鼠李糖乳杆菌燕麦益生乳的研制

探讨了以燕麦和脱脂奶粉为主要原料,燕麦经双酶水解所得的糖化液,配以脱脂奶粉,经杀菌冷却,以鼠李糖乳杆菌为发酵剂,接种发酵而成的含有活性成分且具有保健功能的生物乳,它的活性多糖β-葡聚糖量为236mg/L,酸度为108°T,活菌数高达1010cuf/ml。      

鼠李糖乳杆菌利用不同益生元的增殖及耐受性研究

作者旨在通过对比鼠李糖乳杆菌（Lactiplantibacillus rhamnosus）与不同益生元组合后,在生长情况、pH和胆盐耐受性及乳酸产量方面的变化筛选出鼠李糖乳杆菌与益生元的最佳组合。结果表明,鼠李糖乳杆菌GG（L. rhamnosus GG, LGG）、鼠李糖乳杆菌HN001在以低聚半乳糖为唯一碳源生长时,最大生物量分别为1.253、1.552,最大比生长速率分别为0.316、0.290 h^-1,乳酸产量分别为3.654、10.914 g/L,与其他益生元组合相比,表现出显著优势。为验证这两种组合在不同胁迫条件下的生长情况,进一步测定了其在不同pH和胆盐质量浓度下的耐受性。这两种组合在1 g/L胆盐条件下的最大生物量分别为0.712和0.694,在pH 4.0条件下的最大生物量分别为0.639和0.728,与其他组合相比存在极显著差异。该研究结果有助于推动鼠李糖乳杆菌与低聚半乳糖组合在食品、医疗等领域的广泛应用,为后续益生菌-益生元组合产品的开发提供了理论依据。     

复凝聚法鼠李糖乳杆菌微胶囊工艺优化及储藏稳定性

为提高鼠李糖乳杆菌在贮藏过程中的稳定性,以明胶、阿拉伯胶为壁材,采用复凝聚法制备鼠李糖乳杆菌微胶囊。研究以湿态微胶囊的包埋率为指标,考察pH、壁材浓度、转速和菌添加量对复凝聚法微胶囊制备的影响,在单因素试验的基础上进行正交试验,优化最佳工艺。将最优条件下的湿微胶囊进行喷雾干燥和真空冷冻干燥,并在不同水分活度和不同温度条件下研究了喷雾干燥和真空冷冻干燥鼠李糖乳杆菌微胶囊的储藏稳定性。结果表明,pH 3.75、壁材浓度1.5%、转速200 r/min、菌添加量109 CFU,此条件下制备的鼠李糖乳杆菌微胶囊包埋率最高,为93.21%;复凝聚法制备的鼠李糖乳杆菌湿微胶囊干燥后,每克真空冷冻干燥微胶囊的活菌数比喷雾干燥微胶囊高1.9个对数值;储藏时水分活度越低,温度越低,鼠李糖乳杆菌微胶囊的储藏性越好;与喷雾干燥微胶囊相比,储藏时真空冷冻干燥微胶囊在高水分活度下较稳定,且在不同水分活度、不同温度条件下的活性均高于喷雾干燥微胶囊。因此复凝聚法制备的鼠李糖乳杆菌微胶囊真空冷冻干燥后能更好的保护鼠李糖乳杆菌,延长其储藏期。     

不同益生元对植物乳杆菌生长的影响

研究不同益生元对植物乳杆菌在不同培养条件下的促增殖作用。选用5株生理特性不同的植物乳杆菌为研究对象,利用Bioscreen检测它们的生长情况,进一步通过Baranyi模型拟合曲线,从而得到最大比生长速率和迟滞期。结果表明:在MRS培养基下,添加5种不同的益生元对植物乳杆菌无明显促增殖作用;在以益生元替代葡萄糖作为碳源的MRS培养基中,植物乳杆菌对不同的益生元具有选择偏好性,且具有菌株特异性;在模拟肠道体系下,与对照相比,益生元能明显促进所有植物乳杆菌的增长,其中低聚果糖与低聚半乳糖最优。实验结论显示,模拟肠道体系可以作为最精确和快速的益生元筛选体系。     

