Cluster analysis of rice starch varieties based on processability

摘要

Rice starch as a food additive affects nutritional, process, and texture properties in foods. The processabilityof starch is different depending on variety of rice cultivars. At present, rice starches are categorized by theamylose content which is dependent on the cultivar. However, the processabilities of rice starches are similaror different regardless of amylose content. Thus, it is important to classify cultivars of rice starches based onphysical behaviors during processing. However, it is difficult to categorize the rice starches since there are somany rice cultivars all over the world. For this reason, qualities and functionalities of rice starches have beencontrolled poorly due to lack of a proper classification method. The purposes of this study are to classifystarches of different rice cultivars based on processability such as water solubility and pasting properties andto simplify categorization the varieties of rice cultivars into based on their similarity based characteristics. Inthis study, rice starches were analysed in 12 different cultivars (A to L). Water solubility analysis and rapidvisco analysis (RVA) were performed to characterize the physical properties of the starches, andcorresponding parameters of the analyses were used to classify the cultivars by hierarchical cluster analysis.For comparison, the rice cultivars were categorized based on their amylose content. The cluster analysisbased on the water solubility parameters categorized 12 rice cultivars into five groups as A, C, D, G, H / B,E, I / F, J / K / L. The classification based on the pasting parameters was 5 groups, A/ B / C, D, F, G, H / E, I,J / K, L. The classification of the rice starches were based on amylose content, water-related and pastingparameters. The classification based on the amylose content was slightly different from that base on watersolubility or pasting characteristics. Especially, cultivar E was not within the same group of cultivars F, G,and H although cultivars E, F, G, and H contained similar amount of amylose. The cultivar E showeddifferent water solubility and pasting property from the cultivars with similar amylose content. Thus, theclassification of rice cultivars based on the practical processability is more appropriates useful than that basedon the classical amylose content. Rice cultivars within the category of the classification based on practicalprocessability can be assumed as a similar ingredient. Thus, mixture of the starches from the same categorycan be used as an ingredient for rice processing including starch production. In conclusion, rice starchescategorization can be simplified and standardized by using processibility parameters despite a variety of ricecultivars. The simplified classification of rice ingredients makes industrial utilization easy including ricestarch industries.