Comparative study of chemical and technological properties of Brazilian cocoa butter and industrial blends: triacylglycerol composition and microstructure

摘要

A comparative study of the primary properties of six cocoa butter samples, representative of industrial blends, and cocoa butter extracted from fruits cultivated in different geographical areas in Brazil is presented. The samples were evaluated according to triacylglycerol composition and microstructure. The triacylglycerol contents ranged between 1.35-3.15, 88.39-94.76 and 3.68-10.25% for the trisaturated, disaturatedmonounsaturated and monounsaturated-diunsaturated triacylglycerol classes, respectively. Higher levels of disaturated-monounsaturated triacylglycerols were observed for the industrial blends, while Brazilian samples were characterized by higher percentages of monounsaturated-diunsaturated triacylglycerols. Considering only the “saturated fatty acid - oleic acid - saturated fatty acid” triacylglycerol species, Brazilian samples totaled percentages from 81.33 to 85.25%; for the industrial blends, these values were between 87.11 and 88.48 %. Significant difference was observed among cocoa butter regarding the mean diameter of the crystals with samples mantained at 15°C for 180 minutes. This parameter varied from 5.80 to 41.53 μm for all evaluated samples. The standard blends showed the smallest diameters (5.80 - 6.33 μm). The percentages of crystallized area, for the different samples, ranged between 19.95 and 33.52%. The morphological evaluation indicated disk-shaped crystals, with granular crystalline structure composed of a large number of small sized crystals, excepting one Brazilian sample, which was characterized by a mixed morphology. The results allowed differentiating the samples by their chemical composition and microstructural pattern, as well as regarding the technological adequacies and the potential uses in regions of tropical climate.