西红柿益生菌酸乳的研制

利用鲜牛乳和番茄汁为原料,通过添加嗜酸乳杆菌发酵来制备西红柿益生菌酸乳;通过测定活菌数和感官评定确定了番茄汁最适的添加量,测定了嗜酸乳杆菌的发酵特性,发酵结束后在4℃下贮存,在此过程中测定了嗜酸乳杆菌的存活状态及贮存过程中酸度和pH的变化,分析了番茄汁对嗜酸乳杆菌发酵的影响.实验结果表明,蔗糖添加量为8%,嗜酸乳杆菌发酵剂的接种量为45,发酵温度为37℃,发酵时间为9h,可以得到呈浅红色,状态均匀,酸甜适口的西红柿益生菌酸乳,40C下贮存10d后嗜酸乳杆菌活菌数仍达107cfu/mL以上.     

青脆李益生菌饮品的发酵工艺优化及冷藏对其品质的影响

探索青脆李益生菌饮品适宜的发酵菌株、工艺参数及贮藏条件,为青脆李益生菌饮品开发提供解决方案。对嗜酸乳杆菌、植物乳杆菌、嗜热链球菌及其组合发酵的益生菌饮品感官评价、pH变化进行研究,确定适宜的发酵菌株组合;对其发酵适宜接种量、发酵温度、发酵时间工艺参数进行优化,优化发酵工艺参数;对4 ℃冷藏条件益生菌饮品可滴定酸、pH、可溶性固形物含量、还原糖含量及活菌落总数变化等进行研究,获得适宜的贮藏条件。结果显示:青脆李益生菌饮品适宜发酵菌株组合为植物乳杆菌、嗜热链球菌、嗜酸乳杆菌混合菌株1:1:1,发酵温度25 ℃、发酵时间44 h,接种量0.7‰。验证实验表明感官评分高达9.2。4 ℃冷藏益生菌饮品30 d,可滴定酸含量、pH、可溶性固形物含量、还原糖含量均基本保持稳定,且活菌落总数20 d达8.6×107 CFU·mL?1、30 d达2.0×106 CFU·mL?1,满足活性乳酸菌饮品要求,表明利用青脆李为原料研发益生菌饮品具有可操作性。     

牛羊乳促嗜酸乳杆菌增菌发酵差异性及冷藏存活率比较研究

益生菌的活菌数量是衡量益生菌产品及制剂的营养价值和保健功能的主要指标之一。本研究以嗜酸乳杆菌为发酵剂分析比较牛乳发酵奶和羊乳发酵奶中嗜酸乳杆菌增菌发酵的活力差异,及在冷藏期活菌数量的变化趋势,探讨了牛羊乳在促进嗜酸乳杆菌发酵方面的差异性及在冷藏期存活率变化规律。结果表明:嗜酸乳杆菌在羊乳基质中表现为较好的增菌发酵效能,总活菌数为1.66×1010CFU/mL,大于牛乳基质中的总活菌数3.02×109CFU/mL;羊乳发酵奶和牛乳发酵奶在21d贮藏期内嗜酸乳杆菌的活菌数均维持在较高活力水平,而在21～26d的贮藏期内,其存活性显著降低(p<0.05),存活率分别为84.15%和84.39%。由此说明羊乳基质促嗜酸乳杆菌增菌发酵效能更佳,牛、羊乳发酵奶在贮藏期活菌数变化规律基本一致。     

益生菌发酵葡萄汁饮料工艺研究

以巨峰葡萄为原料,进行益生菌发酵葡萄汁工艺研究。以嗜酸乳杆菌（Lactobacillus acidophilus）L2-16为发酵菌种,活细胞数和感官品质为评价指标,通过单因素试验及正交试验优化发酵工艺条件。结果表明,初始pH值、接种量、发酵温度和发酵时间对嗜酸乳杆菌活菌数和感官品质影响显著,益生菌发酵葡萄汁的最佳工艺条件为初始pH值4.5,接种量2.5%,发酵温度32 ℃,发酵时间26 h。在此优化条件下,发酵葡萄汁饮料活菌数对数值为8.87,感官评分为88.3分,酸度为90.1 °T,可溶性固形物含量17.2%。     

