The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract
The interest to replace synthetic food colorants, preservatives and antioxidants in beverages with natural ones is leading researchers to explore the polyphenols of winery wastes. It is of great interest to see if these compounds could replace synthetic dyes in drinks. However, it is still necessar...
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| Format: | Article |
| Language: | English |
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Galati University Press
2015-12-01
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| Series: | Annals of the University Dunarea de Jos of Galati. Fascicle VI: Food Technology |
| Subjects: | |
| Online Access: | http://www.ann.ugal.ro/tpa/Anale%202015/vol%202/9%20Cristea%20et%20al.pdf |
| _version_ | 1818582546717343744 |
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| author | Elena CRISTEA Rodica STURZA Antoanela PATRAȘ |
| author_facet | Elena CRISTEA Rodica STURZA Antoanela PATRAȘ |
| author_sort | Elena CRISTEA |
| collection | DOAJ |
| description | The interest to replace synthetic food colorants, preservatives and antioxidants in beverages with natural ones is leading researchers to explore the polyphenols of winery wastes. It is of great interest to see if these compounds could replace
synthetic dyes in drinks. However, it is still necessary to study the stability of extracts containing grape phenolics during various technological treatments. This paper presents the study of the stability of the 50% ethanolic extract of marc resulting from the winemaking process. The extract was subjected to the following
temperatures: -2oC for 12 hours; 4oC for 12 hours; 40oC for 15 minutes, 60oC for 15 minutes, 80oC for 15 minutes and 100oC for 2 minutes; after that the antioxidant activity and the colour parameters (CIELab) were measured. Three sets of extracts were kept for 2 weeks at -2oC, 4oC, and 25-30oC and afterwards
the parameters mentioned above were measured once again. Furthermore, the total content of polyphenols and the content of tannins were determined using the Folin-Ciocalteu method. The results were expressed in mg gallic acid equivalents per litre and mg tannic acid equivalents per litre, respectively. The antioxidant
activity was determined using the method based on the interaction with the ABTS radical, the results being expressed in % inhibition. The results have shown that the colour (CIELab parameters) and the antioxidant activity of the ethanolic
extract of marc are relatively stable during thermal processes. High temperatures as well as prolonged storage at room temperature increased the values of antioxidant activity, chroma, and redness. However, they also produced the most significant effect of the overall colour of the extract, leading to the degradation of blue pigments and a shift towards orange hues. |
| first_indexed | 2024-12-16T07:51:07Z |
| format | Article |
| id | doaj.art-171fb5f5f81f40b6922603b9cdaf9b85 |
| institution | Directory Open Access Journal |
| issn | 1843-5157 2068-259X |
| language | English |
| last_indexed | 2024-12-16T07:51:07Z |
| publishDate | 2015-12-01 |
| publisher | Galati University Press |
| record_format | Article |
| series | Annals of the University Dunarea de Jos of Galati. Fascicle VI: Food Technology |
| spelling | doaj.art-171fb5f5f81f40b6922603b9cdaf9b852022-12-21T22:38:51ZengGalati University PressAnnals of the University Dunarea de Jos of Galati. Fascicle VI: Food Technology1843-51572068-259X2015-12-0139296104The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extractElena CRISTEA0Rodica STURZA1Antoanela PATRAȘ2Technical University of Moldova, Chisinau, Republic of MoldovaTechnical University of Moldova, Chisinau, Republic of MoldovaIon Ionescu de la Brad University of Agricultural Sciences and Veterinary Medicine, Iasi RomaniaThe interest to replace synthetic food colorants, preservatives and antioxidants in beverages with natural ones is leading researchers to explore the polyphenols of winery wastes. It is of great interest to see if these compounds could replace synthetic dyes in drinks. However, it is still necessary to study the stability of extracts containing grape phenolics during various technological treatments. This paper presents the study of the stability of the 50% ethanolic extract of marc resulting from the winemaking process. The extract was subjected to the following temperatures: -2oC for 12 hours; 4oC for 12 hours; 40oC for 15 minutes, 60oC for 15 minutes, 80oC for 15 minutes and 100oC for 2 minutes; after that the antioxidant activity and the colour parameters (CIELab) were measured. Three sets of extracts were kept for 2 weeks at -2oC, 4oC, and 25-30oC and afterwards the parameters mentioned above were measured once again. Furthermore, the total content of polyphenols and the content of tannins were determined using the Folin-Ciocalteu method. The results were expressed in mg gallic acid equivalents per litre and mg tannic acid equivalents per litre, respectively. The antioxidant activity was determined using the method based on the interaction with the ABTS radical, the results being expressed in % inhibition. The results have shown that the colour (CIELab parameters) and the antioxidant activity of the ethanolic extract of marc are relatively stable during thermal processes. High temperatures as well as prolonged storage at room temperature increased the values of antioxidant activity, chroma, and redness. However, they also produced the most significant effect of the overall colour of the extract, leading to the degradation of blue pigments and a shift towards orange hues.http://www.ann.ugal.ro/tpa/Anale%202015/vol%202/9%20Cristea%20et%20al.pdfantioxidant activitycolour parametersCIELabgrape marc extracttemperature |
| spellingShingle | Elena CRISTEA Rodica STURZA Antoanela PATRAȘ The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract Annals of the University Dunarea de Jos of Galati. Fascicle VI: Food Technology antioxidant activity colour parameters CIELab grape marc extract temperature |
| title | The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract |
| title_full | The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract |
| title_fullStr | The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract |
| title_full_unstemmed | The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract |
| title_short | The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract |
| title_sort | influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract |
| topic | antioxidant activity colour parameters CIELab grape marc extract temperature |
| url | http://www.ann.ugal.ro/tpa/Anale%202015/vol%202/9%20Cristea%20et%20al.pdf |
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