Volatile Coumponds in Passion Fruit Seed Oil (Passiflora setacea BRS Pérola do Cerrado and Passiflora alata BRS Doce Mel)

Abstract

The use of seed byproducts from fruit processes has contributed to increase the supply of vegetable oils rich in bioactive compounds regarding consolidated cosmetics and functional foods. The aim of this study was to identify the volatile compounds present in the species P. setacea BRS Perola do Cerrado and P. alata BRS Doce Mel passion fruit seed oil. Both species come from research studies of Embrapa Cerrado (Brazil), where genetic modification were conducted in order to select species that meets the standard requirements regarding size, skin color, flesh color, number of seeds and a more sweet pulp flavor. In addition the species selected is more resistant to pests typical of passion fruit cultivation in Brazil. To evaluate the oil content in seeds, the lipid determination was carried out by Soxhlet method. The seeds were dried at 50 °C in aconvective dryer until the equilibrium moisture was achieved. The crude oil was obtained by crushing in continuous press expeller-type. The pressing processes were made at room temperature at 26 ± 2 oC (cold pressing) or above 50 °C (hot pressing). For the heating an electric resistance was coupled to the pressoutput. For comparative purposes, passion fruit oil was also obtained using anhydrous ethanol (PA) as solvent. The volatile compounds analysis of passion fruit seed oil was performed by gas chromatography using Solid-Phase Microextraction technique (SPME) in Dynamic Headspace (HS) mode. The chromatograph was attached to mass spectrometer (GC-MS). Identification of the peaks was performed by comparing the mass spectra obtained with those of the device library (Wiley 6th edition) by comparison of the retention index calculated (Kovatz Index) with values reported in the National Institute of Standards and Technology. Discrimination among samples was performed by Principal Components Analysis (PCA) of the absolute chromatographic areas of identified individual compounds obtained by Dynamic Headspace/Solid-Phase Microextraction/Chromatography/Flame Ionization Detector (HS-SPME-GC-FID) using gray fiber Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CA/PDMS). The Unscrambler software version 10.3 (CAMO CORP) was used for PCA. The PCA shows separation among samples obtained applying different pressing temperatures (hot and cold) and by ethanol extraction. The most abundant volatile compounds from P.setacea oils were terpens (23 %), esters (23 %), alcohols (19 %), aldehydes and ketons (8 %). Regarding P. alata oils, the volatile compounds were in majority esters (35 %), aldehydes (30 %), alcohols (23 %), terpenes and carboxylic acids (9 %). Therefore the volatile profile depends not only on the species, but also on the process used for oil extraction.