Heat stability of milk: influence of modification of lysine and arginine on the heat stability-pH profile.

Several dicarbonyl compounds (glyoxal, substituted glyoxals, diacetyl and 1, 2-cyclohexanedione) had a marked stabilizing effect on the heat stability of milk, especially in the presence of urea. These reagents are believed to modify arginine more or less specifically suggesting an important role for arginine residues in heat stability. In contrast, modification of lysine residues with dansyl chloride, acetic anhydride or cyanoborohydride had little effect on maximum heat stability although it did alter the HCT-pH profile. Since diacetyl is a natural constituent of fermented milks and cheese, it may be acceptable as an additive to increase the heat stability of milk.