益生菌Lactobacillus casei Zhang和Bifidobacterium lactis V9接种比例及乳固形物含量对其活菌数的影响

将益生菌Lactobacillus casei Zhang和Bifidobacterium lactis V9按1∶3、1∶1、3∶1(总接种量为2×106cfu/g)接种于总固形物含量为10%、12%、14%、16%的脱脂牛乳中,37℃恒温发酵至pH 4.5,于4℃贮藏28 d。测定发酵及贮藏结束2株益生菌活菌数。试验结果表明,发酵结束,当研究固形物质量分数相同,接种比例为3∶1时,L.casei Zhang和B.lactis V9的活菌数最高。贮藏结束,当接种比例相同,所含乳固形物质量分数为14%时,两株益生菌存活率显著高于其他固形物含量组(P<0.05)。本研究显示,L.casei Zhang和B.lactis接种比例为3∶1,乳固形物质量分数为14%时,两株益生菌生长良好且存活率高,适宜生产应用。     

益生菌Lactobacillus plantarum P8与Streptococcus thermophilus混合发酵对发酵乳品质的影响

将益生菌Lactobacillus plantarum P8以不同接种比例分别与Streptococcus thermophilus ND03、ND05和ND07复配发酵牛乳,并以S.thermophilus单菌发酵为对照.于0h、发酵结束(pH=4.5)及4℃冷藏24 h,分别测定发酵乳样品的发酵时间,及pH值、黏度、脱水收缩率和活菌数并进行感官鉴评.结果表明,L.plantarum P8与S.thermophilus ND03复配,发酵时间显著高于其他组,各组样品黏度和脱水收缩率差异不显著；L.plantarum P8与S.thermophilus ND05分别以5×106 mL-1接种1∶1复配时,样品中L.plantarum P8的活菌数为5.26×107mL-1,酸度适宜,无乳清析出,有良好的黏度,产品风味较好,将该组合应用于发酵乳生产,较可行.     

Lactobacillus casei Zhang和Bifidobacterium lactis V9在益生菌酸乳中的应用

益生菌在酸乳中的应用已非常普遍,将Lactobacillus casei Zhang单独(样品A)以及与Bifidobacterium lactis V9复合(样品B),同酸乳发酵剂(G027)共同发酵益生菌酸乳,于4℃贮藏21 d。结果表明,整个贮藏期间2组样品间的黏度和持水性差异不显著;贮藏期间2组样品间L.casei Zhang的活菌数没有差异,且L.casei Zhang和B.lactis V9的活菌数不随贮藏时间而降低;L.casei Zhang和B.lactis V9复合益生菌酸奶感官评价优于单独添加L.casei Zhang酸乳。L.casei Zhang和B.lactis V9复合添加,更适合于益生菌酸乳的生产。     

益生菌L.casei Zhang和B.lactis V9在发酵乳中发酵特性的评价

以L.casei Zhang和B.lactis V9为研究对象,评价其发酵特性及对发酵乳品质的影响。研究结果显示,4℃下贮藏21 d,L.casei Zhang和B.lactis V9的添加对发酵乳的p H值、滴定酸度(TA)、黏度和持水性基本无影响;L.casei Zhang和B.lactis V9在发酵乳中存活稳定;B.lactis V9的添加可促进L.casei Zhang的增殖,同时可进一步改善L.casei Zhang发酵乳的气味和风味。     

Bifidobacterium lactis V9在脱脂乳粉中贮藏稳定性的研究

研究Bifidobacterium lactis V9(B.lactis V9)与双歧杆菌B在脱脂乳粉中不同温度条件下存活稳定性,并以Arrhenius方程反映温度与菌体损失率之间关系,预测B.lactis V9与双歧杆菌B相关乳粉产品货架期内菌体损失情况。结果表明,B.lactis V9与双歧杆菌B随温度升高,菌体损失率增大。两菌株在37℃贮藏28 d后,活菌数下降最明显,约两个数量级,且在不同贮藏温度下活菌数随时间变化情况无显著性差异。通过Arrhenius方程和菌体递减模型,建立了B.lactis V9和双歧杆菌B在不同温度下货架期预测模型,该模型可以较好的预测含B.lactis V9和双歧杆菌B乳粉产品在某一温度下菌体损失率和货架期寿命。     

