Physical ageing of crayfish flour at low moisture contents

Abstract

Glass transition temperature of red crayfish flour (moisture 3.56%) was determined using a phase transition analyser (Wenger Technical Centre, USA). Due to the importance of physical ageing in functional properties of red crayfish flour (with 65% protein) the possible occurrence of physical ageing in dry powder of crayfish flour was studied at different temperatures below and close to the glass transition. Endothermic peaks that corresponded to relaxation enthalpy were observed for a commercial crayfish flour with 4.5% moisture. Enthalpy and peak temperature increased on storage of crayfish flour when it was held in the glassy-state at different temperatures (5, 15, 25°C).