Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 feeding enhances humoral immune responses,which are suppressed by the antiviral neuraminidase inhibitor oseltamivir in influenza A virus–infected mice

Antiviral neuraminidase inhibitors, such as oseltamivir, zanamivir, and peramivir, are widely used for treatment of influenza virus infection. We reported previously that oseltamivir inhibits the viral growth cycle, ameliorates symptoms, and reduces viral antigen quantities. Suppressed viral antigen production, however, induces a reduction of acquired antiviral humoral immunity, and increases the incidence of re-infection rate in the following year. To achieve effective treatment of influenza virus infection, it is necessary to overcome these adverse effects of antiviral neuraminidase inhibitors. Feeding of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) OLL1073R-1 is reported to have immune-stimulatory effects on influenza virus infection in mice and humans. In the present study, we assessed the effect of feeding L. bulgaricus OLL1073R-1 yogurt cultures (YC) on local and systemic humoral immune responses, which were suppressed by oseltamivir treatment, in mice infected with influenza A virus. Yogurt culture (1.14 × 10⁸ cfu/0.4 mL per mouse per day) or sterile water (vehicle) was administered by intragastric gavage for 35 d. At d 22, influenza A virus/Puerto Rico/8/34 (H1N1) (PR8; 0.5 pfu/15 μL per mouse) was instilled intranasally, followed immediately by oral administration of oseltamivir (50 μg/100 μL per mouse, twice daily) or 5% methylcellulose (100 μL/mouse) as a vehicle for 13 d. Titers of anti-PR8-specific IgG and IgA in serum and mucosal secretory IgA (S-IgA) and IgG in bronchoalveolar lavage fluid (BALF) were analyzed by ELISA at 14 d after infection. Oseltamivir significantly suppressed the induction of anti-PR8-specific IgG and IgA in serum and S-IgA and IgG in BALF after infection. Feeding YC mildly but significantly stimulated production of PR8-specific IgA in serum, S-IgA in BALF, and IgG in serum without changing the IgG_2a:IgG₁ ratio. We analyzed the neutralizing activities against PR8 in serum and BALF and found that oseltamivir also reduced protective immunity, and YC feeding abrogated this effect. The immune-stimulatory tendency of YC on anti-PR8-specific IgA and IgG titers in serum and BALF was also detected in mice re-infected with PR8, but the effect was insignificant, unlike the effect of YC in the initial infection.     

益生菌制剂及其发酵性乳制品

综述了益生菌的概念和益生菌菌株的选择标准、国外益生菌产品的发展状况、益生菌作为新型酸奶发酵剂的使用情况，以及益生酸奶的生产与消费情况。     

Short communication: Antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an “antiviral food.” At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5 mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28 mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.     

Lactobacillus reuteri in bovine milk fermented decreases the oral carriage of mutans streptococci

The effect of Lactobacillus reuteri against one of the major cariogenic organism, Streptococcus mutans, was studied. Yogurt products containing L.reuteri showed a significant growth inhibitory effect against S. mutans, whilst yoghurts with lactobaccilli other than L. reuteri did not show such inhibition. Further, double-blind, placebo-controlled trial demonstrated that consuming yogurt with L. reuteri significantly reduced the oral carriage of mutans streptococci, compared with the placebo yogurt.     

新疆琐琐葡萄提取物抗流感病毒A(H1N1)亚型作用研究

目的对新疆琐琐葡萄提取物抗流感病毒A(H1N1)亚型作用进行研究。方法1.采用狗肾传代细胞培养法和MTT法研究新疆琐琐葡萄多糖、琐琐葡萄总黄酮、琐琐葡萄总三萜对抗流感病毒A(H1N1)型作用。2.采用Read-muench法计算流感病毒A(H1N1)型在狗肾传代细胞中的半数感染量。3.通过观察细胞病变(CPE)、计算细胞病变CPE抑制率、MTT法测定药物对细胞的保护率等来评价琐琐葡萄多糖、总黄酮、总三萜的抗流感病毒效果。结果琐琐葡萄总黄酮的最大无毒作用浓度(TC0)为20μg/ml,琐琐葡萄总三萜的TC0为1500μg/ml。体外细胞试验中,琐琐葡萄黄酮、多糖提取物表现出对病毒的直接抑制作用,但是琐琐葡萄三萜提取物和利巴韦林(阳性对照)此作用不明显。体外细胞试验中,琐琐葡萄黄酮、多糖、三萜提取物均表现出对感染细胞后病毒的抑制作用,三萜的抑制效果要强于黄酮和多糖,利巴韦林的抑制作用强于黄酮、多糖、三萜。结论新疆特色植物资源—琐琐葡萄提取物抗流感病毒A(H1N1)亚型的作用是多途径的,琐琐葡萄总黄酮、琐琐葡萄多酚、琐琐葡萄三萜分别表现出对流感病毒A(H1N1)亚型感染细胞前、感染细胞后的抑制作用,以及直接抑制作用...     

