Caracterização química de frutos de pequizeiro (Caryocar brasiliense Camb.) oriundos de três municípios do Estado de Goiás

Caracterização química de frutos de pequizeiro (Caryocar brasiliense Camb.)...

(Parte 1 de 3)

Ciência e Tecnologia de AlimentosISSN 0101-2061

Recebido para publicação em 21/12/2007

Aceito para publicação em 7/7/2009 (003103) Departamento de Ciências Biológicas, Universidade Federal de Goiás – UFG, Campus Jataí – CAJ, CP 03, CEP 75800-970, Jataí - GO, Brasil, E-mail: smarianos@uol.com.br Programa de Pós Graduação em Agronomia, Universidade Federal de Goiás – UFG, Campus Jataí – CAJ, CP 03, CEP 75800-970, Jataí - GO, Brasil Universidade Federal de Goiás – UFG, Campus Jataí – CAJ, CP 03, CEP 75800-970, Jataí - GO, Brasil Departamento de Ciência de Alimentos, Universidade Estadual de Goiás – UEG, Av. 31 de maio s/n, setor Epaminondas, CEP 75800-0, Jataí - GO, Brasil *A quem a correspondência deve ser enviada

Chemical characteristics of pequi fruits (Caryocar brasiliense Camb.) native of three municipalities in the State of Goiás – Brazil

Caracterização química de frutos de pequizeiro (Caryocar brasiliense Camb.) oriundos de três municípios do Estado de Goiás

Samuel MARIANO-da-SILVA1*, Joys Dias de Assis BRAIT2, Francys Pimenta de FARIA2, Sueli Maria da SILVA2, Silvio Luis de OLIVEIRA1, Paula Fernanda BRAGA3, Fabiana Maria de Siqueira MARIANO-da-SILVA4

1 Introduction

The occupation and utilization of Cerrado has been done disorderly and in a wrong way, most of the time, without the necessary knowledge about the use and behavior of most native vegetable species. The anthropic activities in the region cause disturbing effects since man transformation capacity is higher than the environmental recovery capacity (ASSAD, 1996).

Thus, a great number of fructiferous species have, systematically, become extinct, therefore, their characteristics cannot be known, preserved, or utilized (ANGELONI et al., 2004).

The species Caryocar brasiliense (pequizeiro) is among the six most important species of Cerrado vegetation whose fruits are commercialized (CEASA, 1995). Firstly, it is the most important species in the Cerrado culinary culture (RIBEIRO; FONSECA; ALMEIDA, 1994). Its fruits are not consumed in natura but after cooking. It is also utilized in fries and as seasoning due to its typical flavor and smell (SILVA et al., 1994). Secondly, (PEREZ, 2004) it is often used as edible oil source since it has a nice aroma and taste. Besides, its lipid fraction has high content of oleic acid.

The pequizeiro flourishes from June to September and its fruits rape from September to February of the following year (ALMEIDA, 1998; NAVES, 1999). It grows in the regions of cerradão, cerrado and secondary vegetation of Distrito Federal, Goiás, Tocantins, Minas Gerais, Mato Grosso, São Paulo, Bahia, and Piauí (PREGNOLATO, W.; PREGNOLATO, N. P., 1985).

Resumo

Para que a utilização de frutíferas do cerrado ocorra de maneira sustentável, estudos no intuito de se conhecer suas características fazem-se necessários. Neste escopo, o presente trabalho teve como objetivo caracterizar alguns parâmetros químicos de frutos de pequizeiro coletados em três municípios do sudoeste do Estado de Goiás (Jataí, Rio Verde e Serranópolis). Em cada município foram selecionadas duas populações de pequizeiros, denominadas áreas. Em cada área, foram eleitas oito árvores para a coleta dos frutos. Nas amostras, foram determinados os teores de fósforo, potássio, cálcio, magnésio, enxofre, cobre, ferro, manganês, nitrogênio, zinco e extrato etéreo. Os resultados indicam que as diferenças entre as características químicas estudadas nos frutos coletados nas diferentes regiões não parecem variar significativamente. Comparando os teores encontrados no presente trabalho com aqueles requeridos diariamente na alimentação humana, novos estudos são recomendados objetivando utilizar o fruto do pequizeiro como uma fonte alternativa complementar de magnésio, manganês e cobre. Palavras-chave: pequi; Caryocar brasiliense; composição química; valor nutricional.

Abstract

In order to assure that the use of cerrado fruits occur in a sustainable way, studies to investigate their characteristics are extremely relevant. In this context, the present study aims to describe some chemical parameters of pequi fruits picked in three municipalities in southwestern Goiás State (Jataí, Rio Verde, and Serranópolis). In each city, two populations of pequi trees – pequizeiros, denominated areas, were selected. In each area, eight trees were selected for the fruit to be picked. The contents of phosphorus, potassium, calcium, magnesium, nitrogen, zinc, and ether extract were determined in the samples. The results demonstrate differences between the chemical characteristics studied for the fruits picked in different areas, which does not seem to vary in a significant way. Comparing the contents obtained in the present study with those required as human daily supply, further studies are recommended aiming at using the pequi fruit as a complementary alternative source of magnesium, manganese, and copper. Keywords: pequi, Caryocar brasiliense; chemical composition; nutritional value.

