Functional properties of laboratory-isolated native starches from Philippine waxy rices as compared with commercial rice starches
2004
Escubio, S. S. P.,Philippine Rice Research Inst., Maligaya, Science City of Muñoz, Nueva Ecija (Philippines) | Abilgos, R. G. | Garcia, G. G.
Waxy rice starches are special because of their very small particle size, clean flavor release, creamy fat-like mouthful, and excellent freeze-thaw stability and viscosity. Hence, this study was undertaken to characterize the thermal and functional properties of Philippine waxy starches. Starch was isolated from three Philippine waxy rice (Buenkitan, IMS2, and IR65) varieties and its functional properties were compared with two commercial (Remyline and sample from National Starch Company) native waxy rice starches. A modified waxy rice starch sample (Remygel of Remy Industries, Belgium) was also included in the study. Sodium content of the extracted starches ranged from 0.1 to 1.0 ppm signifying high purity. Low protein contents were obtained indicating the glutelins were effectively removed using the optimized alkali-extraction method. Results gathered from the iodine-staining method proved that all the test starches have very low amylose content. In addition, starches of IMS2, Buenkitan and IR65 have soft gel consistency, while those of National Starch Company, Remyline and Remygel have medium gel consistency. All the starches have fat absorption index (FAI) values ranging from 1.0048 to 1.2439, with the sample from National Starch Company having the highest value, and Buenkitan having the lowest FAI value. For hydration properties, 1R65 starch exhibited the highest water absorption index of 2.0082, with the rest of the samples ranging from 1.8995 to 1.9966. IR65 and Buenkitan starches are the most freeze-thaw stable having endured up to six to seven freeze-thaw cycles. Viscosity profiles and heat enthalpy measurements of the gels of the waxy rice starches were determined using Rapid-Visco Analyzer (RVA) and Differential Scanning Calorimetry (DSC), respectively.
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