Rheological and Thermal Properties of Extruded Mixtures of Rice Starch and Isolated Soy Protein
Por:
Ortiz, MER, San Martin-Martinez, E, Padilla, LPM
Publicada:
1 oct 2008
Resumen:
Many foods gain new mechanical, thermal and textural properties after being processed due to interactions between carbohydrates and proteins. This effect is characteristic for each foodstuff. The properties of extruded isolated soy protein (ISP) and rice starch were studied considering the following extrusion variables: starch proportion with respect to ISP (0-100%), pH (3-9), moisture content (20-30%) and temperature (140-180 degrees C). The following characteristics were measured: Water absorption index (WAI), water solubility index (WSI), glass transition temperature (T(g)), melting temperature (T(m)), viscosity at 90 degrees C and at 50 degrees C, storage (G'), loss modulus (G '') and tan delta. The results indicate that the extruded starch exhibits higher WAI and WSI values than untreated starch. For extruded ISP these values are much lower than for untreated ISP. Extrudates with higher starch proportion had higher T(g) and T(m) values; pH has a significant effect (p<0.05), at pH
Filiaciones:
Padilla, LPM:
Univ Nacl Autonoma Mexico, FES Cuautitlan, Lab Propriedades Reolog & Func Alimentos, Cuautitlan, Edo De Mexico, Mexico
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