开菲尔粒中乳酸菌的分离与鉴定

从4个不同来源的开菲尔粒中分离得到40株乳酸菌，并对这40株乳酸菌进行了鉴定．结果为德氏乳杆菌8株，德氏乳杆菌保加力亚种6株，高加索奶乳杆菌2株，嗜酸乳杆菌1株，粪肠球菌7株，屎肠球菌2株，嗜热链球菌1株，乳脂链球菌3株。     

The antiallergic effect of kefir Lactobacilli

This study demonstrated that oral feeding of heat-inactivated Lactobacillus (L b.) kefiranofaciens M1 from kefir grains effectively inhibited immunoglobulin (Ig) E production in response to ovalbumin (OVA) in vivo. The pattern of cytokine production by splenocyte cells revealed that the levels of cytokines produced by T helper (Th) 1 cells increased, and those of cytokines produced by Th2 cells decreased in the heat-inactivated M1 feeding group. These findings indicated that Lactobacillus kefiranofaciens M1 in the kefir played an important role in antiallergic activities. By additional analysis using flow cytometry and microarray, the mechanism of suppression of IgE production by oral feeding of the heat-inactivated M1 probably occurs because of upregulation of the expression of Cd2, Stat4, and Ifnr leading to skewing the Th1/Th2 balance toward Th1 dominance, elevation of the CD4(+)CD25(+) regulatory T (Treg) percentage, and reduction of activated CD19(+) B cells. Downregulation of complement system and components was also involved in suppression of IgE production. Practical Application: Kefir has long been considered good for health. Its health benefits include immunoregulatory effects. However, there is a lack of knowledge concerning the immunoregulatory effects induced by kefir lactic acid bacteria (LAB). Our data clearly demonstrated the antiallergic activity of kefir LAB, Lactobacillus (L b.) kefiranofaciens M1. By additional analysis using flow cytometry and microarray, the possible mechanism of suppression of IgE production by oral feeding of the heat-inactivated M1 was also elucidated. Our findings indicated that Lactobacillus kefiranofaciens M1 may have a great potential for utilization in functional food products.     

Assessment of beverages made from milk,soya milk and whey using Iranian kefir starter culture

Kefir starter culture was used for the production of beverages, and some chemical and microbiological parameter changes were determined during 24 h of fermentation and then after 2, 7, 14, 21 and 28 days of storage at 4 °C. Three different substrates (milk, whey and soya milk) were used as fermentation media for the kefir starter culture. After the fermentation, the carbohydrate content and pH decreased, but the dry matter and fat content of the beverages were not significantly different from their substrates. During storage, lactic acid bacteria in the beverages decreased, while yeasts increased and carbohydrate, ethanol and pH changed significantly in the three beverages.     

Purification and characterization of bacteriocin F1, a novel bacteriocin produced by Lactobacillus paracasei subsp. tolerans FX-6 from Tibetan kefir,a traditional fermented milk from Tibet,China

A bacteriocin-producing lactic acid bacteria, FX-6, was isolated from Tibetan kefir using the agar well diffusion assay. Strain FX-6 was identified as Lactobacillus paracasei subsp. tolerans on the basis of 16S rDNA sequence analyses. This bacteriocin, which was designated bacteriocin F1, was purified by a three-step purification procedure. The molecular mass of bacteriocin F1 was 2113.842 Da by MALDI-TOF–MS analyses. It was also discovered to have blocked N-termini, hampering analysis by Edman degradation. Bacteriocin F1 exhibited a wide range of antimicrobial activity, strong heat stability (20 min at 121 °C, or 60 min at 100 °C) and pH stability (pH 3.0–9.0). Following treatment by pepsin and trypsin, the antibacterial activity was partly reduced. Bacteriocin F1 is the first reported bacteriocin produced by L. paracasei subsp. tolerans which can not only inhibit fungi but also bacteria. The characterization of bacteriocin F1 suggested that it was a novel bacteriocin with potential research and application value in food industry.     

