The phenolic compounds, tocopherols, and phytosterols in the edible oil of guava (Psidium guava) seeds obtained by supercritical CO2 extraction Journal of Food Composition and Analysis Narváez-Cuenca, Carlos Eduardo; Inampues-Charfuelan, Mary Lucía; Hurtado-Benavides, Andrés Mauricio; Parada-Alfonso, Fabián; Vincken, Jean Paul https://doi.org/10.1016/j.jfca.2020.103467 This article is made publicly available in the institutional repository of Wageningen University and Research, under the terms of article 25fa of the Dutch Copyright Act, also known as the Amendment Taverne. This has been done with explicit consent by the author. Article 25fa states that the author of a short scientific work funded either wholly or partially by Dutch public funds is entitled to make that work publicly available for no consideration following a reasonable period of time after the work was first published, provided that clear reference is made to the source of the first publication of the work. 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For questions regarding the public availability of this article please contact [email protected] Journal of Food Composition and Analysis 89 (2020) 103467 Contents lists available at ScienceDirect Journal of Food Composition and Analysis journal homepage: www.elsevier.com/locate/jfca Original Research Article The phenolic compounds, tocopherols, and phytosterols in the edible oil of T guava (Psidium guava) seeds obtained by supercritical CO2 extraction Carlos-Eduardo Narváez-Cuencaa,*, Mary-Lucía Inampues-Charfuelana, Andrés-Mauricio Hurtado-Benavidesb, Fabián Parada-Alfonsoa, Jean-Paul Vinckenc a Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Food Chemistry Research Group, Carrera 30 No 45-03, Bogotá, Colombia b Laboratorio de fluidos supercríticos e ingredientes naturales, Universidad de Nariño, 520001 Pasto, Colombia c Laboratory of Food Chemistry, Wageningen University, P.O. Box 17, 6700 AA, Wageningen, The Netherlands ARTICLE INFO ABSTRACT Keywords: An edible oil was obtained from guava seeds by supercritical CO2 extraction. The oil was characterized by its Supercritical fluid extraction fatty acid composition, physicochemical properties, and the contents of phenolic, miscellaneous, phytosterol, Agroindustrial by-products and tocopherol compounds. The oil, obtained with a yield of 8.6 ± 1.2 g oil/100 g guava seeds, had a high Agroindustrial waste content of linoleic acid (78.5 %, w/w), followed by that of oleic acid (13.8 %, w/w). The guava seed oil had Tropical fruit physicochemical properties comparable to those published in previous research, except for the low stability to Linolenic acid oxidation. The chromatographic profile of the phenolic and miscellaneous compounds was dominated by va- Vanillin Cinnamaldehyde nillin (9.6 ± 0.3 mg/100 g oil) and cinnamaldehyde (9.4 ± 0.2 mg/100 g oil), followed by vanillic acid (3.9 ± 0.4 mg/100 g oil), cinnamic acid (2.4 ± 0.1 mg/100 g oil), and minor amounts of other phenolic al- dehydes. Among the phytosterols and tocopherols, β-sitosterol (1048.9 ± 48.4 mg/100 g oil) and γ-tocopherol (82.6 ± 3.7 mg/100 g oil) were the most abundant. The low oxidative stability of the oil compared to that published in previous reports might reflect the high complexity of this matrix. This oil might have applications, directly or after blending with more stable edible oils. 1. Introduction coumaric acid/100 g oil), phytosterols (e.g., up to 437.6 mg β-sitos- terol/100 g oil), and tocopherols (e.g., up to 10.7 mg α-tocopherol/ Guava (Psidium guava) is a perennial tree native to South America, 100 g oil) (Da Silva and Jorge, 2014; Malacrida and Jorge, 2013; and its leaves, bark, and roots are used in traditional medicine Piombo et al., 2006). Furthermore, when the oil was extracted with (Barbalho et al., 2012). The fruit has considerable amounts of vitamin either organic solvents or supercritical CO2 (with ethanol as a co-sol- C, carotenoids, and phenolic compounds (Medina and Herrero, 2016). vent), polyunsaturated fatty acids were reported to account for at least The fruit is consumed fresh and used in the food industry to produce 52 % (w/w) of the total fatty acid profile (Arain et al., 2017; Castro- nectars, jams, jellies, and syrups. In the last ten years, Colombia has Vargas et al., 2011; Cerón et al., 2016; Da Silva and Jorge, 2014; Habib, produced more than 80,000 tons/year of guava fruit with nearly 