Effect of thermal processing (from farm to fork) on free and bound phenolic compounds in gluten free buckwheat spaghetti

At the present there is considerable interest in the consumption of alternative crops as potential recipes for gluten-free products production. Celiac disease is one of the most common lifelong disorders worldwide with as estimated mean prevalence of 1% of the general population. For instance, staple foods in many areas of the world such as bread, bakery products and pasta, contain gluten and should, therefore, be avoided in the diet. At present there is a considerable interest in the consumption of alternative crops as potential recipes for gluten-free products production Therefore, the use of buckwheat for the production of gluten-free pasta has been investigated in the present study. In order to carry out the study, RP-HPLC-ESI-microTOF-MS has been applied for the separation and the characterization of free and bound phenolic compounds in buckwheat flour, dried spaghetti, cooked dried spaghetti and in cooking water. Thus, thirty free and twenty-four bound phenolic compounds in buckwheat flour and spaghetti were characterized and quantified. As far we know, 2-hydroxy-3-O-β-D-glucopyranosil-benzoic acid, 1-O-caffeoyl-6-O-alpha-rhamnopyranosyl-β-glycopyranoside and epicatechin-3-(3’’-O-methyl) gallate in free form and, protochatecuic-4-O-glucoside acid and procyanidin A in bound form were detected in buckwheat for the first time. The sensitivity, mass accuracy and true isotopic pattern of the TOF-MS, legitimated the identification of phenolic compounds present in buckwheat extract. The results demonstrated a decreasing of total free phenolic compounds from farm to fork was about 75 %. The bound phenols decrease was 81 %. The spaghetti making process and the cooking caused the loss of 46 % and 49 % of total phenolic compounds respectively. The 12 % of total phenolic compounds present in dried spaghetti were dissolved in water after cooking.