Chemical and enzymatic modification of butterfat and butterfat-canola oil blends

Chemical interesterification (CIE) and 1,3-specific enzymatic interesterification (EIE) of butterfat lead to decreases in the 32-42 carbon number triglycerides (TAGs) and increases in the 44-54 TAGs. The solid-fat-content (SFC) of butterfat and the 80% blend dropped upon EIE at all temperatures. The SFC for CIE butterfat dropped 2-3% below 15 degrees C and increased ca 5% above 20 degrees C, while for the 80% blend, SFC dropped ca 5% only below 15 degrees C. The hardness index (KI) and storage modulus (G') of butterfat and blends above 70% butterfat decreased upon interesterification. The dropping point (DP) of butterfat increased by 3 degrees C upon CIE. The DP of blends above 60% butterfat did not change significantly upon CIE. The DP of EIE butterfat and blends above 60% decreased 2-5 degrees C. The relative proportion of the beta' polymorph decreased slightly upon CIE and EIE and blending with canola oil. CIE of butterfat lead, however, to a complete conversion to the beta' polymorph. Sensory evaluation of spreads made using these modified fats showed that interesterification improved spreadability significantly, however, at the expense of some of the butter-like flavor. (C) 1999 Canadian Institute of Food Science and Technology. Published by Elsevier Science Ltd. All rights reserved.