Anais da Academia Brasileira de Ciências (2015) 87(3): 1701-1709 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 http://dx.doi.org/10.1590/0001-3765201520140166 www.scielo.br/aabc A comparative study of nutritional composition and potential use of some underutilized tropical fruits of Arecaceae RAQUEL B. SILVA1, EDVALDO V. SILVA-JÚNIOR1, LAÍS C. RODRIGUES1, LAISE H.C. ANDRADE1, SUZENE I. DA SILVA2, WOLFGANG HARAND3 and ANTONIO F.M. OLIVEIRA1 1Departamento de Botânica, Laboratório de Ecologia Aplicada e Fitoquímica, Universidade Federal de Pernambuco, Rua Prof. Moraes Rego, s/n, Cidade Universitária, 50670-901 Recife, PE, Brasil 2Departamento de Biologia, Laboratório de Recursos Econômicos e Fitoquímica, Universidade Federal Rural de Pernambuco, Rua Dom Manoel de Medeiros, s/n, Dois Irmãos, 52171-900 Recife, PE, Brasil 3Centro de Tecnologias Estratégicas do Nordeste, Avenida Professor Luiz Freire, 01, Cidade Universitária, 50740-540 Recife, PE, Brasil Manuscript received on April 14, 2014; accepted for publication on December 15, 2014 ABSTRACT In this study, pulp and kernel of fruits from six Arecaceae species were subjected to proximate analysis, fatty acid composition and total carotenoid content analysis. The species with the highest carbohydrate, lipid and protein values were Ptychosperma macarthurii (70.1 g/100 g in the kernel), Syagrus cearensis (40.6 g/100 g in the kernel), and S. coronata (20.6 g/100 g in the pulp). The ash content ranged from 0.61 to 7.51 g/100 g. Lauric, palmitic, and oleic acids were the major fatty acids identified. The total carotenoid contents and retinol activity equivalents were highest in the Pinanga kuhlii (180.3 µg/g) and Acrocomia intumescens (138.0 µg/g) pulp oils. Retinol activity equivalents varied between the investigated species (456 to 1515 μg RAE/100 g). Native species such as A. intumescens, S. coronata, and S. cearensis are good sources of fresh food for the underserved populations that inhabit poorly developed areas such as the semi-arid region of Brazil. P. macarthurii, an exotic species, is an excellent source of ash and carotenoids, demonstrating its potential both as a food source and as bioactive compounds. Pulp and kernel of A. intumescens, could be a good alternative feedstock for soap and biodiesel production, respectively. Key words: biomass, foods, oleic acid, palm trees. INTRODUCTION to their antioxidant properties, which protect the Numerous species from different Brazilian human body against oxidative stress and serve ecosystems are appreciable sources of amino as precursors of vitamin A. Thus, the intake of acids, carbohydrates, fatty acids, fiber, protein, carotenoid-rich vegetables is very important and minerals (Mayworm et al. 1996, Pinho et (Rodriguez-Amaya and Kimura 2004). al. 2009, Oliveira et al. 2012). Other natural Despite the species diversity in Brazil, compounds, such as carotenoids, also have a wide many of these species are still poorly exploited range of benefits to human health, mainly due as industrial feedstock. Located in the Brazilian semi-arid region, the Caatinga, is a seasonal dry Correspondence to: Antonio Fernando M. Oliveira E-mail: [email protected] tropical forest characterized by dry, spiny and An Acad Bras Cienc (2015) 87 (3) 1702 RAQUEL B. SILVA et al. predominantly deciduous shrub/forest vegetation. Drude, Pinanga kuhlii Blume, Ptychosperma The Caatinga has crucial importance for people macarthurii (H. Wendl. ex H.J. Veitch) H. Wendl. who inhabit this region, and it provides a wide ex Hook. f., Syagrus cearensis Noblick, Syagrus variety of plants that are used as fuel, building coronata Mart. (Becc.) and Veitchia merrillii materials and medicinal resources (Nascimento (Becc.) H.E. Moore were collected between January et al. 2011, 2012). However, few species are and September of 2011 in Recife, Garanhuns and actually used by small local industries, despite Buíque (Northeastern Brazil). The fruits were stored the semi-arid region having approximately 6000 at 4 °C until the chemical analysis was performed. species of angiosperms. MOISTURE AND ASH Arecaceae is one of the largest botanical families of economic importance. It comprises The pulp and kernel (5 g each) were dried overnight 2600 species in 240 genera. In Brazil, the family is at 105 °C in accordance to AOAC method 930.15 represented by 38 genera and 269 species (Leitman (AOAC 2000). The moisture percentage was et al. 2014). The Arecaceae flora of the Brazilian calculated by subtracting the dry weight from the wet Northeast includes 80 native species and in the weight. After determining the moisture content the Pernambuco state (northeast Brazil), there are 17 pulp and kernel were placed in a porcelain crucible species registered (Leitman et al. 2014), most of and incinerated in