雪莲菌发酵提高枸杞原浆甜菜碱含量的工艺优化及品质分析

该研究以混合菌种雪莲菌为发酵菌种,枸杞原浆中甜菜碱含量为指标,通过单因素试验和正交试验对雪莲菌发酵枸杞原浆进行工艺优化,并对发酵后的枸杞原浆进行品质分析。结果表明,最佳发酵工艺条件为雪莲菌接种量5%（m/V）,发酵时间48 h,发酵温度25 ℃,此条件下甜菜碱含量为18.95 mg/mL,比未发酵枸杞原浆甜菜碱含量增加2.54倍,总酚含量为2.03 mg/mL、黄酮含量为0.68 mg/mL、总糖含量为11.92 mg/mL。雪莲菌发酵后枸杞原浆中共检测出65种挥发性成分,包括21种醇类、27种酯类、1种醛类、1种酮类、8种酸类、3种烷类、2种酚类和2种烯类,与发酵前相比新增24种,且醇类、酯类和酸类物质较发酵前显著性增加,挥发性成分总含量由8.94 mg/mL增加至39.76 mg/mL,为制备高品质枸杞原浆提供理论依据,为枸杞产业化深加工提供指导。     

Short communication: Sensory analysis of a kefir product designed for active cancer survivors

Kefir is a fermented milk product that is a good source of protein and health-promoting bacteria. It has the potential to improve recovery from exercise and the health and well-being of cancer survivors. The purpose of this study was to explore cancer survivor attitudes about and acceptance of a kefir recovery beverage made from cultured milk, whole fruit, natural sweeteners, and other natural ingredients. Kefir was made by inoculating and fermenting milk with kefir grains. The kefir was then mixed with a fruit base and given to cancer survivors (n = 52) following a bout of exercise. Participants evaluated the acceptability of the beverage samples (overall appearance, aroma, taste, mouthfeel, and overall liking) using a 9-point hedonic scale, and they evaluated the smoothness using a 3-category just-about-right scale (not enough, just about right, and too much). They also expressed their physical and psychological feelings about the beverage using a 5-point scale (1 = not at all to 5 = extremely) and indicated their purchase intent using a binomial (yes/no) response. The health benefits of kefir were then explained, and participants sampled a second beverage (the same product), answering the same questions related to overall liking, feeling, and intent to purchase. We used a paired Student's t-test to compare beverage liking and emotion scores before and after participants learned about the health benefits of kefir. Data are presented as mean ± standard deviations. The beverage scored significantly higher for overall liking after the health benefits were explained (6.5 ± 1.8 and 7.0 ± 1.7 out of 9 before and after the explanation of health benefits, respectively). Participants showed a high intent to purchase before they learned about the health benefits (75% of participants indicated an intent to purchase, and 89% after they learned about the health benefits). The beverage received high scores overall and, except for an improvement in overall liking, we observed no significant differences in physical and psychological feelings before and after participants learned that it contained kefir and had potential health benefits. We found the beverage to be acceptable for consumption by cancer survivors, and the majority of participants showed an interest in purchasing for after exercise.     

产胆盐水解酶乳酸菌的分离、鉴定及降解胆固醇机理的初步研究

本文从开菲尔粒中分离出15株能降低胆固醇的菌,通过生理生化反应以及其他指标对这15株菌株进行鉴定,其中7株为球菌,8株为杆菌。对这15株菌进行复筛,最终筛选出一株能产胆盐水解酶的菌株,用全自动生化鉴定仪对这株菌做进一步的鉴定,其鉴定结果为干酪乳杆菌。     

利用开菲尔粒制备酸豆奶酒最佳发酵条件的研究

利用传统酸牛奶酒(Kefir)的发酵剂--开菲尔粒(KefirGrains)制作的发酵剂,对豆奶与牛奶的混合原料进行发酵,采用L16(45)正交试验设计筛选制备酸豆奶酒(一种新型发酵豆奶制品)的最佳发酵条件。结果表明:豆奶与鲜牛奶的搭配比例是8:2,接种量为3%,发酵温度25℃,发酵时间14h,添加10%的白砂糖。产品的酸度为83°T,乙醇含量为0.26%。