Supercritical CO2 extraction of uxi (Endopleura uchi) oil: Global yield isotherms, fatty acid profile, functional quality and thermal stability

https://doi.org/10.1016/j.supflu.2020.104932Get rights and content

Highlights

  • Uxi (Endopleura uchi) is a native species from the Amazon region.

  • The fruits have potential for edible vegetable oil production, due to their chemical composition.

  • Uxi oil was obtained with high yields at temperatures of 40 and 60 °C and pressures of 300 and 400 bar.

  • The functional quality indices express that uxi oil can be consumed in the human diet as table oil, similarly to olive oil.

Abstract

In this research, uxi (Endopleura uchi) oil was obtained via supercritical CO2 extraction in order to promote the valorization of the species in the industrial scenario, showing the potential of its oil as a functional food. The oil was extracted at temperatures of 40 and 60 °C and pressures of 200−400 bar. The highest yield was obtained at 60 °C / 400 bar (24.48 ± 0.20 %) in db. The oil showed a composition with predominance of oleic acid (n-9), as well as a stable thermal behavior up to 300 °C. The uxi oil obtained via supercritical CO2 is presented as a potential product for the food industry due to its good functional quality.

Introduction

Uxi (Endopleura uchi) is a native species from the Amazon region, and its fruits are widely consumed by the local population [[1], [2], [3]]. Uxi wood is commercially desirable by the civil construction industry (manufacture of posts and beams), which contributes to the indiscriminate extraction of its species' trees, causing deforestation in the Amazon region [4]. The fruits have potential for edible vegetable oil production, due to their chemical composition [5]. The study by Berto et al. [6] showed that the lipid fraction of the uxi fruit contains a predominance of unsaturated fatty acids. Other characteristic compounds in the uxi oil include phytosterols, tocopherols and carotenoids [[7], [8], [9]]. The phytochemical profile of the species also indicates the presence of bergenin in the bark of its trunk [10].

Unsaturated fatty acids are structural components of cell membranes, incorporated into phospholipids, which regulate the fluidity and function of the membrane, in addition to having the role of metabolites precursors with biological properties of interest. A major effect attributed to linoleic acid (n-6) is the decrease in cholesterol levels in the blood, due to the reduction in the levels of low-density plasma lipoproteins, contributing to the prevention of cardiovascular diseases [11]. The benefits of linoleic acid (n-6) include the reduction of atherosclerosis, carcinogenesis, obesity, diabetes and inflammatory processes [12].

Obtaining high quality lipid products depends on factors related to the extraction process, such as temperature, nature of the solvent, solvent/raw material ratio, extraction period, atmospheric composition and preparation of the raw material. The compounds degradation can be accelerated by the mechanical pressing system, while the use of organic solvents can increase the oils toxicity. Conventional methods, although allowing high yields, are lengthy, exposing raw materials to hydrolytic and oxidative rancidity processes, contributing to the loss of the quality of the final product [13,14].

Considering this scenario, the application of supercritical fluid turn out to be an alternative to obtain high quality vegetable oil, preserving the nature of the characteristic compounds, as in the case of unsaturated fatty acids and other substances of interest (bioactive compounds). Extraction with supercritical CO2 is considered to be a green technique, environmentally friendly, due to the characteristics of the used solvent, especially because it is non-corrosive, non-toxic, non-flammable, presents low cost and easy removal of the extracted product, besides allowing high profitability in mass and shorter process time [15,16].

In this context, extraction with supercritical CO2 represents an important tool to replace conventional methods, and it can be applied for the production of uxi oil. This proposal allows the development of a new product and the valorization of the species, especially in terms of environmental preservation. In this research, uxi (Endopleura uchi) oil was obtained via supercritical CO2 extraction in order to promote the valorization of the species in the industrial scenario, showing the potential of its oil as a functional food.

