Milk kefir: Composition, microbial cultures, biological activities, and related products

Frontiers in Microbiology

Volumn 6, Issue OCT, 2015, Pages

  Prado, Maria R ^a   Blandón, Lina Marcela ^a   Vandenberghe, Luciana P S ^a   Rodrigues, Cristine ^a   Castro, Guillermo R ^b   Thomaz Soccol, Vanete ^a   Soccol, Carlos R ^a  

^a FEDERAL UNIVERSITY OF PARANÁ   (Brazil)

^b UNIVERSIDAD NACIONAL DE LA PLATA   (Argentina)

Author keywords

Biological activity; Kefir; Kefiran; Microbial composition; Polysaccharides

Indexed keywords

EXOPOLYSACCHARIDE; KEFIR;

ANTIDIABETIC ACTIVITY; ANTIMICROBIAL ACTIVITY; ANTIOXIDANT ACTIVITY; BIOLOGICAL ACTIVITY; DAIRY PRODUCT; FERMENTATION; FLOW KINETICS; FOOD INDUSTRY; FOOD PRESERVATION; IMMUNOMODULATION; LACTIC ACID BACTERIUM; LACTOBACILLUS ACIDOPHILUS; MICROBIAL CONSORTIUM; MICROBIAL DIVERSITY; MICROBIAL GROWTH; MILK; NONHUMAN; PHYSICAL CHEMISTRY; REVIEW; SACCHAROMYCES CEREVISIAE;

EID: 84946842489     PISSN: None     EISSN: 1664302X     Source Type: Journal    
DOI: 10.3389/fmicb.2015.01177     Document Type: Review

References (98)