荧光定量PCR法检测益生菌饮料中Lactobacillus casei Zhang和Bifidobacterium lactis V9

益生菌活菌数是益生菌产品最重要的指标,而检测益生菌方法的准确性和科学性则至关重要.本文采用荧光定量PCR法同时定量检测益生菌饮料中Lactobacillus casei Zhang(L.casei Zhang)和Bifidobacterium lactis V9(B.lactis V9)的活菌数,并与平板菌落计数法进行比较.结果表明,荧光定量PCR法测得L.casei Zhang活菌数与平板菌落计数法测得活菌数差异不显著;而采用荧光定量PCR法测得B.lactis V9活菌数显著高于平板菌落计数法.荧光定量PCR法灵敏、特异、简便快速,可定量检测并真实反应L.casei Zhang和B.lactis V9的活菌数.     

人源多菌株益生菌发酵条件的研究

为生产出具有降胆固醇功能特性的发酵乳,以酸度、黏度、游离氨基酸和活菌数为响应面研究L. rhamnosus LV108、L. casei grx12及L. fermentum grx08不同配比的发酵特性,以活菌数和感官评价优化多菌株人源益生菌的发酵工艺。结果表明:混合乳酸菌(L.rhamnosus LV108∶L. casei grx12∶L. fermentum grx08=2∶1∶1)发酵时间适当、后酸化较弱、黏度较强、游离氨基酸较多且产品活菌数高。按照该比例制备的酸奶,其最佳工艺条件为接种量为5.0%,蔗糖添加量为8.0%,发酵温度为37℃,乳固形物含量为12.0%。     

基于产酸能力和高活菌数的益生菌复合菌种发酵技术研究

为了提高益生菌发酵乳的活菌数及发酵过程中的产酸能力,本研究以干酪乳杆菌、嗜酸乳杆菌、双歧杆菌、嗜热链球菌、保加利亚乳杆菌为试验菌种,通过单菌种发酵和复合菌种发酵试验,筛选出最佳的复合菌种组合.试验结果表明:在接种量为5％,接种比例为1∶1,发酵温度为37℃,葡萄糖的添加量为2.5％(质量分数),脱脂乳乳固体质量分数为12％的条件下,干酪乳杆菌和双歧杆菌复合发酵效果最佳,最大滴定酸度可达到328°T,最大活菌数达到2.3×1011 mL-1,与其他菌种组合相比,提高了一个对数级,且在贮藏过程中活菌数下降速度较慢.     

基于微流变技术研究不同嗜热链球菌对发酵乳凝胶化的影响

使用3株嗜热链球菌分别与保加利亚乳杆菌ND02复合发酵牛乳,评价在37℃发酵过程中及4℃贮藏期间黏度、酸度及活菌数等变化。利用微流变技术研究不同嗜热链球菌对发酵乳凝胶化过程的影响,筛选出1株具有优良发酵特性的嗜热链球菌。结果表明:3组发酵乳样品在发酵过程及贮藏期间黏度、酸度有显著差异(P0.05),活菌数高于1×10~6CFU/mL。3株嗜热链球菌在发酵乳凝胶形成过程中,对凝胶结构的影响存在差异,其中嗜热链球菌GW21-4可以改善发酵乳品质,强化凝胶结构,其在乳制品开发中具有良好的应用潜力。     

基于高活菌数的瑞士乳杆菌和鼠李糖乳杆菌混合发酵工艺优化

以瑞士乳杆菌和鼠李糖乳杆菌混合发酵培养,利用两菌株细胞代谢的差异,以静置发酵24 h后得到的活菌数目为指标,通过单因素实验和正交实验,研究了瑞士乳杆菌和鼠李糖乳杆菌高活菌数混合发酵的最适发酵条件。结果表明,瑞士乳杆菌和鼠李糖乳杆菌高活菌数混合发酵的最优条件为:发酵温度37℃,初始pH=6.8,接种量6%,瑞士乳杆菌:鼠李糖乳杆菌=1∶2,瑞士乳杆菌优先接种3 h。最终得到乳酸菌总活菌数为7.2×10~9m L~(-1)。与在相同条件下单独发酵的瑞士乳杆菌和鼠李糖乳杆菌活菌数相比,分别提高了1∶8倍和10.2倍。为乳酸菌的高活菌数发酵奠定了基础。     

