菊粉寡糖促进嗜酸乳杆菌生长的研究

对菊粉可促进嗜酸乳杆菌的生长进行了初步研究。结果表明 ,用菊粉代替培养基中部分葡萄糖 ,嗜酸乳杆菌的生长得到明显的促进 ,当MRS培养基中葡萄糖与菊粉的质量比为 1∶1时 ,嗜酸乳杆菌的生物量及酸度得到提高 ,在 3 7℃下培养 48h ,活菌的数量及酸度比对照组分别提高 1 0 10CFU/mL和 1 0°T。     

嗜酸乳杆菌高密度培养时的化学去胁迫

采用向发酵液中添加适当的碱或碱性盐等物质的方法,消除了影响嗜酸乳杆菌生长的有机酸的胁迫作用,达到单位体积的发酵液内含有更多活菌体的目的。结果表明,在发酵过程中,添加一定量的柠檬酸钠可减少乳酸对嗜酸乳杆菌的胁迫作用,从而提高了活菌密度。     

Effect of slaughter weight and aging time on the quality of meat from Awassi ram lambs

Thirty Awassi ram lambs were used to investigate the effects of live weight at slaughter (SW) and aging time (AT) on meat quality attributes of Mm. Semitendinosus, Semimembranosus, Biceps femoris and Longissimus. Lambs were slaughtered at 20, 30 or 40 kg live weight, and muscles of each lamb carcass were aged for either 24 h or 7 days. Warner–Bratzler shear force values increased (P < 0.01) with increasing live weight and decreased (P < 0.01) by increasing AT in both M. Semimembranosus and Biceps femoris. Lightness (L*) of the four muscles decreased (P < 0.001) with increasing weight but was not affected by AT. Aging time increased (P < 0.05) redness (a*) in Mm.Semitendinosus and Longissimus. Cooking loss was reduced (P < 0.001) by increased AT in M. Longissimus and by increasing (P < 0.001) live weight in M.Semitendinosus. Aging time had no effect on expressed juice of all muscles but it was improved (P < 0.001) with increasing live weight in M. Semimembranosus. pH values were significantly influenced for Mm. Semimembranosus and Biceps femoris and values were higher for lighter weight and decreased with increasing weight. Aging time did not influenced pH. In conclusion, meat quality for lambs slaughtered up to 30 kg was better than for lambs slaughtered at 40 kg with quality being improved by increasing aging time.     

热激处理对嗜酸乳杆菌耐热性的影响

研究了以MRS为培养基的嗜酸乳杆菌在不同培养时间段的耐热性,并选取不同的温度对嗜酸乳杆菌进行热激处理,测定热激处理对其耐热性的影响。研究表明,嗜酸乳杆菌本身具有良好的耐热能力,并且在培养11 h时,耐热能力尤其突出。最适的热激温度是45℃,最适热激时间是30 min。热激处理后的嗜酸乳杆菌在经80℃水浴5 min的热处理后活菌数达到1.56×105,比原来可提高一个数量级,并且热激处理后在进行热处理的嗜酸乳杆菌的发酵能力明显优于未热激直接进行致死处理的嗜酸乳杆菌。     

Rennet paste from lambs fed a milk substitute supplemented with Lactobacillus acidophilus: effects on lipolysis in ovine cheese

