Modification of pasta structure induced by high drying temperatures. Effects on the in vitro digestibility of protein and starch fractions and the potential allergenicity of protein hydrolysates
Abstract
The effects of drying on pasta structure, starch and protein digestibility and potential allergenicity were investigated. Pasta was dried at low (55 °C, LT), high (70 °C, HT) and very high temperature (90 °C) applied either at the beginning (VHT) or at the end of the drying profile (VHT_LM). Changes in dried and in cooked pasta structure were determined regarding protein solubility, thermal properties of starch, microscopic and rheological measurements. Changes were moderate up to 70 °C and increased at higher temperatures and especially for VHT_LM drying. VHT_LM drying tended to decrease starch digestibility and significantly decreased protein digestibility of cooked pasta by 10% probably due to the formation of highly-aggregated proteins linked by very strong covalent bonds. None of the drying profiles were found to remove the allergenic properties of pasta. IgE-reactive peptides from prolamins and albumins/globulins fractions were found in all digestion juices; VHT-LM drying increased the latter.