真菌多糖对鼠李糖乳杆菌性质的影响

研究了不同质量浓度的真菌多糖对鼠李糖乳杆菌的影响。结果表明,质量浓度为15g/L的真菌多糖对鼠李糖乳杆菌的增殖效果最显著,其活菌数最大可达到3.08×1010mL-1,能够使发酵周期提前2～3h。其产酸能力得到明显的提高,并且此真菌多糖益生元较好地提高了鼠李糖乳杆菌的耐酸、耐胆盐的能力。     

中药多糖对鼠李糖乳杆菌性质的影响

研究不同浓度的甘草多糖和党参多糖对鼠李糖乳杆菌的影响,发现1.5%(m/v)的党参多糖对鼠李糖乳杆菌的增殖影响最大,其活菌数最大可达到2.18×109cfu/mL,能够使其提前2～3h达到最大产酸量,缩短发酵时间,较好地提高其耐酸、耐胆盐及耐高温的能力,其多糖的利用率可高达70.5%。     

壳聚糖黄原胶鼠李糖乳杆菌微胶囊的制备及其特性的研究

本研究利用壳聚糖和黄原胶作为壁材,用乳化法包埋鼠李糖乳杆菌,以包埋率为指标,探究其最佳的制备工艺,发现当壳聚糖浓度为0.8%,黄原胶浓度为1.0%,转速为900 r/min时效果最佳,最佳包埋率为88.9%。制备的微胶囊粒径在300μm左右,分布较为均匀。在模拟胃液和模拟胆液中静置2 h后仍分别有3.56 lg CFU/m L和3.4 lg CFU/m L活菌体,表明其对菌体有较强的保护作用。      

除氧剂及益生元对双歧杆菌BB01和BB28微胶囊化的影响

以双歧杆菌BB01和BB28为试验菌株,通过单因素试验研究不同浓度的除氧剂及益生元对其微胶囊效果的影响。结果表明:在双歧杆菌BB01微胶囊化的过程中,除氧剂半胱氨酸盐酸盐及异抗坏血酸钠的影响效果更佳,最适加入量分别为0.05%,0.09%,半胱氨酸盐酸盐对应的微胶囊活菌数及包埋率分别为2.2×109 CFU/mL,54%,异抗坏血酸钠对应的分别为2.9×109 CFU/mL,82%。益生元菊糖及低聚果糖对其微胶囊化的过程影响效果更佳,最适加入量分别为3%,5%,菊糖所对应的分别为4.6×109 CFU/mL,80%,低聚果糖所对应的分别为1.7×109 CFU/mL,80%;在双歧杆菌BB28微胶囊化的过程中,除氧剂抗坏血酸钠及异抗坏血酸钠对双歧杆菌的影响效果更佳,最适加入量分别为0.05%,0.03%,抗坏血酸钠所对应的分别为3.9×109 CFU/mL,77%,异抗坏血酸钠所对应的的微胶囊活菌数及包埋率分别为1.7×109 CFU/mL,66%。益生元低聚木糖及低聚果糖对其微胶囊化的包埋效果影响更佳,二者最适加入量均为7%,低聚木糖对应的微胶囊活菌数及包埋率分别为4.9×109 CFU/mL,60%,低聚果糖所对应的微胶囊活菌数及包埋率分别为4.3×109 CFU/mL,80%。     

真菌多糖对鼠李糖乳杆菌体外增殖的研究

通过液体发酵提取曲霉和云芝胞内胞外多糖,脱蛋白,制成一定浓度溶液.选用MRS培养基,采取试管法,试验曲霉和云芝多糖对鼠李糖乳杆菌增殖的影响,并将其应用于鼠李糖乳杆菌发酵乳的研究中.结果表明,0.5%(m/v)、1%(m/v)的曲霉多糖和云芝多糖对鼠李糖乳杆菌体外增殖均有极显著的效果(P＜0.05).不同浓度相比,2%(m/v)的曲霉多糖和1%(m/v)的云芝多糖更能提高鼠李糖乳杆菌的活性,缩短凝乳时间.初步显示,曲霉多糖和云芝多糖中含促生长因子.     

