Journal article published in Journal of Agricultural and Food Chemistry, volume 62, pp. 8437–8451.

Authors: Susana Río Segade, Fabrizio Torchio, Simone Giacosa, Davide Ricauda Aimonino, Paolo Gay, Milena Lambri, Roberta Dordoni, Vincenzo Gerbi and Luca Rolle.

Abstract

This study was performed to evaluate and compare the effects of different pre-treatments of whole grape berries (freezing with dry ice or in a cold room, steam blanching with different exposure times, and microwave heating with different exposure times and microwave power density) on total content of some phenolic compounds and the composition of individual anthocyanins released into the pulp during the treatment and those extracted during the maceration step. Two red winegrape varieties with different proportions of di- and trisubstituted anthocyanins were used (Nebbiolo and Barbera, respectively). Pulp- extracted anthocyanins were more significantly influenced by the pre-treatment. The results highlighted that freezing with dry ice, followed by freezing in a cold room and steam blanching for 5 min, have a great potential from an industrial point of view. They facilitated the extraction of anthocyanins in the must prior to maceration, when compared with the control samples, increasing their total content (+37.8−83.6%), and modifying the anthocyanin profile through the enrichment in the most stable compounds (+2.8−6.6% malvidin derivatives) to the detriment of others more prone to oxidation (−0.8−11.0% cyanidin derivatives). In Nebbiolo winegrapes, an improved extraction of low- and high-molecular weight flavanols into the pulp was also observed (+60.4−73.4%). Significant relationships between the phenolic composition of treated berries and the corresponding skin mechanical properties were also studied, but they were variety dependent. Discriminant analysis permitted a correct classification of the samples according to the variety and pre-treatment.

Key words grape pre-treatments; anthocyanins; flavanols; extraction; skin mechanical properties; dry ice; microwave; peonidin-3-glucoside/malvidin-3-glucoside ratio

BibTeX entry: click to show

@article{
	2318_148060,
	url = {https://hdl.handle.net/2318/148060},
	author = {Río Segade, Susana and Torchio, Fabrizio and Giacosa, Simone and Ricauda Aimonino, Davide and Gay, Paolo and Lambri, Milena and Dordoni, Roberta and Gerbi, Vincenzo and Rolle, Luca},
	title = {Impact of several pre-treatments on the extraction of phenolic compounds in winegrape varieties with different anthocyanin profile and skin mechanical properties},
	year = {2014},
	journal = {Journal of Agricultural and Food Chemistry},
	volume = {62},
	abstract = {This study was performed to evaluate and compare the effects of different pre-treatments of whole grape berries (freezing with dry ice or in a cold room, steam blanching with different exposure times, and microwave heating with different exposure times and microwave power density) on total content of some phenolic compounds and the composition of individual anthocyanins released into the pulp during the treatment and those extracted during the maceration step. Two red winegrape varieties with different proportions of di- and trisubstituted anthocyanins were used (Nebbiolo and Barbera, respectively). Pulp- extracted anthocyanins were more significantly influenced by the pre-treatment. The results highlighted that freezing with dry ice, followed by freezing in a cold room and steam blanching for 5 min, have a great potential from an industrial point of view. They facilitated the extraction of anthocyanins in the must prior to maceration, when compared with the control samples, increasing their total content (+37.8−83.6\%), and modifying the anthocyanin profile through the enrichment in the most stable compounds (+2.8−6.6\% malvidin derivatives) to the detriment of others more prone to oxidation (−0.8−11.0\% cyanidin derivatives). In Nebbiolo winegrapes, an improved extraction of low- and high-molecular weight flavanols into the pulp was also observed (+60.4−73.4\%). Significant relationships between the phenolic composition of treated berries and the corresponding skin mechanical properties were also studied, but they were variety dependent. Discriminant analysis permitted a correct classification of the samples according to the variety and pre-treatment.},
	keywords = {grape pre-treatments; anthocyanins; flavanols; extraction; skin mechanical properties; dry ice; microwave; peonidin-3-glucoside/malvidin-3-glucoside ratio},
	doi = {10.1021/jf502656d},	
	pages = {8437--8451}
}

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