Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity
Every year great amounts of high-quality wine grapes are left on the vine unpicked, and consequently lost, to control the overproduction in wine areas with limited appellation production yield. In the context of circular bioeconomy, the valorization of these grapes as a potential source of natural a...
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MDPI AG
2022-03-01
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| Online Access: | https://www.mdpi.com/2079-9276/11/3/33 |
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| author | Edurne Elejalde María Carmen Villarán Iratxe Lopez-de-Armentia Daniel Ramón Raquel Murillo Rosa María Alonso |
| author_facet | Edurne Elejalde María Carmen Villarán Iratxe Lopez-de-Armentia Daniel Ramón Raquel Murillo Rosa María Alonso |
| author_sort | Edurne Elejalde |
| collection | DOAJ |
| description | Every year great amounts of high-quality wine grapes are left on the vine unpicked, and consequently lost, to control the overproduction in wine areas with limited appellation production yield. In the context of circular bioeconomy, the valorization of these grapes as a potential source of natural antioxidants is of great interest. The study carried out is focused on the polyphenolic profile characterization of different unpicked grape varieties using the ultrasound-assisted extraction technique to extract the polyphenolic fractions. Moreover, the evaluation of the antioxidant capacity by several assays was carried out: oxygen radical absorbance capacity (ORAC), stability of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing antioxidant capacity (FRAP), cupric reducing antioxidant capacity (CUPRAC) and stability of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) assays. The results showed a strong relationship between total phenolic content and hydroxycinnamic acids (R<sup>2</sup> = 0.9088) followed by flavan-3-ols (R<sup>2</sup> = 0.8792) and tannins (R<sup>2</sup> = 0.7705). The antioxidant capacity of the grapes was dependent on the total phenolic content. These results supply new information for a better understanding of the importance of giving an added value to the unpicked grapes due to their high content of polyphenols. These findings help the wine sector to consider the valorization of the unpicked grapes, classified as wastes, as an interesting source of natural antioxidants to be used as food supplements and with potential applications in the pharmaceutical industry. |
| first_indexed | 2024-03-09T12:44:11Z |
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| issn | 2079-9276 |
| language | English |
| last_indexed | 2024-03-09T12:44:11Z |
| publishDate | 2022-03-01 |
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| series | Resources |
| spelling | doaj.art-b7fa1faf066a461b80d1b156e7654cae2023-11-30T22:14:42ZengMDPI AGResources2079-92762022-03-011133310.3390/resources11030033Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant CapacityEdurne Elejalde0María Carmen Villarán1Iratxe Lopez-de-Armentia2Daniel Ramón3Raquel Murillo4Rosa María Alonso5TECNALIA, Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Álava, c/Leonardo Da Vinci 11, 01510 Miñano, Álava, SpainTECNALIA, Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Álava, c/Leonardo Da Vinci 11, 01510 Miñano, Álava, SpainTECNALIA, Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Álava, c/Leonardo Da Vinci 11, 01510 Miñano, Álava, SpainTECNALIA, Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Álava, c/Leonardo Da Vinci 11, 01510 Miñano, Álava, SpainTECNALIA, Basque Research and Technology Alliance (BRTA), Parque Tecnológico de Álava, c/Leonardo Da Vinci 11, 01510 Miñano, Álava, SpainAnalytical Chemistry Department, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Vizcaya, SpainEvery year great amounts of high-quality wine grapes are left on the vine unpicked, and consequently lost, to control the overproduction in wine areas with limited appellation production yield. In the context of circular bioeconomy, the valorization of these grapes as a potential source of natural antioxidants is of great interest. The study carried out is focused on the polyphenolic profile characterization of different unpicked grape varieties using the ultrasound-assisted extraction technique to extract the polyphenolic fractions. Moreover, the evaluation of the antioxidant capacity by several assays was carried out: oxygen radical absorbance capacity (ORAC), stability of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), ferric reducing antioxidant capacity (FRAP), cupric reducing antioxidant capacity (CUPRAC) and stability of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) assays. The results showed a strong relationship between total phenolic content and hydroxycinnamic acids (R<sup>2</sup> = 0.9088) followed by flavan-3-ols (R<sup>2</sup> = 0.8792) and tannins (R<sup>2</sup> = 0.7705). The antioxidant capacity of the grapes was dependent on the total phenolic content. These results supply new information for a better understanding of the importance of giving an added value to the unpicked grapes due to their high content of polyphenols. These findings help the wine sector to consider the valorization of the unpicked grapes, classified as wastes, as an interesting source of natural antioxidants to be used as food supplements and with potential applications in the pharmaceutical industry.https://www.mdpi.com/2079-9276/11/3/33unpicked grapepolyphenolsantioxidant capacityultrasound-assisted extractiongrape valorization |
| spellingShingle | Edurne Elejalde María Carmen Villarán Iratxe Lopez-de-Armentia Daniel Ramón Raquel Murillo Rosa María Alonso Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity Resources unpicked grape polyphenols antioxidant capacity ultrasound-assisted extraction grape valorization |
| title | Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity |
| title_full | Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity |
| title_fullStr | Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity |
| title_full_unstemmed | Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity |
| title_short | Study of Unpicked Grapes Valorization: A Natural Source of Polyphenolic Compounds and Evaluation of Their Antioxidant Capacity |
| title_sort | study of unpicked grapes valorization a natural source of polyphenolic compounds and evaluation of their antioxidant capacity |
| topic | unpicked grape polyphenols antioxidant capacity ultrasound-assisted extraction grape valorization |
| url | https://www.mdpi.com/2079-9276/11/3/33 |
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