Jueves, 22 Diciembre 2016 16:58

A method that reduces processing time and increases antioxidant effects of sweet wine

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Researchers at Agricultural Chemistry Department of University of Córdoba and Agrifood Campus of International Excellence ceiA3 have developed a new method for making sweet red wines from Tempranillo, Cabernet Sauvignon, Syrah and Merlot grape varieties, as reported by Fundación Descubre. According to experts, these varieties are characterized by their intense red color and have been widely implemented in the Andalusian wine production sector in recent years. Specifically, scientists have focused on the red grape drying process. Using a chamber under controlled conditions of temperature and humidity, they have managed to keep the maximum typical red color of the musts, decrease time, avoid appearance of the brown color that commonly takes place as a result of traditional sun-drying  and increase associated antioxidant activity.

Researchers at Agricultural Chemistry Department of University of Córdoba and Agrifood Campus of International Excellence ceiA3 have developed a new method for making sweet red wines from Tempranillo, Cabernet Sauvignon, Syrah and Merlot grape varieties, as reported by Fundación Descubre. 

 

In the article ‘Anthocyanin Evolution and Color changes in Red Grapes During their Chamber Drying’, published in the Journal of Agricultural and Food Chemistry, the research team has shown that controlling the temperature and humidity in the chamber reduces the time of the red grape drying step and helps to maintain its flavor and color properties. 'This new method shortens the dehydration period required for grape to raisin maturation from the usual seven-to-ten days to three days. A further advantage is a five to 10 times increase of the antioxidant effect increasing and red tones of the musts. Importantly, the process is also independent of climate, i.e. it can be performed at any location and it does not depend on sunlight', explains Julieta Mérida, researcher at the University of Cordoba to Fundacion Descubre.
To develop this new method of making sweet red wine, the team firstly collected the grapes in the Montilla- Moriles region of Cordob . ' Then, we grouped them in batches of 30 kg and placed in a drying chamber at a constant temperature of 40° C and initial moisture of 20%', explains Merida. 'Applying a controlled drying process in a chamber allowed us to choose the desired degree of ripeness of the grapes and to prevent the growth of fungi and other contaminating factors during the maturation process'.
Expand the range of wines
This research addresses a new approach to study different parameters that favor production of sweet red wines, providing researchers with a new opportunity to expand the wine offer in Andalusia. 'These types of wines are becoming increasingly more common in our community, thus studies on the drying behavior of red grape varieties will help to improve and expand knowledge of this growing product', says Merida.
Based on these results, the team has now opened new lines of research to optimize drying processes in other red fruits, such as blueberries or raspberries. 'Next step, after this initial success with white and red grape raisining process for production of sweet wines, will be an application of the same method, i.e., dehydration under controlled temperature conditions, in other fruits with high antioxidant capacity that may be used either for direct consumption or for production of low alcohol drinks', she concludes.

According to experts, these varieties are characterized by their intense red color and have been widely implemented in the Andalusian wine production sector in recent years. Specifically, scientists have focused on red grape drying process. Using a chamber under controlled conditions of temperature and humidity, they have managed to keep the maximum typical red color of musts, decrease production time, avoid brown color that commonly appears as a result of traditional sun-drying and increase associated antioxidant activity.

In the article ‘Anthocyanin Evolution and Color changes in Red Grapes During their Chamber Drying’, published in the Journal of Agricultural and Food Chemistry, the research team has shown that controlling chamber temperature and humidity reduces time of red grape drying step and helps to maintain its flavor and color properties. 'This new method shortens the dehydration period required for grape-to-raisin maturation from the usual seven-to-ten days to three days. A further advantage is a 5 to 10 times increase of must antioxidant actibity and red tones. Importantly, the process is also independent of climate, i.e. it can be performed at any location and it does not depend on sunlight', explains Julieta Mérida, researcher at the University of Cordoba, to Fundacion Descubre.

To develop this new method for production of sweet red wine, the team firstly collected the grapes in the Montilla-Moriles region of Cordoba. 'Then, we grouped them in batches of 30 kg and placed them in a drying chamber at a constant temperature of 40° C and initial moisture of 20%', explains Merida. 'Applying a controlled drying process in a chamber allowed us to choose the desired degree of grape ripeness and to prevent growth of fungi and other contaminating factors during the maturation process'.


Expand the range of wines

This research addresses a new approach to study different parameters that favor production of sweet red wines, providing researchers with a new opportunity to expand Andalusian wine offer. 'These types of wines are becoming increasingly more common in our community, thus studies on the drying behavior of red grape varieties will help to improve and expand knowledge of this growing product', says Merida.

Based on these results, the team has now opened new lines of research to optimize drying processes in other red fruits, such as blueberries or raspberries. 'Next step, after this initial success with optimization of white and red grape raisining process for production of sweet wines, we will be applying the same method, i.e. dehydration under controlled temperature conditions, in other fruits with high antioxidant capacity that may be used either for direct consumption or for production of low alcohol drinks', she concludes.

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