M. Isabel Spranger

Isolation and purification of dimeric and trimeric procyanidins from grape seeds

An improved method used for the isolation and purification of low-molecular-mass procyanidins (i.e., dimeric B1, B2, B3, B4, B1-3-O-gallate, B2-3-O-gallate, B2-3′-O-gallate, trimer C1 and trimer T2) from grape seeds, is described. Pre-fractionation in oligomers and polymers was performed by chromatography on an open column (LiChroprep RP-18). The oligomer fraction, rich in dimeric and trimeric procyanidins, was then chromatographed on a Toyopearl TSK HW-40 (F) column. The major fractions obtained from Toyopearl TSK HW 40 (F) chromatography were further separated by semi-preparative HPLC, to obtain pure procyanidins. The main advantages of this method are that it is easy to use, less time-consuming and gives very high yield of dimeric and trimeric procyanidins by each manipulation.

Influence of Botanical Species and Geographical Origin on the Content of Low Molecular Weight Phenolic Compounds of Woods Used in Portuguese Cooperage

Summary The influence of botanical species (Quercus and Castanea sativa) and geographical origin (Portugal—three different sites, France and North America) on the qualitative and quantitative content of some extractable low molecular weight phenolic compounds was assessed by HPLC. Chestnut wood had the highest total content of low molecular weight phenolic compounds, followed by the Portuguese oaks and the French oaks, whereas the American oak had the lowest content of these compounds. The contents of phenolic acids, phenolic aldehydes, scopoletin and umbelliferone were significantly different among the studied woods. Both the botanical species and the geographical origin affect the content of low molecular weight organic compounds of woods used in Portuguese cooperage. The results also show that the botanical species seem to be more important than the geographical origin to explain the difference in the wood phenolic composition. So, the separation of trees according to their origin is of considerable interest for coopers and winemakers to choose wisely the woods for the ageing of brandies.