The present work was undertaken to evaluate the effects of Lactobacillus acidophilus supplementation of a milk substitute on the features of lamb rennet paste used for cheese making. Lipolysis in cheese manufactured with rennet paste from lambs receiving supplemented milk was also evaluated. Lambs were subjected to 3 different feeding regimens (mother suckling, MS; artificial rearing, AR; and artificial rearing with 7 log₁₀ cfu/mL of Lb. acidophilus supplementation of the milk substitute, ARLb) and slaughtered at 20 and 40 d of age for each feeding treatment. Abomasa of the lambs were processed to rennet paste. Microbial loads, enzymatic activities (chymosin, pepsin, and lipases), and renneting characteristics of the lamb rennet paste were determined. Free fatty acids and conjugated linoleic acids were detected in cheese at 60 d of ripening. Addition of 7 log₁₀ cfu/mL of Lb. acidophilus to the milk substitute was carried out successfully. Total recovery of viable cells was recorded in milk supplied daily to the lambs in the ARLb group. The ARLb rennet had greater amounts of lactobacilli than did the MS or AR rennet, irrespective of the slaughter age of the lambs, and the ARLb rennet had higher concentrations of lactococci when lambs were slaughtered at 40 d of age. Chymosin and lipase activities were also higher in ARLb rennet than in MS or AR rennet from lambs slaughtered at an older age. Milk supplementation of ARLb lambs resulted in improved coagulating ability of the rennet and enhanced cheese lipolysis after 60 d of ripening. A reduction of all free fatty acids was observed in all cheeses when passing from 20 to 40 d of slaughter of the lambs. Conjugated linoleic acids were more abundant in ARLb cheeses at both 20 and 40 d. Therefore, supplementation of the milk substitute with Lb. acidophilus improved the enzymatic features of rennet and the healthful and nutritional characteristics of it the ovine cheese. Moreover, the addition of lactobacilli to the milk substitute made it possible to increase the slaughter age of lambs without detrimental effects on rennet characteristics.     

嗜酸乳杆菌生物抗性的研究

选择一株嗜酸乳杆菌优良菌株为研究对象,用平板菌落计数法测定嗜酸乳杆菌在各因素的作用下的存活率来研究其耐酸、耐渗透压、耐胆盐能力以及模拟人体肠胃环境研究胃酸、食盐、胆盐对嗜酸乳杆菌的综合影响;从实验结果得出嗜酸乳杆菌具有一定的抗性能力。     

Effect of tomato juice addition on the growth and activity of Lactobacillus acidophilus.

Addition of tomato juice to skimmed milk stimulated the growth of Lactobacillus acidophilus. It resulted in higher viable counts, shorter generation time and improved sugar utilization with more acid produced and lower pH for the strains tested. Varying results were obtained for the five strains examined.     

酸奶中嗜酸乳杆菌和植物乳杆菌检测方法的研究

根据嗜酸乳杆菌、植物乳杆菌、嗜热链球菌和保加利亚乳杆菌对不同碳水化合物的选择性利用，设计了适合上述4种乳酸菌的选择性计数培养基，并对其效果进行了验证。结果表明，利用MRS培养基、麦芽糖-MRS培养基和山梨醇-MRS培养基(两种培养基共同使用)能满足选择性计数的要求。以所设计的选择性培养基，研究了含有4种乳酸菌的酸奶中不同乳酸菌在产品货架期内活菌数的变化规律。     

嗜酸乳杆菌粉末发酵剂的研制

研究了来自动物、植物及微生物的天然复合有机营养物对嗜酸乳杆菌在高温下的保护作用。结果表明,植物寡聚糖和动物多肽,植物寡聚糖和藻类浸提物,植物寡聚糖和动物多肽和真菌多糖,植物寡聚糖和真菌多糖和藻类浸提物,植物寡聚糖和动物多肽和藻类浸提物分别与脱脂乳混合使用,其抗热效果显著,菌存活率分别为32.8％、25.6％、41.8％、29.9％和72.2％,而对照组只有1.21％。以植物寡聚糖和动物多肽和藻类浸提物和质量分数为15％牛乳的混合物为培养基,培养菌体,经喷雾干燥,制得的嗜酸乳杆菌发酵剂,经检测,质量指标均符合发酵剂要求,其中嗜酸乳杆菌活菌数达8.7×108g-1。     

嗜酸乳杆菌发酵乳保藏性的研究

对嗜酸乳杆菌发酵乳在冷藏条件下保藏性进行了研究. 结果表明, 7 ℃条件下 14 d两株嗜酸乳杆菌发酵乳中细菌的存活率分别为 3.43% 和 2.20%, 且活菌数仍在 108 mL 1以上, 酸度为 90 ° T和 107 ° T, 双乙酰分别增加了 11.80% 和 56.41%, 乙醛含量分别为 2.993 mmol/ mL和 2.561 mmol/ mL, 使发酵乳具有良好风味.     