Microstructure and rheology of yogurt made with cultures differing only in their ability to produce exopolysaccharides

Yogurt was made using an exopolysaccharide-producing strain of Streptococcus thermophilus and its genetic variant that only differed from the mother strain in its inability to produce exopolysaccharides. The microstructure was investigated using confocal scanning laser microscopy, allowing observation of fully hydrated yogurt and the distribution of exopolysaccharide within the protein network. Yogurt made with the exopolysaccharide-producing culture exhibited increased consistency coefficients, but lower flow behavior index, yield stress, viscoelastic moduli and phase angle values than did yogurt made with the culture unable to produce exopolysaccharide. The exopolysaccharides, when present, were found in pores in the gel network separate from the aggregated protein. These effects could be explained by the incompatibility of the exopolysaccharides with the protein aggregates in the milk. Stirring affected the yogurt made with exopolysaccharide differently from yogurt without exopolysaccharide, as it did not exhibit immediate syneresis, although the structural breakdown was increased. The shear-induced microstructure in a yogurt made with exopolysaccharide-producing culture was shown to consist of compartmentalized protein aggregates between channels containing exopolysaccharide, hindering syneresis as well as the buildup of structure after stirring.     

添加益生元对酸乳凝胶过程及微观结构的影响

为研究菊粉、低聚果糖和低聚半乳糖3 种益生元对酸乳凝胶过程及微观结构的影响,以未添加益生元的酸乳为对照,利用光学微流变仪、Turbiscan稳定分析仪和扫描电子显微镜分别检测添加益生元酸乳在发酵期间及后熟贮藏期间流变学参数、稳定性和微观结构,并进行对比研究。结果表明：添加菊粉更有助于酸乳形成较为均匀、疏松的微观结构;含低聚果糖的酸乳固液平衡值低于0.5,更有利于增强酸乳的固体性质;添加低聚半乳糖的酸乳微观稳定性较好。因此,3 种益生元对酸乳的凝胶过程及微观结构的影响各不相同,未来还可对3 种益生元进行复配处理,添加到酸乳中进一步探究对其综合品质的影响。     

A 100-Year Review: Yogurt and other cultured dairy products

The history of the last 100 years of the science and technology of yogurt, sour cream, cultured butter, cultured buttermilk, kefir, and acidophilus milk has been one of continuous development and improvement. Yogurt leads the cultured dairy product category in terms of volume of production in the United States and recent research activity. Legal definitions of yogurt, sour cream and acidified sour cream, and cultured milk, including cultured buttermilk, are presented in the United States Code of Federal Regulations and summarized here. A tremendous amount of research has been done on traditional and novel ingredients, starter cultures and probiotics, mix processing, packaging, chemical aspects, physical and sensory properties, microstructure, specialized products, composition, quality and safety of yogurt and various manufacturing methods, addition of flavorings, viscosity measurements, and probiotic use for sour cream. Over time, there have arisen alternative manufacturing methods, flavor problems, addition of flavorings, and use of probiotics for cultured buttermilk. Many health benefits are provided by yogurt and other cultured dairy products. One hundred years of testing and development have led to wider uses of cultured dairy products and new processing methods for enhanced shelf life and safety. Future research directions will likely include investigating the effects of probiotic dairy products on gut microbiota and overall health.     

魔芋甘露寡糖对酸奶免疫调节活性的影响

益生元用于发酵乳制品可改善其质构特性和感官品质,同时强化其健康功效。本研究采用环磷酰胺（cyclophosphomide,CTX）诱导BALB/C小鼠建立免疫抑制模型,评价功能性低聚糖类益生元——魔芋甘露寡糖（konjac mannanoligosaccharides,KMOS）的添加对于酸奶免疫调节活性的影响。结果表明,KMOS可强化酸奶对于CTX诱导小鼠免疫抑制的改善作用。KMOS添加量为0.5%（以鲜牛乳质量计）时酸奶对免疫抑制小鼠基本生理状态、腹腔巨噬细胞吞噬活性、脾淋巴细胞增殖率、血清中免疫球蛋白质量浓度以及腹腔巨噬细胞炎症因子的释放等均有显著改善作用,且添加KMOS的酸奶可提高免疫抑制小鼠肠道中非优势菌群的相对丰度,抑制梭菌属的增殖并增加有益菌数量,从而调节免疫抑制小鼠肠道菌群结构及组成。本研究可为基于功能性低聚糖的新型发酵乳制品开发提供借鉴。     

Invited review: Probiotic yogurt quality criteria,regulatory framework,clinical evidence,and analytical aspects

