Abstract
The present study aims to compare yield and quality of pequi pulp oil when applying two distinct processes: in the first, pulp drying in a tray dryer at 60ºC was combined with enzymatic treatment and pressing to oil extraction; in the second, a simple process was carried out by combining sun-drying pulp and pressing. In this study, raw pequi fruits were collected in Mato Grosso State, Brazil. The fruits were autoclaved at 121ºC and stored under refrigeration. An enzymatic extract with pectinase and CMCase activities was used for hydrolysis of pequi pulp, prior to oil extraction. The oil extractions were carried out by hydraulic pressing, with or without enzymatic incubation. The oil content in the pequi pulp (45% w/w) 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. Aqueous extraction has presented lower efficiency and higher oxidation of unsaturated fatty acids. On the other hand, pequi pulp pressing at room temperature has produced better quality oil. However its efficiency is still smaller than the combined enzymatic treatment and pressing process. This combined process promotes cellular wall hydrolysis and pulp viscosity reduction, contributing to at least 20% of oil yield increase by pressing.
Highlights
The cerrado occupies about 21% of Brazilian territory with a great fauna and flora diversity
The C. brasiliense is widely distributed in Brazilian cerrado mainly in Minas Gerais, Mato Grosso and Goiás States
Pequi fruits (Caryocar brasiliense) are an important option of income and food for the populations living in the cerrado regions of Brazil
Summary
The cerrado occupies about 21% of Brazilian territory with a great fauna and flora diversity. The main fatty acids in the pequi pulp oil are oleic and palmitic acids, 60% and 34%, respectively. Aqueous extraction at high temperatures is the main method used for pequi pulp oil production in the cerrado area. The enzymatic process mainly hydrolyzes the structural polysaccharides, forming the cell wall of oilseeds or the proteins, which form the cell and lipid body membrane (Rosenthal et al, 1994) This technology has been developed in bench scale to extract oil from many vegetable raw materials such as rapeseed, soybean, peanuts, sesame, rice bran corn germ, palm, sunflower; avocado, coconut (Rosenthal, Pyle & Niranjan, 1996; Hanmoungjai et al, 2001; Caetano et al, 2002; Freitas et al, 2003; Sant’anna et al, 2003). The last process can be adopted in rural areas, mainly by indigenous communities living in the Brazilian cerrado regions aiming to achieve a sustainable development
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