Experimental and modeling study of polyphenols in Olea europaea leaves through ultrasound-assisted extraction

Abstract

Olive tree (Olea europaea) leaves were extracted by ultrasound-assisted extraction (UAE). The attention was focused on the yield of extract and its polyphenols, and extraction kinetics to contribute to the application of the extraction process industrially. Samples were extracted with water, ethanol, methanol, and their aqueous solutions (50%, v/v) under temperature values ranging from 30 to 50 °C. Additionally, the temperature interval changed between 30 and 80 °C, when water was used as solvent. Backing the solvents with water enhanced the polyphenolic yield. Total phenolic content (TPC) from water extracts decreased after a certain temperature point, as a result of degradation problems. The second-order model was followed for characterizing the kinetic of the UAE process of TPC from olive leaves under various solvents and temperatures. Major phenolic component was also quantified for each solvent system  by means of High Performance Liquid Chromatography (HPLC).

Keywords

• Agroindustrial byproducts; Mathematical model; Olive leaves; Polyphenols extraction.

References

1. 1. Brahmi F, Mechri B, Dhibi M, Hammami M. Variations in phenolic compounds and antiradical scavenging activity of Olea europaea leaves and fruits extracts collected in two different seasons. Industrial Crops and Products. 2013; 49: 256–264.
2. 2. Salido S, Pérez-Bonilla M, Adams RP, Altarejos J. Phenolic Components and Antioxidant Activity of Wood Extracts from 10 Main Spanish Olive Cultivars. Journal of Agricultural and Food Chemistry. 2015; 63: 6493–6500.
3. 3. Talhaoui N, Taamalli A, Gómez-Caravaca AM, Fernández-Gutiérrez A, Segura-Carretero A. Phenolic compounds in olive leaves: Analytical determination, biotic and abiotic influence, and health benefits. Food Research Interntional. 2015; 77: 92–108.
4. 4. Elhussein EAA, Şahin S. Drying behaviour, effective diffusivity and energy of activation of olive leaves dried by microwave, vacuum and oven drying methods. Heat and Mass Transfer. 2018; 54: 1901–1911.
5. 5. Şahin S, Samli R, Tan ASB, Barba FJ, Chemat F, Cravotto G, Lorenzo JM. Solvent-Free Microwave-Assisted Extraction of Polyphenols from Olive Tree Leaves: Antioxidant and Antimicrobial Properties. Molecules. 2017; 22: 1056.
6. 6. Bouaziz M, Sayadi S. Isolation and evaluation of antioxidants from leaves of a Tunisian cultivar olive tree. European Journal of Lipid Science and Technology. 2005; 107: 497–504.
7. 7. Şahin S, Bilgin M. Olive tree ( Olea europaea L.) leaf as a waste by-product of table olive and olive oil industry: a review. Journal of the Science of Food and Agriculture. 2018; 98: 1271–1279.
8. 9. Şahin S, Elhussein E, Bilgin M, Lorenzo JM, Barba FJ, Roohinejad S. Effect of drying method on oleuropein, total phenolic content, flavonoid content, and antioxidant activity of olive ( Olea europaea ) leaf. Journal of Food Processing and Preservation. 2018; 42: e13604.

9. 10. Şahin S, Sayım E, Bilgin M. Effect of olive leaf extract rich in oleuropein on the quality of virgin olive oil. Journal of Food Science and Technology. 2017; 54: 1721–1728.
10. 11. Bilgin M, Şahin S. Effects of geographical origin and extraction methods on total phenolic yield of olive tree (Olea europaea) leaves. Journal of the Taiwan Instute of Chemical Engineers. 2013; 44: 8–12.
11. 12. Soria AC, Villamiel M. Effect of ultrasound on the technological properties and bioactivity of food: a review. Trends in Food Science and Technology. 2010; 21: 323–331.
12. 13. Novak I, Janeiro P, Seruga M, Oliveira-Brett AM. Ultrasound extracted flavonoids from four varieties of Portuguese red grape skins determined by reverse-phase high-performance liquid chromatography with electrochemical detection. Analaytica Chimica Acta. 2008; 630: 107-115.
13. 14. Joana Gil-Chávez G, Villa JA, Fernando Ayala-Zavala J, Basilio Heredia J, Sepulveda D, Yahia EM, González-Aguilar GA. Technologies for Extraction and Production of Bioactive Compounds to be Used as Nutraceuticals and Food Ingredients: An Overview. Comprehensive Reviews in Food Science and Food Safety. 2013; 12: 5–23.
14. 15. Wang L, Weller CL. Recent advances in extraction of nutra- ceuticals from plants. Trends in Food Science and Technology. 2006;17: 300–312.
15. 16. Esclapez MD, García-Pérez JV, Mulet A, Cárcel JA. Ultrasound-Assisted Extraction of Natural Products. Food Engineering Reviews. 2011; 3: 108–120.
16. 17. Leighton TG. What is ultrasound? Progress in biophysics and molecular biology. 2007; 93: 3–83.
17. 18. Şahin S, Saeed N, Malik A, Perez JL, Brockington JE. Seasonal Changes of Individual Phenolic Compounds in Leaves of Twenty Olive Cultivars Grown in Texas. Journal of Agricultural Science and Technology B. 2012; 2: 242–247.
18. 19. Malik NSA, Bradford JM. Changes in oleuropein levels during differentiation and development of floral buds in “Arbequina” olives. Scientia Horticulturae. 2006; 110: 274–278.
19. 20. Şahin S, Şaml R. Optimization of olive leaf extract obtained by ultrasound-assisted extraction with response surface methodology. Ultrasonic Sonochemistry. 2013; 20: 595–602.
20. 21. Lang Q, Wai CM. Supercritical fluid extraction in herbal and natural product studies — a practical review. Talanta, 2001; 53: 771–782.
21. 22. Spigno G, De Faveri DM. Microwave-assisted extraction of tea phenols: A phenomenological study. Journal of Food Engineering. 2009; 93: 210–217.
22. 23. Co M, Zettersten C, Nyholm L, Sjöberg PJR, Turner C. Degradation effects in the extraction of antioxidants from birch bark using water at elevated temperature and pressure. Analytica Chimica Acta. 2012; 716: 40–48.
23. 24. Alañón ME, Ivanović M, Gómez-Caravaca AM, Arráez-Román D, Segura-Carretero A. Choline chloride derivative-based deep eutectic liquids as novel green alternative solvents for extraction of phenolic compounds from olive leaf. Arabian Journal of Chemistry. 2018; in press, doi:10.1016/J.ARABJC.2018.01.003.