An Assessment of Alkali Degradation, Waxy Protein and Their Relation to Amylose Content in Thai Rice Cultivars

ABSTRACT: In this study, the amount of waxy protein and starch properties including amylose content and alkali digestibility, and their correlation were investigated in a collection of Thai rice cultivars. We found that glutinous rice lacked Wx protein, whereas nonglutinous rice showed a positive correlation between amylose content and the amount of Wx protein (r = 0.97, p<0.01). Starch granules of glutinous rice varieties showed high levels of disintegration in alkali (KOH) solution, while starch granules of nonglutinous rice cultivars were significantly more resistant to alkali digestibility (t = 12.2, p< 0.01).

a Walai Rukhavej Botanical Research Institute, Mahasarakham University, Mahasarakham 44000 Thailand.
b Department of Chemistry, Faculty of Science, Mahasarakham University, Mahasarakham 44000 Thailand.
c Department of Biotechnology, Faculty of Technology, Mahasarakham University, Mahasarakham 44000 Thailand.
d Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400 Thailand.

* Corresponding author, E-mail: preecha.p@.msu.ac.th