富硒活性乳酸菌功能性酸乳的工艺研究

本研究将亚硒酸钠添加在活性乳酸菌发酵剂中,通过活性乳酸菌的生物转化,使活性乳酸菌发酵剂富集有机硒,再用活性乳酸菌发酵剂和鲜乳等加工制成富硒功能性酸乳。L9(33)正交试验表明,最佳工艺条件为:富硒发酵剂接种量9%,加糖量8%,温度41℃,发酵时间5h。该酸乳硒含量达0.45μg/ml,转化硒为0.4157μg/ml,转化率为92.43%。与普通乳酸菌发酵酸乳相比,硒含量提高了约450倍。     

提高酸乳中嗜酸乳杆菌活性的研究

从市售合生元中分离鉴定出嗜酸乳杆菌,以脱脂乳培养基或MRS液体培养基培养菌株,探讨嗜酸乳杆菌的生长特性,研究不同pH、保藏温度以及西红柿汁含量对嗜酸乳杆菌活性的影响。结果表明:嗜酸乳杆菌在pH6.5培养基中培养6h后的活菌数最大,且在pH2.5的培养基中0～2h内保持106CFU/mL以上,即能在较低的胃酸环境保持其益生作用;嗜酸乳杆菌酸乳在4℃下保藏活菌存活期较长;在脱脂乳培养基中添加西红柿汁对嗜酸乳杆菌的生长起促进作用,且以添加15%的西红柿汁效果最佳。     

提高酸乳中嗜酸乳杆菌活性的研究

从市售合生元中分离鉴定出嗜酸乳杆菌,以脱脂乳培养基或MRS液体培养基培养菌株,探讨嗜酸乳杆菌的生长特性,研究不同pH、保藏温度以及西红柿汁含量对嗜酸乳杆菌活性的影响。结果表明:嗜酸乳杆菌在pH6.5培养基中培养6h后的活菌数最大,且在pH2.5的培养基中0～2h内保持106CFU/mL以上,即能在较低的胃酸环境保持其益生作用;嗜酸乳杆菌酸乳在4℃下保藏活菌存活期较长;在脱脂乳培养基中添加西红柿汁对嗜酸乳杆菌的生长起促进作用,且以添加15%的西红柿汁效果最佳。      

玫瑰茄发酵酸乳生产工艺研究

目的:将具有抗氧化活力的玫瑰茄与酸乳发酵结合起来,开发玫瑰茄发酵酸乳。方法:玫瑰茄活性物质采用温水浸提法,获得玫瑰茄花茶并将p H调整至6.0后进行酸乳的发酵。玫瑰茄活性物质通过测定540nm和280 nm吸光度值,分别对应玫瑰茄色素与精油的含量;玫瑰茄发酵酸乳的生产工艺以感官评价分数为响应值,通过单因素试验与响应面优化,最终获得玫瑰茄发酵酸乳的最佳生产工艺。结果:玫瑰茄浸液会对乳酸菌的生长造成一定的影响,玫瑰茄用量要小于0.5%;玫瑰茄浸提活性物质最佳条件为40℃温水浸提40 min。结论:最终确定的玫瑰茄发酵酸乳最佳生产工艺为玫瑰茄用量0.3%、奶粉用量5%、发酵时间24 h。     

菊芋浓缩液对酸乳中益生菌的生长和功能的影响研究

将菊芋浓缩液按不同的量添加到脱脂鲜乳中,考察了复合酸乳的酸度和菌数以及菌体的生长情况,结果表明凝乳时的酸度和菌数都随着添加量的增多而增大;在以上实验的基础上,同时以菊芋复合酸乳对小鼠进行灌胃,结果发现以菊芋复合酸乳灌胃小鼠的肠道乳杆菌数比纯酸乳灌胃组小鼠和空白组都有提高,说明添加菊芋浓缩液的酸乳促进了小鼠肠道乳酸菌的增殖.     

骆驼酸乳中乳酸菌的抑菌实验研究

对新疆3个不同地区的骆驼酸乳中分离出来的10株乳酸菌(编号1～10)的抑菌作用进行研究,并用滤纸片法对大肠杆菌、绿脓杆菌、金黄色葡萄球菌、白色念珠菌、白色葡萄球菌、枯草芽孢杆菌进行抑菌实验,结果表明,对大肠杆菌具有抑菌作用的是菌株3、6、7、10;对绿脓杆菌具有抑菌作用的是菌株7、8、9、10:对金黄色葡萄球菌具有抑菌作用的是菌株6、7、8;对白色念珠菌有抑菌作用的是菌株6、7;对白色葡萄球菌具有抑菌作用的是菌株8、9;但这lO株乳酸菌发酵上清液对枯草芽孢杆菌均无抑菌作用.本实验提示从新疆3个不同地区的骆驼酸乳中分离出来的部分乳酸菌对指示菌具有抑菌作用.     

