一株芽孢杆菌对河蟹蚤状一期幼体益生作用的初步研究

通过单株细菌感染河蟹蚤状幼体的方法获得一株对河蟹蚤状一期幼体有益生作用的菌株No.7,与对照组相比提高河蟹一期幼体的成活率13%,5d时与对照组相比变态率增加31%,该菌株有望成为河蟹幼体的益生菌株.对菌株No.7进行形态观察和16SrDNA序列分析,初步鉴定为芽孢杆菌属(Bacillus sp.).     

益生菌在宠物食品中的应用研究

通过给试验犬饲喂添加益生菌的犬粮,采用气相色谱法检测宠物代谢物如乙酸、丙酸、丁酸、异戊酸、对甲酚、吲哚、3-甲基吲哚的含量,研究益生菌的添加对宠物消化代谢的影响。结果表明:在宠物食品中添加益生菌,试验犬粪便中乙酸、丙酸、丁酸的含量明显增加,异戊酸、吲哚、3-甲基吲哚等腐败物质的含量均有所下降。     

不同蛋白质包埋壁材对益生菌在人体模拟胃液中的保护效果

为了提高益生菌在人体胃液中的存活率,本研究以大豆蛋白(SPI)、乳清蛋白(WPI)、酪蛋白(Casein)、明胶(Gelatin)为壁材,采用转谷氨酰胺酶交联的乳化凝胶方法,将Lactobacillus gasseri和Bifidobacterium bifidum包埋于蛋白质胶囊中,通过测定这两种益生菌在人体模拟胃液中的存活率,结果表明:相比于未经过包埋处理的细胞,包埋于蛋白质微胶囊中的细胞具有较高的存活率,并且还发现大豆蛋白微胶囊对菌的保护效果最好,明胶微胶囊最差。对于Lactobacillus gasseri,在加和未加胃蛋白酶的模拟胃液中,菌在这四种蛋白质微胶囊中的D值分别为:73.1、59.7、63.9、47.3min及246.6、240.5、220.0、90.2min。对于Bifidobacterium bifidum,在加和未加胃蛋白酶的模拟胃液中,菌在这四种蛋白质微胶囊中的D值分别为:31.7、24.2、22.7、18.7min和124.3、103.5、97.6、47.8min。除此之外,还比较了蛋白质的四种理化特性(乳化能力,凝胶强度,乳化稳定性、渗透性),其结果:乳化能力大小为SPI>Casein>WPI>Gelatin,凝胶强度大小为Gelatin>SPI>Casein>WPI,模拟胃液的渗透性大小为Gelatin>SPI=Casein>WPI,缓冲能力大小为Casein>WPI=SPI>Gelatin。通过上述结果可以推测蛋白质的缓冲能力与保护效果有很大的相关性,但缓冲能力并不是唯一决定因素,蛋白质其它的理化性质都有可能影响其保护效果。     

7株鸡源肠球菌的分离、鉴定及益生性能比较

对从健康6日龄AA肉仔鸡肠道中分离出的7株肠球菌进行了体外生物学特性研究。利用肠球菌选择性培养基进行分离,采用16S rRNA和Biolog两种方法进行菌种鉴定,并测定其生长、产乳酸、抑制病原菌、耐人工胃肠液等益生性能指标。研究发现,从小鸡肠道中分离得到的7株菌,经鉴定为粪肠球菌(Entero-coccus faecalis)或屎肠球菌(Enterococcus faecium),通过对7株菌的益生性能进行综合评价比较后,筛得菌株Enterococcus faecium GJ01013,其具有生长速度快(代时<30 min)、延滞期短、产L-乳酸能力强(达6.5 g/L)、对致病型大肠杆菌K88/K99、多杀性巴氏杆菌、鸡白痢沙门氏菌及金黄色葡萄球菌有较强的抑制作用(最大抑菌圈直径可达21.5 mm)、人工胃肠液中存活率高(最高达93.5%)等优良特点,为饲用益生菌产品开发提供了菌种来源。     

仔猪复合微生态制剂的液体发酵工艺优化

对仔猪复合微生态制剂液体发酵产酶工艺进行了优化。采用响应面分析法得到最佳培养条件为:pH6.0、发酵温度30℃、培养时间65h、接种量10%,在此培养条件下,菌体生物量理论值为2.95×1012个/ml;对最佳培养条件进行验证性试验,重复3次得到菌体生物量平均值为3.04×1012个/ml。在最优混合培养条件下研究了发酵液中的纤维素酶、淀粉酶、糖化酶的酶活性,3种酶的最大酶活力分别为1 085、492和1 192U/ml。     

Dried Tomato‐Flavored Probiotic Cream Cheese with Lactobacillus paracasei

Abstract: A dried tomato‐flavored probiotic cream cheese (P) containing Lactobacillus paracasei Lpc‐37 was developed for the purpose of this study. The same product, but without probiotic addition (C) was used as control. Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris were used as lactic starter cultures. Chemical composition analyses and sensory tests were performed on days 1 and 7, respectively. Titratable acidity, pH value and L. paracasei population were determined every 7 d during the refrigerated storage (21 d) of the cream cheeses. The experiment and analyses were performed in triplicate, using standard methods. Probiotic population remained greater than 10⁷ CFU/g throughout the storage period, thereby characterizing the product as potentially probiotic. Cream cheeses C and P did not differ on the sensory tests, both obtaining good overall acceptance by the consumers, of which 82.6% stated that they certainly or probably would buy the product. Practical Application: Lactobacillus paracasei Lpc‐37 is a probiotic bacterium and clinical studies have shown that this microorganism beneficially affects its host. In general, dried tomato‐flavored products and cream cheese are products with good acceptance by the consumers. Thus, regular consumption of the probiotic cream cheese developed in this study may have positive effects on health and well being of people if incorporated into their diet.     

干酪内微生物及其功能的研究进展

干酪是一种营养丰富的发酵乳制品,在其制作过程中内含的微生物菌群不是一成不变的,而是动态的。在干酪成熟过程中,有脂解、蛋白水解等各种生化反应进行,这些反应多与微生物产生的酶有关。干酪内微生物对于干酪形成独特的质构和风味至关重要,同时它也与干酪内一些功能物质的形成有关。该文主要阐述了干酪内微生物的生长与干酪品质及一些功能物质的关系,同时也阐述了干酪作为益生菌载体与益生菌之间的关系。     

Ecological Adaptations of Gut Microbiota Members and Their Consequences for Use as a New Generation of Probiotics

In this review, we link ecological adaptations of different gut microbiota members with their potential for use as a new generation of probiotics. Gut microbiota members differ in their adaptations to survival in aerobic environments. Interestingly, there is an inverse relationship between aerobic survival and abundance or potential for prolonged colonization of the intestinal tract. Facultative anaerobes, aerotolerant Lactobacilli and endospore-forming Firmicutes exhibit high fluctuation, and if such bacteria are to be used as probiotics, they must be continuously administered to mimic their permanent supply from the environment. On the other hand, species not expressing any form of aerobic resistance, such as those from phylum Bacteroidetes, commonly represent host-adapted microbiota members characterized by vertical transmission from mothers to offspring, capable of long-term colonization following a single dose administration. To achieve maximal probiotic efficacy, the mode of their administration should thus reflect their natural ecology.