Identification of Some Volatile Carbonyl Compounds from Nonfat Dry Milk

Evidence is presented, in the form of compound identification, that lipid oxidation, as well as Maillard-type browning, occurred in instant nonfat dry milk (NFDM) stored at room temperature for 1 yr. The compounds identified from instant NFDM were formaldehyde, acetaldehyde, acetone, butanone, methylpropanal, 3-methylbutanal, furfural, diacetyl, hexanal, and nonanal. Evidence is also presented for the presence of heptanal, octanal, decanal, dodecanal, and tetradecanal. The isolated compounds are believed to be largely responsible for the cereal-type flavor which sometimes develops in NFDM. It was estimated that the flavorful carbonyl compounds existed in reconstituted NFDM at levels of a few parts per billion.