Direct Determination of Moisture in Powder Milk Using Near Infrared Spectroscopy
Moisture content in commercially available milk powder was investigated using near infrared (NIR) diffuse reflectance spectroscopy with an Indian low-cost dispersive NIR spectrophotometer. Different packets of milk powder of the same batch were procured from the market. Forty-five samples with moisture range 4–10% were prepared in the laboratory. Spectra of the samples were collected in the wavelength region 800–2500 nm. Moisture values of all the samples were simultaneously determined by Karl Fischer (KF) titration. These KF values were used as reference for developing calibration model using partial least squares regression (PLSR) method. The calibration and validation statistics are , , and , . Five samples of unknown moisture contents were taken for NIR prediction using developed calibration model. The agreement between NIR predicted results and those of Karl Fischer values is appreciable. The result shows that the instrument can be successfully used for the determination of moisture content in milk powder.
- H.-D. Isengard, “Water content, one of the most important properties of food,” Food Control, vol. 12, no. 7, pp. 395–400, 2001.
- C. A. De Caro, A. Aichert, and C. M. Walter, “Efficient, precise and fast water determination by the Karl Fischer titration,” Food Control, vol. 12, no. 7, pp. 431–436, 2001.
- H.-D. Isengard and P. Heinze, “Determination of the water content in different sugar syrups by halogen drying,” Food Control, vol. 12, no. 7, pp. 483–486, 2001.
- P. C. Williams, K. H. Norris, C. W. Gehrke, and K. Bernstein, “Comparison of near infrared method for measuring protein and moisture in wheat,” Cereal Foods World, vol. 28, pp. 149–152, 1983.
- M. J. Adams, K. Latham, N. W. Barnett, and A. J. Poynton, “Calibration models for determining moisture and fat content of processed cheese using near-infrared spectrometry,” Journal of the Science of Food and Agriculture, vol. 79, no. 10, pp. 1232–1236, 1999.
- N. Özkan, B. Withy, and X. D. Chen, “Effects of time, temperature, and pressure on the cake formation of milk powders,” Journal of Food Engineering, vol. 58, no. 4, pp. 355–361, 2003.
- B. R. Nielsen, H. Stapelfeldt, and L. H. Skibsted, “Early prediction of the shelf-life of medium-heat whole milk powders using stepwise multiple regression and principal component analysis,” International Dairy Journal, vol. 7, no. 5, pp. 341–348, 1997.
- E. L. Celestino, M. lyer, and H. Roginski, “The effects of refrigerated storage of raw milk on the quality of whole milk powder stored for different periods,” International Dairy Journal, vol. 7, no. 2-3, pp. 119–127, 1997.
- J. Štencl, “Water activity of skimmed milk powder in the temperature range of 20-45,” Acta Veterinaria Brno, vol. 68, no. 3, pp. 209–215, 1999.
- T. K. Kockel, S. Allen, C. Hennigs, and T. A. G. Langrish, “An experimental study of the equilibrium for skim milk powder at elevated temperatures,” Journal of Food Engineering, vol. 51, no. 4, pp. 291–297, 2002.
- H. Stapelfeldt, B. R. Meisen, and L. H. Skibsted, “Effect of heat treatment, water activity and storage temperature on the oxidative stability of whole milk powder,” International Dairy Journal, vol. 7, no. 5, pp. 331–339, 1997.
- I. Ben-Gera and K. H. Norris, “Influence of fat concentration on the absorbtion spectrum of milk in the near infrared region,” The Israeli Journal of Agricultural Research, vol. 18, pp. 117–124, 1968.
- S. Rückold, K. H. Grobecker, and H.-D. Isengard, “Determination of the contents of water and moisture in milk powder,” Fresenius' Journal of Analytical Chemistry, vol. 368, no. 5, pp. 522–527, 2000.
- C. Reh, S. N. Bhat, and S. Berrut, “Determination of water content in powdered milk,” Food Chemistry, vol. 86, no. 3, pp. 457–464, 2004.
- R. J. De Knegt and H. Van Den Brink, “Improvement of the drying oven method for the determination of the moisture content of milk powder,” International Dairy Journal, vol. 8, no. 8, pp. 733–738, 1998.
Copyright © 2006 R. Nagarajan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.