The Effects of Temperature and Milk Fat Content on the Electrical Conductivity of Kefir during the Incubation

Kaptan Binnur^1, and Kayişoğlu Serap²

¹Department of Food Engineering, Agriculture Faculty, Namık Kemal University, 59030, Tekirdağ, Turkey

²Namık Kemal University, Vacational School, 59030, Tekirdağ, Turkey

Cite this paper:
Kaptan Binnur and Kayişoğlu Serap. The Effects of Temperature and Milk Fat Content on the Electrical Conductivity of Kefir during the Incubation. American Journal of Food Science and Technology. 2016; 4(1):25-28. doi: 10.12691/ajfst-4-1-5

Abstract

In this study, the relationships between the electrical conductivity and temperature for different milk fat contents were investigated during the incubation of kefir. For kefir production, three milk samples at different fat contents (0.15, 1.7 and 3.0%) and two incubation temperatures (25 °C and 35 °C) were selected. The inoculum level was 2%. The kefir fermentation time was approximately 10 h and the pH of kefir samples were 4.4 in the last stage. The test results showed that electrical conductivity (EC) increased at both the temperatures. The average EC values of non fat milk kefir were in the range of 4.72 mS/cm – 6.4 mS/cm at 35 °C, and 4.72 mS/cm – 5.71 mS/cm at 25 °C. The average EC values of full fat milk kefir were in the range of 4.84 mS/cm – 6.41 mS/cm at 35 °C, and 4.84 mS/cm – 5.63 at 25 °C. The average EC values of low fat milk kefir were in the range of 4.54 mS/cm – 6.39 mS/cm at 35 °C, and 4.54mS/cm – 5.5 mS/cm at 25 °C. Electrical conductivity of samples showed little improvement at low incubation temperature and fat content. Statistically, there was a significant difference (p < 0.05) in EC among samples.

Keywords:
electrical conductivity kefir fermentation

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References:

