Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-26T14:35:50.242Z Has data issue: false hasContentIssue false

Storage of lactose-hydrolysed dried milk: effect of water activity on the protein nutritional value

Published online by Cambridge University Press:  01 June 2009

Anders Burvall
Affiliation:
Department of Applied Nutrition, Chemical Centre, University of Lund, P.O. Box 740, S-220 07 Land 7, Sweden
Nils-Georg Asp
Affiliation:
Department of Applied Nutrition, Chemical Centre, University of Lund, P.O. Box 740, S-220 07 Land 7, Sweden
Agneta Bosson
Affiliation:
Department of Applied Nutrition, Chemical Centre, University of Lund, P.O. Box 740, S-220 07 Land 7, Sweden
Carmen San José
Affiliation:
Department of Applied Nutrition, Chemical Centre, University of Lund, P.O. Box 740, S-220 07 Land 7, Sweden
Arne Dahlqvist
Affiliation:
Department of Applied Nutrition, Chemical Centre, University of Lund, P.O. Box 740, S-220 07 Land 7, Sweden

Summary

The retention of the protein nutritional value during storage of lactosehydrolysed dried milk at different water activities (aw) was studied and compared with that of ordinary milk. In the lactose-hydrolysed milk biologically available lysine decreased much more rapidly than in the ordinary milk at all the different aw studied. Thus, at conditions normally accepted for ordinary dried milk (aw ~0·2; moisture ~ 4 %) there was an available lysine loss in the hydrolysed milk of about 25 % after 2 months and about 40 % after 6-months storage at room temperature. This occurred without any visible browning. It is concluded that drying to very low aw (≦ 0·11) is necessary to obtain good stability of the protein nutritional value (PNV) in lactose-hydrolysed milk. The drying, however, must be done so that losses in nutritional value are minimal during that process. It should also be noted that fat oxidation might be a problem at such low aw. A chemical method for available lysine assay (guanidination and assay of homoarginine) gave values in good agreement with the biological evaluations with rats.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1978

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bender, A. E. (1973). In Proteins in Human Nutrition, p. 167. (Eds Porter, J. W. G. and Rolls, B. A..) London and New York: Academic Press.Google Scholar
Boehringer, C. F. & Söhne, , Biochemical Department (1967). Galactose and Lactose: Laboratory Information. Mannhein: Boehringer.Google Scholar
Burvall, A., Asp, N.-G., Dahlqvist, A. & Öste, R. (1977). Journal of Dairy Research 44, 549.CrossRefGoogle Scholar
Carpenter, K. J. (1960). Biochemical Journal 77, 604.CrossRefGoogle Scholar
Dahlqvist, A., Asp, N.-G., Burvall, A. & Rausing, H. (1977). Journal of Dairy Research 44, 541.CrossRefGoogle Scholar
Eggum, B. O. (1973). Beretning fra Forsogslaboratoriet, no. 406. National Institute of Animal Science. Copenhagen.Google Scholar
Eichner, K. (1975). In Water Relations of Foods. International Symposium, 1974, p. 417. (Ed. Duckworth, R. B.). London: Academic Press.Google Scholar
Eichner, K. & Karel, M. (1972). Journal of Agriculture and Food Chemistry 20, 218.CrossRefGoogle Scholar
Fao/who (1973). FAO Nutrition Meetings Report Series no 52. World Health Organization Technical Reports Series, no. 622.Google Scholar
Forsum, E., Hambraeus, L. & Siddiqi, I. H. (1973). Nutrition Reports International 8, 39.Google Scholar
Henry, K. M., Kon, S. K., Lea, C. H. & White, J. C. D. (1948). Journal of Dairy Research 15, 292.CrossRefGoogle Scholar
Hägerdal, B. & Löfqvist, B. (1973). Journal of Agricultural and Food Chemistry 21, 445.CrossRefGoogle Scholar
Labuza, T. P., McNally, L., Gallagher, D., Hawkes, J. & Hurtado, F. (1972). Journal of Food Science 37, 154.CrossRefGoogle Scholar
Labuza, T. P., Tannenbaum, S. R. & Karel, M. (1970). Food Technology 24, 543.Google Scholar
Labuza, T. P. & Warren, R. (1976). Abstracts of Papers, American Chemical Society 172, AGFD 58.Google Scholar
Lea, C. H. (1948). Journal of Dairy Research 15, 369.CrossRefGoogle Scholar
Lea, C. H. & Hannan, R. S. (1949). Biochimica et Biophysica Acta 3, 313.CrossRefGoogle Scholar
Loncin, M., Bimbenet, J. J. & Lenges, J. (1968). Journal of Food Technology 3, 131.CrossRefGoogle Scholar
Mauron, J. & Bujard, E. (1963). 6th International Congress in Nutrition, p. 167.Google Scholar
Rao, N. M. & Rao, M. N. (1972). Journal of Food Science and Technology, (Mysore) 9, 66.Google Scholar
Reynolds, T. M. (1965). Advances in Food Research 14, 167.CrossRefGoogle Scholar
Roach, D. & Gehrke, C. W. (1969). Journal of Chromatography 44, 269.CrossRefGoogle Scholar
Robinson, R. A. & Stokes, R. H. (1959). Electrolyte Solutions, 2nd edn, London: Butterworths.Google Scholar
San José, C., Asp, N.-G., Burvall, A. & Dahlqvist, A. (1977). Journal of Dairy Science 60, 1539.CrossRefGoogle Scholar
Warmbier, H. C., Schnickels, R. A. & Labuza, T. P. (1976). Journal of Food Science 41, 528.CrossRefGoogle Scholar
Warren, R. M. & Labuza, T. P. (1977). Journal of Food Science 42, 429.CrossRefGoogle Scholar