1. Ahmed, Z., Wang, Y., Ahmad, A., Khan, S. T., Nisa, M., Ahmad, H., et al. (2013). Kefir and health: a contemporary perspective. Crit. Rev. Food Sci. Nutr. 53, 422-434. doi: 10.1080/10408398.2010.540360
2. Altay, F., Karbancioglu-Güler, F., Daskaya-Dikmen, C., and Heperkan, D. (2013). A review on traditional Turkish fermented non-alcoholic beverages: microbiota, fermentation process and quality characteristics. Int. J. Food Microbiol. 167, 44-56. doi: 10.1016/j.ijfoodmicro.2013.06.016
3. Anselmo, R. J., Viora, S. S., Ojeda, P. A., and Lausada, L. I. (2010). Efecto antagónico del kefir sobre endosporas y células vegetativas de Bacillus cereus y Clostridium perfringens. (Spanish) Antagonistic effect of the kefir on endospores and vegetative cells of Bacillus cereus and Clostridium perfringens. Inf. Tecnol. 21, 131-138.
4. Badel, S., Bernardi, T., and Michaud, P. (2011). New perspective for Lactobacilli exopolysaccharides. Biotecnol. Adv. 29, 54-66. doi: 10.1016/j.biotechadv.2010.08.011
5. Bensmira, M., Nsabimana, C., and Jiang, B. (2010). Effects of fermentation conditions and homogenization pressure on the rheological properties of Kefir. Food Sci. Technol. 43, 1180-1184.
6. Bolla, P. A., Carasi, P., Bolla Mde, L., De Antoni, G. L., and Serradell Mde, L. (2013). Protective effect of a mixture of kefir-isolated lactic acid bacteria and yeasts in a hamster model of Clostridium difficile infection. Anaerobe 21, 28-33. doi: 10.1016/j.anaerobe.2013.03.010
7. Botelho, P. S., Maciel, M. I., Bueno, L. A., Marques Mde, F., Marques, D. N., and Sarmento Silva, T. M. (2014). Characterization of a new exopolysaccharide obtained from of fermented kefir grains in soymilk. Carbohydr. Polym. 107, 1-6. doi: 10.1016/j.carbpol.2014.02.036
8. Carasi, P., Trejo, F. M., Pérez, P. F., De Antoni, G. L., and Serradell Mde, L. (2012). Surface proteins from Lactobacillus kefir antagonize in vitro cytotoxic effect of Clostridium difficile toxins. Anaerobe 18, 135-142. doi: 10.1016/j.anaerobe.2011.11.002
9. Cevikbas, A., Yemni, E., Ezzedenn, F. W., Yardimici, T., Cevikbas, U., and Stohs, S. J. (1994). Antitumoural, antibacterial and antifungal activities of kefir and kefir grain. Phytother. Res. 8, 78-82. doi: 10.1002/ptr.2650080205
10. Cheirsilp, B., and Radchabut, S. (2011). Use of whey lactose from dairy industry for economical kefiran production by Lactobacillus kefiranofaciens in mixed cultures with yeasts. N. Biotechnol. 28, 574-580. doi: 10.1016/j.nbt.2011.01.009
11. Cheirsilp, B., Shimizu, H., and Shioya, S. (2003). Enhanced kefiran production by mixed culture of Lactobacillus kefiranofaciens and Saccharomyces cerevisiae. J. Biotechnol. 100, 43-53. doi: 10.1016/S0168-1656(02)00228-6
12. Chen, H. C., Wang, S. Y., and Chen, M. J. (2008). Microbiological study of lactic acid bacteria in kefir grains by culture-dependent and culture-independent methods. Food Microbiol. 25, 492-501. doi: 10.1016/j.fm.2008.01.003
13. Chen, Y. P., Hsiao, P. J., Hong, W. S., Dai, T. Y., and Chen, M. J. (2012). Lactobacillus kefiranofaciens M1 isolated from milk kefir grains ameliorates experimental colitis in vitro and in vivo. J. Dairy Sci. 95, 63-74. doi: 10.3168/jds.2011-4696
14. Chen, Z., Shi, J., Yang, X., Nan, B., Liu, Y., and Wang, Z. (2015). Chemical and physical characteristics and antioxidant activities of the exopolysaccharide produced by Tibetan kefir grains during milk fermentation. Int. Dairy J. 43, 15-21. doi: 10.1016/j.idairyj.2014.10.004
15. De Vuyst, L., and Degeest, B. (1999). Heteropolysaccharides from lactic acid bacteria. FEMS Microbiol. Rev. 23, 153-177. doi: 10.1111/j.1574-6976.1999.tb00395.x
16. De Vuyst, L., De Vin, F., and Kamerling, J. P. (2001). Recent developments in the biosynthesis and applications of heteropolysaccharides from lactic acid bacteria. Int. Dairy J. 11, 687-707. doi: 10.1016/S0958-6946(01)00114-5
