Pasting, Thermal and Gel Texture Properties of Three Varieties of Nigeria Rice Flours and Starches
O. J. Odejobi *
Applied Thermodynamics and Process Design Research Laboratory, Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria.
M. M. Ige
Department of Food Science and Technology, Obafemi Awolowo University, Ile-Ife, Nigeria.
K. A. Adeniyi
Applied Thermodynamics and Process Design Research Laboratory, Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Flours and starches from three Nigeria rice varieties CISADANE (Faro51), OS6 (Faro11) and NERICA 19 were evaluated for their pasting, thermal and gel texture properties. Their thermal properties were evaluated with Differential Scanning Calorimeter (DSC) andpasting properties were obtained using a Rapid Viscography Analyser (RVA). Light transmittance of their gel textural properties was determined using UV-vis spectrophotometer. The results showed that Glass transition temperature (Tg) was highest in CISADANE (Faro51) (222ºC) and almost the same in OS6 (Faro11). Melting point (MP) temperature was highest for OS6 (Faro11)(264ºC) and almost the same for NERICA 19 and CISADANE (Faro51) flour. Tg values of starches were almost the same in CISADANE (Faro51) and NERICA 19 (264ºC). CISADANE (Faro51) starch showed highest melting point (237ºC), almost the same for the other two starches. It was observed that defatting caused degradation in the physical properties of flours and starches of all the three rice varieties investigated.It was concluded that proteins and fats could influence the glass transition and other physical properties of rice flours and their respective starches.
Keywords: Flours, starches, pasting characteristic, thermal properties, gel texture properties