30E-20 |
Texture characterization of high-pressure processed starches with different amylose content |
G. TABILO-MUNIZAGA1, F. Fernández-Martín2, and G. V. Barbosa-Cánovas1. (1) Biological Systems Engineering Dept., Washington State Univ., PO Box 646120, Pullman, WA 99164-6120, (2) Dept. de Ingeniería, Instituto del Frío (CSIC), Ciudad Universitaria, Madrid, E-28040, Spain Few studies have been done to evaluate the effect of high hydrostatic pressure (HHP) on starches, even though it is known HHP can gelatinize starches even at room temperature. Research results indicate that pressure induced gelatinization is significantly different from heat gelatinization. During starch heat gelatinization, many changes take place simultaneously or successively, which include granule swelling, loss of birefringence, increase of viscosity and fragmentation of the granule. However, pressurization swells starch granules allowing them to keep their granule-like and gelatinized structures (without retrogradation). The objective of this study was to evaluate textural properties of high pressure treated starches with different amylose content (AM). Starch suspensions with AM ranging from 25 to 75% were treated from 150 to 650 MPa for 30 min at room temperature. Native and treated samples were physically characterized by their rheological and textural behavior. Texture profile analysis (TPA) was carried out with a TA-XT2 Texture Analyser with a 5-kg load cell. Viscosity changes were monitored with a Paar-Physica Reomether with concentric cylinders. Seven TPA textural parameters were considered, hardness, fracturability, adhesiveness, springiness, cohesiveness, chewiness and gumminess. Starches with 25% AM and 35% AM partially gelatinized from 400MPa and up, but pressurization produced low-quality and brittle gels. The TPA results show that the main differences among samples were obtained in adhesiveness and fracturability, where these parameters were significantly higher in starches treated by HHP (-16.39 and 3.43 for 25% AM, and 5.83 and 3.17 for 35% AM, respectively) than those treated with heat. On the other hand, the pressurized suspensions behaved as time-independent, pseudoplastic fluids. The two samples with 55% AM and 70% AM did not gelatinized at all, even at 650MPa. The highest-amylose starch exhibited the lowest viscosity. These results shows that HHP processed food products containing amylose should be carefully formulated to avoid unexpected behaviors.
Session 30E, Food Engineering: Rheology and texture
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