冷诱导胡萝卜粗提物对嗜酸乳杆菌的保护作用

为了检测冷诱导的胡萝卜蛋白质粗提物对嗜酸乳杆菌的冻干保护作用,从冷诱导的胡萝卜中制备蛋白质粗提物,设计6组冻干保护剂配方,以细菌存活率作为指标检测该粗提物的冻干保护效果;并在扫描电镜下观察冻干菌粉的形态特征。试验结果显示:冷诱导胡萝卜在12.5 ku和36 ku分子量处出现疑似抗冻蛋白条带;不同保护剂对嗜酸乳杆菌的冻干保护效应差异显著(P<0.05),添加冷诱导胡萝卜粗提物的复合保护剂冻干保护效果最优,其细菌存活率达到76.02%;最佳保护剂组配方为:10%脱脂乳,10%麦芽糊精,10%海藻糖,1.0%L-Cys,2.0%VC,2.0%甘油,0.8%硫酸锰和15%冷诱导胡萝卜粗提物。     

嗜酸乳杆菌工业发酵性状的研究

鉴于适宜的收获期、优良的产酸、产黏、产香特性是衡量发酵剂质量的重要工业指标，本实验采用传统方法对嗜酸乳杆菌进行了以上指标的研究。结果表明，所测试的嗜酸乳杆菌表现出较强的产酸、产黏特性。     

嗜酸乳杆菌增菌培养研究

对培养嗜酸乳杆菌的基础培养基进行筛选,确定为11％NFM培养基。采用正交试验对增殖因子进行优化,得到最优增菌培养基:基础培养基+5％番茄汁+10％萝卜汁+0.1％肝浸汁+5％啤酒。以最优增菌培养基测定生长曲线、pH值和滴定酸度的变化,确定增菌培养终止时间为10hr,此时活菌数达7.49×10~9cfu/ml。     

嗜酸乳杆菌和双歧杆菌益生特性的研究

以两株嗜酸乳杆菌和三株动物双歧杆菌为研究对象,详细研究它们的耐胃酸性、耐胆汁盐性、抑菌性和抗药性。结果表明:五株益生菌具有良好的耐酸耐胆汁盐性,双歧杆菌的耐酸性较强于嗜酸乳杆菌;抑菌性和抗药性结果表明:五株益生菌对致病菌大肠杆菌、金黄色葡萄球菌和沙门氏菌均有抑制作用,嗜酸乳杆菌的抑菌性较强于双歧杆菌;五株益生菌对三种抗生素乙酰螺旋霉素、链霉素和青霉素均敏感,敏感程度各异。     

Sensory evaluation of probiotic Minas fresh cheese with Lactobacillus acidophilus added solely or in co-culture with a thermophilic starter culture

Sensory acceptance of formulations of probiotic Minas fresh cheese was investigated. Cheeses were prepared and supplemented with Lactobacillus acidophilus (T1 – probiotic), Lactobacillus acidophilus + Streptococcus thermophilus (T2 – probiotic + starter) or produced with no addition of cultures (T3 – control). Sensory acceptance tests were performed after 7 and 14 days of storage at 5 °C, using a 9‐point hedonic scale (1 = dislike extremely; 9 = like extremely). After 7 days, no significant difference was detected among cheeses T1, T2 and T3 (P > 0.05). After 14 days, cheeses T1 and T2 presented higher acceptance and differed significantly from cheeses T3. Cheeses T3 presented significant difference between 7 and 14 days of storage (P < 0.05), whereas probiotic cheeses T1 and T2 were stable in the same period (P > 0.05). The addition of L. acidophilus, either solely or in co‐culture with a thermophilic starter culture, resulted in good acceptance of Minas fresh cheese, improving sensory performance of the product during storage.     

The fatty acid,phospholipid and cholesterol content of control and polyunsaturated lamb aorta

Lambs trained to drink liquid supplements containing various levels of sunflower oil showed increased incorporation of linoleic acid into the aortic phospholipids with associated decreases in the percentage of C18:3ω3, C20:3ω9, C20:5ω3 and the C22ω3 fatty acids, while there was no significant change in the percentage of C20: 4ω6 fatty acid. The levels of cholesterol, total phospholipid and phospholipid fractions, did not vary significantly with increasing oil intake.     

