Modified soybean lecithins as inducers of the acceleration of cocoa butter crystallization

Abstract

Modified soy lecithins are introduced in chocolate processing as an alternative to standard lecithin to improve rheological characteristics and the fat crystallization process. The influence of the type of these additives (hydroxylated, enzymatically hydrolyzed, acetylated, and defatted lecithins) as well as the amount added (0.2, 0.5, 0.8% [w/w]) to cocoa butter was evaluated. The results were compared to samples containing standard lecithin and polyglycerol polyricinoleate (PGPR). The influence of emulsifier addition was investigated measuring the melting and crystallization properties by differential scanning calorimetry (DSC) and the crystallization kinetics using a Nuclear Magnetic Resonance (NMR) spectrometer. The addition of modified lecithins to cocoa butter increased fat crystallization rates, mainly at the lowest concentration evaluated. The isothermal crystallization of the emulsifiers suggests that lecithins may act as co-crystallizers in cocoa butter crystallization. Thus, the acceleration of the crystallization events can be attributed to presence of the high melting point phospholipids and also to solids present in lecithins. Pure PGPR did not crystallize and did not influence the cocoa butter crystallization. The use of modified lecithins in cocoa butter decreased the maximum temperature of melting (Tmax) and increased the crystallization (DHc) and melting (DHm) enthalpies.