17. Diniz, R., Garla, L., Schneedorf, J., and Carvalho, J. C. (2003). Study of anti-inflammatory activity of Tibetan mushroom, a symbiotic culture of bacteria and fungi encapsulated into a polysaccharide matrix. Pharmacol. Res. 47, 49-52. doi: 10.1016/S1043-6618(02)00240-2
18. Diosma, G., Romanin, D. E., Rey-Burusco, M. F., Londero, A., and Garrote, G. L. (2014). Yeasts from kefir grains: isolation, identification, and probiotic characterization. World J. Microbiol. Biotechnol. 30, 43-53. doi: 10.1007/s11274-013-1419-9
19. Dobson, A., O'Sullivan, O., Cotter, P. D., Ross, P., and Hill, C. (2011). High-throughput sequence-based analysis of the bacterial composition of kefir and an associated kefir grain. FEMS Microbiol. Lett. 320, 56-62. doi: 10.1111/j.1574-6968.2011.02290.x
20. Duarte, J., Vinderola, G., Ritz, B., Perdigon, G., and Matar, C. (2006). Immunomodulating capacity of commercial fish protein hydrolysate for diet supplementation. Immunobiology 211, 341-350. doi: 10.1016/j.imbio.2005.12.002
21. Farnworth, E. R. (2005). Kefir-a complex probiotic. Food Sci. Technol. Bull. Funct. Foods 2, 1-17. doi: 10.1616/1476-2137.13938
22. Farnworth, E. R., and Mainville, I. (2003). "Kefir: a fermented milk product". in Handbook of Fermented Functional Foods, ed. E. R. Farnworth (Boca Raton, FL: CRC Press), 77-112.
23. Fontán, M. C. G., Martínez, S., Franco, I., and Carballo, J. (2006). Microbiological and chemical changes during the manufacture of Kefir made from cows' milk, using a commercial starter culture. Int. Dairy J. 16, 762-767. doi: 10.1016/j.idairyj.2005.07.004
24. Gao, J., Gu, F., Abdella, N. H., Ruan, H., and He, G. (2012). Investigation on culturable microflora in Tibetan kefir grains from different areas of China. J. Food Sci. 77, 425-433. doi: 10.1111/j.1750-3841.2012.02805.x
25. Gao, J., Gu, F., He, J., Xiao, J., Chen, Q., Ruan, H., et al. (2013a). Metagenome analysis of bacterial diversity in Tibetan kefir grains. Eur. Food Res. Technol. 236, 549-556. doi: 10.1007/s00217-013-1912-2
26. Gao, J., Gu, F., Ruan, H., Chen, Q., He, J., and He, G. (2013b). Induction of apoptosis of gastric cancer cells SGC7901 in vitro by a cell-free fraction of Tibetan kefir. Int. Dairy J. 30, 14-18. doi: 10.1016/j.idairyj.2012.11.011
27. Garofalo, C., Osimani, A., Milanovic, V., Aquilanti, L., De Filippis, F., Stellato, G., et al. (2015). Bacteria and yeast microbiota in milk kefir grains from different Italian regions. Food Microbiol. 49, 123-133. doi: 10.1016/j.fm.2015.01.017
28. Garrote, G. L., Abraham, A. G., and De Antoni, G. L. (2001). Chemical and microbiological characterisation of kefir grains. J. Dairy Res. 68, 639-652. doi: 10.1017/S0022029901005210
29. Garrote, G. L., Abraham, A. G., and De Antoni, G. L. (2010). "Microbial Interactions in Kefir: a Natural Probiotic Drink". in Biotechnology of Lactic Acid Bacteria, eds F. Mozzi, R. R. Raya, and G. M. Vignolo (Ames, IO: Wiley-Blackwell), 327-340.
30. Ghasemlou, M., Khodaiyan, F., Jahanbin, K., Mohammad, S., Gharibzahedi, T., and Taheri, S. (2012). Structural investigation and response surface optimisation for improvement of kefiran production yield from a low-cost culture medium. Food Chem. 133, 383-389. doi: 10.1016/j.foodchem.2012.01.046
31. Grishina, A., Kulikova, I., Alieva, L., Dodson, A., Rowland, I., and Jing, J. (2011). Antigenotoxic effect of kefir and ayran supernatants on fecal water-induced DNA damage in human colon cells. Nutr. Cancer 63, 73-79. doi: 10.1080/01635581.2010.516873
32. Guzel-Seydim, Z. B., Seydim, A. C., Greene, A. K., and Ta, T. (2006). Determination of antimutagenic properties of acetone extracted fermented milks and changes in their total fatty acid profiles including conjugated linoleic acids. Int. J. Dairy Technol. 59, 209-215. doi: 10.1111/j.1471-0307.2006.00265.x