益生菌对发酵乳理化性质影响的研究

通过比较不同菌种发酵乳和酸乳在4℃下贮藏21d的pH、酸度、活菌数与持水力的差异,并对后熟24h的发酵乳和酸乳进行质构特性分析。结果显示,益生菌发酵乳和乳酸菌酸乳的pH、活菌数与酸乳持水力均随时间的延长而降低,酸度呈上升趋势,益生菌发酵乳酸度值比乳酸菌酸乳更高。添加干酪乳杆菌与植物乳杆菌的益生菌发酵乳在硬度、稠度、凝聚性与黏度上与乳酸菌酸乳相比,均有所增加,其中添加植物乳杆菌的益生菌酸乳在硬度与稠度上较乳酸菌酸乳相比有显著增加(p<0.05),为发酵乳制品提供开发导向并为实际生产提供理论依据。     

十一种香辛料对乳酸菌生长及抑菌性的影响

主要研究了不同香辛料对嗜酸乳杆菌和乳酸乳球菌生长及抑菌性能的影响。选取白芷、高良姜、生姜、白胡椒、丁香、肉桂、花椒、八角、香叶、芫荽子、辣椒这11种香辛料,以水作为提取剂加热浸提,制备香辛料提取液。研究不同香辛料对嗜酸乳杆菌LA、乳酸乳球菌LL生长的影响,并以两种常见食源性致病菌大肠杆菌Escherichia coli O157:H7ATCC 43895、金黄色葡萄球菌Staphylococcus aureus CMCC(B)26003为指示菌株,采用牛津杯法测定不同香辛料对乳酸菌发酵液抑菌性的影响。结果表明,香辛料浓度为20mg/mL时,丁香对嗜酸乳杆菌LA的增殖抑制作用最明显,其次为香叶;八角对乳酸乳球菌LL的增殖抑制作用最明显。白芷、高良姜、白胡椒、花椒、芫荽子对嗜酸乳杆菌LA、乳酸乳球菌LL的生长影响较小。高良姜能明显提高嗜酸乳杆菌LA发酵液对大肠杆菌的抑菌性;辣椒能明显提高嗜酸乳杆菌LA发酵液对金黄色葡萄球菌的抑菌性;丁香则明显降低嗜酸乳杆菌发酵液对大肠杆菌的抑菌活性。香叶的添加有利于提高乳酸乳球菌发酵液对大肠杆菌的抑菌活性,花椒的添加有利于提高乳酸乳球菌LL对金黄色葡萄球菌的抑菌性。白芷、高良姜、生姜等多数香辛料的添加会降低乳酸乳球菌LL发酵液对大肠杆菌Escherichia coli O157:H7ATCC 43895、金黄色葡萄球菌Staphylococcus aureus CMCC(B)26003的抑菌性。嗜酸乳杆菌LA、乳酸乳球菌LL发酵液对大肠杆菌Escherichia coli O157:H7ATCC 43895、金黄色葡萄球菌Staphylococcus aureus CMCC(B)26003的抑菌活性主要受pH的影响,抑菌活性成分主要为有机酸类或受酸度影响的物质。泡菜等相关生产发酵过程中通过选择适宜的乳酸菌菌种及香辛料,能起到有效防止致病菌污染的作用,更有利于实现生产的安全性控制。     

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。     

嗜酸乳杆菌应用高质量分数脱脂乳的发酵工艺优化

将筛选出的嗜酸乳杆菌接种于25%的高质量分数脱脂乳中发酵,在单因素pH值、温度以及接种量试验的基础上,采用响应面法优化发酵工艺,获得高浓度的嗜酸乳杆菌活菌。结果表明:高质量分数25%脱脂乳培养基对菌株的生长有一定促进作用,得到高活菌数嗜酸乳杆菌的最佳发酵工艺为发酵pH值为5.81、发酵温度37.30℃、接种量3.18%,活菌数可达2.78×109mL-1。     

