Produção e caracterização de micropartículas lipídicas, obtidas por spray cooling, para utilização como agentes de nucleação na produção de chocolates

Abstract

Fats crystallization is a complex phenomenon which, when controlled, can be applied in several chemical and food industries sectors. In chocolate production, the use of nucleating agents can occur by the incorporation of high melting point triglycerides, melted or in solid form. The seeds can be added directly in the chocolate mass or in the cocoa butter, resulting in a large number of well-defined crystallization nuclei, which are the basis for the structural arrangement of the fat crystal network. In this way, the seeds can improve and/or accelerate the chocolate tempering step. Based on these facts, the objective of this research was to produce and to characterize solid lipid microparticles (SLM) from fully hydrogenated oils (hardfats) of palm (FHPO), cottonseed (FHCO), soybean (FHSO) and crambe (FHCrO), using the spray cooling (SC) technique in order to study the influence of the addition of these SLM as nucleating agents in dark chocolate tempering process. The SLM were produced by varying the process parameters: hardfats maintenance temperature (70 to 85 °C), SLM solidification temperature (0 to 24 °C), nozzle diameter (0.7 to 1 mm) and atomiser air pressure (1.25 to 1.75 kgf/cm 2 ). The SLM produced presented  polymorphism, spherical shape and mean diameter between 56.12 and 2514.32 µm, depending on the hardfats and process conditions used. The polymorphic transition kinetics of SLM stored at 25, 35 and 45 °C was investigated by 141 days evaluating the visual configuration, the thermal melting behavior and the SLM polymorphism. The full transition from SLM to polymorphism of their respective hardfats occurred more quickly at 45 °C, with full transition of SLM observed in the SLM of FHSO, FHPO and FHCO after 24 hours, without altering the visual aspect. At 35 °C, the SLM transition of FHPO and FHCO occurred after 4 days, and at 25 °C the complete transition was observed only in the SLM of FHCO. For SLM of FHCrO,  polymorphism was predominant in the treatments at 25 and 35 °C and there was only polymorphic transition in the treatment at 45 °C after 15 days. It was observed time reduction on the tempering chocolates steps with the addition of SLM of FHSO with  polymorphism, which showed similar rupture tension and color to the chocolate subjected to the conventional way of tempering. The results indicate that SC technique is suitable for the SLM production of the studied hardfats. However, for use of these SLM as crystallization agents is required to induce the polymorphic transition for the most stable polymorph, preferably non-static way in order to avoid the agglomerates formation.