Dry Fractionation of Cupuassu (Theobroma grandiflorum) Fat: Physical-Chemical Properties and Polymorphic Behavior

Physical chemical properties of cupuassu fat were modified by dry fractionation. Stearin and olein fractions were obtained at 29, 26, and 24 degrees C. Polymorphic behavior of unfractionated cupuassu fat (UCF) and its fractions were studied in situ by small-angle (SAXS) and wide-angle (WAXS) X-ray scattering using synchrotron light. Polymorphic transitions were followed in real time tempering samples with a thermal cycle. For UCF, the main polymorphic form crystallized under selected conditions was the beta'(2). alpha and beta'(1)-forms appeared in trace amounts. beta(2)-form was obtained after storage at 25 degrees C for 3 months. Stearins obtained at 26 (S-26) and 24 degrees C (S-24) showedasimilar polymorphic behavior. However, S-26 with improved physical properties might be more suitable for chocolate production or as atrans-fat alternative than UCF. Stearin fraction obtained at 29 degrees C (S-29) had a complex polymorphic behavior. The alpha-form was the first polymorphic form detected followed by beta'(2)-form. There was a polymorphic transition from alpha to beta'(1)-form but no transition between beta'-forms. They were independent to each other showing fractionation in two different solid solutions. Increased contents of the triacylglycerols (TAG) SOA and SOB together with lower contents of SOO compared to UCF led to co-crystallization because there was no complete compatibility among all TAG present in S-29. beta(1)-form crystallized after storage forming crystals with a double-layer arrangement and a characteristic morphology. This form could be useful for accelerating crystallization process in melted liquid systems.