Effect of Amylose Content on Gelatinization, Retrogradation and Pasting Properties of Flours from Different Cultivars of Thai Rice
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English Slovak |
| ISSN: | ISSN 0038-9056 |
| Online Access: | http://www.viks.sk/chk/star_9_03_410_415.doc |
| Abstract: | Summaries. Presently, rice cultivars are categorized according to amylose content into three groups: low, medium and high amylose content cultivars. The correlation of amylose content with gelatinization properties, retrogradation, and pasting properties of eleven cultivars of Thai rice were investigated. Rice flour was prepared from milled rice by the wet grinding process. Onset (To), peak (TP) and conclusion (Tc) temperatures of gelatinization, (determined by DSC) were found to be highly positively correlated with amylose levels. This correlation could be used for prediction of amylose content of rice flour. Low amylose starch could also be characterized by low degree of retrogradation (%R). The data obtained from RVA-viscograms (peak viscosity, breakdown, setback, and pasting temperature) can be used only for characterization of the group of low amylose starches (waxy rice). It was demonstrated that low amylose rice starch provided the highest peak viscosity and breakdown and the lowest setback and pasting temperature among the groups investigated. Conclusions. Amylose content provided a highly positive correlation with the gelatinization temperatures (onset, peak and conclusion temperatures) of starch isolated from Thai rice cultivars. The amylose content in Thai rice starch could be predicted from the gelatinization temperature. The data obtained from the RVA viscogram (peak viscosity, breakdown, setback and pasting temperature) can be used only for categorization of the group of low amylose starch (waxy rice). It was demonstrated that low amylose rice starch provided the highest peak viscosity and breakdown and the lowest setback and pasting temperature among the groups. |
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| ISSN: | ISSN 0038-9056 |
