Evaluation of Some Physicochemical Properties of Milk Caused by Acidification

Rodica Căpriță

Abstract


The objective of this study was to evaluate changes in some physicochemical properties of milk during acidification. The milk samples were analyzed for titratable acidity expressed as % lactic acid (LA), pH, electrical conductivity (EC) and lactose content. In fresh milk LA and pH exhibit a weak negative correlation (r = -0.3210). When acid production starts, LA increases proportionally, whereas the pH decreases (r = -0.8043). The acidifying process induced concomitantly an increase in EC. The decrease in pH from 6.578±0.088 to 5.732±0.195, and in lactose content from 5.469±0.256g% to 4.97±0.385g% was accompanied by an increase in EC from 5.337±0.434 mS/cm to 5.940±0.493 mS/cm.

Keywords


milk, pH, lactic acid, electrical conductivity

Full Text:

PDF

References


Singh, H., McCarthy, O.J., and Lucey, J.A., Physico-chemical properties of milk, in: Advanced Dairy Chemistry, vol. 3, Lactose, Water, Salts and Vitamins, 2nd edn., P.F. Fox (ed.), Chapman and Hall, London, 1997, pp. 469–518.

McCarthy, O.J., and Singh, H., Physico-chemical Properties of Milk, in: Advanced Dairy Chemistry, vol. 3: Lactose, Water, Salts, and Minor Constituents, McSweeney, P.L.H. and Fox, P.F. (eds.) Springer, London, 2009, pp. 691-758.

Kailasapathy, K., Chemical Composition, Physical and Functional Properties of Milk and Milk Ingredients, in: Dairy Processing and Quality Assurance, John Wiley & Sons, 2008, pp. 75-103.

Sherbon, J.W., Physical properties of milk, in: Fundamentals of Dairy Chemistry, 3rd edn., Wong N.P., Jenness R., Kenny M., Marth E.H., (eds.), Van Nostrand Reinhold, New York, 1988, pp. 410–414.

Walstra, P., Wouters, J.T.M., and Geurts, T.J., Dairy Science and Technology, 2nd ed., Taylor and Francis Group, Boca Raton, London, 2006, pp.160-162.

Colinet, F. G., Soyeurt, H., Anceau, C., Vanlierde, A., Keyen, N., Dardenne, P., Gengler, N., and Sindic, M., Potential estimation of titratable acidity in cow milk using mid-infrared spectrometry, in: 37th International Committee for Animal Recording (ICAR) Meeting, Riga, Latvia, 2010, http://www.icar.org/ Documents/Riga_2010/ppt/Colinet.pdf.

Salaün, F., Mietton, B., and Gaucheron, F., Buffering capacity of dairy products, Int. Dairy J., 2005, 15, 95-109.

St-Gelais, D., Champagne, C.P., Erepmoc, F., and Audet, P., The use of electrical conductivity to follow acidification of dairy blend, Int. Dairy Journal, 1995, 5(5), 427-438.

Muchetti, G., Gatti, M., and Neviani, E., Electrical conductivity changes in milk caused by acidification: Determining factors, J. Dairy Sci., 1994, 77 (4) 940-945.

Felice, C.J., Madrid, R.E., Olivera, J.M., Rotger, V.I., and Valentinuzzi, M.E., Impedance microbiology; quantification of bacteria content in milk by means of capacitance growth curves, Journal of Microbiological Methods, 1999, 35, 37-42.

Lawton, B.A., and Pethig, R., Determining the fat content of milk and cream using AC conductivity measurements, Measurement Sci. and Tech., 1993, 4, 38-41.

Mabrook, M. F., and M. C., Petty, Application of electrical admittance measurements to the quality control of milk, Sensors and Actuators B., 2002, 84, 136-141.

Neilen, M., Deluyker, H., Schukken, Y.H., and Brand, A., Electrical conductivity of milk measurement, modifiers and meta analysis of mastitis detection performance, J. Dairy Sci., 1992, 75, 606-614.

AOAC, 2000. Official Methods of Analysis International. 17th edn., Association of Official Analytical Chemists, Washington DC.

Căpriţă, R., Principii şi tehnici biochimice, Ed. Gutenberg, Arad, 2001, pp. 147-149.

Clayden, J., Greeves, N., Warren, S., and Wothers, P., Organic Chemistry, Ed. Oxford University Press Inc., New York, 2001.

Briggadike H., Ohnstad I., and Hillerton, E., Proc. British Mastitis Conf., 2000, 56-61


Refbacks

  • There are currently no refbacks.


Copyright (c)


Scientific Papers Animal Science and Biotechnologies publish open access articles under the terms of the Creative Commons Attribution 4.0 Licence (read full legal code).


LUCRARI STIINTIFICE ZOOTEHNIE SI BIOTEHNOLOGII (SCIENTIFIC PAPERS ANIMAL SCIENCE AND BIOTECHNOLOGIES)

ISSN print 1841 - 9364
ISSN online 2344 - 4576
ISSN-L  1841 - 9364
(former ISSN 1221-5287, E-ISSN 1841-9364)

PUBLISHER: AGROPRINT Timisoara, Romania
PAPER ACCESS: Full text articles available for free
FREQUENCY: Semiannual
PUBLICATION LANGUAGE: English
_________________________________________________________________

Banat´s University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" from Timisoara
Bioengineering Faculty of Animal Resources
300645, Timişoara, Calea Aradului 119, Romania

E-mail: spasb [at] animalsci-tm.ro
Phone: +40-256-277160, Fax.: +40-256-277110