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Stem and pomace of a white grape (Vitis vinifera) variety, Prensal Blanc, were studied for the first time: general composition and dietary fibre components together with the total soluble polyphenol content and antioxidant activity. Both by-products present high contents of total dietary fibre (TDF), 790 g kg )1 d.m. (stem) and 716 g kg )1 d.m. (pomace). Values of the soluble dietary fibres in relation to TDF differed: 5% (stem) and 14.4% (pomace). Similar values of Klason lignin were found: 229 g kg )1 (stem) and 278 g kg )1 (pomace), however, the pomace exhibited more than twice the content of the condensed tannins (168 g kg )1 ) with regard to the stem (79 g kg )1 ). Notable were the high resistant protein contents of both by-products. Stem and pomace showed appreciable amounts of total soluble polyphenols (87 g kg )1 against 35 g kg )1 respectively). The free radical scavenging capacity of the former by-products was determined using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) method, obtaining EC 50 values of 0.79 g d.m. g )1 DPPH (stem) and 1.32 g d.m. g )1 DPPH (pomace). These data shows that both vinification by-products from the Prensal Blanc variety are a good source of dietary fibre and have antioxidant properties.

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Raisins had a moisture content of ca 14% and were stored over an 11 mo period. The initial SOI content was ca 640 ppm. Moisture content, water activity, color, browning, texture, SO2 content, soluble sugars, acidity and pH were periodically determined. A substantial decrease in SO2 content was observed, especially in samples stored at room temperature (20-25°C) which had higher browning indexes. No substantial changes were detected in water activity, acidity and pH. No sugaring was observed. Refrigerated samples (stored at 4 and 1l'C) were of higher quality in comparison with nonrefrigerated samples. Both were suitable for consumption after storage.