EFFECT OF TEMPERING ON THE TEXTURE AND POLYMORPHIC BEHAVIOR OF MARGARINE FATS

Separated fats from commercial soft (soft fat) and stick (stick fat) margarines and mixtures of hydrogenated super olein (H-olein) and canola oil, were temperature cycled between 4 degrees C and 15, 20 and 25 degrees C. The polymorphic form, SFC and texture of the fats were evaluated. Temperature cycling of soft fats between 4 and 20 degrees C resulted in the crystals being either in the beta polymorphic form or mixtures of beta' and beta. When temperature cycled between 4 and 15 degrees C the presence of beta' crystals was improved, but there were soft fats that after the fourth cycle contained only beta crystals. When stick fats were temperature cycled between 4 and 20 degrees C, the crystals after the fourth cycle were either in the beta' form or contained mixtures of beta' and beta. Mixtures of H-olein-canola showed superior beta' stability throughout. A mixture of 20% H-olein/canola oil compared well with the SFC and texture of soft margarines while a mixture of 40% H-olein/canola oil with those of stick margarines. Texture was evaluated by constant speed penetration. Texture of fats is very dependent on temperature history. DSC crystallization curves of the fats showed a variety of patterns.