Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves
The effect of freeze-drying and gamma irradiation at 0.5, 1, and 2 kGy on the physicochemical composition (moisture, fat, ash, mineral, and chlorophyll contents), microstructure, total phenolic content, and antioxidant capacity of stevia leaves was investigated in the present study. The results obta...
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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | Journal of Food Quality |
| Online Access: | http://dx.doi.org/10.1155/2021/5378157 |
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| author | Nadia Hidar Abdelhamid Noufid Ayoub Mourjan El Mustapha El Adnany Safa Mghazli Mohammed Mouhib Abderrahim Jaouad Mostafa Mahrouz |
| author_facet | Nadia Hidar Abdelhamid Noufid Ayoub Mourjan El Mustapha El Adnany Safa Mghazli Mohammed Mouhib Abderrahim Jaouad Mostafa Mahrouz |
| author_sort | Nadia Hidar |
| collection | DOAJ |
| description | The effect of freeze-drying and gamma irradiation at 0.5, 1, and 2 kGy on the physicochemical composition (moisture, fat, ash, mineral, and chlorophyll contents), microstructure, total phenolic content, and antioxidant capacity of stevia leaves was investigated in the present study. The results obtained indicated that freeze-drying and gamma irradiation treatments caused significant reduction (p ≤ 0.05) of moisture and fat contents in comparison with those of commercial leaves, while ash content was not significantly affected. Mineral composition was analysed. Among the analysed elements, potassium and iron levels were higher in the freeze-dried and irradiated samples, respectively. The microstructure was analysed using a scanning electron microscope. Micrographs revealed that a higher porous size structure was obtained by freeze-drying, and degradation of cell wall structure was more clearly visualized by irradiation at 2 kGy. However, the main functional groups were stable as confirmed by Fourier transform infrared spectroscopy analysis. The effects on chlorophyll content, phenolic profile, and antioxidant properties were evaluated before and after ten months of storage. In terms of chlorophyll contents, the freeze-dried leaves exhibited the highest content. Chlorophylls a and b decreased when storage progressed for freeze-dried leaves as well as for gamma-irradiated leaves. Both preservation methods gave significant advantages in increasing the total phenolic content and DPPH scavenging activity. Moreover, a significant increase of bioactive compounds and antioxidant activity was observed as the gamma irradiation dose increased. In addition, the storage time increased the amounts of polyphenols and DPPH scavenging activity. After 10 months of storage, gamma-irradiated leaves had the highest total phenolic content as well as the DPPH scavenging activity followed by freeze-dried leaves. The results indicate that freeze-drying and gamma irradiation at the studied doses could be effective postharvest methods for preservation of stevia leaf quality. |
| format | Article |
| id | doaj-art-ea29ab0968064f8f90503108a2b1497e |
| institution | Kabale University |
| issn | 1745-4557 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Journal of Food Quality |
| spelling | doaj-art-ea29ab0968064f8f90503108a2b1497e2025-02-03T06:00:50ZengWileyJournal of Food Quality1745-45572021-01-01202110.1155/2021/5378157Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia LeavesNadia Hidar0Abdelhamid Noufid1Ayoub Mourjan2El Mustapha El Adnany3Safa Mghazli4Mohammed Mouhib5Abderrahim Jaouad6Mostafa Mahrouz7SCIMATOP (LICVEDD) Laboratory of Innovation and Sustainable Development & Expertise in Green ChemistryDepartment of Civil EngineeringLaboratory of Valorization and Safety of Food ProductsSCIMATOP (LICVEDD) Laboratory of Innovation and Sustainable Development & Expertise in Green ChemistryLaboratoire des Bioressources et Sécurité Sanitaire des AlimentsUnité de Recherche sur Les Techniques Nucléaires de L’Environnement et La Qualité (URTNEQ)SCIMATOP (LICVEDD) Laboratory of Innovation and Sustainable Development & Expertise in Green ChemistrySCIMATOP (LICVEDD) Laboratory of Innovation and Sustainable Development & Expertise in Green ChemistryThe effect of freeze-drying and gamma irradiation at 0.5, 1, and 2 kGy on the physicochemical composition (moisture, fat, ash, mineral, and chlorophyll contents), microstructure, total phenolic content, and antioxidant capacity of stevia leaves was investigated in the present study. The results obtained indicated that freeze-drying and gamma irradiation treatments caused significant reduction (p ≤ 0.05) of moisture and fat contents in comparison with those of commercial leaves, while ash content was not significantly affected. Mineral composition was analysed. Among the analysed elements, potassium and iron levels were higher in the freeze-dried and irradiated samples, respectively. The microstructure was analysed using a scanning electron microscope. Micrographs revealed that a higher porous size structure was obtained by freeze-drying, and degradation of cell wall structure was more clearly visualized by irradiation at 2 kGy. However, the main functional groups were stable as confirmed by Fourier transform infrared spectroscopy analysis. The effects on chlorophyll content, phenolic profile, and antioxidant properties were evaluated before and after ten months of storage. In terms of chlorophyll contents, the freeze-dried leaves exhibited the highest content. Chlorophylls a and b decreased when storage progressed for freeze-dried leaves as well as for gamma-irradiated leaves. Both preservation methods gave significant advantages in increasing the total phenolic content and DPPH scavenging activity. Moreover, a significant increase of bioactive compounds and antioxidant activity was observed as the gamma irradiation dose increased. In addition, the storage time increased the amounts of polyphenols and DPPH scavenging activity. After 10 months of storage, gamma-irradiated leaves had the highest total phenolic content as well as the DPPH scavenging activity followed by freeze-dried leaves. The results indicate that freeze-drying and gamma irradiation at the studied doses could be effective postharvest methods for preservation of stevia leaf quality.http://dx.doi.org/10.1155/2021/5378157 |
| spellingShingle | Nadia Hidar Abdelhamid Noufid Ayoub Mourjan El Mustapha El Adnany Safa Mghazli Mohammed Mouhib Abderrahim Jaouad Mostafa Mahrouz Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves Journal of Food Quality |
| title | Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves |
| title_full | Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves |
| title_fullStr | Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves |
| title_full_unstemmed | Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves |
| title_short | Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves |
| title_sort | effect of preservation methods on physicochemical quality phenolic content and antioxidant activity of stevia leaves |
| url | http://dx.doi.org/10.1155/2021/5378157 |
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