Sunday, May 4, 2008
1-33

The enzymatic technology to improved oil extraction from pequi pulp (Caryocar brasiliense Camb.)

Sônia Couri, Embrapa Agroindústria de Alimentos, Avenida das Américas 29501, Rio de Janeiro, Brazil, Renata G.B. Mariano, Technologia de Alimentos, Universidade Federal Rural do Rio de Janeiro, BR-465, Km 7, Seropédica, Rio de Janeiro, 23890-000, Brazil, and Suely Pereira Freitas, Escola de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, Centro de Tecnologia, Bloco E., Rio de Janeiro, 21941-909, Brazil.

The pequi is wide distributed in the Brazilian cerrado. Its' fruits are normally used for food, cosmetics and 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  pectinase and CMCase activities 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: 0.5% volume of enzyme per weight of the sample, 60oC and 1 hour of incubation time in pre-treatment stage and 340 bars in the pressing stage. The oil content in the pequi pulp (45%) and the physicochemical characteristic of the oil was determined according to standard analytical methods. Free fatty acids, 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 than the 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%.

Key-words: Pequi,  oil extraction, enzyme-based process.