乳酸菌发酵对刺五加叶活性成分、体外抗氧化作用与降血糖相关酶的影响

为了对刺五加叶在益生菌发酵保健品领域的应用提供理论基础,以刺五加叶为原料,采用嗜酸乳杆菌、干酪乳杆菌、植物乳杆菌3种乳酸菌进行发酵,对发酵前后刺五加叶中活性成分含量变化进行研究,并评价刺五加叶乳酸菌发酵物的体外抗氧化作用与对降血糖相关酶的影响.结果表明:不同菌种的发酵能力存在差异,植物乳杆菌、嗜酸乳杆菌发酵显著增加了刺...     

酪蛋白水解产物对含益生菌酸奶中益生菌数量的影响

文研究了牛奶蛋白水解产物对发酵牛奶中益生菌生长的促进作用,并对在两周的贮存期内活性益生菌菌数的稳定性进行了比较研究。实验以益生菌菌株-嗜酸乳杆菌作为研究用菌种。利用novo型碱性蛋白酶水解酪蛋白获得水解度分别为4.7%、7.1%、8.8%、10.1%、12.6%的酪蛋白水解产物,研究以0.5、1、2和4g/L四个添加水平加入发酵酸奶中,分析其对益生菌生长情况的影响。结果证明,酪蛋白水解产物的添加普遍促进了嗜酸乳杆菌在酸奶中的生长。随着添加量的增加,嗜酸乳杆菌在发酵牛奶中的稳定性得到了同步提高。但综合分析,水解度为8.8%的水解产物,添加量为2g/L时,可使益生菌的生长活性和稳定性状态最佳。研究结果证实,选择优化的酪蛋白水解产物对发酵牛奶中益生菌的生长及维持其生存能力均会产生积极地促进作用,也对发酵乳行业生产符合国际标准的益生菌产品具有重要的理论和实践的价值。     

The viability of three probiotic organisms grown with yoghurt starter cultures during storage for 21 days at 4°C

This study investigated the viability of probiotic ( Lactobacillus acidophilus LA5, Lactobacillus rhamnosus LBA and Bifidobacterium animalis subsp . lactis BL-04) in milk fermented with Lactobacillus delbrueckii subsp . bulgaricus LB340 and Streptococcus thermophilus TAO (yoghurt – Y). Each probiotic strain was grown separately in co-culture with Y and in blends of different combinations. Blends affected fermentation time(s), pH and firmness during storage at 4°C. The product made with Y plus B. animalis subsp . lactis and L. rhamnosus had counts of viable cells at the end of shelf life that met the minimum required to achieve probiotic effect. However, L. acidophilus and L. delbrueckii subsp . bulgaricus were inhibited.     

响应面法优化牛初乳免疫球蛋白热保护剂的配方

为筛选一种最佳的牛初乳免疫球蛋白（Immunoglobulin G,IgG）热保护剂,以牛初乳为原料对其IgG进行提取,在单因素实验基础上,以IgG活性保留率作为响应值,选取甘氨酸、麦芽糖醇和菊粉三种物质作为响应因子,采用Box-Behnken响应面法对IgG热保护剂配方进行优化,并通过傅里叶变换红外光谱和内源性荧光光谱表征不同方式处理的牛初乳IgG结构。结果表明,IgG热保护剂的最佳配方:甘氨酸0.48%,菊粉14.98%,麦芽糖醇12.50%,在75 ℃,5 min条件下热处理的IgG活性保留率为36.59%,各因素添加量对IgG活性保留率的影响主次顺序均为:麦芽糖醇>甘氨酸>菊粉。傅里叶变换红外光谱和内源性荧光光谱分析结果表示:与未添加复合热保护剂的牛初乳IgG相比,添加复合热保护剂后的牛初乳IgG,β-折叠含量显著下降（P<0.05）,无规则卷曲含量显著下降（P<0.05）,二级构象呈现较为有序的状态;荧光强度降低,IgG分子堆积更加紧密,结果表明添加复合热保护剂后的牛初乳IgG结构稳定性有所提高。本研究探索出一种新型牛初乳IgG的复合热保护剂配方,为牛初乳功能性食品的进一步开发和利用提供了参考。     