33. Guzel-Seydim, Z., Wyffels, J. T., Seydim, A. C., and Greene, A. K. (2005). Turkish kefir and kefir grains: microbial enumeration and electron microscopic observation. Int. J. Dairy Technol. 58, 25-29. doi: 10.1111/j.1471-0307.2005.00177.x
34. Hamet, M. F., Londero, A., Medrano, M., Vercammen, E., Van Hoorde, K., Garrote, G. L., et al. (2013). Application of culture-dependent and culture-independent methods for the identification of Lactobacillus kefiranofaciens in microbial consortia present in kefir grains. Food Microbiol. 36, 327-334. doi: 10.1016/j.fm.2013.06.022
35. Hong, W. S., Chen, H. C., Chen, Y. P., and Chen, M. J. (2009). Effects of kefir supernatant and lactic acid bacteria isolated from kefir grain on cytokine production by macrophage. Int. Dairy J. 19, 244-251. doi: 10.1016/j.idairyj.2008.10.010
36. Huseini, H. F., Rahimzadeh, G., Fazeli, M. R., Mehrazma, M., and Salehi, M. (2012). Evaluation of wound healing activities of kefir products. Burns 38, 719-723. doi: 10.1016/j.burns.2011.12.005
37. Ismaiel, A. A., Ghaly, M. F., and El-Naggar, A. K. (2011). Milk kefir: ultrastructure, antimicrobial activity and efficacy on aflatoxin b1 production by Aspergillus flavus. Curr. Microbiol. 62, 1602-1609. doi: 10.1007/s00284-011-9901-9
38. Jianzhong, Z., Xiaoli, L., Hanhu, J., and Mingsheng, D. (2009). Analysis of the microflora in Tibetan kefir grains using denaturing gradient gel electrophoresis. Food Microbiol. 26, 770-775. doi: 10.1016/j.fm.2009.04.009
39. Kabak, B., and Dobson, A. D. (2011). An introduction to the traditional fermented foods and beverages of Turkey. Crit. Rev. Food Sci. Nutr. 51, 248-260. doi: 10.1080/10408390903569640
40. Kesmen, Z., and Kacmaz, N. (2011). Determination of lactic microflora of kefir grains and kefir beverage by using culture-dependent and culture-independent methods. J. Food Sci. 76, 276-283. doi: 10.1111/j.1750-3841.2011.02191.x
41. Khoury, N., El-Hayek, S., Tarras, O., El-Sabban, M., El-Sibai, M., and Rizk, S. (2014). Kefir exhibits anti-proliferative and pro-apoptotic effects on colon adenocarcinoma cells with no significant effects on cell migration and invasion. Int. J. Oncol. 45, 2117-2127. doi: 10.3892/ijo.2014.2635
42. Kim, Y., Kim, J. U., Oh, S., Kim, Y. J., Kim, M., and Kim, S. H. (2008). Technical optimization of culture conditions for the production of exopolysaccharide (EPS) by Lactobacillus rhamnosus ATCC 9595. Food Sci. Biotechnol. 17, 587-593.
43. Kok-Tas, T., Ekinci, F. Y., and Guzel eSeydim, Z. B. (2012). Identification of microbial flora in kefir grains produced in Turkey using PCR. Int. J. Dairy Technol. 65, 126-131. doi: 10.1111/j.1471-0307.2011.00733.x
44. Kooiman, P. (1968). The chemical structure of kefiran, the water-soluble polysaccharide of the kefir grain. Carbohydr. Res. 7, 220-221. doi: 10.1016/S0008-6215(00)81138-6
45. Korsak, N., Taminiau, B., Leclercq, M., Nezer, C., Crevecoeur, S., Ferauche, C., et al. (2015). Short communication: evaluation of the microbiota of kefir samples using metagenetic analysis targeting the 16S and 26S ribosomal DNA fragments. J. Dairy Sci. 98, 3684-3689. doi: 10.3168/jds.2014-9065
46. Kwon, C. S., Park, M. Y., Cho, J. S., Choi, S. T., and Chang, D. S. (2003). Identification of effective microorganisms from kefir fermented milk. Food Sci. Biotechnol. 12, 476-479.
47. Leite, A. M. O., Mayoa, B., Rachid, C. T., Peixoto, R. S., Silva, J. T., Paschoalin, V. M., et al. (2012). Assessment of the microbial diversity of Brazilian kefir grains by PCR-DGGE and pyrosequencing analysis. Food Microbiol. 31, 215-221. doi: 10.1016/j.fm.2012.03.011
48. Leite, A. M. O., Miguel, M. A., Peixoto, R. S., Rosado, A. S., Silva, J. T., and Paschoalin, V. M. (2013). Microbiological, technological and therapeutic properties of kefir: a natural probiotic beverage. Braz. J. Microbiol. 44, 341-349. doi: 10.1590/S1517-83822013000200001
