THE EFFECT OF MICROWAVE-HEATING ON VITAMIN-B-1 AND VITAMIN-E, AND LINOLEIC AND LINOLENIC ACIDS, AND IMMUNOGLOBULINS IN HUMAN-MILK

Breast milk was treated with: (1) conventional heating (in water bath) vs microwave heating; (2) microwave heating at two power levels (30% and 100%); (3) increasing final temperatures; and (4) microwave thawin g vs refrigerator thawing and examined for changes in specific immunog lobulins to a pool of E. coli and poliovirus type 1 antigens, vitamins E and B-1, and the polyunsaturated fatty acids linoleic and linolenic acid. Immunoglobulin activities were stable until final milk temperat ures of around 60-65 degrees C were reached, and total inactivation oc curred at 77 degrees C. Heating even to high final temperatures did no t change contents of vitamins and polyunsaturated fatty acids. No diff erences in immunoglobulins and nutrients were demonstrated between mic rowave heating and conventional heating, and between power levels or t hawing methods. The study shows that microwave heating of human milk c an be performed without significant losses of examined immunoglobulins and nutrients, provided that final temperatures are below 60 degrees C.