[1]	Anonimous Turkish Ministry of Agriculture. (2002). Rules for general and nutritional labelling of food materials. Notice. No. 2002/58. Turkish Food Codex. Turkish Ministry of Agriculture, Ankara, Turkey
[2]	Anonimous Turkish Food Codex. (2009).Communiqué no: 2009/25. Femented milk product. 6.02.2009-27143 Teblig No: 2009/25, Ankara, Turkey www.resmigazete.gov.tr/eskiler/2009/02/20090216-8.htm.
[3]	AOAC (Association of Official Analytical Chemists) (2006). Official Method 18: (2006a). Fat content of raw and pasteurized whole milk. Official methods of analysis of the association of official analytical chemists (18th ed.)AOAC, Arlington.
[4]	AOAC (Association of Official Analytical Chemists). (2006). Official Method 991.20 (2006b). Nitrogen (Total) in milk. Kjeldahl methods. Official methods of analysis of the association of official analytical chemists (18th ed.)AOAC, Arlington.
[5]	Baynes NC, Comrie J & Prain JH (1983). Detection of bacterial growth by the Malthus conductance meter. Med Lab Sci 40, 149-158.
[6]	AOAC (Association of Official Analytical Chemists).(1995) Official Methods 972.16.Lane-Eynon methods. Official methods of analysis of the association of official analytical chemists (16th ed.) Arlington.
[7]	IDF International Dairy Federation standard,(2007). 119 Milk and milk products. Determination of calcium, sodium, potassium and magnesium contents. Atomic absorption spectrometric method. IDF Standard 119. International Dairy Federation, Brussels, Belgium. http://www.iso.org/iso.
[8]	Curda L & Plocková M (1995).Impedance measurement of growth of lactic acid bacteria in dairy cultures with honey addition. International Dairy Journal 5, 727-733.
[9]	Dejmek P (1989).Precision conductometry in milk renneting. Journal of Dairy Research 56, 69-78.
[10]	García-Golding F, Giallorenzo M, Moreno N, & Chang V (1995).Sensor for determining the water content of oil-in-water emulsion by specific admittance measurement. Sensors and Actuators A: Physical 47, 337-341.
[11]	Guzel-Seydim ZB, Seydim AC, Greene AK, Bodine AB (2000). Determination of organic acids and volatile flavor substances in kefir during fermentation, J. Food Compos. Anal. 13 (1) (2000) 35-43.
[12]	Harding F (1995).Adulteration of milk, in: Harding, F. (Ed.), Milk Quality. Springer US, pp. 60-74.
[13]	Henningsson M, Östergren K, & Dejmek P (2005).The Electrical Conductivity of Milk—The Effect of Dilution and Temperature.International Journal of Food Properties 8, 15-22.
[14]	Ilie LI, Tudor L, Galis AM.(2010) The electrical conductivity of cattle milk and the possibility of mastitis diagnosis in Romania. Medicina Veterinara. 2010;43(2):220-227.
[15]	Koroleva NS (1988).Technology of kefir and kumis. Bull. Int. Dairy Fed. 227, 96-100.
[16]	Lanzanova M, Mucchetti G, & Neviani E (1993).Analysis of Conductance Changes as a Growth Index of Lactic Acid Bacteria in Milk. Journal of Dairy Science 76, 20-28.
[17]	Latrille E, Picque D, & Corrieu G (1994).General Method for Lactic Acid Batch Fermentation Processes Monitoring, in: Yano, T., Matsuno, R., Nakamura, K. (Eds.), Developments in Food Engineering. Springer US, pp. 558-560.
[18]	Lawton BA,& Pethig R (1993). Determining the fat content of milk and cream using AC conductivity measurements. Measurement Science and Technology 4, 38.
[19]	Leite, A M O, Mayo B, Rachid C T C C, Peixoto R S, Silva J T, Paschoalin V M F, and Delgado S (2012). Assessment of the microbial diversity of Brazilian kefir grains by PCR-DGGE and pyrosequencing analysis. Food Microbiol. 31:215-221.
[20]	Mabrook M F and Petty M C 2002 Application of electrical admittance measurements to the quality control of milk Sensors Actuators B 84 136-41.
[21]	Mabrook M F, & Petty M C (2003). Effect of composition on the electrical conductance of milk. Journal of Food Engineering 60, 321-325.
[22]	Magalhaes K T, Melo Pereira G V de, Campos C R, Dragone G, and Schwan R F (2011). Brazilian kefir: Structure, microbial communities and chemical composition. Braz. J. Microbiol. 42: 693-702
[23]	Mitchell FRG, & Alwis AAPd (1989).Electrical conductivity meter for food samples. Journal of Physics E: Scientific Instruments 22, 554.
[24]	Nielen M, Deluyker H, Schukken YH, Brand A.(1992) Electrical conductivity of milk: measurement, modifiers, and meta analysis of mastitis detection performance. Journal of Dairy Science. 1992; 75(2): 606-614.[PubMed]
[25]	Öner Z, Karahan AG, and Çakmakçı M L (2010). Effects of different milk types and starter cultures on kefir, Gıda 35; 177-182.
[26]	Palaniappan S, & Sastry SK (1991).Electrical conductivity of selected juices: influences of temperature, solids content, applied voltage, and particle size. Journal of Food Process Engineering 14, 247-260.
[27]	Paquet J, Lacroix C, Audet P, & Thibault J (2000).Electrical conductivity as a tool for analysing fermentation processes for production of cheese starters. International Dairy Journal 10, 391-399.
[28]	Prentice JH (1962).The conductivity of milk—the effect of the volume and degree of dispersion of the fat. Journal of Dairy Research 29, 131-139.
[29]	Ruhlman KT, Jin ZT, & Zhang QH (2001).Physical properties of liquid foods for pulsed electric fields treatment, in: Barbosa- Cánovas, G.V.a.Z., Q.W. (Ed.), In Pulsed Electric Field in Food Processing: Fundamental Aspect and Application,. Technomic Publishing., Pennsylvannia.
[30]	Schwann HP (1985).Determination of biological impedance, in: Physical Technique in Biological Research, Academic Press, London, UK, 1985, pp. 323-407.
[31]	Shee F LT, Angers P, Bazinet L (2005). Relationship between electrical conductivity and demineralization rate during electroacidification of cheddar cheese whey Journal of Membrane Science.
[32]	Swaisgood H 1985 Characteristics of Edible Fluids of Animal Origin: Milk in Food Chemistry 2nd edn (New York: Dekker) pp 791-827.
[33]	Witthuhn RC, Schoeman T, & Britz TJ (2005).Characterisation of the microbial population at different stages of Kefir production and Kefir grain mass cultivation. International Dairy Journal 15, 383-389.
[34]	Yongsawatdigul J, Park JW, & Kolbe E (1995).Electrical Conductivity of Pacific Whiting Surimi Paste during Ohmic Heating. Journal of Food Science 60, 922-925.