酸奶中乳酸细菌计数法的改进

本文了在酸奶检验中，采用改进后乳酸细菌的计数方法－－牛奶培养基、Ｌ型破棒涂布法；烛缸中微需氧培养、温度４０℃左右培养２４ｈ。该法具有快速、准确、简便等优点。     

外界因素对嗜酸乳杆菌WS所产细菌素的影响

细菌素是某些细菌利用核糖体合成机制产生的一种具有抗菌作用的蛋白质或多肽类物质。嗜酸乳杆菌是乳酸菌的一种，可以产生有机酸、细菌素、双已酰、过氧化氢等多种天然抑菌物质，具有维持肠道内菌群平衡，提高机体免疫力，促进营养物质的吸收等多种功能。是肠道的主要益生菌之一。尤其是嗜酸乳杆菌产生的具有抑菌活性的代谢产物细菌素，不仅可以改善肠道生态，而且是一类具有潜在开发能力的天然食品防腐剂和饲料添加剂。     

螺旋藻益生菌酸乳的研制

探讨了在纯鲜牛乳中添加螺旋藻制剂,经益生乳酸菌发酵,制得一种浅绿色、风味独特的新型营养保健酸奶.通过四因素三水平L9(34)正交试验确定了最佳配方工艺为:合格鲜牛乳,白砂糖7.0%,果胶0.08%(均为质量分数),益生菌L.casei Zhang 4×106g-1,直投式发酵剂CHR HANSEN YC-X11 0.006%,螺旋藻提取液6.0%,发酵温度42℃,发酵时间4 h.     

益生菌酸乳开发中的关键问题

根据益生菌生物特性并结合国内外发展及应用状况,讨论了益生菌菌株的选择,发酵剂设计,生产与保藏过程中品质的控制等产品开发中的关键问题.     

Survival of free and encapsulated probiotic bacteria and their effect on the sensory properties of yoghurt

The survival and effect of free and calcium-induced alginate-starch encapsulated probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium lactis) on pH, exopolysaccharide production and influence on the sensory attributes of yogurt were studied over 7 weeks storage. Addition of probiotic bacteria (free or encapsulated) reduced acid development in yogurt during storage. Post-acidification in yogurt with encapsulated probiotic bacteria was slower compared to yogurt with free probiotic bacteria. More exopolysaccharides were observed in yogurts with probiotic cultures compared to those without probiotic cultures. The results showed that there was an increased survival of 2 and 1 log cell numbers of L. acidophilus and B. lactis, respectively due to protection of cells by microencapsulation. The addition of probiotic cultures either in the free or encapsulated states did not significantly affect appearance and colour, acidity, flavour and after taste of the yogurts over the storage period. There were, however, significant differences (P<0.05) in the texture (smoothness) of the yogurts. This study has shown that incorporation of free and encapsulated probiotic bacteria do not substantially alter the overall sensory characteristics of yogurts and microencapsulation helps to enhance the survival of probiotic bacteria in yogurts during storage.     

提高乳品中益生菌存活力的方法

从选择耐酸和耐胆汁的菌珠、合适的包装容器、合适的接种量,采取二步发酵法、微胶囊技术、添加蛋白质,肽和氨基酸、抗坏血酸、半胱氨酸及利用超声波降解乳酸菌释放β－半乳糖酶等10个方面,探讨了提高乳品中益生菌存活力的方法。     

酸奶中乳酸菌数及酸度的检测与评价

酸奶中乳酸菌的含量是评价产品对于人们营养与健康作用的重要指标,而酸奶的酸度直接影响成品的质量、风味与口感。新的酸奶国家标准(GB2746-1999)中规定产品中的乳酸菌数不得低于1×106mL-1,酸度应≥70°T。本试验通过对部分市售酸奶及自制产品的检测与分析表明,酸奶成品中的乳酸菌数普遍大于1×109mL-1,个别也应大于4×108～8×108mL-1水平,而酸度均大于80°T。故笔者认为酸奶中乳酸菌数定为大于1×108mL-1及酸度大于80°T更适合产品本身的实际情况。     

红薯乳酸菌发酵酸奶的研制

以红薯液、牛乳为原料,发酵制得营养丰富、口味独特的红薯酸牛奶;将保加利亚乳杆菌和嗜热链球菌按1∶1的比例3%的接种量接入原料中,结果表明:红薯液与牛乳以5:5混合、发酵温度39℃、发酵时间12 h比较适宜.     

