The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium
Various protein-rich foods are traditionally immersed in virgin olive oil (VOO), a medium rich in phenols, which are health-promoting and sensorially important compounds. Immersing tofu in VOO may modify the sensory properties and nutritional value of both due to the oil’s hydrophilic phenol interac...
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2025-02-01
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| author | Olivera Koprivnjak Valerija Majetić Germek Paula Žurga Karolina Brkić Bubola |
| author_facet | Olivera Koprivnjak Valerija Majetić Germek Paula Žurga Karolina Brkić Bubola |
| author_sort | Olivera Koprivnjak |
| collection | DOAJ |
| description | Various protein-rich foods are traditionally immersed in virgin olive oil (VOO), a medium rich in phenols, which are health-promoting and sensorially important compounds. Immersing tofu in VOO may modify the sensory properties and nutritional value of both due to the oil’s hydrophilic phenol interactions with proteins and water. In this study, cubes of fresh tofu (T) (70% water) and freeze-dried tofu (FD-T) (5% water) were immersed in VOO for 7 days of cold storage. The changes in the phenolic compound content and standard quality parameters of the oil were noted after 1, 3, 5, and 7 days of contact with the tofu. The total phenols in the oil were determined using the Fast Blue BB assay, while single phenols were analyzed by HPLC-UV/VIS. During the 7 days, the total phenols in the oil decreased by up to 56% and 26% under the influence of fresh and freeze-dried tofu, respectively, including a significant decrease in hydroxytyrosol, oleacein, tyrosol, and oleocanthal. The water content and its release from fresh tofu significantly contributed to this decline. The degradation of the quality of the oil in contact with the fresh tofu was observed only in its sensory properties, with a marked reduction in the intensity of its fruitiness, bitterness and pungency. |
| format | Article |
| id | doaj-art-c8110c41558643f5b4dcd2156d268233 |
| institution | DOAJ |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | MDPI AG |
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| series | Molecules |
| spelling | doaj-art-c8110c41558643f5b4dcd2156d2682332025-08-20T02:48:10ZengMDPI AGMolecules1420-30492025-02-0130367210.3390/molecules30030672The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion MediumOlivera Koprivnjak0Valerija Majetić Germek1Paula Žurga2Karolina Brkić Bubola3Department of Food Technology and Quality Control, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, CroatiaDepartment of Food Technology and Quality Control, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000 Rijeka, CroatiaTeaching Institute of Public Health of Primorsko-Goranska County, Krešimirova 52a, 51000 Rijeka, CroatiaInstitute of Agriculture and Tourism, Karla Huguesa 8, 52440 Poreč, CroatiaVarious protein-rich foods are traditionally immersed in virgin olive oil (VOO), a medium rich in phenols, which are health-promoting and sensorially important compounds. Immersing tofu in VOO may modify the sensory properties and nutritional value of both due to the oil’s hydrophilic phenol interactions with proteins and water. In this study, cubes of fresh tofu (T) (70% water) and freeze-dried tofu (FD-T) (5% water) were immersed in VOO for 7 days of cold storage. The changes in the phenolic compound content and standard quality parameters of the oil were noted after 1, 3, 5, and 7 days of contact with the tofu. The total phenols in the oil were determined using the Fast Blue BB assay, while single phenols were analyzed by HPLC-UV/VIS. During the 7 days, the total phenols in the oil decreased by up to 56% and 26% under the influence of fresh and freeze-dried tofu, respectively, including a significant decrease in hydroxytyrosol, oleacein, tyrosol, and oleocanthal. The water content and its release from fresh tofu significantly contributed to this decline. The degradation of the quality of the oil in contact with the fresh tofu was observed only in its sensory properties, with a marked reduction in the intensity of its fruitiness, bitterness and pungency.https://www.mdpi.com/1420-3049/30/3/672virgin olive oiltofuphenolssensory properties |
| spellingShingle | Olivera Koprivnjak Valerija Majetić Germek Paula Žurga Karolina Brkić Bubola The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium Molecules virgin olive oil tofu phenols sensory properties |
| title | The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium |
| title_full | The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium |
| title_fullStr | The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium |
| title_full_unstemmed | The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium |
| title_short | The Influence of Standard and Freeze-Dried Tofu on the Phenols and Quality of Virgin Olive Oil Used as an Immersion Medium |
| title_sort | influence of standard and freeze dried tofu on the phenols and quality of virgin olive oil used as an immersion medium |
| topic | virgin olive oil tofu phenols sensory properties |
| url | https://www.mdpi.com/1420-3049/30/3/672 |
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