キヌア澱粉の諸性質と糊化特性

Abstract

The use of cereals is being reexamined as people become more health conscious. When compared to grass cereals, quinoa is richer in proteins, lipids, vitamins, minerals and dietary fibers. Quinoa has also been investigated as a food that prevents lifestyle diseases, and is emerging as a promising new food material with health-promoting functions. In the present study, quinoa starch was prepared from quinoa flour, and the basic characteristics of quinoa starch were compared to those of both rice and corn starches. Quinoa starch was found to be smaller than both rice and corn starch. Scanning electron microscopy (SEM) showed that quinoa starch was much finer, and, in terms of particle-size distribution, the average particle-size for quinoa, rice and corn starches was 2. 5, 4. 3 and 9. 8μm, respectively. X-ray diffraction showed that, like rice and corn starches, quinoa starch exhibited a typical type A pattern for cereal starches. The amylose content, as assessed by amperometric titration, for quinoa, rice and corn starches was 18. 7, 12. 7 and 27. 2%, respectively. Photopastegraphy, differential scanning calorimetry (DSC) and Rapid Visco Analyzer (RVA) measurements showed that the gelatinization onset temperature was slightly higher than the RVA value for all three starches. When compared to rice and corn starches, the breakdown and set-back values for quinoa starch were particularly lower and did not change much after cooling. Its specific curve indicates that quinoa starch is more resistant to senescence.