THE EFFECT OF SOME PROCESSING VARIABLES ON NON-COLORED PHENOLIC-COMPOUNDS IN PORT WINES

The non-coloured phenolic fraction of fortified port wines was studied . Trials using several mash-extraction techniques which may be used du ring Fort wine making were evaluated for their effectiveness by measur ing qualitative and quantitative differences in phenolics. Total pheno lic compounds measured by spectrophotometry and HPLC analysis were com pared, and the greater values obtained using spectrophotometry are att ributable to the contribution of anthocyanins and non-phenolic UV-abso rbing compounds. Quantitative and qualitative differences in compositi on were observed depending on the extraction mode. The greatest total phenolic content was found in port wine made by traditional foot tread ing, while early addition of extra alcohol to the mash had a neutral o r negative effect on the yield of phenolic compounds.