Yogurt is a milk-based product manufactured by lactic acid fermentation enabled by symbiotic yogurt cultures. Yogurt is largely considered to be a health product, and it is employed to deliver probiotics and prebiotics to the consumer. However, not all yogurts are probiotic, neither are they all functional products. There is increasing demand for health-promoting beverages, which is prompting the dairy industry to develop functional probiotic yogurts to meet the demand. However, there seems to be a scarcity of reviews providing critical information on regulatory frameworks in regions of the world, clinical trial outcomes, and methodological approaches for enumerating multiprobiotic strains in yogurt. This review, relating to functional probiotic yogurt, covers the newest information on the topic for the period mostly between 2014 and 2019. Conformance to regulations is paramount and hence, global regulatory frameworks for probiotic yogurt and prebiotic and nonprebiotic ingredients included in yogurt are reviewed. The paper emphasizes the need for convincing clinical trial outcomes that provide the dairy industry with an opportunity to market products with substantiated beneficial claims. The paper also discusses probiotic strains in functional yogurt, which is required to have population levels above the recommended therapeutic minimum during shelf life. The multiprobiotic species added to yogurt may present challenges relating to methodological and analytical approaches needed to determine viability of each strain contained in such yogurt. Hence, the review also presents the pros and cons of the culture-dependent and culture-independent approaches for the enumeration of probiotic cells in yogurt. The review is arguably valuable to the dairy industry, functional food developers, related scientists, and researchers, as well as policy makers.     

动物双歧杆菌、植物乳杆菌与传统发酵剂共培养对发酵乳抗氧化特性的影响

动物双歧杆菌（Bifidobacterium animalis subsp. lactis,Ba）、植物乳杆菌（Lactobacillus plantarum,Lp）与传统酸奶发酵剂（Y）共培养条件下,对发酵乳的酸化特性（pH值和滴定酸度）、蛋白水解活力、胞外多糖（exopolysaccharide,EPS）含量、肽含量、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除率、羟自由基清除率、Fe2＋螯合能力及还原能力进行研究,以探讨共发酵对发酵乳抗氧化特性的影响。结果表明,在冷藏过程中,发酵乳的酸化能力和蛋白水解活力增加（P＜0.05）。EPS主要由传统发酵剂产生,不是造成不同菌种发酵乳抗氧化能力差异的原因。发酵乳在冷藏期间肽含量和还原能力均表现出上升-下降的趋势,于第7天达到峰值。与单一Y相比,Ba或Lp与Y共发酵可提高发酵乳的蛋白水解活力、肽含量和抗氧化能力（P＜0.05）。Y-Ba/Lp发酵乳在冷藏期内具有最高的DPPH自由基清除率、羟自由基清除率、Fe2＋螯合能力和还原能力（P＜0.05）;Y-Lp比Y-Ba发酵乳有较低的DPPH自由基清除率、Fe2＋螯合能力和还原能力,但有较高的羟自由基清除率（P＜0.05）。本研究表明,益生菌共培养可以提高发酵乳的抗氧化能力,这种作用主要源于益生菌的蛋白水解特性。     

Enhancing the natural killer cell activity and anti-influenza effect of heat-treated Lactobacillus plantarum nF1-fortified yogurt in mice

Influenza A virus (IAV) infection is a global public health concern. It causes respiratory diseases ranging from mild illness to fatal disease. Natural killer (NK) cells are an innate immune component that kill infected cells and secrete cytokines to modulate the adaptive immune system; they constitute the first-line defense and play important roles in controlling IAV infection. This study evaluated the effect of daily administration of heat-treated Lactobacillus plantarum nF1-fortified yogurt on immunity and protection against IAV infection. Mice administered with heat-treated L. plantarum nF1-fortified yogurt showed elevated NK cell-related cytokine expression levels. Daily administration of the L. plantarum nF1-fortified yogurt before IAV infection also enhanced splenic NK activity, lung inflammatory cytokine responses, and survival rate. Thus, daily administration of nF1-fortified yogurt enhances host immunity and helps prevent IAV infection.     

