93 Am. J. Enol. Vitic. 60:1 (2009) The visual characteristic of red wine is mainly due to anthocyanins that are present in the grape skin at harvest and that dissolve in the red wine during the maceration/ fermentation process (Amrani Joutei and Glories 1995, Romero-Cascales et al. 2005a). Anthocyanins accumu- late gradually in berry skins during ripening (Fernán- dez-López et al. 1992), and their total amount at harvest depends on variety (i.e., pink, red, or black skin variety) and many other factors, including environmental param- eters and agronomic practice (Guidoni et al. 2008). The types and the amounts of various anthocyanins in grape skins (their “profile”) determine the color of resulting wines, but their extraction from the grape skin into the wine depends on the tendency of the berry skin to release them (González-Neves et al. 2004, Romero-Cascales et al. 2005b). The extractability of anthocyanins increases throughout grape ripening as a consequence of cell wall degradation by pectolytic enzymes (Ribéreau-Gayon et al. 2000). Differences in polysaccharides based on galac- tose and arabinose, the cellulose content, and the degree of methylation of the pectins could be responsible for the difference in anthocyanin extractability (Ortega-Regules et al. 2006, 2008). Several studies have attempted to define the best method to evaluate polyphenolic compounds in grapes and their ease of release. These analytical methods are generally rather complex and often require long analysis times (Cagnasso et al. 2008). Furthermore, some data in- terpretation may be difficult (Venencie et al. 1998). Texture analysis is a current analytical technique used for measurement of the physical properties of food. For winegrapes, the literature contains studies on modifica- tions of some grape textural properties during ripeness (Abbal et al. 1992, Robin et al. 1997, Lee and Bourne 1980, Grotte et al. 2001) and the influence of climate and growing location on mechanical behavior (Le Moigne et al. 2008). The aim of this work was to examine the relation- ship between skin hardness, determined by puncture test, and the ease of extractability of anthocyanins in berries at different ripening stages. The study was carried out on Brachetto, an important aromatic red grape variety used for production of sweet sparkling wines (6–7.5% vol ethanol) and grown in Piedmont (northwest Italy). The ease and rapidity of extraction are important qualita- tive parameters for Brachetto grapes. These aromatic red grapes are subjected to very short fermentation-macera- tion (24–48 hr) because the product obtained must not exceed 3.5% vol ethanol before the second fermentation ( prise de mousse). Reduced maceration times, low fer- mentation temperature (17–18°C) to preserve aromatic components, and low alcohol concentrations frequently lead to reduced pigment extraction and wines with un- satisfactory color. Knowledge of the extractability of an- thocyanin compounds measured via berry skin hardness could permit harvesting at an optimal stage of ripeness and suitable operative choices in the prefermentation and maceration phases. 1 Researcher, 2 Ph.D. student, 3 Professor, Di.Va.P.R.A., Microbiology and Food Technology sector, University of Turin, Via L. da Vinci 44, 10095 Grugliasco, Torino, Italy. *Corresponding author (email: luca.rolle@unito.it; tel: 39 0116708558; fax: 39 0116708549) Acknowledgment: This study was funded by Consorzio Tutela Vini d’Acqui, Brachetto d’Acqui. Manuscript submitted May 2008, revised July 2008, accepted Sept 2008. Publication costs of this article defrayed in part by page fees. Copyright © 2009 by the American Society for Enology and Viticulture. All rights reserved. Research Note Relationship between Skin Break Force and Anthocyanin Extractability at Different Ripening Stages Luca Rolle, 1 * Fabrizio Torchio, 2 Giuseppe Zeppa, 1 and Vincenzo Gerbi 3 Abstract: The extractability of anthocyanins from winegrapes with different skin hardness at two different ripening stages was evaluated. Skin hardness was assessed by texture analysis, a rapid and low-cost analytical technique. Grape berries of cv. Brachetto were calibrated according to their density estimated by flotation in 10 different salt solutions. Skin hardness was measured via a puncture test, and two groups of berries with different skin hardness were selected for each ripening stage: soft (<0.40 N) and hard (>0.50 N). Anthocyanin skin extrac- tion was evaluated in a hydroalcoholic model solution and the kinetics of skin dissolution was monitored. For each ripening stage, the harder skin had greater anthocyanin extractability. Significant interactions between ripening stage and skin hardness were found in the composition of individual anthocyanins present in the extract. Key words: extractability, anthocyanin, skin hardness, texture analysis, puncture test