Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts
It is expected that any processing and handling of lees (e.g., drying, storage or removal of residual alcohol using various concentration techniques) will expose the material to oxidation and the consequences of oxidation on the biological activity of the lees and the lees extracts are unknown. The...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-04-01
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| Series: | Antioxidants |
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| Online Access: | https://www.mdpi.com/2076-3921/12/4/931 |
| _version_ | 1797606622469554176 |
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| author | Zhijing Ye Jinlin Shi Roland Harrison Richard Hider Alaa El-Din A. Bekhit |
| author_facet | Zhijing Ye Jinlin Shi Roland Harrison Richard Hider Alaa El-Din A. Bekhit |
| author_sort | Zhijing Ye |
| collection | DOAJ |
| description | It is expected that any processing and handling of lees (e.g., drying, storage or removal of residual alcohol using various concentration techniques) will expose the material to oxidation and the consequences of oxidation on the biological activity of the lees and the lees extracts are unknown. The effects of oxidation (using horseradish peroxidase and hydrogen peroxide model system) on phenolic composition and their antioxidant and antimicrobial activities were investigated in (i) a flavonoid model system composed of catechin and grape seed tannin (Cat:GST) extracts at various ratios and (ii) in Pinot noir (PN) and Riesling (RL) wine lees samples. For the flavonoid model, oxidation had a minor or no impact on total phenol content but increased (<i>p</i> < 0.05) total tannin content from approximately 145 to 1200 µg epicatechin equivalent/mL. An opposite observation was found in the PN lees samples where oxidation reduced (<i>p</i> < 0.05) the total phenol content (TPC) by approximately 10 mg GAE/g dry matter (DM) lees. The mean degree of the polymerization (mDP) values of the oxidized flavonoid model samples ranged from 15 to 30. The Cat:GST ratio and interaction of the Cat:GST ratio with oxidation were found significantly to affect the mDP values of the flavonoid model samples (<i>p</i> < 0.05). Oxidation increased the mDP values in all oxidized flavonoid model samples except for Cat:GST 0:100. The mDP values of the PN lees samples ranged from 7 to 11 and remained the same after oxidation. There was no significant reduction in the antioxidant activities (DPPH and ORAC) of the model and wine lees after oxidation except the PN1 lees sample (decreased from 3.5 to 2.8 mg Trolox equivalent/g DM extracts). In addition, no correlation was observed between mDP (approximately 10 to 30) and DPPH (0.09) and ORAC assay (−0.22), which indicates that the higher mDP resulted in a poor ability to scavenge DPPH· and AAPH· free radicals. Antimicrobial activities of the flavonoid model were found to be improved after the oxidation treatment against <i>S. aureus</i> and <i>E. coli</i> with minimum inhibition concentration (MIC) of 1.56 and 0.39 mg/mL. This may indicate that new compounds were formed during the oxidation treatment, and these compounds showed more effective microbicidal activity. LC-MS work is required in the future to identify the compounds that are newly formed during the oxidation of the lees. |
| first_indexed | 2024-03-11T05:17:49Z |
| format | Article |
| id | doaj.art-44fca2ef79e8433787cc8116bf720546 |
| institution | Directory Open Access Journal |
| issn | 2076-3921 |
| language | English |
| last_indexed | 2024-03-11T05:17:49Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Antioxidants |
| spelling | doaj.art-44fca2ef79e8433787cc8116bf7205462023-11-17T18:06:26ZengMDPI AGAntioxidants2076-39212023-04-0112493110.3390/antiox12040931Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees ExtractsZhijing Ye0Jinlin Shi1Roland Harrison2Richard Hider3Alaa El-Din A. Bekhit4School of Viticulture and Wine Science, Te Pūkenga, Trading as Eastern Institute of Technology, Napier 4112, New ZealandSchool of Viticulture and Wine Science, Te Pūkenga, Trading as Eastern Institute of Technology, Napier 4112, New ZealandDepartment of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln 7647, New ZealandDepartment of Wine, Food and Molecular Biosciences, Lincoln University, Lincoln 7647, New ZealandDepartment of Food Science, The University of Otago, Dunedin 9054, New ZealandIt is expected that any processing and handling of lees (e.g., drying, storage or removal of residual alcohol using various concentration techniques) will expose the material to oxidation and the consequences of oxidation on the biological activity of the lees and the lees extracts are unknown. The effects of oxidation (using horseradish peroxidase and hydrogen peroxide model system) on phenolic composition and their antioxidant and antimicrobial activities were investigated in (i) a flavonoid model system composed of catechin and grape seed tannin (Cat:GST) extracts at various ratios and (ii) in Pinot noir (PN) and Riesling (RL) wine lees samples. For the flavonoid model, oxidation had a minor or no impact on total phenol content but increased (<i>p</i> < 0.05) total tannin content from approximately 145 to 1200 µg epicatechin equivalent/mL. An opposite observation was found in the PN lees samples where oxidation reduced (<i>p</i> < 0.05) the total phenol content (TPC) by approximately 10 mg GAE/g dry matter (DM) lees. The mean degree of the polymerization (mDP) values of the oxidized flavonoid model samples ranged from 15 to 30. The Cat:GST ratio and interaction of the Cat:GST ratio with oxidation were found significantly to affect the mDP values of the flavonoid model samples (<i>p</i> < 0.05). Oxidation increased the mDP values in all oxidized flavonoid model samples except for Cat:GST 0:100. The mDP values of the PN lees samples ranged from 7 to 11 and remained the same after oxidation. There was no significant reduction in the antioxidant activities (DPPH and ORAC) of the model and wine lees after oxidation except the PN1 lees sample (decreased from 3.5 to 2.8 mg Trolox equivalent/g DM extracts). In addition, no correlation was observed between mDP (approximately 10 to 30) and DPPH (0.09) and ORAC assay (−0.22), which indicates that the higher mDP resulted in a poor ability to scavenge DPPH· and AAPH· free radicals. Antimicrobial activities of the flavonoid model were found to be improved after the oxidation treatment against <i>S. aureus</i> and <i>E. coli</i> with minimum inhibition concentration (MIC) of 1.56 and 0.39 mg/mL. This may indicate that new compounds were formed during the oxidation treatment, and these compounds showed more effective microbicidal activity. LC-MS work is required in the future to identify the compounds that are newly formed during the oxidation of the lees.https://www.mdpi.com/2076-3921/12/4/931wine leesphenolic compoundsantioxidantantimicrobial activityoxidation |
| spellingShingle | Zhijing Ye Jinlin Shi Roland Harrison Richard Hider Alaa El-Din A. Bekhit Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts Antioxidants wine lees phenolic compounds antioxidant antimicrobial activity oxidation |
| title | Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts |
| title_full | Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts |
| title_fullStr | Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts |
| title_full_unstemmed | Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts |
| title_short | Studies on the Effect of Oxidation on Bioactivity of Phenolics and Wine Lees Extracts |
| title_sort | studies on the effect of oxidation on bioactivity of phenolics and wine lees extracts |
| topic | wine lees phenolic compounds antioxidant antimicrobial activity oxidation |
| url | https://www.mdpi.com/2076-3921/12/4/931 |
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