THE PHENOLIC COMPOUNDS EVOLUTION IN A DURUM WHEAT CULTIVAR DURING STORAGE
AT DIFFERENT TEMPERATURES
The aim of this work was to investigate the influence of storage temperature and time on Total Phenolic Content (TPC) in a romanian durum wheat cultivar. The biological material was represented by fall durum wheat grains from which there were formed control and working samples (grains, flour and bran). The control samples were stored at 10°C, and the working ones at four thermal thresholds (40°C, 60°C, 120°C and 180°C) for 5 days. After 1, 3 and 5 days it has estimated Total Phenolic Content (TPC) through a colorimetric assay, by measuring the ability of phenols to reduce Folin-Ciocalteu reagent. In all analyzed samples, compared to controls (samples stored at 10°C), the largest decreases of Total Phenolic Content were after 5 days of storage, with significant percentage reductions at 180°C and 120°C, in flour type 480 (WF), and in whole-wheat flour (WWF). After 1 and 3 days of storage, significant percentage reductions of TPC were only in flour type 480 samples stored at 180°C and 120°C too. Keeping of durum wheat samples under high temperature as flour caused a greater reduction in the total content of phenolic compounds, compared to grains or bran.
Key words: wheat, flour, bran, phenolic content