Open Access
Review
Publication ahead of print
Journal
OCL
Section Niche products and crop diversification: in search of added value / Produits de niche et cultures de diversification : à la recherche de valeur ajoutée
DOI https://doi.org/10.1051/ocl/2017040
Published online 08 September 2017

© A.M.M. Guedes et al., Published by EDP Sciences, 2017

Licence Creative Commons
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1 Introduction

Pequi, also known as pequierim, pequiá, pequi-rasteiro, is a native fruit from Brazil, found in the Amazon, Caatinga, Cerrado and Atlantic Rain Forest regions (Caryocaraceae, 2017), and mostly distributed in the central and southeastern regions of Cerrado. It also occurs in other South American countries and in Central America (Fig.1).

The Brazilian Cerrado is the richest savanna in the world in terms of number of species and the second largest biome in Brazil, after Amazonia, comprising 21% of the land area. It is mainly located in Central Brazil extending over several states, such as Goiás, Tocantins, Ceará, Mato Grosso, Minas Gerais, and Pará. Endemism and human pressure turned this biome into one of the priority areas for conservation of biodiversity in the world (Oliveira and Scariot, 2010; Silva and Fonseca, 2016; Silva et al., 2001).

The fruit is cooked before consumption and the pulp is used in the preparation of several dishes. The most popular uses of pequi are in flavoring rice, chicken, and in homemade fruit preserves (Araujo, 1995; Silva and Fonseca, 2016). Homemade soaps are also produced when the fruit is not suitable for cooking. The kernel is used as an ingredient in preparations of roasted cassava or maize flour mixtures and fruit preserves, or is consumed as a salted snack. The pulp is rich in edible oil. The chemical composition of the oil has encouraged researchers to study its industrial applications in different products.

thumbnail Fig. 1

Pequi tree and fruits (Photo: Nilton T. V. Junqueira).

2 Extractive production and general uses

Pequi tree is a perennial slow growing tree with the ability to resprout and persist for a long period of heavy fruit harvesting pressure. Caryocar seed dispersal is limited due to the lack of long distance seed dispersers, which contributes to its total density. It occurs in 61% of the Cerrado, being well adapted to low fertility soils (Giroldo and Scariot, 2015).

Sixteen species of Caryocar L. genus have been reported, three of them of higher economic importance: Caryocar brasiliense, C. villosum, and C. coriaceum. The main product obtained from these species is the oil, which can be extracted from both the mesocarp and the kernel (Araujo, 1995).

The cutting and commercialization of its wood have been prevented by law, in Brazil, since 1987 (IBDF, 1987). Additionally, there are specific rules to protect Caryocar, such as the prohibition of harvesting fruit from the tree, i.e., before falling to the ground. Besides, farms have common areas of native vegetation preserved by law (“Legal Reserves”) [Giroldo and Scariot, 2015]; however, there are fruit collectors who pick most of fruits of the tree, thus reducing its propagation (Leite et al., 2006).

It is a plant with great potential for sustainable development use in the central region of Brazil. It has an estimated average production of 7027 ton of fruits corresponding to C. brasiliense plus C. coriaceum (IBGE, 2011), an underestimated production based on official data. In Brazil, pequi is quite popular due to its culinary and therapeutic applications.

In the north area of Minas Gerais State, the second largest producer in terms of area of C. brasiliense, there is no homogeneous seeding. The fruits are collected from preserved areas. The harvesting is organized by cooperatives and generates income to 2400 small farmers' families. Pequi has not been domesticated and its production is therefore the result of extractivism. However, the awareness of some communities about biome preservation has led to the planting of  seedlings. The price of the fruits changes depending on harvest quality, which in turns, depends on climatic factors, such as drought. A minimum price policy is applied to help preserving Caryocar species (CONAB, 2012).

Some technical assistance and rural extension companies support producers to increase tree propagating and prevent from disease and pests (CONAB, 2013, 2016).

Since the number of native pequi trees is not enough to meet the increasing demand, Embrapa is currently studying the possibility of cultivation. In this line, grafting as a method of vegetative propagation has been used for domestication, cultivation, and further propagation. With the help of this method, the productivity would increase from 2 ton per hectare (5 years after planting) to 40 ton per hectare by using suitable agronomic practices, which means 2.4 tons of oil per hectare, considering the sum of both pulp and kernel oil (Nilton Junqueira, personal communication, 2016).

Pequi plays an important role for local populations and industries, either ecologically and economically, through the exploitation of its fruits and kernels.

The mesocarp is thick, and divided into an external layer and an internal yellowish layer with a strong and distinct taste and smell. The endocarp is woody, muricate and spiny on the outside. The endocarp is about one sixth of the fruit weight, and the kernel is one third (Fig. 2). The flowering period usually occurs before and at the beginning of the rainy season, from June to September, with maturation lasting beyond the end of the rainy season, when dispersal of the seeds take place (Araujo, 1995).

thumbnail Fig. 2

Pequi Fruit (Photo: Nilton T. V. Junqueira).

