Data were subjected to ANOVA and Tukey tests (Statistica 7.0 software) at a 0.05 level of significance. Five samples (n = 5) of each variety were analysed, all assays being carried out in triplicate. The soluble solids extraction yields obtained from the grape pomace samples

are given in Fig. 2. The Cabernet Sauvignon extract had a higher content of soluble solids (25.2 g/100 g). Significant differences CX-5461 chemical structure (P < 0.05) between the Merlot and Bordeaux varieties were not observed. There were significant differences (P < 0.05) between the total content of phenolic compounds in the extracts of the varieties analysed ( Table 1). This is to be expected since the phenolic concentration in grapes is dependent on the type of vinification process as well as the genetic, environmental and cultural characteristics ( Doshi, Adsule, & Banerjee, 2006). The Cabernet Sauvignon extract had a higher total phenolic content, being around twice the content observed in the Isabel extract. The Cabernet Sauvignon also had a higher total phenolic compounds content than Pinot Noir (73.66 mg/g) and Regente (49.73 mg/g), also produced

in Brazil and evaluated in a previous study ( Rockenbach, Silva, Rodrigues, Gonzaga, & Fett, 2007). Sánchez-Alonso, Jiménez-Escrig, Saura-Calixto, and Borderías (2008) evaluated the total polyphenol content extracted from dietary fibre obtained from grape pomace of the Airén variety (produced in Spain) and obtained a value of 78.5 mg/g. This content is higher than those observed in the present study, with only a small difference for Cabernet Sauvignon. Bozan, Tosun, Y-27632 and Özcan (2008) found 103.7 and 105.7 mg/g of total phenolic contents in grape seeds from Cabernet Farnesyltransferase Sauvignon and Merlot, respectively. In another study,

Yemis, Bakkalbasi, and Artik (2008), on evaluating seeds from grapes cultivated in Turkey, found mean values for total phenolics of 49.31 mg/g for five white grape varieties and 50.41 for seven red grape varieties (on a dw basis). These grape seed contents are higher than those found in Merlot and Isabel pomaces, but do not reach the phenolic content of Cabernet Sauvignon and Bordeaux pomaces. Thus, the whole fractions of grape pomace, as well as seeds, can be considered important sources of polyphenols and, depending on the end use, separation of fractions in preliminary steps are not always necessary. Table 1 also gives the total monomeric anthocyanins contents of the extracts evaluated by the pH-differential method. Significant differences (P < 0.05) were observed among extracts and, in contrast to the total phenolic content, the pomace of the Bordeaux variety had a higher content of anthocyanins (11.22 mg/g), being six times higher than that of the Isabel variety (1.84 mg/g). Pastrana-Bonilla, Akoh, Sellappan, and Krewer (2003) evaluated total anthocyanins in grape skin by the pH-differential method and reported values ranging from 4.85 to 10.86 mg/g in five different purple muscadine grapes grown in southern Georgia.