,发酵得乳酸菌发酵饮料。通过正交试验的方法,对活性乳酸菌饮料的最佳工艺条件进行研究。结果表明,最佳工艺条件为发酵乳8%、白砂糖7%、接种量4%、在40℃下发酵培养时间4h,所制备的乳酸菌饮料的感官指标、理化指标和微生物指标均达到相关规定标准。     

小片球菌在发酵香肠中的应用--在成熟过程中的微生物和理化变化

试验就小片球菌(P.parvulus)对发酵香肠在成熟过程中的微生物和理化变化的影响进行了研究.结果表明,小片球菌(P.parvulus)作为单一发酵剂加入到发酵香肠中能迅速启动产品的发酵作用,消耗环境中的糖,使pH值快速降低,从而抑制环境中的非乳酸菌,尤其是肠杆菌的生长,提高产品的安全性.小片球菌(P.parvulus)对产品的总氮、游离脂肪和灰分的变化没有影响.但其能降低终产品中水分的含量.同时还具有一定的水解蛋白质的能力,这对产品优良风味的形成是非常重要的.     

直投式发酵剂对发酵牛肉干品质的影响

将干酪乳杆菌和木糖葡萄球菌按一定比例混合制备直投式复合发酵剂,再将其应用于发酵牛肉干,研究其对牛肉干发酵过程中理化指标和微生物特性的影响。试验被分为自然发酵对照组、普通发酵剂组和直投式发酵剂组。研究结果表明:添加普通发酵剂和直投式发酵剂均可降低牛肉干的p H,且显著低于自然发酵组(P0.05);3组牛肉干的水分含量、水分活度和红度值之间无显著差异(P0.05);添加发酵剂的牛肉干的乳酸菌总数、葡萄球菌总数和细菌总数较自然发酵组高(P0.05),感官品质较好(P0.05),这说明直投式发酵剂具有良好的发酵活力,能够提高发酵牛肉干的品质,缩短发酵时间。     

甜菊甙A3对酸菜腌制过程中主要微生物变化的研究

研究以乳酸菌粉为发酵剂,分别加入一定量的甜菊甙A3,使发酵液中甜菊甙A3含量为5％、10％、15％,进行酸菜发酵,同时做对照试验.分阶段测定腌制过程中酸菜主要微生物指标(乳酸菌、霉菌和酵母菌、大肠杆菌)和感官评定进行评价,探讨添加甜菊甙A3对酸菜腌制过程的微生物影响.结果表明,添加甜菊甙A3对乳酸菌的生长无显著影响,同时通过测定发酵过程中酵母菌、霉菌和大肠杆菌数量变化,也未见影响,说明甜菊甙A3对酸菜发酵过程中微生物生长无显著影响,并可以赋予了酸菜新的口感,酸甜适口.     

应用复合发酵剂加工发酵干香肠过程中的理化及微生物特性

本文揭示了发酵干香肠生产过程中水分活度、pH值、酸价、过氧化物值、蛋白水解指数等理化指标及微生物指标的变化情况。研究表明,添加发酵剂的产品比自然发酵产品的pH值、水分活度、水分含量下降得更快,蛋白水解指数更大,风味更好,并明显抑制杂菌的生长;但两类产品最终具有相同的乳酸菌数、酸价和过氧化物值。这说明在发酵干香肠的加工过程中,产品pH值、水分含量、水分活度、蛋白水解程度等受发酵剂种类的影响,而脂肪氧化程度与发酵剂关系不大。     

干酪中非发酵剂乳酸菌

非发酵剂乳酸菌是干酪中主要的次生菌群，不属于发酵微生物，通常不能很好的在牛奶中生长，不能产酸，但对干酪的风味形成有很重要作用。本文概述了非发酵剂乳酸菌的一些特征，包括不同原料制成的干酪中非发酵剂乳酸菌的来源、生长能源的利用、自身存在的蛋白分解系统对干酪风味形成影响及作为一种提高干酪品质的附属发酵剂的应用展望。     

