Extração do óleo da polpa de pequi (Caryocar brasiliense) por processos convencionais combinados com tecnologia enzimática

Abstract

The pequi is wide distributed in the Brazilian cerrado. Its' fruits are normally used for food, cosmetics, lubricants production. The pequi pulp is mainly composed of lipids (45 to 50%) and fiber. The integral fruits were collected in the Mato Grosso State, Brazil. The fruits were autoclaved at 121ºC for peroxidase inactivation and stored under refrigeration for subsequent use. In this study, an enzymatic extracts with high pectinase and CMCase activities, respectively 83 and 21 U/g, was used for hydrolysis of pequi pulp prior to oil extraction. The enzyme was produced in bench-scale reactor by solid state fermentation using a mutant Aspergillus niger 3T5B8. The oil extractions were carried out by centrifugation or by hydraulic pressing, with or without enzymatic incubation. The best oil yield was obtained in the following operational conditions: 1,0 % volume of enzyme per weight of the sample, 45oC and 1 hour of incubation time in pre-treatment stage and 10000 psi during 1 hour in the pressing stage. The oil content in the pequi pulp (36%) and the physicochemical characteristic of the oil was determined according to official analytical methods. Acidity, peroxide values, iodine and saponification indices were respectively 1.46 mgKOH/g, 2.98 meq/kg, 49.13 and 189.40. The acidity and peroxide values were lower that obtained values in commercial oil samples respectively, 2.48 mgKOH/g and 5.22 meq/kg. This combined process promotes, simultaneously, the cellular wall hydrolysis and the viscosity reduction of the pulp, contributing to increased the oil yield by pressing in at least 20%.