The concentrations of some hormones and growth factors in bovine and human colostrums: Short communication

This study compared different levels of certain hormones and growth factors between bovine and human colostrums. Colostrums were collected from seven Holstein cows and seven healthy humans. Prolactin, epidermal growth factor (EGF) and nerve growth factor (NGF) had higher levels in human colostrums over the 3 days. A higher level of platelet‐derived growth factor (PDGF) was found in bovine colostrums on day three; estradiol had higher levels on day three in both human and bovine colostrums. To minimise the differences of active components’ concentrations between these two types of colostrums, prolactin, EGF and NGF should be considered for addition into bovine colostrum products.     

The effect of probiotics on the genotoxicity of furazolidone

Antigenotoxic activity of probiotic bacteria against furazolidone was studied using the short-term bacterial assay SOS chromotest, with Escherichia coli PQ37 as the test organism. The supernatants from probiotic and furazolidone co-incubation exhibited rather strong suppression on SOS induction produced by furazolidone on E. coli PQ 37 (sfiA: lacZ). Genotoxicity inhibition was found for all strains of the examined bacteria belonging to three genera. The highest genotoxicity inhibition was detected for Bifidobacterium lactis Bb-12 (92.0%) and for Lactobacillus acidophilus T20 (81.9%).     

Characterization and purification of a bacteriocin produced by a potential probiotic culture, Lactobacillus acidophilus 30SC

Lactobacillus acidophilus 30SC was tested for its potential as a probiotic culture. The strain exhibited good acid tolerance in an artificial gastric solution as well as bile resistance in media containing 0.3% bile acids. The strain produced a heat-stable antimicrobial compound that was shown to be proteinaceous in nature and, therefore, referred to as a bacteriocin. The bacteriocin was active over a wide pH range and inhibited a number of gram-positive bacteria including Listeria ivanovii and pathogenic strains. The bacteriocin was purified by 50% ammonium sulfate precipitation followed by hydrophobic interaction column chromatography. The SDS-PAGE of the active fractions resulted in a single band with estimated molecular mass of 3.5 kDa. These results demonstrate the potential of L. acidophilus 30SC as a probiotic culture that can be utilized in the manufacturing of dairy foods and dietary supplements.     

具有α-葡萄糖苷酶和二肽基肽酶IV抑制作用降糖益生菌的筛选

以实验室保藏的13 株乳酸杆菌为研究对象,研究其细胞代谢物（cell-free excretory supernatants,CFS）和细胞内容物（cell-free extracts,CFE）对α-葡萄糖苷酶和二肽基肽酶IV（dipeptidyl peptidase IV,DPP-IV）的抑制活性;然后对酶抑制率较高的菌株进行益生特性评价,以期筛选出具有潜在降糖作用的益生菌。结果表明,13 株乳酸杆菌的CFS对α-葡萄糖苷酶具有一定的抑制作用,抑制率为0%～12.13%;CFE对α-葡萄糖苷酶无抑制作用。13 株乳酸杆菌CFS和CFE对DPP-IV均表现出一定的抑制作用,抑制率分别为0%～7.13%和0%～55.42%。选取酶抑制率较高的嗜酸乳杆菌KLDS1.1003、KLDS1.0901和KLDS1.0902进行益生特性的研究。其中嗜酸乳杆菌KLDS1.0901表现出较高的酸耐受性,嗜酸乳杆菌KLDS1.1003表现出较高的胆盐耐受性和疏水性。主成分分析表明嗜酸乳杆菌KLDS1.1003的综合性能最佳：其对α-葡萄糖苷酶的抑制活性可达10.29%;对DPP-IV的抑制率为CFS 7.13%,CFE 50.14%;于pH 2.0的条件下孵育1 h后,存活率达到51.55%;在0.3%的胆盐条件下孵育,滞后时间为2.26 h;在二甲苯、乙酸乙酯和氯仿溶剂中的疏水率分别为134.33%、20.51%和344.08%,总体上嗜酸乳杆菌KLDS1.1003具有较高的酶抑制活性和良好的益生特性。     