1986; Iha et al., 2018; Malacrida and Jorge, 2013; Opute, 1978; Prasad 10,000 ha dedicated to this crop. As projected by the Colombian gov- and Azeemoddin, 1994). Concentrations of phenolic compounds, phy- ernment, in the near future, it will be necessary to produce tosterols, and tocopherols as well as those of polyunsaturated fatty acids 200,000 tons/year of guava fruit because of guava jelly production in guava seed oil are higher or comparable to those found in other fruit (Agronet, 2019). During guava fruit processing, seeds are a by-product seed oils, including those extracted from the seeds of the Isabela grape that account for up to 30 % (w/w) of the fruit weight (Iha et al., 2018), (Vitis labrusca L.), melon (Cucumis melo var. inodorus Naudin), passion representing an environmental and phytosanitary problem. Guava fruit (Passiflora edulis Sims), pumpkin (Cucurbita moschata), soursop seeds, however, have potential use as a source of edible oil and (Annona muricata L.), and tomato (Solanum lycopersicum)(Da Silva and bioactive compounds (Da Silva and Jorge, 2014). Jorge, 2014). The oil extracted from guava seeds with organic solvents contains Oil extraction by supercritical CO2 is considered to be fast and ef- bioactive compounds, including phenolic compounds (e.g., 4.8 mg p- ficient, with low or no use of organic solvents, yielding a product in ⁎ Corresponding author at: Departamento de Química, Universidad Nacional de Colombia, AA 14490 Bogotá, Colombia. E-mail address: [email protected] (C.-E. Narváez-Cuenca). https://doi.org/10.1016/j.jfca.2020.103467 Received 23 May 2019; Received in revised form 11 February 2020; Accepted 29 February 2020 Available online 02 March 2020 0889-1575/ © 2020 Elsevier Inc. All rights reserved. C.-E. Narváez-Cuenca, et al. Journal of Food Composition and Analysis 89 (2020) 103467 3 which degradation of components, such as fatty acids and bioactive 35.7 MPa (density of CO2: 895 kg/m ) at a constant flow of 30 g CO2/ compounds, is lower compared to that of other extraction techniques min for 150 min according to an optimization process extraction eval- (Sahena et al., 2009). Oil has been obtained from guava seeds by su- uated by Cerón et al. (2016). Extraction was performed in triplicate percritical CO2 extraction under different conditions of pressure and using three different samples. After supercritical CO2 extraction, an oil temperature to find the optimum extraction conditions, and its fatty was obtained (21.4 ± 0.3 g). The extracted oil was aliquoted into ∼2g acid profile was evaluated (Castro-Vargas et al., 2011; Cerón et al., aliquots in amber glass vials, flushed with N2 gas, and stored at -20 °C 2016). Because supercritical fluid extraction has been shown to have an until analyses were completed. important effect on the type and concentration of bioactive compounds present in an extract compared to that obtained by organic solvents, 2.4. Fatty acid composition of guava seed oil e.g., the Soxhlet method (Mezzomo et al., 2010), it was hypothesized that a different composition might be obtained when extracting oil from The fatty acid composition was evaluated after interesterification guava seeds by supercritical CO2 extraction. To the best of our knowl- with methanol under acidic conditions, and analysis of the fatty acid edge, nevertheless, no information on the composition of bio-active methyl esters was conducted with gas chromatography (GC) with a compounds, such as phenolic compounds, phytosterols, and toco- flame ionization detector (FID) as described elsewhere (Hurtado- pherols, in guava seed oil obtained by supercritical CO2 extraction is Benavides et al., 2016). Esterification with methanol was performed by available. The aim of this research was, therefore, to characterize an incubating 200 μL of oil with 5 mL of 5% (v/v) HCl in methanol at 50 °C edible oil obtained from guava seeds by supercritical CO2 extraction on for 8 h. Next, the fatty acid methyl esters were extracted twice with such features. 2mL n-hexane. Then, the n-hexane extract was analysed by GC-FID. A Shimadzu GC 17A version 3 instrument (Shimadzu, Kyoto, Japan) 2. Materials and methods equipped with a split/splitless injector, a DB-WAX column (30 m × 0.25 mm I.D., and 0.25 μm df, J&W Agilent Scientific, Folsom, 2.1. Plant material CA, USA), and a FID was used. The n-hexane extract (1 μL) was injected in split mode (split ratio 1:10) at 250 °C.