黄参粗多糖对植物乳杆菌CGMCC-15801和鼠李糖乳杆菌CGMCC-16103增殖的影响

益生菌发酵乳具有巨大的经济价值和市场前景,在发酵乳中针对性地添加益生元,可保护和促进益生菌的增长。黄参是伞形科迷果芹属植物,该实验以黄参粗多糖(crude Sphallerocarpus gracilis polysaccharides,CSGP)为研究对象,以低聚果糖和菊粉为阳性对照,测定CSGP的单糖组成,在人工胃肠液中的水解度以及对植物乳杆菌和鼠李糖乳杆菌增殖的影响。结果表明,CSGP主要由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖组成,摩尔比为16.3:15.5:5.1:8.2:37.1:17.8;CSGP在人工胃液中的水解度仅为2.0%,显著低于菊粉和低聚果糖(P<0.05);在21 d货架期内,当CSGP的添加量为3.5%时,植物乳杆菌在第14天的增殖率达到最高(410%),分别是阳性对照低聚果糖组的5.09倍,菊粉组的8.99倍;当CSGP添加量为3.0 g/100mL时,鼠李糖乳杆菌在第21天的增值率达到最高(405%),分别是阳性对照低聚果糖组的36.52倍,菊粉组的11.67倍,故推测CSGP是潜在的益生元。该实验为以CSGP为益生元的新型共生发酵乳的研发提供理论基础。     

Effects of Lactobacillus rhamnosus GG addition in ice cream

A 2⁴ full factorial experimental design was applied to verify the effects of Lactobacillus rhamnosus GG (LGG) addition in retail-manufactured ice cream stored at two different freezing temperatures (−16°C and −28°C) and containing two different levels of sugar (15–22%) and fat (5–10%). In addition to microbial counts, the pH, acidity, viscosity of the mixes and functional properties of the ice creams were evaluated. Both fresh and frozen-thawed LGG cells underwent preliminary resistance tests to bile, antibiotics and acidity. The LGG strain proved to be highly resistant to most of the stress factors. When the micro-organism was added to ice cream mixes in a quantity of 10⁸ cfu/g, it did not change the overrun, firmness or melting behaviour of the finished product. Regardless of formulation, no count decay of LGG cells was observed in ice cream stored for up to 1 year.     

Survival of Lactobacillus rhamnosus GG as Influenced by Storage Conditions and Product Matrixes

Abstract: Mortality resulting from diarrhea especially that occurs in children younger than 5 y of age ranks 3rd among all deaths caused by infectious diseases worldwide. Probiotics such as Lactobacillus rhamnosus GG are clinically shown to effectively reduce the incidence of diarrhea in children. A food substrate is one of the major factors regulating the colonization of microorganisms in human gastrointestinal tracts. Peanut butter is a nutritious, low‐moisture food that could be a carrier for probiotics. In this study, we observed the influence of storage conditions and product matrixes on the survival of L. rhamnosus GG. Cells of L. rhamnosus GG were inoculated into full fat or reduced fat peanut butter at 10⁷ CFU/g. Inoculated peanut butter was stored at 4, 25, or 37 °C for 48 wk. Samples were drawn periodically to determine the populations of L. rhamnosus GG. Results showed that there was no significant decrease in the viable counts of L. rhamnosus GG in products stored 4 °C. The survivability of L. rhamnosus GG decreased with increasing storage temperature and time. Product matrixes did not significantly affect the survival of L. rhamnosus GG except at 37 °C. Populations of L. rhamnosus GG were preserved at >6 logs in products stored at 4 °C for 48 wk and at 25 °C for 23 to 27 wk. At 37 °C, the 6‐log level could not be maintained for even 6 wk. The results suggest that peanut butter stored at 4 and 25 °C could serve as vehicles to deliver probiotics. Practical Application: Lactobacillus rhamnosus GG is clinically shown to effectively reduce the incidence of diarrhea in children. A food substrate is one of the major factors regulating the colonization of microorganisms in human gastrointestinal tracts. Peanut butter is a nutritious, low‐moisture food that could be a carrier for probiotics. In this study, we demonstrated the influence of storage conditions and product matrixes on the survival of L. rhamnosus GG. Results suggest that peanut butters could be effective delivery systems for probiotics and that probitic peanut butter could be used as one of the strategies to control diarrhea and malnutrition in developing countries.     