Fat-free plain yogurt manufactured with inulins of various chain lengths and Lactobacillus acidophilus

ABSTRACT:  Inulin is a prebiotic food ingredient that increases the activity of Lactobacillus acidophilus , increases calcium absorption, and is a good source of dietary fiber. The objective was to determine the effect of short, medium, and long chain inulins on the physicochemical, sensory, and microbiological characteristics of fat-free plain yogurt containing L. acidophilus . Inulins of short (P95), medium (GR), and long (HP) chain lengths were incorporated at 1.5% w/w of the yogurt mix. Viscosity, pH, syneresis, sensory properties (flavor, body and texture, and appearance and color), L. acidophilus counts, and color ( L *, a *, and b *) of yogurts were determined at 1, 11, and 22 d after yogurt manufacture. The P95 containing yogurt had a significantly lower pH than the remaining yogurts, higher flavor scores than the yogurt containing HP, and comparable flavor scores with the control. The yogurts containing HP had less syneresis than the control and a better body and texture than the remaining yogurts. Yogurts containing prebiotics of different chain lengths had comparable L. acidophilus counts with each other but higher counts than the control. However, inulins of various chain lengths did not affect viscosity, color, and product appearance. Chain length of prebiotics affected some quality attributes of probiotic yogurts.     

Effects of feeding heat-treated colostrum on passive transfer of immune and nutritional parameters in neonatal dairy calves

The first objective of this study was to describe the effect of on-farm heat treatment of colostrum on colostral bacteria counts and IgG concentrations. The second objective was to describe the effect of feeding heat-treated (vs. raw) colostrum on passive transfer of colostral immune and nutritional parameters in neonatal calves. Pooled batches of colostrum were mixed and divided equally: one half was fed raw whereas the other half was fed after heat treatment at 60°C for 60 min using a commercial on-farm batch pasteurizer. Colostrum samples were cultured for total bacteria count and total coliform count and analyzed for total IgG concentration. Forty-nine Holstein calves were fed either raw colostrum (n = 24) or heat-treated colostrums (n = 25) within 1 to 2 h after birth. Serum samples collected from calves at 0 h (precolostrum) and 24 h (postcolostrum) were assayed for serum total protein; IgG, IgA, and IgM concentrations; peripheral total leukocyte counts; neutrophil counts; lymphocyte counts; lymphocyte phenotypes; vitamin A, vitamin E, cholesterol, and β-carotene concentrations. Serum samples collected from 2- to 5-d-old calves were tested for immunoglobulin function via a bovine viral diarrhea virus type I serum neutralization titer and for neutrophil bacterial opsonization activity. On-farm batch heat treatment of colostrum at 60°C for 60 min resulted in lower colostrum bacteria concentrations while maintaining colostral IgG concentration. Calves fed heat-treated colostrum had significantly greater serum total protein and IgG concentrations at 24 h, plus greater apparent efficiency of IgG absorption (total protein = 6.3 mg/dL; IgG = 22.3 mg/mL; apparent efficiency of absorption = 35.6%) compared with calves fed raw colostrum (TP = 5.9 mg/dL; IgG = 18.1 mg/mL; apparent efficiency of absorption = 26.1%). There was no effect of treatment on serum concentrations of IgA, IgM, vitamin A, vitamin E, cholesterol, β-carotene or vitamin E:cholesterol ratio, or on serum bovine viral diarrhea virus type I serum neutralization titers. There was no difference between treatment groups when examining calf plasma total leukocyte counts, neutrophil counts, lymphocyte counts, or neutrophil opsonization activity. However, the latter results were considered inconclusive.