Acoustically assisted supercritical CO2 extraction of cocoa butter: Effects on kinetics and quality

Autores UPV
Revista The Journal of Supercritical Fluids


tThe effect of high power ultrasound (US) application and pressure on the supercritical fluid extraction(SFE) kinetics of cocoa butter and on characteristics of the extracted cocoa butter (fatty acids composi-tion, transition temperatures, polyphenol content and antioxidant activity) has been evaluated. Extractionexperiments were carried out at 40◦C and at two pressure levels of 400 bar and 550 bar, without and withUS application of 50 ± 5 W, the extraction yield being significantly improved as the pressure increasedand the ultrasound was applied. A Weibull model allowed the accurate simulation of the extractioncurves, considering a constant shape factor ² which was affected only by the US application, whilstthe rate constant ¡ was affected by both pressure and US application. In general, for all cocoa buttersamples, the transition temperatures observed corresponded to the polymorph ², Tc= 9.9 ± 0.3◦C andTm= 20.2 ± 0.4◦C. With regard to the fatty acid composition, the stearic (37.8 ± 0.8%), oleic (33.7 ± 0.2%),and palmitic (26.0 ± 0.6%) were the major acids, and none were found to be influenced by either pres-sure or ultrasound application. Similarly, the total polyphenol content and antioxidant activity werenot affected by extraction conditions. The microstructure of cocoa beans after processing was affectedby pressure and also by ultrasound application which promoted a breaking of the cell arrangement,facilitating the butter extraction