Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable Valorization
The olive oil industry generates large volumes of by-products, creating notable environmental and economic concerns. Among these, olive cake (OC)—a primary by-product of olive oil extraction—stands out due to its high content of bioactive compounds and potential for value-added recycling. This study...
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2024-11-01
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| Series: | Antioxidants |
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| author | Jessica Paié-Ribeiro Filipa Baptista Maria José Gomes Alfredo Teixeira Victor Pinheiro Divanildo Outor-Monteiro Ana Novo Barros |
| author_facet | Jessica Paié-Ribeiro Filipa Baptista Maria José Gomes Alfredo Teixeira Victor Pinheiro Divanildo Outor-Monteiro Ana Novo Barros |
| author_sort | Jessica Paié-Ribeiro |
| collection | DOAJ |
| description | The olive oil industry generates large volumes of by-products, creating notable environmental and economic concerns. Among these, olive cake (OC)—a primary by-product of olive oil extraction—stands out due to its high content of bioactive compounds and potential for value-added recycling. This study focused on characterizing six OC samples from the Trás-os-Montes and Alto Douro regions, collected at different processing times and mills. The samples included two derived from pressing (COC), two from two-phase centrifugation (TPOC; one partially pitted and one dehydrated), and two exhausted OC (EOC) samples. Fundamental analyses assessed total phenols, <i>ortho</i>-diphenols, flavonoids, antioxidant capacity, and tannin content. Results revealed significant variation (<i>p</i> < 0.05) in phenolic composition, namely <i>ortho</i>-diphenols and flavonoid levels among the samples. EOC 2 exhibited the highest concentrations (19.61, 21.82, and 20.12 mg CAT/g, respectively), while COC 2 had the lowest (5.08, 5.08, and 2.76 mg GA/g, respectively). This correlated with elevated antioxidant activity in EOC 2, as measured by FRAP, DPPH, and ABTS assays (129.98, 78.00, and 56.65 μmol Trolox/g). In contrast, COC 1 and COC 2 displayed the lowest antioxidant activities (32.61 μmol Trolox/g in FRAP and 17.24 and 18.98 μmol Trolox/g in DPPH). Tannin analysis showed the highest total tannin content in the dehydrated and pitted OC samples (250.31 and 240.89 mg CAT/100 g), with COC 2 showing the lowest (88.17 mg CAT/100 g). Condensed tannin content varied significantly, with EOC 2 presenting the highest level (328.17 mg CAT/100 g) and COC 2 the lowest one (20.56 mg CAT/100 g). Through HPLC-PDA-MS, 22 compounds were identified, with luteolin and verbascoside being particularly prevalent. This in-depth characterization supports the potential valorization of olive by-products, advancing sustainability and promoting a circular economy in the olive oil sector. |
| format | Article |
| id | doaj-art-c024d356e7e34808afdf8405f251979c |
| institution | DOAJ |
| issn | 2076-3921 |
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| series | Antioxidants |
| spelling | doaj-art-c024d356e7e34808afdf8405f251979c2025-08-20T02:53:34ZengMDPI AGAntioxidants2076-39212024-11-011312147010.3390/antiox13121470Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable ValorizationJessica Paié-Ribeiro0Filipa Baptista1Maria José Gomes2Alfredo Teixeira3Victor Pinheiro4Divanildo Outor-Monteiro5Ana Novo Barros6Animal Science Department, University of Trás-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, PortugalCentre for the Research and Technology of Agro-Environmental and Biological Sciences, CITAB, University de Trás-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, PortugalAnimal Science Department, University of Trás-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, PortugalMountain Research Center (CIMO), Polytechnic Instituto of Bragança, Campus de Santa Apolónia, 5300-253 Bragança, PortugalAnimal Science Department, University of Trás-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, PortugalAnimal Science Department, University of Trás-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, PortugalCentre for the Research and Technology of Agro-Environmental and Biological Sciences, CITAB, University de Trás-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, PortugalThe olive oil industry generates large volumes of by-products, creating notable environmental and economic concerns. Among these, olive cake (OC)—a primary by-product of olive oil extraction—stands out due to its high content of bioactive compounds and potential for value-added recycling. This study focused on characterizing six OC samples from the Trás-os-Montes and Alto Douro regions, collected at different processing times and mills. The samples included two derived from pressing (COC), two from two-phase centrifugation (TPOC; one partially pitted and one dehydrated), and two exhausted OC (EOC) samples. Fundamental analyses assessed total phenols, <i>ortho</i>-diphenols, flavonoids, antioxidant capacity, and tannin content. Results revealed significant variation (<i>p</i> < 0.05) in phenolic composition, namely <i>ortho</i>-diphenols and flavonoid levels among the samples. EOC 2 exhibited the highest concentrations (19.61, 21.82, and 20.12 mg CAT/g, respectively), while COC 2 had the lowest (5.08, 5.08, and 2.76 mg GA/g, respectively). This correlated with elevated antioxidant activity in EOC 2, as measured by FRAP, DPPH, and ABTS assays (129.98, 78.00, and 56.65 μmol Trolox/g). In contrast, COC 1 and COC 2 displayed the lowest antioxidant activities (32.61 μmol Trolox/g in FRAP and 17.24 and 18.98 μmol Trolox/g in DPPH). Tannin analysis showed the highest total tannin content in the dehydrated and pitted OC samples (250.31 and 240.89 mg CAT/100 g), with COC 2 showing the lowest (88.17 mg CAT/100 g). Condensed tannin content varied significantly, with EOC 2 presenting the highest level (328.17 mg CAT/100 g) and COC 2 the lowest one (20.56 mg CAT/100 g). Through HPLC-PDA-MS, 22 compounds were identified, with luteolin and verbascoside being particularly prevalent. This in-depth characterization supports the potential valorization of olive by-products, advancing sustainability and promoting a circular economy in the olive oil sector.https://www.mdpi.com/2076-3921/13/12/1470olive cakefood waste valorizationbioactive compoundsantioxidant capacitynutraceuticals |
| spellingShingle | Jessica Paié-Ribeiro Filipa Baptista Maria José Gomes Alfredo Teixeira Victor Pinheiro Divanildo Outor-Monteiro Ana Novo Barros Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable Valorization Antioxidants olive cake food waste valorization bioactive compounds antioxidant capacity nutraceuticals |
| title | Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable Valorization |
| title_full | Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable Valorization |
| title_fullStr | Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable Valorization |
| title_full_unstemmed | Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable Valorization |
| title_short | Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable Valorization |
| title_sort | exploring the variability in phenolic compounds and antioxidant capacity in olive oil by products a path to sustainable valorization |
| topic | olive cake food waste valorization bioactive compounds antioxidant capacity nutraceuticals |
| url | https://www.mdpi.com/2076-3921/13/12/1470 |
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