双蛋白益生菌发酵乳的研制与品质分析

为丰富发酵乳的品类并满足消费者的多样化需求,本研究以一定比例的纯牛乳和花生蛋白粉为原料,添加益生菌制作了一种双蛋白益生菌发酵乳。将纯牛乳与不同比例的花生蛋白混合,巴氏灭菌后,将混合物与发酵物一起发酵（嗜热链球菌S10:动物双歧杆菌乳亚种菌株V9:干酪乳杆菌Zhang=10:10:1）,从感官特性、酸度、粘度、持水力及益生菌活菌数等角度,评价了贮藏期内28 d实验组及对照组发酵乳的品质及贮藏特性。结果表明,花生蛋白:牛乳蛋白=3:7时,发酵乳酸甜适口、色香兼具、组织细腻且凝聚性好,感官评分为（94±3）分,发酵时间5.4 h。经4℃下贮藏28 d后,3:7实验组的后酸化程度与对照组相比较弱,内聚性及黏度指数均高于两个对照组（分别为-20.24±1.77 g、-20.63±2.79 g·s）。与此同时,3:7实验组的粘度最高可达（1085±100）m Pa·s,持水力可平均稳定在75%左右,发酵乳中的干酪乳酪杆菌Zhang及动物双歧杆菌乳亚种V9的活菌数均可保持在1×107 CFU/mL以上。因此,通过花生蛋白替代部分牛乳蛋白来制作发酵乳的工艺是可行的,产品在28 d贮藏期内能够保持良好的...     

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.     

益生菌山药饮料发酵工艺优化及其冷藏稳定性

本研究以山药粉为原料,益生菌Lactobacillus plantarum P-8和Bifidobacterium lactis V9为发酵剂,对发酵工艺进行优化,以得到一种兼具山药营养价值与益生菌益生特性的益生菌山药饮料。通过单因素实验研究发酵时间、接种量、发酵温度对饮料中活菌数、滴定酸度以及pH的影响,在此基础上结合响应面分析获得发酵益生菌山药饮料最优发酵工艺参数,即接种量为 2×106 CFU/mL、发酵时间为19.1 h、发酵温度为37 ℃。在此条件下饮料活菌数为4.3×108 CFU/mL,滴定酸度为105.3 °T。对饮料在4 ℃下贮藏28 d,贮藏期内饮料活菌数稳定维持在108 CFU/mL,饮料组织状态良好、风味及口感稳定。     

益生菌混合菌种在发酵豆乳中的优化

采用益生菌混合物AST和TLB分别在42℃进行豆乳的发酵,在发酵豆乳的发酵和贮存过程中(4℃下28d),观察pH值和活菌数的变化情况。在AST益生菌混合物(嗜酸性乳杆菌,双歧杆菌和嗜热链球菌)的培育下,42℃下发酵时间减少到8h。但嗜酸性乳杆菌在冷藏的过程中生存状态较差,其活菌数在冷藏后一周后未达到标准。将豆乳在42℃下用TLB益生菌(嗜热链球菌,保加利亚乳杆菌和动物双歧杆菌乳酸亚种Bb12)进行发酵,结果发酵时间缩短到4h,双歧杆菌活菌数目的对数增加了约一半,而且经过28d的冷藏,细菌数仍然维持在107 CFU/mL以上。     

Raffinose family of oligosaccharides from lupin seeds as prebiotics: application in dairy products

The raffinose family of oligosaccharides (RFOs) isolated from lupin seeds (Lupinus albus var. Multolupa) was evaluated for bifidogenic effects during the manufacture of probiotic fermented milk. A mixed starter inoculum was composed of Bifidobacterium lactis Bb-12 and Lactobacillus acidophilus (1:1). Lupins are a rich source of RFOs that can be used as functional food ingredients. The addition of RFOs to milk increased B. lactis Bb-12 and L. acidophilus populations at the final fermentation time compared with controls. Final fermentation products are positively affected by addition of RFOs, and time of fermentation was reduced from 12 to 10 h. When RFOs were added to milk, they were preferentially used as a carbon source (57.7%) compared with lactose (23.7%) at the end of fermentation. These results suggest that the eventual choice of B. lactis Bb-12 and L. acidophilus in a mixed culture at a 1:1 ratio and addition of RFOs to produce a fermented milk product would have the advantages of rapid growth and acidificationrate and would likely increase the probiotic effect of the final functional product.     