a muffle furnace (Tecnal, 1100- which have some economic value (Medeiros-Costa 1P, Piracicaba, Brazil) at 550 °C until light gray ash 2002, Rufino et al. 2008). resulted, in accordance with AOAC method 923.03 Although some of the Arecaceae species, (AOAC 2000). The crucibles were transferred to including some species from Brazil, have been a desiccator and cooled to room temperature. The previously analyzed for centesimal composition loss in mass was determined gravimetrically. (Crepaldi et al. 2000, Hiane et al. 2003, Menezes TOTAL LIPIDS AND FATTY ACID METHYL ESTER ANALYSIS et al. 2008, Teixeira da Silva de La Salles et al. 2010, Coimbra and Jorge 2011), there is still a The pulp and kernel (5 g each) were dried at 45 °C, lack of research on the industrial applications powdered and extracted with n-hexane (60 - 80 °C) of some palm trees. The aim of this work was for 8h in a Soxhlet extractor (Ahmad 1981). The to perform proximate analysis, fatty acid oil content of the pulp and kernel was calculated composition determination and total carotenoid by dividing the initial weight by the weight analysis of the fruits of six tropical Arecaceae, of the extracted lipids. The oil from each fruit some of which have not been reported to date, to pulp and kernel was hydrolysed (separately) at evaluate their potential use as food and for other 100 °C for 10 min in a water bath with 1.5 mL industrial purposes. of KOH in methanol (0.5 M). After cooling on ice for 5 min, 2.5 mL of 14% boron trifluoride MATERIALS AND METHODS methanolic (Sigma-Aldrich, St. Louis, Missouri) was added, and the sample was placed in a water PLANT MATERIALS bath for 30 min and then cooled again for 5 min. The species were selected based mainly on the After methylation, 2.5 mL NaCl (1%) and 3 mL results of previous ethnobotanical studies, on of n-heptane were added, and the sample was their economic importance and on underexploited centrifuged at 730.8 g for 5 min. The organic potential (Medeiros-Costa 2002, Lorenzi et al. phase was collected, and excess moisture was 2004). Fruit samples from Acrocomia intumescens removed by adding 0.1 g of anhydrous Na2SO4. An Acad Bras Cienc (2015) 87 (3) NUTRITIONAL COMPOSITION AND POTENTIAL USE OF ARECACEAE 1703 The free fatty acids methylated were analyzed TOTAL CAROTENOIDS DETERMINATION by GC/FID and GC/MS (QP5050 Shimadzu, The oil from the pulp or the kernel (1 g each) was Kyoto, Japan). The oven temperature was started at separated and diluted in 100 mL of petroleum ether 150 °C, and then was increased to 250 °C at 4 °C/ (60-80 °C), and the absorbance was measured at 450 min and held for 20 min. The chromatograph was nm in a Genesys 10S UV/VIS spectrophotometer equipped with a capillary DB-column and helium (Thermo Scientific, Waltham, MA, USA), in was used as the carrier gas with a flow rate of 1 accordance with Rodriguez-Amaya et al. (2008). cm3/min. The detector and injector temperatures The carotenoid content was expressed as β-carotene were set to 280 °C. The injection volume was 1.0 equivalents (µg/g). The retinol activity equivalent µL, and the split ratio was 30:1. All mass spectra (RAE) levels were calculated using a conversion were acquired using the electron impact (EI) mode factor of 1 µg retinol to 12 µg of dietary all-trans- at 70 eV. Fatty acids were identified as methyl β-carotene and were expressed in µg RAE/100 g esters by comparison using authentic standard (IOM 2001). (FAME SupelcoTM mix C4-C24, Bellefonte, PA, USA) and by comparison with mass spectra in the STATISTICAL ANALYSES Wiley 229 database (Wiley, New York) and the NIST/EPA/NIH Mass Spectral Library (NIST05). At least three replications of the experiment were The relative amount of the FAME was calculated performed. The data were analyzed by One-way from the integrated area of each peak and expressed ANOVA and Tukey’s HSD test. All tests were set as a percentage of the total area of all peaks. at 0.05 level of significance and analyzed using GraphPad Prism software (GraphPad, San Diego, PROTEINS CA, USA). The pulp and kernel (5 g each) were dried at room RESULTS temperature (approximately 30 °C) under forced blowing until the sample reached a constant weight, The results of the proximate analysis for the six after which the sample was ground to a powder form. Arecaceous fruits studied are shown in Table I. All The crude protein was determined by the Kjeldahl studied species, except P. kuhlii, had high levels of method in accordance with AOAC method 960.52 moisture (ranging from 60 to 75%). In most species, (AOAC 2000). The protein percentage was calculated the pulp had more moisture than the kernel. In P. using conversion factors of 6.25 and 5.30 for the pulp macarthurii, the moisture values were the same for and the kernel, respectively (Jones 1941).