发酵剂对发酵香肠微生物及理化特性的影响

采用3种复合型发酵剂(VBL-97、VBM-60、SHI-59)和1种单一型发酵剂(BOM-13)生产发酵香肠,研究不同发酵剂对发酵香肠微生物及理化性质的影响。结果表明4组发酵香肠在发酵和成熟过程中,乳酸菌始终保持为优势菌,当达到成熟时,乳酸菌数在7.21~8.13 lgcfu/g范围内,葡萄球菌(除BOM-13外)高于5.50 lgcfu/g,肠杆菌科菌数低于3.00 lgcfu/g。BOM-13型发酵剂由单一清酒乳杆菌组成,发酵和成熟时间长于其他三组,所以成品的硫代巴比妥酸值(TBARS值,0.84 mg/100 g)和非蛋白氮值(NPN,0.46%)高于其它3组产品。由此可知由于发酵剂组成不同,相应地发酵条件(温度和时间)和成熟时间亦不同,但最终四种发酵剂都可生产出高品质产品(p H值5.3;AW0.82;NPN值高;TBARS值1.0 mg/kg;乳酸菌为优势菌且7.0 lgcfu/g;肠杆菌科菌3.0lgcfu/g)。VBL-97型发酵剂产酸能力和抗氧化能力强,而BOM-13型发酵香肠蛋白分解程度最高。     

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.     

发酵肉制品中高抗氧化肉品发酵剂的筛选鉴定

为获得高抗氧化活性的天然肉品发酵剂,通过清除自由基、还原能力和抗脂质过氧化实验对来源于5种发酵肉制品中30株乳酸菌的发酵上清液、菌体细胞和胞内提取物的抗氧化活性进行研究,并按照肉品发酵剂的筛选标准对高抗氧化性的菌株进行筛选,鉴定出符合要求的菌株。结果表明:这30株乳酸菌具有不同的抗氧化能力且不同组分的抗氧化活性之间存在很大差异,发现菌株L23、L26和L28具有较高的抗氧化活性,其中L23符合肉品发酵剂的筛选标准,可作为天然高抗氧化性肉品发酵剂用于生产。经鉴定L23为希腊魏斯氏菌。     

Effects of indigenous starter cultures on the microbial and physicochemical characteristics of Urutan, a Balinese fermented sausage

Urutan is a Balinese traditional dry fermented sausage prepared from lean pork and various kinds of spice. Urutan is different from the European sausages, because it is fermented under warm condition with fluctuating temperatures of approximately 25 degrees C at night to 50 degrees C during sun drying. In this study, two of the 71 strains of lactic acid bacteria (LAB) isolated from natural urutan fermentation were used as starter cultures: Lactobacillus plantarum U201, the dominant LAB, and Pediococcus acidilactici U318, a bacteriocin producer. A soft urutan with yellowish brown color was produced using these strains as multiple starters. The starter cultures grew in characteristic succession which reconstructed the natural fermentation process. Lactobacilli were dominant until 48 h fermentation and pediococci dominated at the later stage of fermentation. Proliferation of starter cultures produced lactic acid which resulted in the decrease in pH and coagulation of soluble protein in urutan. Both strains could eliminate the Enterobacteriaceae in urutan after 24 h fermentation, and could suppress and eliminate the occurrence of micrococci at 120 h fermentation. By using a single starter culture, no succession was observed to occur in urutan and the time of elimination of Enterobacteriaceae was delayed. Thus, the strains of L. plantarum U201 and P. acidilactici U318 have great potential for use as multiple starter cultures in urutan fermentation.     

Microbiota dynamics and lactic acid bacteria biodiversity in raw goat milk cheeses

Raw goat milk collected at 11 Andalusian dairy plants was used to individually manufacture cheeses without starter culture addition. Microbial groups were monitored during ripening for 60 days. A total of 1442 lactic acid bacteria (LAB) isolates randomly chosen were identified by molecular methods. Counts of mesophilic LAB exceeded 9 log cfu g⁻¹ on day 1 and decreased 0.5 log units during ripening whereas counts of lactobacilli and leuconostocs increased and those of enterococci remained constant. Thirty-three LAB species belonging to eight different genera were isolated, with higher biodiversity on day 1 (26 species) than on day 60 (20 species). Structural genes coding for nisin, lacticin 481, lactococcin B, six plantaricins and five enterocins were detected in LAB isolates. The information obtained on the technological properties of selected isolates may be useful in developing specific starters for goat milk cheeses, capable of maintaining their distinctive sensory characteristics.     