EFFECT OF COLD STORAGE ON CULTURE VIABILITY AND SOME RHEOLOGICAL PROPERTIES OF FERMENTED MILK PREPARED WITH YOGURT AND PROBIOTIC BACTERIA

ABSTRACT

We examined the effect of storage time on culture viability and some rheological properties (yield stress, storage modulus, loss modulus, linear viscoelastic region, structural recuperation and firmness) of fermented milk made with Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus (LA) and Bifidobacterium animalis ssp. lactis in coculture with Streptococcus thermophilus (ST). Acidification profiles and factors that affect viability (postfermentation acidification, acidity and dissolved oxygen) were also studied during 35 days at 4C. Fermented milk prepared with a coculture of ST and Bifidobacterium lactis gave the most constant rheological behavior and the best cell viability during cold storage; it was superior to ST plus LA for probiotic fermented milk production.

PRACTICAL APPLICATIONS

Probiotic cultures should grow quickly in milk, provide adequate sensory and rheological properties to the product, and remain viable during storage. Commercially, it is very common to use yogurt starter culture (i.e. Streptococcus thermophilus[ST] and Lactobacillus delbrueckii ssp. bulgaricus) in combination with the probiotic bacteria in order to reduce fermentation time. However, LB tends to post acidify fermented milk, which reduces the viability of the probiotic bacteria; thus, it is recommended to use starter cultures devoid of this species. We found that the technological properties and the viability of the probiotic bacterium Bifidobacterium animalis ssp. lactis BL O4 in coculture with ST make it suitable for probiotic fermented milk production; it produces rheological characteristics similar to those of yogurt.     

Potential of functional strains, isolated from traditional Maasai milk, as starters for the production of fermented milks

The purpose of this research was the evaluation of technological features and of the ability of functional LAB strains with desirable sensory characteristics, to produce fermented milk. Eight strains of Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus paracasei and Lactococcus lactis, isolated from Maasai traditional fermented milk in Kenya and previously tested for their probiotic properties, were selected for this investigation. Technological features such as growth kinetics in fresh heat-treated whole milk medium and survival in the final product during storage at 4 degrees C, were studied. The strains Lb. acidophilus BFE 6,059, Lb. paracasei BFE 5,264 and Lc. lactis BFE 6,049 showed the best potential and were thus selected for use as starter cultures in further trials with the objective to improve their technological performance and to optimise the sensory features of fermented milk obtained. The effects of fat (F), non-fat milk solids (S) and fermentation temperature (T), modulated according to a Central Composite Design, on fermentation rates and viability losses during refrigerated storage of the chosen starters, and on product texture parameters, were studied. From the data analysis, it was possible to select optimum conditions for enhancing positive sensory traits of final products and for improving the survival of these potentially probiotic cultures.     

不同发酵剂对黑枣酸奶品质的影响

使用不同益生菌组合制备黑枣酸奶,并探究不同益生菌组合对发酵和质构特性的影响。结果表明,不同益生菌组合会显著影响黑枣酸奶的理化指标和质构特性（P＜0.05）;相比传统酸奶发酵剂,强化植物乳杆菌、嗜酸乳杆菌和乳双歧杆菌（1∶1∶1）发酵可显著提高黑枣酸奶的可滴定酸度（46.48%）、持水力（4.75%）、可溶性固形物含量（3.85%）和胞外多糖含量（12.63%）。此外,益生菌强化发酵可使黑枣酸奶中乳酸菌活菌数达到9.63 lg CFU/mL,且有效改善黑枣酸奶的质构特性,其硬度值、弹性、内聚性和回复性分别为151.24 g、1.04 mm、0.96 g·s和0.28。