Impact of extrusion parameters on the properties of rice products: A physicochemical and X-ray tomography study

Publication date: Available online 28 June 2015 Source:Food Structure Author(s): Hélène Chanvrier , Christine Nordstroem , Greet Vandeputte , Adrian Haiduc , Valérie Leloup , Jean-Claude Gumy Rice pellets were produced by extrusion according to an experimental design varying temperature (120–135 - 150°C), moisture content (17–20–23%) and screw speed (300–400–500rpm). The internal expanded structure of the pellets was assessed by X-ray tomography and texture with a texture analyser. The extent of starch depolymerisation and the types of protein depolymerisation/interactions were studied in complement to the starch-proteins morphology assessed by microscopy. The physico-chemical properties of the pellets were mainly affected by moisture and temperature, with moisture having the highest impact. High moisture content (23%) resulted in higher mean walls thickness of the extruded pellet, less starch depolymerisation, more protein aggregation through disulfides bonds and harder pellets. The internal expanded structure and texture of the rice pellets was mainly explained by protein changes and less by the extent of starch depolymerisation in this study. When proteins mainly interacted through medium energy interactions (disulfide bonds), protein aggregates were larger, cells walls thicker and pellets were less porous and harder with more fractures events. On the contrary, when proteins interacted through low energy (hydrogen and hydrophobic bonds) and high ene...
Source: Food Structure - Category: Food Science Source Type: research