植物乳杆菌微胶囊发酵对胡萝卜脆片品质的影响

本研究以海藻酸钠和分离乳清蛋白为壁材,应用挤压法制备植物乳杆菌微胶囊。以植物乳杆菌微胶囊发酵的胡萝卜脆片为试验组,未经微胶囊处理发酵的胡萝卜脆片为对照组,探讨植物乳杆菌微胶囊发酵对胡萝卜脆片品质的影响及其在冷冻干燥和模拟胃液条件下活菌数的变化。结果表明:试验组和对照组的胡萝卜片在质构、色泽、总糖含量、胡萝卜素含量和抗坏血酸含量差异不显著（P>0.05）。在冷冻干燥和模拟胃液环境下,试验组的活菌数明显高于对照组,分别保持在（8.47±0.02）和（8.31±0.01） lg（CFU/g）。植物乳杆菌微胶囊发酵对胡萝卜脆片的品质没有产生显著影响,但可以提高植物乳杆菌对不良环境（如冷冻干燥和胃液）的抗性。     

鼠李糖乳杆菌对黄曲霉毒素B1的降解及对 肝损伤的保护作用

目的分析鼠李糖乳杆菌(Lactobacillus rhamnosus GG,LGG)对黄曲霉毒素B_1(aflatoxin B_1,AFB_1)的降解能力,阐述LGG对由AFB_1引起的肝损伤的保护作用。方法利用LGG培养液、LGG上清液组、LGG菌体、热处理后上清液和热处理后LGG菌体处理AFB_1,利用高效液相色谱法测定AFB_1的残留量,分析LGG对AFB的降解能力。利用低、中和高剂量的LGG菌液灌胃由AFB_1引起肝损伤的大鼠,并以空白和阳性作为对照组,测定大鼠的血清肝功能及肝组织抗氧化指标,分析LGG对肝损伤的保护作用。结果 AFB_1降解实验表明LGG菌液对AFB_1具有显著的降解作用(P0.05),36 h能够降解(92.01±2.02)%的AFB_1。降解作用是由菌体和LGG的代谢产物共同作用的结果。大鼠血清肝功能及肝组织抗氧化指标结果表明低、中和高剂量的LGG灌胃给药均能显著改善因AFB_1引起的大鼠肝功能和肝组织抗氧化指标异常(P0.05)。结论 LGG对AFB_1具有良好的降解作用,且能够有效抑制因AFB_1引起的肝损伤。     

Microencapsulated Lactobacillus rhamnosus GG powders: relationship of powder physical properties to probiotic survival during storage

Freeze-dried commercial Lactobacillus rhamnosus GG (LGG) were encapsulated in an emulsion-based formulation stabilized by whey protein and resistant starch and either spray-dried or freeze-dried to produce probiotic microcapsules. There was no difference in loss of probiotics viability after spray drying or freeze drying. Particle size, morphology, moisture sorption, and water mobility of the powder microcapsules were examined. Particle size analysis and scanning electron microscopy showed that spray-dried LGG microcapsules (SDMC) were small spherical particles, whereas freeze-dried LGG microcapsules (FDMC) were larger nonspherical particles. Moisture sorption isotherms obtained using dynamic vapor sorption showed a slightly higher water uptake in spray-dried microcapsules. The effect of water mobility, as measured by nuclear magnetic resonance (NMR) spectroscopy, at various water activities (a(w) 0.32, 0.57, and 0.70) and probiotic viability during storage at 25 °C was also examined. Increasing the relative humidity of the environment at which the samples were stored caused an increase in water mobility and the rate of loss in viability. The viability data during storage indicated that SDMC had better storage stability compared to FDMC. Although more water was adsorbed for spray-dried than freeze-dried microcapsules, water mobility was similar for corresponding storage conditions because there was a stronger water-binding energy for spray-dried microcapsule. This possibly accounted for the improved survival of probiotics in spray-dried microcapsules.     