Chemical characteristics of pequi fruits is exceeded only by the buriti pulp (16.7%) since the other native fruits of Cerrado (araticum, baru, cagaita, jatobá and mangaba) contain values under 1% (ALMEIDA, 1998). Its vitamin B1 content is considered similar to that of avocado, strawberry, genipap, and papaya; the vitamin B2 content is equivalent to that of egg yolk (CARVALHO; BURGER, 1960; POZO, 1997).

Almeida (1998) also argues that a great variation in vitamin

C contents can be observed among Cerrado fruits, while pequi fruit stands out for containing approximately 78.72 mg.100 g–1. Moreover, according to the author, this value is higher than that found in fruits traditionally cultivated and consumed by Brazilian population such as orange (approximately 40.9 mg.100 g–1) and lemon (approximately 26.4 mg.100 g–1).

In Goiás Stock Center (CEASA-GO), the most commonly commercialized native fruit of cerrado is pequi. By the year 2006, the commercialized fruit volume was approximately 3.342 tons with an average price around R$ 468.0 per ton (CEASA, 2006).

Nevertheless, besides its great economic and nutritional potential (RODRIGUES, 2005; SANTANA; NAVES, 2003), the trees have not been cultivated yet, and fruit picking is done in an extractive and predatory way (VARMA, 1986). The intensive extractivism may even produce genetic material losses since high quality fruits, originally from higher genotypes, are collected and commercialized (MELO-JUNIOR et al., 2004).

To start a process of rational economic exploitation of native fructiferous species of Cerrado, it is necessary to have knowledge about their characteristics and interaction with the environment. However, there is not much available information about the chemical composition of these fruits. The existent data are scattered or do not follow a scientific criterion.

The current work aims to characterize some chemical parameters of native pequizeiro fruits of six regions in three municipalities in the State of Goiás.

2 Materials and methods

2.1 Selection of the area to be studied

In three municipalities in the State of Goiás (Rio Verde,

Jataí and Serranópolis), six areas for the pequizeiro fruit samples collection were selected. Table 1 shows the geographic coordinates of each area. The areas were selected especially according to some standards (area with little anthropic action,

It is widely spread over the region of Cerrados, often growing in several places (RIBEIRO et al., 1997; SANTOS; AOKI, 1992; SILVA et al., 1994).

According to Gribel (1986) and Gribel and Hay (1993), the pequizeiro presents a great proportion of fruits formed by crossed pollination, significantly higher than those formed by autopollination. The flowers are visited by a range of insect and bird species, which have the function of pollinating agents such as: moth, wasps, humming birds, and bees although the most efficient pollination process is done by bats. Furthermore, the pequizeiro is a plant which has a typically zoochoric dispersion. The main fruit consumers are: rhea (Rhea americana), jackdaw (Cyanocorax crostatellus), and agouti (Dasyprocta sp.), which can act as seed spreaders to small distances by sinzoochoria.

Its generic name is derived from the Greek “Karyon” which means stone and from the Latin “Caro” which means drupaceous and fleshy fruit. The vernacular “piqui” is originally from native Brazilian Indian languages, as “py” is equivalent to skin and “qui” to thorn. Therefore, “py-qui” means fruit pulp full of thorns (MIRANDA, 1986).

Pequi fruit is a drupe up to 10 cm diameter, green, with an average weight of 104.4 g, containing one to five seeds with an average weight of 14.2 g, coated by woody endocarp with thorns and yellow fleshy mesocarp (CARVALHO et al., 1996). It is constituted, approximately, of 76.72% peel, 8.50% pulp, and 13.10% seed (VERA et al., 2007). The pulp is rich in oil constituent (61.7%) and almond (12.2%) (FERREIRA et al., 1987).

Almeida (1998), who has been studying several fruits of native species of the Brazilian Cerrado (araticum, baru, buriti, cagaita, jatobá, and mangaba), states that pequi fruit stands out with 2.64% of protein, value lower than jatobá (6%) and baru (3.87%) only. Concerning the lipid contents, the pequi fruit presented the highest value (20%) in relation to other native species (which varied from 5% to less than 1%), and the concentrations found by the author are comparable to the contents found in açaí and buriti, native fruits of the Amazon and the Cerrado region as well.

Vilas Boas (2004) states that the fiber content in the pequi fruit is considered high (average of 14%) while the carbohydrate concentrations found (average of 19.60%) are considered intermediate. Besides, the author affirms that the high acidity values range from 0.9 to 2.0.

Almeida (1998) considers that the pequi fruit stands out because of its high pectin contents, an important parameter for fruits industrialization and commercialization. According to the author, the pequi pulp contains 2.3% of pectin approximately, while other species such as buriti, cagaita, and mangaba contain values under 1%. The author compared the contents found with those present in other fruits which are also used in Brazilian diets and verified that these values are almost equivalent to those present in oranges (approximately 2.36%).