Section snippets

Uxi samples

The uxi fruits were collected in the municipality of Bujaru, Pará, Brazil (-01°64′09″S, -48°02′73″W), in March 2018. After 48 h of ripening, the material was transported to the Extraction Laboratory of the Federal University of Pará, where manual pulping was performed. The pulp was frozen in an ultra-freezer at −80 °C for 24 h. Dehydration was carried out in a freeze dryer (Alpha, 2–4 LD Plus, Germany) for 72 h. The dehydrated pulp was crushed in a processor (Croydon, LR03, Brazil) and stored

Freeze-dried uxi pulp characteristics

The real density of the uxi pulp was 1200 ± 10 kg/m3, while the apparent density was equal to 504.48 ± 9.36 kg/m3. The bed porosity was 0.58 ± 0.01. The average diameter of the pulp particles was 0.82 ± 0.02 mm. The centesimal composition of the dehydrated uxi pulp showed moisture equal to 6.96 ± 0.02 %; ash content of 1.49 ± 0.01 %; lipid content equal to 25.61 ± 0.02 %; protein content of 3.87 ± 0.05 % and total carbohydrates of 62.07 %.

Global yield

The extraction performance and global yields of uxi oil

Conclusion

The process parameters analyzed in this study showed that the density of supercritical CO2 was the main factor to obtain high mass yield of uxi oil, with the use of temperature close to the CO2 critical point, which contributed to the quality of the obtained product. The fatty acids and triglycerides profiles (by prediction) and the thermogravimetric study showed that uxi oil has interesting functional quality due to the majority composition of unsaturated fatty acids that can be used to

Acknowledgements

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001.

References (47)

  • V.M.B. Cunha et al.

    Bacaba-de-leque (Oenocarpus distichus Mart.) oil extraction using supercritical CO2 and bioactive compounds determination in the residual pulp

    J. Supercrit. Fluids

    (2019)
  • M.E. Araújo et al.

    Improving phase equilibrium calculation with the Peng-Robinson EOS for fats and oils related compounds/supercritical CO2 systems

    Fluid Phase Equilib.

    (2000)
  • I. Ashour et al.

    Modified carnahan-starling-soave equation for the calculation of vapor pressures for saturated fatty acids

    J. Supercrit. Fluids

    (1989)
  • W. Wagner

    New vapour pressure measurements for argon and nitrogen and a new method for establishing rational vapour pressure equations

    Cryogenics (Guildf).

    (1973)
  • C.H. Tu

    Group-contribution method for the estimation of vapor pressures

    Fluid Phase Equilib.

    (1994)
  • M. Zou et al.

    Fluid-Liquid phase equilibria of fatty acids and fatty acid methyl esters in supercritical carbon dioxide

    J. Supercrit. Fluids

    (1990)
  • T.L.V. Ulbricht et al.

    Coronary heart disease: seven dietary factors

    Lancet.

    (1991)
  • J. Santos-Silva et al.

    Effect of genotype, feeding system and slaughter weight on the quality of light lambs. II. Fatty acid composition of meat

    Livest. Prod. Sci.

    (2002)
  • M.P. Silva et al.

    Supercritical CO2 extraction of lyophilized Açaí (Euterpe oleracea Mart.) pulp oil from three municipalities in the state of Pará, Brazil

    J. CO2 Util.

    (2019)
  • X. Palomer et al.

    Palmitic and Oleic Acid: The Yin and Yang of Fatty Acids in Type 2 Diabetes Mellitus

    Trends Endocrinol. Metab.

    (2018)
  • K.H. Zirnheld et al.

    Dietary fatty acids and bioactive fatty acid metabolites in alcoholic liver disease

    Liver Res.

    (2019)
  • M.A. Belury et al.

    Linoleic acid, glycemic control and Type 2 diabetes, Prostaglandins Leukot

    Essent. Fat. Acids.

    (2018)
  • D. Ollivier et al.

    Differentiation of French virgin olive oil RDOs by sensory characteristics, fatty acid and triacylglycerol compositions and chemometrics

    Food Chem.

    (2006)
  • Cited by (0)

    View full text