49. Liu, J. R., Wang, S. Y., Lin, Y. Y., and Lin, C. W. (2002). Antitumor activity of milk, kefir and soya milk kefir in tumor bearing mice. Nutr. Cancer 44, 183-187. doi: 10.1207/S15327914NC4402_10
50. Londero, A., Hamet, M. F., De Antoni, G. L., Garrote, G. L., and Abraham, A. G. (2012). Kefir grains as a starter for whey fermentation at different temperatures: chemical and microbiological characterisation. J. Dairy Res. 79, 262-271. doi: 10.1017/S0022029912000179
51. Lopitz, F. O., Rementeria, A., Elguezabal, N., and Garaizar, J. (2006). Kefir: una comunidad simbiótica de bacterias y levaduras con propiedades saludables. Rev. Iberoam. Micol. 23, 67-74. doi: 10.1016/S1130-1406(06)70016-X
52. Maeda, H., Zhu, X., Suzuki, S., Suzuki, K., and Kitamura, S. (2004). Structural characterization and biological activities of an exopolysaccharide kefiran produced by Lactobacillus kefiranofaciens WT-2B(T). J. Agric. Food Chem. 52, 5533-5538. doi: 10.1021/jf049617g
53. Magalhães, K. T., Pereira, G. V. M., Campos, C. R., Dragone, G., and Schwan, R. F. (2011). Brazilian kefir: structure, microbial communities and chemical composition. Braz. J. Microbiol. 42, 693-702. doi: 10.1590/S1517-838220110002000034
54. McCue, P. P., and Shetty, K. (2005). Phenolic antioxidant mobilization during yogurt production from soymilk using Kefir cultures. Process Biochem. 40, 1791-1797. doi: 10.1016/j.procbio.2004.06.067
55. Medrano, M., Pérez, P. F., and Abraham, A. G. (2008). Kefiran antagonizes cytopathic effects of Bacillus cereus extracellular factors. Int. J. Food Microbiol. 122, 1-7. doi: 10.1016/j.ijfoodmicro.2007.11.046
56. Miguel, M. G. C. P., Cardoso, P. G., Lago, L. A., and Schwan, R. F. (2010). Diversity of bacteria present in milk kefir grains using culture-dependent and culture-independent methods. Food Res. Int. 43, 1523-1528. doi: 10.1016/j.foodres.2010.04.031
57. Mobili, P., Serradell Mde, L. A., Trejo, S. A., Avilés Puigvert, F. X., Abraham, A. G., et al. (2009). Heterogeneity of S-layer proteins from aggregating and non-aggregating Lactobacillus kefir strains. Antonie Van Leeuwenhoek 95, 363-372. doi: 10.1007/s10482-009-9322-y
58. Nalbantoglu, U., Cakar, A., Dogan, H., Abaci, N., Ustek, D., Sayood, K., et al. (2014). Metagenomic analysis of the microbial community in kefir grains. Food Microbiol. 41, 42-51. doi: 10.1016/j.fm.2014.01.014
59. Oliveira, A. M. L., Miguel, M. A. L., Peixoto, R. S., Rosado, A. S., Silva, J. T., and Paschoalin, V. M. F. (2013). Microbiological, technological and therapeutic properties of kefir: a natural probiotic beverage. Braz. J. Microbiol. 44, 341-349. doi: 10.1590/S1517-83822013000200001
60. Piermaria, J., Bosch, A., Pinotti, A., Yantorno, O., Garcia, M. A., and Abraham, A. G. (2010). Kefiran films plasticized with sugars and polyols: water vapor barrier and mechanical properties in relation to their microstructure analyzed by ATR/FT-IR spectroscopy. Food Hydrocoll. 25, 1261-1269. doi: 10.1016/j.foodhyd.2010.11.024
61. Pogacic, T., Sinko, S., Zamberlin, S., and Samarzija, D. (2013). Microbiota of kefir grains. Mljekarstvo 63, 3-14.
62. Powell, J. E., Witthuhn, R. C., Todorov, S. D., and Dicks, L. M. T. (2007). Characterization of bacteriocin ST8KF produced by a kefir isolate Lactobacillus plantarum ST8KF. Int. Dairy J. 17, 190-198. doi: 10.1016/j.idairyj.2006.02.012
63. Punaro, G. R., Maciel, F. R., Rodrigues, A. M., Rogero, M. M., Bogsan, C. S. B., Oliveira, M. N., et al. (2014). Kefir administration reduced progression of renal injury in STZ-diabetic rats by lowering oxidative stress. Nitric Oxide 37, 53-60. doi: 10.1016/j.niox.2013.12.012
64. Raja, A., Gajalakshmi, P., Raja, M. M. M., and Imran, M. M. (2009). Effect of Lactobacillus laceis cremoris isolated from Kefir against food spoilage bacteria. Am. J. Food Technol. 4, 201-209. doi: 10.3923/ajft.2009.201.209
