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Journal of Thai Traditional & Alternative Medicine Vol. 7 No. 2 May-August (Supplement) 2009 ˘Û

OP-32

Rapidly and slowly available glucose of the selected Thai rice and the effect

of various cooking methods on their values

Sriwatana Songchitsomboon, Thanintorn Mayakarn

Faculty of Medicine RamaThibodi Hospital, Mahidol University, Bangkok, 10400 Thailand

Rationale: Data from the latest national survey (2003) showed that 60 - 70 % of total energy intake of Thais

came from rice. The biodiversity of rice genotypes is larger than that of other cereal grains. This large biodiversity
encourages the exploration of factors that determine digestion rate which influence glycemic response which
become a topic of interest and research in North America, Asia, and Europe.

Objectives: The aim of this study was to determine rapidly available glucose and slowly available glucose
of new breeding varieties that contain higher iron dense and antioxidant capacity. The effect of cooking

methods and ratios of mixture between brown rice and polished on values of RAG and SAG of selected rice
were also evaluated
Methodology: The rapidly available glucose (RAG) and slowly available glucose (SAG) were determined

by Englyst method in eight new rice varieties and also glutinous rice RD6, both brown and polished rice. The
effect of cooking methods as steaming and boiling as well as the ratios mixture of brown rice (BR) and polished

rice (PR) as solely BR, 1/3 BR (BR: PR=1:2), 1/4 BR (BR: PR=1:3), 1/5 BR (BR: PR=1:4) and solely PR on the values
of RAG and SAG were also determined in three selected rice varieties (rice no.1000-11-2-26 or no.313-1-9-1-1
and Khao Dawk Mali 105).

Results: The results showed that rice varieties 1000-11-2-26, 313-19-1-1, IR57501 x Pinkaset no.3-1-22-6-1
and Pinkaset, which mean values of RAG of brown rice were significantly lower than polished rice. Moreover,
only brown rice no.1000-11-2-26, 313-1-9-1-1 and polished rice no.1000-11-2-26 cooked by steaming (khaaosuay)

have RAG values significantly lower than boiling (khaaotom). The effect of 5 different ratios between brown rice
and polished rice showed that the values of RAG either solely of brown rice no 1000-11-2-26 or no.313-1-9-1-1
were significantly lowest from the other ratios.

Conclusion: The values of RAG of brown rice no.1000-11-2-26, 313-1-9-1-1 and polished rice no.1000-11-2-
26 by the steaming were significantly lower than by boiling method. In addition, the effect of 5 different ratios

between brown rice and polished rice before steaming on digestibility rate showed that the values of RAG
either solely of brown rice no 1000-11-2-26 or no.313-1-9-1-1 were significantly lowest from the other ratios. Our
result suggested that low GI brown rice no.1000-11-2-26 and no.313-1-9-1-1 should be cooked as solely brown

rice by steaming to have lower RAG values.