Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree Materials
Olive tree vegetal materials are considered a powerful source for the isolation of bioactive compounds—mainly phenols and triterpenic acids. However, the high humidity content of them reduces their preservation and extractability to a liquid solvent. Accordingly, a drying step is crucial to homogeni...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-07-01
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| Series: | Foods |
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| Online Access: | https://www.mdpi.com/2304-8158/12/14/2684 |
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| author | Ana Castillo-Luna Hristofor Miho Carlos A. Ledesma-Escobar Feliciano Priego-Capote |
| author_facet | Ana Castillo-Luna Hristofor Miho Carlos A. Ledesma-Escobar Feliciano Priego-Capote |
| author_sort | Ana Castillo-Luna |
| collection | DOAJ |
| description | Olive tree vegetal materials are considered a powerful source for the isolation of bioactive compounds—mainly phenols and triterpenic acids. However, the high humidity content of them reduces their preservation and extractability to a liquid solvent. Accordingly, a drying step is crucial to homogenize the material and to obtain an efficient extraction. We studied the influence of the drying process on the extraction efficiency of bioactive compounds from olive vegetal material. For this purpose, we evaluated the effects of four drying processes on the solid–liquid extraction of bioactive compounds from two by-products, olive leaves and pomace, and olive fruits harvested from two cultivars, Alfafara and Koroneiki. Infrared-assisted drying (IAD) was the most suited approach to obtain extracts enriched in oleuropein from leaves (28.5 and 22.2% dry weight in Alfafara and Koroneiki, respectively). In the case of pomace, lyophilization and microwave-assisted drying led to extracts concentrated in oleacein and oleuropein aglycone, whereas IAD and oven-drying led to extracts with enhanced contents of hydroxytyrosol glucoside and hydroxytyrosol, respectively. The drying process considerably affected the chemical composition of extracts obtained from fruits. Changes in the composition of the extracts were explained essentially by the drying process conditions using auxiliary energies, temperature, and time, which promoted chemical alterations and increased the extractability of the compounds. Therefore, the drying protocol should be selected depending on the phenolic content and initial raw material. |
| first_indexed | 2024-03-11T01:05:17Z |
| format | Article |
| id | doaj.art-fe50974c279c4c0e87c636b5f39c94ac |
| institution | Directory Open Access Journal |
| issn | 2304-8158 |
| language | English |
| last_indexed | 2024-03-11T01:05:17Z |
| publishDate | 2023-07-01 |
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| record_format | Article |
| series | Foods |
| spelling | doaj.art-fe50974c279c4c0e87c636b5f39c94ac2023-11-18T19:19:50ZengMDPI AGFoods2304-81582023-07-011214268410.3390/foods12142684Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree MaterialsAna Castillo-Luna0Hristofor Miho1Carlos A. Ledesma-Escobar2Feliciano Priego-Capote3Department of Analytical Chemistry, Campus of Rabanales, University of Córdoba, 14014 Córdoba, SpainDepartment of Agronomy, Maria de Maeztu Unit of Excellence, Campus of Rabanales, University of Cordoba, 14014 Córdoba, SpainDepartment of Analytical Chemistry, Campus of Rabanales, University of Córdoba, 14014 Córdoba, SpainDepartment of Analytical Chemistry, Campus of Rabanales, University of Córdoba, 14014 Córdoba, SpainOlive tree vegetal materials are considered a powerful source for the isolation of bioactive compounds—mainly phenols and triterpenic acids. However, the high humidity content of them reduces their preservation and extractability to a liquid solvent. Accordingly, a drying step is crucial to homogenize the material and to obtain an efficient extraction. We studied the influence of the drying process on the extraction efficiency of bioactive compounds from olive vegetal material. For this purpose, we evaluated the effects of four drying processes on the solid–liquid extraction of bioactive compounds from two by-products, olive leaves and pomace, and olive fruits harvested from two cultivars, Alfafara and Koroneiki. Infrared-assisted drying (IAD) was the most suited approach to obtain extracts enriched in oleuropein from leaves (28.5 and 22.2% dry weight in Alfafara and Koroneiki, respectively). In the case of pomace, lyophilization and microwave-assisted drying led to extracts concentrated in oleacein and oleuropein aglycone, whereas IAD and oven-drying led to extracts with enhanced contents of hydroxytyrosol glucoside and hydroxytyrosol, respectively. The drying process considerably affected the chemical composition of extracts obtained from fruits. Changes in the composition of the extracts were explained essentially by the drying process conditions using auxiliary energies, temperature, and time, which promoted chemical alterations and increased the extractability of the compounds. Therefore, the drying protocol should be selected depending on the phenolic content and initial raw material.https://www.mdpi.com/2304-8158/12/14/2684phenolstriterpenesdryinginfraredmicrowaveslyophilization |
| spellingShingle | Ana Castillo-Luna Hristofor Miho Carlos A. Ledesma-Escobar Feliciano Priego-Capote Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree Materials Foods phenols triterpenes drying infrared microwaves lyophilization |
| title | Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree Materials |
| title_full | Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree Materials |
| title_fullStr | Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree Materials |
| title_full_unstemmed | Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree Materials |
| title_short | Comparison of Drying Techniques for Extraction of Bioactive Compounds from Olive-Tree Materials |
| title_sort | comparison of drying techniques for extraction of bioactive compounds from olive tree materials |
| topic | phenols triterpenes drying infrared microwaves lyophilization |
| url | https://www.mdpi.com/2304-8158/12/14/2684 |
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