65. Rimada, P. S., and Abraham, A. G. (2006). Effects of different fermentation parameters on quality characteristics of kefir. Int. Dairy J. 16, 33-39. doi: 10.3168/jds.2012-5753
66. Rizk, S., Maalouf, K., and Baydoun, E. (2009). The Antiproliferative effect of kefir cell-free fraction on HuT-102 malignant T lymphocytes. Clin. Lymphoma Myeloma 9, 198-203. doi: 10.3816/CLM.2009.s.012
67. Rodrigues, K. L., Caputo, L. R. G., Carvalho, J. C. T., Evangelista, J., and Schneedorf, J. M. (2005a). Antimicrobial and healing activity of kefir and kefiran extract. Int. J. Antimicrob. Agents 25, 404-408. doi: 10.1016/j.ijantimicag.2004.09.020
68. Rodrigues, K. L., Carvalho, J. C. T., and Schneedorf, J. M. (2005b). Anti-inflammatory properties of kefir and its polysaccharide extract. Inflammopharmacology 13, 485-492. doi: 10.1163/156856005774649395
69. Ruas-Madiedo, P., Hugenholtz, J., and Zoon, P. (2002). An overview of the functionality of exopolysaccharides produced by lacti acid bacteria. Int. Dairy J. 12, 163-171. doi: 10.1016/S0958-6946(01)00160-1
70. Saija, N., Welman, A., and Bennett, R. (2010). Development of a dairy-based exopolysaccharide bioingredient. Int. Dairy J. 20, 603-608. doi: 10.1016/j.idairyj.2010.03.011
71. Saloff-Coste, C. J. (1996). Kefir. Nutritional and health benefits of yoghurt and fermented milks. Dannone World Newsl. 11, 1-7.
72. Serafini, F., Turroni, P., Ruas-Madiedo, G. A., Lugli, C., Milani, S., Duranti, N., et al. (2014). Kefir fermented milk and kefiran promote growth of Bifidobacterium bifidum PRL2010 and modulate its gene expression. Int. J. Food Microbiol. 178, 50-59. doi: 10.1016/j.ijfoodmicro.2014.02.024
73. Simova, E., Beshkova, D., Angelov, A., Hristozova, T., Frengova, G., and Spasov, Z. (2002). Lactic acid bacteria and yeasts in kefir grains and kefir made from them. J. Ind. Microbiol. Biotechnol. 28, 1-6. doi: 10.1038/sj.jim.7000186
74. Soccol, C. R., Prado, M. R. M., Garcia, L. M. B., Rodrigues, C., and Medeiros, A. B. P. (2014). Current developments in probiotics. J. Microb. Biochem. Technol. 7, 011-020. doi: 10.4172/1948-5948.1000175
75. St-Onge, M. P., Farnworth, E. R., Savard, T., Chabot, D., Mafu, A., and Jones, P. J. (2002). Kefir consumption does not alter plasma lipid levels or cholesterol fractional synthesis rates relative to milk in hyperlipidemic men: a randomized controlled trial. BMC Complement. Altern. Med. 2:1. doi: 10.1186/1472-6882-2-1
76. Suresh Kumar, A., Mody, K., and Jha, B. (2008). Bacterial exopolysaccharides-a perception. J. Basic Microbiol. 47, 103-117. doi: 10.1002/jobm.200610203
77. Van Hijum, S. A., Kralj, S., Ozimek, L. K., Dijkhuizen, L., and Van Geel-Achutten, I. G. (2006). Structural-function relationships of glucansucrases and fructan enzymes from lactic acid bacteria. Microbiol. J. Biol. Macromol. 70, 157-176.
78. Vinderola, G., Perdigon, G., Duarte, J., Farnworth, E., and Matar, C. (2006). Effects of the oral administration of the products derived from milk fermentation by kefir microflora on immune stimulation. J. Dairy Res. 73, 472-479. doi: 10.1017/S002202990600197X
79. Vujicic, I. F., Vulic, M., and Könyves, T. (1992). Assimilation of cholesterol in milk by kefir cultures. Biotechnol. Lett. 14, 847-850. doi: 10.1007/BF01029151
80. Wang, S. Y., Chen, K. N., Lo, Y. M., Chiang, M. L., Chen, H. C., Liu, J. R., et al. (2012). Investigation of microorganisms involved in biosynthesis of the kefir grain. Food Microbiol. 32, 274-285. doi: 10.1016/j.fm.2012.07.001
81. Wang, Y., Ahmed, Z., Feng, W., Li, C., and Song, S. (2008). Physicochemical properties of exopolysaccharide produced by Lactobacillus kefiranofaciens ZW3 isolated from Tibet kefir. Int. J. Biol. Macromol. 43, 283-288. doi: 10.1016/j.ijbiomac.2008.06.011
