Mathematical Modeling of pH Variation as a Function of Temperature and Time in Kefir Production
[1]
Binnur Kaptan, Department of Food Science, Faculty of Agriculture, Namık Kemal Univetsity, Tekirdağ, Turkey.
[2]
Serap Kayısoglu, Namık Kemal University, Vacational School, Tekirdağ, Turkey.
[3]
Omer Oksuz, Department of Food Science, Faculty of Agriculture, Namık Kemal Univetsity, Tekirdağ, Turkey.
A mathematical model was developed to describe the effect of temperature and fermentation time on the kinetic parameters of pH change by kefir grains yeast population, using whole milk, semi-skimmed milk and skim milk of cows. Fermentation temperature (25–35 ºC), total fat level (3.0, 1.7, 0.15 %) and inoculum level (2%) w/v had simultaneous effects on the acidification process in kefir fermantation. The changes in pH of pasteurized cow milk inoculated with 2 % culture were investigated during fermentation at 25-35 ºC. Measurement of pH change was followed first order kinetics during kefir fermentation. The optimal kinetics model for pH change during fermentation of kefir was the linear mathematical model. Furthermore, statistical analysis indicated that fermentation temperature and time significantly affected pH change of kefir. pH reduction rate of kefir was maximum at semi-skimmed milk (1.7 %) at 35 ºC.
Kefir, pH, Kinetic, Milk Fat, Fermentation, Time
[1]
Bosch, A., Golowczyc, M. A., Abraham, A. G., Garrote, G. L., De Antoni, G. L., & Yantorno, O. (2006). Rapid discrimination of lactobacilli isolated from kefir grains by FT-IR spectroscopy. International Journal of Food Microbiology, 111(3), 280-287.
[2]
Chen, H.-C., Wang, S.-Y., & Chen, M.-J. (2008). Microbiological study of lactic acid bacteria in kefir grains by culture-dependent and culture-independent methods. Food Microbiology, 25(3), 492-501.
[3]
Güzel-Seydim, Z. B., Seydim, A. C., Greene, A. K., & Bodine, A. B. (2000). Determination of Organic Acids and Volatile Flavor Substances in Kefir during Fermentation. Journal of Food Composition and Analysis, 13(1), 35-43.
[4]
Ismaiel, A. A., Ghaly, M., & El-Naggar, A. (2011). Some physicochemical analyses of kefir produced under different fermentation conditions. Journal of Scientific and Industrial Research (JSIR), 70(5), 365-372.
[5]
Leite, A. M. O., Mayo, B., Rachid, C. T. C. C., Peixoto, R. S., Silva, J. T., Paschoalin, V. M. F., & Delgado, S. (2012). Assessment of the microbial diversity of Brazilian kefir grains by PCR-DGGE and pyrosequencing analysis. Food Microbiology, 31(2), 215-221.
[6]
Levenspiel, O. (1974). Chemical reaction engineering. India: Wiley Eastern Publication, New Delhi
[7]
Magalhães, K. T., Dragone, G., de Melo Pereira, G. V., Oliveira, J. M., Domingues, L., Teixeira, J. A., e Silva, J. B. A., & Schwan, R. F. (2011). Comparative study of the biochemical changes and volatile compound formations during the production of novel whey-based kefir beverages and traditional milk kefir. Food Chemistry, 126(1), 249-253.
[8]
Motaghi M, Mazaheri M, Moazami N, Farkhondeh A, Fooladi MH, & EM., G. (1997). Short Communication: Kefir production in Iran. World J Microbiol Biotechnol, 13(5), 579-581.
[9]
Öner, Z., Karahan, A., & Çakmakçı, M. (2010). Effect of different milk types and starter cultures on kefir. Gıda, 35(3), 177-182.
[10]
Özdestan, Ö., & Üren, A. (2010). Biogenic amine content of kefir: a fermented dairy product. European Food Research and Technology, 231(1), 101-107.
[11]
Torriani, S., Gardini, F., Guerzoni, M. E., & Dellaglio, F. (1996). Use of response surface methodology to evaluate some variables affecting the growth and acidification characteristics of yoghurt cultures. International Dairy Journal, 6(6), 625-636.
[12]
Varghese K, S., & Mishra, H. N. (2008). Modelling of acidification kinetics and textural properties in dahi (Indian yogurt) made from buffalo milk using response surface methodology. International Journal of Dairy Technology, 61(3), 284-289.
[13]
Witthuhn, R. C., Schoeman, T., & Britz, T. J. (2005). Characterisation of the microbial population at different stages of Kefir production and Kefir grain mass cultivation. International Dairy Journal, 15(4), 383-389.
[14]
Zajšek, K., & Goršek, A. (2010). Mathematical modelling of ethanol production by mixed kefir grains yeast population as a function of temperature variations. Biochemical Engineering Journal, 49(1), 7-12.
[15]
Zanatta, P., & Basso, A. (1992). A new approach to the characterization of Streptococcus salivarius subsp thermophilus based on acidification rates. Lait, 72(3), 285-295.