两歧双歧杆菌与嗜酸乳杆菌微生态制剂的工业化生产工艺研究

研究了两歧双歧杆菌和嗜酸乳杆菌双联微生态制剂的工业化生产工艺。对发酵培养基及发酵条件进行了研究和优化，并确定了发酵奶的冷冻干燥工艺条件。冻干后的产品中两歧双歧杆菌和嗜酸乳杆菌的活菌数均达到了10^9-10^10g^-1，而且在冻干工艺条件下，发酵产物中的各种活性成分得以最大限度地保存下来，使产品可以达到作为微生态制剂应用的相关标准。     

Prevention of gastrointestinal infection using immunobiological methods with milk fermented with Lactobacillus casei and Lactobacillus acidophilus

The protective effect of feeding milk fermented with a mixture of Lactobacillus casei sp. and Lb. acidophilus sp. against Salmonella typhimurium infection in mice was compared with that obtained feeding milks fermented with these microorganisms individually. The survival rate obtained after oral infection with Sal. typhimurium was 100% in mice pretreated by feeding during 8 d with the mixture of Lb. casei and Lb. acidophilus fermented milks. Similar treatments with the individual milks were ineffective. Moreover, mice became more susceptible to infection with Sal. typhimurium after such treatment. The colonization of liver and spleen with the pathogen was markedly inhibited by the pretreatment with the mixture of fermented milk, while such inhibition was not observed using the Lb. casei and Lb. acidophilus milks. The highest levels of anti-salmonellae antibodies in serum and in intestinal fluid were found in the group of mice fed with the mixture and with Lb. casei fermented milk respectively. However, this latter milk was not effective in protecting against Sal. typhimurium. When the mice were first infected with Sal. typhimurium and then fed with the mixture of fermented milks, pathogen colonization was not prevented. The results suggest that the augmentation of resistance to salmonellae caused by the treatment with Lb. casei- + Lb. acidophilus-fermented milk was due to the anti-salmonellae protective immunity mainly mediated by the mucosal tissue. Milk fermented with this mixture could be used as an immunobiological method to prevent gastrointestinal infection.     

温度对嗜酸乳杆菌和干酪乳杆菌发酵羊奶的影响

以鲜羊奶为原料,保加利亚乳杆菌和嗜热乳链球菌为基础发酵剂,在此基础上分别添加嗜酸乳杆菌和干酪乳杆菌,研究温度对两菌株发酵羊奶过程中酸度、pH、活菌数及总活茵数的影响.结果表明:嗜酸乳杆菌酸羊奶的最佳发酵温度为37℃,此时凝乳时间为4h,酸度、pH、嗜酸乳杆菌数和总活菌数分别为97.8 0T、3.88、1.8×107 CFU/mL和1.38×109 CFU/mI,感官评价总分可达到8.35分;干酪乳杆菌羊奶的最佳发酵温度为39℃,此时酸羊奶凝固时间为4.5h,酸度、pH、干酪乳杆菌数和总茵数分别为79.2 °T、4.48、1.56×108 CFU/mL和1.81×109 CFU/mL,感官评价总分可达到7.00分.     

氨酸对嗜酸乳杆菌生长及冻干的影响

探讨了氨基酸对嗜酸乳杆菌生长的影响.采用单因子试验研究了16种氨基酸对嗜酸乳杆菌增菌效果和抗冷冻效应,结果表明,谷氨酸、精氨酸、亮氨酸、赖氨酸、甲硫氨酸、脯氨酸、苯丙氨酸显著促进嗜酸乳杆菌生长,丙氨酸、异亮氨酸、半胱氨酸、丝氨酸、苯丙氨酸、大冬氨酸、甘氨酸、脯氨酸能提高嗜酸乳杆菌抗冷冻能力.研究发现,向发酵液中添加异亮氨酸0.03g/L、半胱氨酸0.03g/L、天冬氨酸0.03g/L、丝氨酸0.03g/L、甘氨酸0.03g/L组成的复合氨基酸或半胱氨酸0.03g/L、天冬氨酸0.03g/L、丙氨酸0.03g/L、甘氨酸0.03g/L组成的复合氨基酸,均可使嗜酸乳杆菌冻干存活率达到95%以上,而对照组只有42.95%.