Cocoa Butters and Equivalents in Blends with M i l k Fat * ByB. P e t e r s s o n ++ Earlieq in part 1 of this paper, a method for Solid Fat Content (SFC) determination with pulsed NMR has been described for cocoa butters and cocoa butter equivalents. The present work (part 11) is a continuation with these fats togetherwith 10 to30uh~milkfat.These fatblendsneedamodified pre-treatment before NMR analysis. Crystallisation of the melted fat should be done at 00 C for 1.50 min and subsequent tempering performed at 19.00 C for 40 h. No other deviations from the earlier reported method have been carried out. Also SFC determination for chocolate has been described and used asatoolforthedevelopment ofaproperNMR method,givingSFCona pure fat blend more or less equal to SFC in corresponding milk chocolate. Different pre-treatments (i.e. tempering temperatures) have given very different SFC results. A crystallographic understanding of these were achieved using X-ray, microscope and thermal analysis techniques. The chosen tempering temperature 19.00 C gave a single solid solution, which is essential in chocolate if the right properties of the fat are to be reached. Differences in SFC on pure fat blends by different tempering temperatures could, in the same way, be found in milk chocolates stored at corresponding temperatures. Storage temperature can, to a certain degree, be chosen in ordertooptimizeandcontrol theSFC(i.e.properties) inachocolateproduct.
Thechoice ofinitial temperatureespecially will strongly inlluence the SFC in chocolate and the crystal lattice remains virtually unaffected by changes in storage temperature.
I n t r o d u c t i o n
Previously, a pulsed NMR method for Solid Fat Content (SFC) in tempering fats i.e. Cocoa Butter (CB) or Cocoa Butter Equivalents (CBE) has been published I. Following Part IIofthepaperisacontinuationwith 10 to30VuMilkFat (MF) in mixture with CB or CBE. No established methods for determination of SFC in such mixtures can be found in literature. However, a method would be of great importance, as the SFC would give a good picture of the properties of the fat phase in the milk chocolate i.e. snap, hardness, melting behaviom, waxiness etc. The usefulness of different CB, CBE and different levels of MF could then easily be evaluated. Milk fat is quite a unique fat, which can be blended in a high proportion with CB without altering its polymorphism. G. M. Chapman et al. have investigated mixtures of up to 30% MF and found the same six polymorphic forms as in pure CB, however, with lowered melting points and slower polymorphic transitions. R. E. Timms has reported that CB together with the addition of up to 50% MF still exist as a single solid solution of p(V)-3 crystals. This is of the greatest importance in chocolate if problems such as bloom formation, poor gloss or inadequate contraction are to be avoided as reported by R R. Paulicka '.The high compatibility of MF with CB is due to the low content of solid fat in MF at normal temperatures ' . * Based on a lecture presented a t the 4Ith DGF meeting held on Illh September 198.5 in Gottingen.