The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract
Închide
Conţinutul numărului revistei
Articolul precedent
Articolul urmator
91 0
SM ISO690:2012
CRISTEA, Elena; STURZA, Rodica; PATRAȘ, Antoanela. The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract. In: Annals of the University Dunarea de Jos of Galati, Fascicle VI: Food Technology. 2016, nr. 2(39), pp. 96-104. ISSN 1843-5157.
EXPORT metadate:
Google Scholar
Crossref
CERIF

DataCite
Dublin Core
Annals of the University Dunarea de Jos of Galati, Fascicle VI: Food Technology
Numărul 2(39) / 2016 / ISSN 1843-5157 /ISSNe 2068-259X

The influence of temperature and time on the stability of the antioxidant activity and colour parameters of grape marc ethanolic extract


Pag. 96-104

Cristea Elena1, Sturza Rodica1, Patraș Antoanela2
 
1 Technical University of Moldova,
2 “Ion Ionescu de la Brad” Iasi University of Life Sciences
 
Disponibil în IBN: 4 august 2022


Rezumat

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: -2°C for 12 hours; 4°C for 12 hours; 40°C for 15 minutes, 60°C for 15 minutes, 80°C 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 -2°C, 4°C, and 25-30°C 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.

Cuvinte-cheie
antioxidant activity, CIELab, colour parameters, grape marc extract, temperature