82. Wang, Y. P., Li, C., Liu, P., Zaheer, A., Xiao, P., and Bai, X. (2010). Physical characterization of exopolysaccharide produced by Lactobacillus plantarum KF5 isolated from Tibet Kefir. Carbohydr. Polym. 82, 895-903. doi: 10.1016/j.carbpol.2010.06.013
83. Wei-Sheng, H., Yen-Po, C., and Ming-Ju, C. (2010). The Antiallergic effect of kefir Lactobacilli. J. Food Sci. 75, 244-253. doi: 10.1111/j.1750-3841.2010.01787.x
84. Welman, A. D., and Maddox, I. S. (2003). Exopolysaccharides from lactic acid bacteria: perspectives and challenges. Trends Biotechnol. 21, 269-274. doi: 10.1016/S0167-7799(03)00107-0
85. Witthuhn, R. C., Schoeman, T., and Britz, T. J. (2004). Isolation and characterisation of the microbial population of different South African kefir grains. Int. J. Dairy Technol. 57, 33-37. doi: 10.1111/j.1471-0307.2004.00126.x
86. Witthuhn, R. C., Schoeman, T., and Britz, T. J. (2005). Characterisation of the microbial population at different stages of kefir production and kefir grain mass cultivation. Int. Dairy J. 15, 383-389. doi: 10.1016/j.idairyj.2004.07.016
87. Wszolek, M., Kupiec-Teahan, B., Skov Gulard, H., and Tamime, A. Y. (2006). "Production of kefir, koumiss and other related products". in Fermented Milks, ed. A. Y. Tamime (Oxford: Blackwell Publishing), 174-216.
88. Wyder, M. T., Meile, L., and Teuber, M. (1999). Description of Saccharomyces turicensis sp. nov., a new species from kefyr. Syst. Appl. Microbiol. 3, 420-425. doi: 10.1016/S0723-2020(99)80051-4
89. Yang, X. J., Fan, M. T., Shi, J. L., and Dang, B. (2007). Isolation and identification of preponderant flora in Tibetan kefir. China Brewing 171, 52-55.
90. Yanping, W., Nv, X., Aodeng, X., Zaheer, A., Bin, Z., and Xiaojia, B. (2009). Effects of Lactobacillus plantarum MA2 isolated from Tibet kefir on lipid metabolism and intestinal microflora of rats fed on high-cholesterol diet. Appl. Microbiol. Biotechnol. 84, 341-347. doi: 10.1007/s00253-009-2012-x
91. Ying, H., Fei, W., Xiaojun, W., Yujie, S., Longfei, Y., and Jinfeng, W. (2013). Characterization of Lactobacillus plantarum Lp27 isolated from Tibetan kefir grains: a potential probiotic bacterium with cholesterol-lowering effects. J. Dairy Sci. 96, 2816-2825. doi: 10.3168/jds.2012-6371
92. Young-In, K., Apostolidis, E., and Shetty, K. (2006). Anti-diabetes functionality of kefir culture-mediated fermented soymilk supplemented with Rhodiola extracts. Food Biotechnol. 20, 13-29. doi: 10.1080/08905430500522055
93. Yüksekdag, Z. N., Beyatli, Y., and Aslim, B. (2004). Determination of some characteristics coccoid forms of lactic acid bacteria isolated from Turkish kefirs with natural probiotic. Food Sci. Technol. 37, 663-667.
94. Zajšek, K., Goršek, A., and Kolar, M. (2013). Cultivating conditions effects on kefiran production by the mixed culture of lactic acid bacteria imbedded within kefir grains. Food Chem. 139, 970-977. doi: 10.1016/j.foodchem.2012.11.142
95. Zajšek, K., Kolar, M., and Goršek, A. (2011). Characterisation of the exopolysaccharide kefiran produced by lactic acid bacteria entrapped within natural kefir grains. Int. J. Dairy Technol. 64, 544-548. doi: 10.1111/j.1471-0307.2011.00704.x
96. Zanirati, D. F., Abatemarco, M., Cicco Sandesb, S. H., Nicolia, J. R., Nunes, A. C., and Neumanna, E. (2015). Selection of lactic acid bacteria from Brazilian kefir grains for potential use as starter or probiotic cultures. Anarobe 32, 70-76. doi: 10.1016/j.anaerobe.2014.12.007
97. Zhang, B., Xu, N., Xi, A. D., and Wang, Y. P. (2009). Screening and identification of cholesterol-reducing KF5 strain. J. Tianjin Univ. Sci. Technol. 24, 17-20.
98. Zheng, Y., Lu, Y., Wang, J., Yang, L., Pan, C., and Huang, Y. (2013). Probiotic properties of Lactobacillus strains isolated from Tibetan Kefir grains. PLoS ONE 8:e69868. doi: 10.1371/journal.pone.0069868