The involvement of ATPase activity in the acid tolerance of Lactobacillus rhamnosus strain GG

This study examined the survival and acid stress response of nine lactic acid bacteria (LAB) including Lactobacillus rhamnosus strain GG in commercially available yoghurt products (low pH environment) during the long‐term storage. Under the storage conditions investigated (52 weeks period at 5 °C), there was a loss of the viability of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium sp. within 35 weeks. However, L. rhamnosus strain GG, one of starter strains in a commercially available yoghurt product, exhibited excellent survival throughout the whole storage period. Our results indicate that the viability of L. rhamnosus strain GG was increased by modulating the stress‐related factors as well as the activity of ATPase with exposure to the low pH conditions.     

巯基化党参多糖对鼠李糖乳杆菌肠道黏附定植作用的影响

益生菌的肠道黏附是其实现长期肠道定植的关键因素。为增加外源性益生菌的肠道黏附性,对前期分离所得党参多糖(CPP-2)采用羧甲基化和巯基化两步化学修饰法,制备巯基化党参多糖(sC-CPP-2)。通过体外黏附实验和激光共聚焦显微镜法分析在添加sC-CPP-2情况下肠黏液对鼠李糖乳杆菌(LGG)的黏附效果,利用党参多糖及其修饰组分与海藻酸钠形成的复合薄膜,间接验证sC-CPP-2对LGG的黏附性,并利用流变仪和经典拉伸实验检测sC-CPP-2与肠道黏液之间的相互作用关系。结果表明：羧甲基党参多糖(C-CPP-2)的取代度为0.588±0.026,sC-CPP-2中巯基含量为(279.50±5.97)μmol/g, C-CPP-2经巯基化修饰后处于巯基和羧基共存状态。sC-CPP-2表面巯基可与LGG表面蛋白质上的半胱氨酸残基形成二硫键,增加LGG的肠道黏附性。sC-CPP-2与肠黏液的最大分离力为(101.82±5.78) mN,黏附总功为(120.07±6.81)μJ,二者间相互作用力增强,表观黏度变大,黏合力显著增强。sC-CPP-2能够起到连接LGG与肠黏液的中介作用,增强LGG的肠道...     

Microencapsulation of Lactobacillus rhamnosus GG by Transglutaminase Cross‐Linked Soy Protein Isolate to Improve Survival in Simulated Gastrointestinal Conditions and Yoghurt

Microencapsulation is an effective way to improve the survival of probiotics in simulated gastrointestinal (GI) conditions and yoghurt. In this study, microencapsulation of Lactobacillus rhamnosus GG (LGG) was prepared by first cross‐linking of soy protein isolate (SPI) using transglutaminase (TGase), followed by embedding the bacteria in cross‐linked SPI, and then freeze‐drying. The survival of microencapsulated LGG was evaluated in simulated GI conditions and yoghurt. The results showed that a high microencapsulation yield of 67.4% was obtained. The diameter of the microencapsulated LGG was in the range of 52.83 to 275.16 μm. Water activity did not differ between free and microencapsulated LGG after freeze‐drying. The survival of microencapsulated LGG under simulated gastric juice (pH 2.5 and 3.6), intestinal juice (0.3% and 2% bile salt) and storage at 4 °C were significantly higher than that of free cells. The survival of LGG in TGase cross‐linked SPI microcapsules was also improved to 14.5 ± 0.5% during storage in yoghurt. The microencapsulation of probiotics by TGase‐treated SPI can be a suitable alternative to polysaccharide gelation technologies.