The fruits contain high contents of vitamin A, B1, and B2

(OLIVEIRA et al., 2006; PEREZ, 2004). The carotenoids content (vitamin A precursor) in the pequi pulp (approximately 7.46%)

Table 1. Geographic co-ordinates from the six areas for collecting pequi fruits.

Area Municipalities Latitude Longitude IRio Verde17° 30’ 31”51° 30’ 25” IIRio Verde18° 05’ 20”50° 20’ 37” IIIJataí18° 30’ 40”51° 30’ 25” IVJataí17° 50’ 26”51° 52’ 0” VSerranópolis18° 10’ 56”52° 50’ 12” VISerranópolis18° 30’ 45”51° 5’ 48”

Mariano-da-Silva et al.

dissolved 1:100 in distilled water. The potassium content was measured by flame spectrophotometry (gas GLP) in an Analyser spectrophotometer (MIYAZAWA, 1999).

2.8 Iron, copper, manganese, and zinc quantification

Approximately 0.5 g of the pequi sample was mineralized by

2:5:3 sulfuric acid (H2SO4), nitric acid (HNO3), and perchloric acid (HClO4) digestion at 220 °C for 3 hours. The mineral content was measured by atomic absorption spectrophotometry with atomization by acetylene flame in a Perkin Elmer model Analyst 100 atomic absorption spectrophotometer (VARMA, 1986).

2.9 Sulfur quantification

Approximately 0.5 g of the pequi sample was mineralized by 2:1 hydrogen peroxide (H2O2) and perchloric acid (HClO4) digestion at 220 °C for 3 hours. The mineralized sample was dissolved 1:100 in distilled water after which 1 mL of

6 M chloric acid (HCl) and 0.5 g of barium chloride (BaCl2) were added. After 5 minutes, the color was measured in the spectrophotometer at 420 nm (MIYAZAWA, 1999).

2.10 Phosphorus quantification

Approximately 0.5 g of the pequi sample was mineralized by 2:1 hydrogen peroxide (H2O2) and perchloric acid (HClO4) digestion at 220 °C for 3 hours. The mineralized sample was dissolved 1:100 in distilled water, and 2 mL of 0.25% ammonium metavanadate (NH4VO3) and 2 mL of 5% ammonium molybdate

([NH4]2MoO4) were added. After 15 minutes, the color was measured with a colorimeter at 660 nm (MIYAZAWA, 1999).

2.1 Nitrogen quantification

Approximately 0.5 g of the pequi sample was mineralized by 2:1 hydrogen peroxide (H2O2) and perchloric acid (HClO4) digestion at 220 °C for 3 hours. The nitrogen content was then determined by the Microkjeldahl method (HART; FISCHER, 1971).

2.12 Statistical analysis

The results were statistically analyzed using the orthogonal contrasts method (SNEDECOR; COCHRAN, 1967). Two hypothesis and fifteen contrasts were formulated. The formulated hypothesis and contrasts can be seen in Table 2.

3 Results and discussion

In Table 3, it is possible to observe the obtained results for quantitative determinations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), barium (B), copper (Cu), iron (Fe), manganese (Mg), zinc (Zn), pH, and lipid fraction (E) in the pulp (mesocarp) of the sampled fruits.

The abundance of different mineral elements in this fruit stands out in the comparison of these data with the values obtained for the different fruits economically cultivated (NEPA, typical Cerrado formations and with more occurrence in this kind of study).

2.2 Fruits collection

Mature pequizeiro fruits (Caryocar brasiliensis) were picked between November and December 2006, according to maturation on the following dates: November 15th, 2006 (area I); November 29th, 2006 (area I); December 10th, 2006 (area I); December 05th, 2006 (area IV); December 07th, 2006 (area V), and November 30th, 2006 (area VI). In each area, eight trees were selected and disposed in an imaginary square with 10,0 m2. Next, 5 fruits from each tree were picked, according to the cardinal points and the center (BRAIT, 2003). Fruits of all varieties of size, weight, and color were picked at randomly. After picking, the fruits were immediately stored in paper packs and sent to the laboratory.

2.3 Preparation of pequi samples and pH measuring

Right after taking them to the laboratory, the fruits were opened and the pH of the pulp was determined according to the methodology proposed by Pregnolato, W.; Pregnolato, N. P. (1985). The pulp was then submitted to heat drying at 70 °C for 20 hours. The samples were triturated in a plastic bush container (MIYAZAWA, 1999), and the fruits from the same tree were homogenized originating a sample. The homogenized samples were stored in polyprophylene bottles until the analysis.

2.4 Material preparation

All reusable items (glass, quartz, polyethylene, teflon, etc.) were prepared for use by washing with detergent in ultra pure water and soaked in a mixture of nitric acid, hydrochloric acid, and water (1 + 2 + 9) for 4 hours, followed by rinsing with ultra pure water and heat drying (McDANIEL, 1992).

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