分离自藏灵菇的乳酸菌的益生特性

从藏灵菇中分离纯化5株乳酸菌,初步鉴定2株为嗜酸乳杆菌,3株为乳酸乳球菌。选取其中2株菌研究其益生特性。结果表明,从藏灵菇中分离出的乳酸菌具有良好的益生特性,2株乳酸菌在pH值为4～6可生长良好;耐热范围为30～60℃;胆盐耐受性为0.1%～0.5%;发酵液对金黄色葡萄球菌、沙门氏菌、大肠杆菌等肠道病原菌有抑制作用;对抗生素有不同程度的耐药性。     

五味子果浆对乳酸菌生长的影响及五味子酸奶的加工

对五味子酸奶的加工工艺进行了初步探讨。结果表明，五味子果浆(质量浓度为0．1g／L)与牛奶按l：9的比例混合，加入质量分数为9％绵白糖及0．1％的酸奶发酵剂，接入质量分数为3％保加利亚乳杆菌与嗜热链球菌比例为l：l的发酵刺，在42．5℃条件下发酵5h，可得品质优良的五味子酸奶。     

益生乳酸菌对氟喹诺酮类药物耐药机制的研究进展

益生乳酸菌对抗菌药物的耐药性机制是生物医药研究的重要领域。概述了益生乳酸菌对氟喹诺酮类药物的3种耐药性机制(靶位突变、外排泵作用、质粒介导)及其可能出现的耐药机制。显示出国内关于益生乳酸菌对氟喹诺酮类药物的耐药机制研究甚少的现状,提出对益生乳酸菌的耐药机制进行全面深入的研究的重要性。     

Interactions among lactic acid starter and probiotic bacteria used for fermented dairy products

Interactions among lactic acid starter and probiotic bacteria were investigated to establish adequate combinations of strains to manufacture probiotic dairy products. For this aim, a total of 48 strains of Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium spp. (eight of each) were used. The detection of bacterial interactions was carried out using the well-diffusion agar assay, and the interactions found were further characterized by growth kinetics. A variety of interactions was demonstrated. Lb. delbrueckii subsp. bulgaricus was found to be able to inhibit S. thermophilus strains. Among probiotic cultures, Lb. acidophilus was the sole species that was inhibited by the others (Lb. casei and Bifidobacterium). In general, probiotic bacteria proved to be more inhibitory towards lactic acid bacteria than vice versa since the latter did not exert any effect on the growth of the former, with some exceptions. The study of interactions by growth kinetics allowed the setting of four different kinds of behaviors between species of lactic acid starter and probiotic bacteria (stimulation, delay, complete inhibition of growth, and no effects among them). The possible interactions among the strains selected to manufacture a probiotic fermented dairy product should be taken into account when choosing the best combination/s to optimize their performance in the process and their survival in the products during cold storage.     

番茄汁酸奶的研制

用保加利亚乳杆菌（L.bulgaricus）与嗜热链球菌（S.thermophilus）按1：1比例混合作发酵剂，用新鲜优质牛乳为原料，加入0.2%-0.3%的稳定剂，经90-95℃加热处理5min，冷却至45℃左右，加入经杀菌后的新鲜蕃茄汁8%，按2%-3%比例加入发酵剂，装瓶于39-43℃培养2-2.5h，冷藏可制得风味纯正，营养价值高的酸奶。     

Textural properties of mango soy fortified probiotic yoghurt: optimisation of inoculum level of yoghurt and probiotic culture

The effect of yoghurt bacteria and probiotic culture on the textural characteristics of mango soy fortified probiotic yoghurt (MSFPY) is studied. The TA-XT2 Texture Analyser was used to measure the textural characteristics of MSFPY prepared from blends containing varying proportions of yoghurt bacteria [ Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB)] and probiotic culture [ Bifidobacterium bifidus (BB), Lactobacillus acidophilus (LA)]. MSFPY samples were prepared by using blends of 78.3% toned milk, 14.5% soy milk and 7.2% mango pulp. Texture profile data were used to develop regression models for dependent variables – hardness, cohesiveness, adhesiveness, springiness and gumminess. The optimisation of culture addition was done by comparing the yoghurt with the MSFY as control sample (ST and LB at 2%, 1:1) The mean optimum culture addition rate of –1.43 (0.79%) ST, –1.51 (0.75%) LB, –1.43 (0.79%) BB and –1.10 (0.95%) LA is recommended for yielding an acceptable and good quality of MSFPY.