3 Oil composition

Considering the main species of Caryocar, the chemical composition of pulp oil (36–66% of fruit, d.b.) [Faria-Machado et al., 2015] and kernel oil (14–48% w.b.) [Rogério et al., 2012] consists of palmitic (35–40%) and oleic (55–60%) as the major fatty acids (Facioli and Gonçalves, 1998; Guedes et al., 2017; Lima et al., 2007; Silva and Fonseca, 2016. The pulp oil has a high content of carotenoids up to 246 μg/g (Aquino et al., 2009).

The triacylglycerol composition may vary according to location for the same species and between species. The main triacylglycerols found in pulp oil are POP (1,3-dipalmitoyl-2-oleyl-glycerol), POO (1,2-dioleyl-3-palmitoyl-glycerol), and POS (palmitoyl-oleyl-stearoyl-glycerol) [Facioli and Gonçalves, 1998; Guedes et al., 2017].

Pequi oil has exhibited biological effects, such as antioxidant properties, due to the high carotenoid content of C. brasiliense pulp oil, which may slow atherogenesis in the initial stages (Aguilar et al., 2012). Wound and gastric healing effect of C. coriaceum oil has been reported (Quirino et al., 2009). Topical anti-inflammatory effect of C. coriaceum pulp and kernel oils was also demonstrated (Oliveira et al., 2010; Saraiva et al., 2011).

4 Extraction methods

The first collected fruits have higher quality and are sold in natura, mainly for use in culinary preparations. As long as its price is reduced, the fruits are used for oil production.

Endocarp plus internal mesocarp are boiled in water on a low fire and stirred until the oil is extracted. The oil rises to the surface, and is skimmed with a spoon. Since it is a rudimentary technique, the production of around six liters of oil can take up to two days (Oliveira and Scariot, 2010). Alternatively, the oil is carefully filtered to remove tiny thorns, and then heated to release excess water (Araujo, 1995).

The oil can also be extracted by solvents, such as acetone, ethanol, and hexane that must be eliminated in the final stage of processing. In this case, a previous drying of the pulp material is necessary. Oil yield and total carotenoid content are dependent on the solvent used, as well as the drying process (Aquino et al., 2009, 2011). Mechanical extraction of the dried pulp followed by filtration has also been reported. However, the amount of carotenoids and quality properties of the oil are reduced (Ribeiro et al., 2012).

5 Potential uses

The high content of the monounsaturated fatty acid, around 60% of oleic acid, is interesting for food, cosmetic and oleochemical uses. Additionally, pequi oil contains around 35% palmitic acid (C16:0), which makes it suitable for margarine and shortening applications (Guedes et al., 2017). Both fatty acids can affect physical stability of the oil in tropical regions.

Despite showing lack of functionality for direct industrial use due to its physical properties, such as melting and crystallization behavior, the triacylglycerol composition reported by Guedes et al. (2017) indicates pequi oil as a good source of POP, enabling its application as cocoa butter substitutes.

Due to its fatty acid composition, pequi oil has a tendency to fractionate in storage. This issue can be eliminated by chemical interesterification, which produces a new zero trans fat with different applications in food fat industry, with new polymorphism, different crystallization and melting profiles, thus offering a wider range of functionality at room and cold temperatures (Guedes et al., 2017). In addition, the product obtained by this process is an alternative to fats rich in trans fatty acids whose negative effects are well documented (Mozaffarian et al., 2006).

The oil can also be enzymatically modified using Lipozyme in order to incorporate stearic acid in the sn-1,3 position of triacylglycerols and obtain a cocoa butter-like fat (Facioli and Gonçalves, 1998)

Homemade and cold pressed pequi kernel oils tested in vivo showed hepatoprotective effects, due to their antioxidant and anti-inflammatory properties (Torres et al., 2016).

The oil extracted from the kernel has a pleasant light smell and is used in the cosmetic industry, although the oil from the pulp has also been used for the same purpose (Battermann and Hippe, 2014; José Antonio dos Santos, personal communication, 2016).

Jelly capsules of aqueous and organic extracts of pequi claimed to induce antioxidant and antimutagenic effects were reported and have been marketed in Brazil (Grisólia et al., 2007).

Despite the high saturated fatty acids content, and the tendency to crystallize, the use of the oil as biodiesel has been investigated (Abreu et al., 2004; Borges et al., 2012).

6 Conclusion

Pequi pulp and kernel oils have similar fatty acid composition, with approximately balanced proportions of saturated and unsaturated fatty acids, contributing to their fractionation in storage in tropical regions. The oil is a source of POP, a triacylglycerol of great interest in food industry. Pequi pulp oil is also a specialty oil with the presence of bioactive compounds requiring further information. Sustainable cultivation of the plant and higher fruit production followed by improvements in extraction methods would increase oil production, and would certainly contribute to add value to its production chain.

References

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Cite this article as: Guedes AMM, Antoniassi R, de Faria-Machado AF. 2017. Pequi: a Brazilian fruit with potential uses for the fat industry. OCL, DOI: 10.1051/ocl/2017040

All Figures

thumbnail Fig. 1

Pequi tree and fruits (Photo: Nilton T. V. Junqueira).

In the text
thumbnail Fig. 2

Pequi Fruit (Photo: Nilton T. V. Junqueira).

In the text

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