EFFECT OF HEAT-TREATMENT ON THE VITAMIN-B -12 AVAILABILITY IN THE MILKS

In this work, a combined HPLC-radioassay method allowed to show that a denosylcobalamin and methylcobalamin are decreased in pasteurized and sterilized milks, as well as in dry milk powder while cyandcobalamin i ncreased in these three milks. So, hydroxocobalamin amount decreases i n the pasteurized and sterilized milk but increases in the dry milk po wder compared with fresh milk By further using an in vitro gastro-inte stinal method, using pepsin and pancreatin as well as 'R' and intrinsi c factors, if was possible to evaluate cobalamin availability in some heated milks. Vitamin B-12 was relatively more available in the pasteu rized milk (1.91 pmol/ml) than in fresh milk (1.54 pmol/ml), sterilize d milk (1.25 pmol/ml) and dry milk powder (1.27 pmol/ml), indicating a possible influence of heat treatment on the Vitamin B-12 availability in these products and the conversion between vitamers during in vitro digestion.