开菲尔发酵剂发酵特性研究

以三种开菲尔发酵剂和一种普通酸奶菌种为发酵剂,制作成发酵乳。通过监测四种发酵剂发酵过程的pH值变化趋势,以及在4 ℃冷藏过程中酸度、pH值、黏度、乳酸菌活菌数、酵母菌、口感等指标,分析开菲尔发酵剂与普通酸奶发酵剂的发酵特点及其产品在保质期内特性变化。结果表明,与普通酸奶菌种相比,开菲尔发酵剂凝乳时间较长,发酵时间约为12～20 h,在保质期内,酸度增长较为缓慢,黏度较低,乳酸菌活菌数较高,口感方面优于普通发酵剂酸奶。     

三种益生菌发酵剂固态发酵对豆粕营养品质的影响

采用三种益生菌发酵剂固态发酵豆粕,通过测定发酵豆粕的感官品质、pH值、有益微生物含量、营养指标及卫生指标,比较三种益生菌发酵剂对豆粕品质的影响,以期筛选出适宜豆粕发酵的最优益生菌发酵剂。结果表明,益生菌发酵剂A和C对发酵豆粕的感官性状影响不大,三种益生菌发酵剂均能够显著降低发酵豆粕的pH值、大肠杆菌（Escherichia coli）和霉菌数量（P＜0.05）,显著提高有益微生物数量、粗蛋白、酸溶蛋白、总酸和有机酸含量（P＜0.05）。三种益生菌中以益生菌发酵剂A和益生菌发酵剂C效果即乳酸菌和酵母菌固态发酵豆粕效果较好,结合成本考虑优先选择益生菌发酵剂C。     

两株乳酸菌的发酵特性及在发酵驴肉肠中的应用

戊糖片球菌(Pediococcus pentosaceus,P.p)与干酪乳杆菌(Lactobacillus casei,L.c)常作为发酵剂应用于发酵香肠的制作,但能否作为驴肉香肠的发酵剂以及发酵剂的配比、菌液浓度等一直没有明确的指标限制。本研究对P.p、L.c的生长曲线、产酸率、耐盐性等特性进行研究分析并进行混菌培养试验,两种乳酸菌均符合发酵肉制品发酵剂的要求并可作为混合发酵剂。将发酵剂不同配比、菌液浓度、添加量等进行单因素试验,pH和感官品评作为评价指标进行四因素三水平的正交试验,得到在当前加工条件下较优的发酵条件:混合乳酸菌发酵剂菌种配比为L.c:P.p=1:1,菌种菌液浓度1×106 CFU/mL,发酵剂添加量1%,发酵温度35℃,发酵时间20 h,此条件下发酵驴肉肠色泽呈枣红色,pH为4.83,符合良好发酵香肠的感官标准。     

Utilization of various starter cultures in the production of Amasi, a Zimbabwean naturally fermented raw milk product

Fermented milk was prepared from unpasteurised milk using natural fermentation (R), back-slopping (B) and by addition of two different starter cultures (C1 and DL). The numbers of Escherichia coli, coliforms, lactic acid bacteria (LAB) and the changes in pH, carbohydrates, organic acids and volatile compounds were recorded during 48-h fermentation. After 48-h fermentation, the highest numbers of E. coli were found in R and B fermentations and the lowest in the DL fermentation. The DL culture reduced the pH faster than the other starter cultures. The DL and C1 had higher levels of LAB in the beginning of the fermentation than the other two. Galactose and lactic acid increased fastest in the DL and C1 fermentation, and R was slowest. The highest levels of succinate, ethanol and malty compounds were found in the R and B fermentations. Lower levels of LAB in the first part of the fermentations, but higher number of E. coli could explain the increased levels of succinate, ethanol and malty compounds.