Ingestion of yogurt containing Lactobacillus acidophilus and Bifidobacterium to potentiate immunoglobulin A responses to cholera toxin in mice

Lactic acid bacteria have been reported to have benefits for the prevention and treatment of some forms of diarrhea and related conditions. To determine whether these effects might involve direct stimulation of the gastrointestinal immune response, we administered yogurt to try to enhance mucosal and systemic antibodies against an orally presented immunogen, cholera toxin. Yogurts were manufactured with starter cultures containing different species and strains of lactic acid bacteria. Mice were fed these yogurts for 3 wk, during which they were also orally immunized twice with 10 micrograms of cholera toxin. Blood was collected on d 0 and 21, and fecal pellets were collected weekly. Mice that were immunized orally with cholera toxin responded by producing specific intestinal and serum immunoglobulin (Ig)A anti-cholera toxin. Antibody responses of the IgA isotype were significantly increased in mice fed yogurts made with starters containing the conventional yogurt bacteria Lactobacillus bulgaricus and Streptococcus thermophilus supplemented with Lactobacillus acidophilus, Bifidobacterium bifidum, and Bifidobacterium infantis. Yogurt that was manufactured with starters containing only conventional yogurt bacteria produced less IgA anti-cholera toxin than did the control group fed nonfat dry milk. Although strong responses were also observed for IgG anti-cholera toxin in serum, the responses did not differ among groups. Thus, administration of yogurt supplemented with L. acidophilus and Bifidobacterium spp. enhanced mucosal and systemic IgA responses to the cholera toxin immunogen.     

Short communication: Chia seed extract enhances physiochemical and antioxidant properties of yogurt

Yogurt is a healthy dairy food fermented by lactic acid bacteria (LAB). Because consumers demand healthier and more nutritious yogurt, numerous substances have been used to supplement yogurt. Chia seed has been reported to contain abundant phenolic compounds, dietary fiber, and n-3 fatty acids and therefore is a potential functional food additive. The aim of this study was to investigate the influence of chia seed extracts on the physicochemical and bioactive properties of set-type yogurt. Yogurt was fortified with chia seed water extract (CSWE) or chia seed ethanol extract (CSEE) at 0.05 or 0.1% (vol/vol). Results showed that supplementation with CSWE or CSEE significantly accelerated the fermentation rate and growth of LAB. Both CSWE and CSEE improved the viscosity, syneresis, and water-holding capacity of yogurt. The radical scavenging activity of yogurt was increased with both extracts, and the 0.1% CSEE yogurt exhibited the highest radical scavenging activity. Furthermore, 0.1% CSEE yogurt significantly inhibited lipopolysaccharide-induced production of hydrogen peroxide in human colon cells. Addition of chia seed extract improves the growth of LAB, the physiochemical properties, and the health-beneficial effects of set-type yogurt.     

MODIFIED WHEAT STARCHES USED AS STABILIZERS IN SET-STYLE YOGURT

Yogurt was formulated with gelatin; native wheat starch (NWS); and modified wheat starches (MWS) (acetylated cross‐linked, hydroxypropylated, or hydroxypropylated cross‐linked). Yogurt samples were evaluated for chemical (fat, total solids, pH, titratable acidity); microbiological (yeasts/molds and lactic acid bacteria); and physical (rheological, textural, color, syneresis) properties during 60 days of refrigerated storage. Yogurt formulated with NWS exhibited a significantly greater storage modulus (G′) and firmness compared with yogurts prepared with MWS. Minimal syneresis was measured in all yogurt samples. The titratable acidity of yogurt samples increased and pH decreased during storage. Yeasts/molds were not detected while lactic acid bacteria counts decreased ～ 1 log CFU/g by day 60 in all yogurt samples. This study showed that the characteristics of yogurt formulated with NWS and gelatin were similar, so NWS may be used as an alternative stabilizer. The MWS stabilized yogurts were stable but had different consistencies than gelatin‐ and NWS‐stabilized yogurts.     

A(H1N1)流感病毒及抗病毒新药的筛选

A(H1N1)流感病毒是2009年3～4月在美国和墨西哥发现的一种流感病毒变异的新病毒株.这类流感疫情的蔓延引起了世界各国和世界卫生组织的严重关注.本文介绍了A(H1N1)流感新病毒株及感染这种病毒患者的症状,A(H1N1)流感病毒的致命力和传播,流感病毒变异对抗病毒药的抗药性,以及1918年流感大流行病毒聚合酶特性,人流感病毒和禽流感病毒聚合酶的结晶结构及其在感染中的作用.据此,提出了抗流感病毒药的筛选思路和研究方向,为抗流感病毒新药的设计和开发提供有益的参考.     

Yogurt Thickness: Effects on Flavor Perception and Liking

Nine flavored stirred‐style yogurts (thick and thin textured, colored and uncolored, flavored as either cotton candy, lemon‐lime, or strawberry) were evaluated by 120 panelists aged 11 to 14 y to analyze the interactive effects of flavor, thickness, and color on thickness intensity, flavor intensity, and degree‐of‐liking. Yogurt flavor did not affect thickness intensity nor liking ratings. Yogurt thickness did not affect flavor intensity, but flavor liking was affected by both flavor and thickness. Strawberry yogurt was liked equally in both texture systems, but cotton candy and lemon‐lime yogurts were liked more in a thick textured yogurt than a thin yogurt. Colored yogurts were thicker and more flavorful than uncolored yogurts.