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Title: Addressing the dilemmas of measuring amylose in rice

Author
item FITZGERALD, MELISSA - International Rice Research Institute
item BERGMAN, CHRISTINE - University Of Nevada
item RESSURRECCION, ADORACION - International Rice Research Institute
item MOLLER, JURGEN
item JIMENEZ, ROSARIO - International Rice Research Institute
item REINKE, RUSSEL
item MARTIN, MARGRIT
item BLANCO, PEDRO - National Institute For Agricultural Research (INIAP)
item MOLINA, FEDERICO - National Institute For Agricultural Research (INIAP)
item Chen, Ming Hsuan
item KURI, VICTORIA - National Institute For Agricultural Research (INIAP)
item ROMERO, MARISSA - International Center For Tropical Agriculture (CIAT)
item HABIBI, FATEMEH - Rice Research Institute Of Iran
item UMEMOTO, TAKAYUKI - National Institute Of Crop Science - Japan
item JONGDEE, SUPANEE - Ubon Ratchathani Rice Research Centre
item GRATEROL, EDUARDA
item REDDY, K
item BASSINELLO, PRISCILA - Embprapa
item SIVAKAMI, RAJESWARI - Tamil Nadu Agricultural University
item RANI, N - Rajendra Institute
item DAS, SANJUKTA - Central Rice Research Institute
item WANG, YA-JANE - University Of Arkansas
item INDRASSI, SITI - Indonesian Agency For Agricultural Research And Development
item RAMLI, ASFALIZA - Pusat Penyelidikan Padi Dan Tanaman Industri
item RAUF, AHMAD - National Agricultural Research Center - Pakistan
item DIPTI, SHARIFA - Bangladesh Rice Research Institute
item XIE, LIHONG - China National Rice Research Institute
item LANG, NGUYEN - Cuu Long Delta Rice Research Institute
item SINGH, PRATIBHA - Govind Ballabh Pant University Of Agriculture And Technology
item TORO, DAMASO - Instituto De Investigaciones Del Arroz
item TAVASOLI, FATEMEH - Govind Ballabh Pant University Of Agriculture And Technology

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2009
Publication Date: 9/1/2009
Citation: Fitzgerald, M.A., Bergman, C.J., Ressurreccion, A.P., Moller, J., Jimenez, R., Reinke, R.F., Martin, M., Blanco, P., Molina, F., Chen, M., Kuri, V., Romero, M.V., Habibi, F., Umemoto, T., Jongdee, S., Graterol, E., Reddy, K.R., Bassinello, P.Z., Sivakami, R., Rani, N.S., Das, S., Wang, Y., Indrassi, S.D., Ramli, A., Rauf, A., Dipti, S.S., Xie, L., Lang, N.T., Singh, P., Toro, D.C., Tavasoli, F. 2009. Addressing the dilemmas of measuring amylose in rice. Cereal Chemistry. 86(5):492-498.

Interpretive Summary: Amylose content is a parameter that correlates with cooked rice texture and other cooking properties. It is measured at the earliest possible stages of rice improvement programs to enable breeders to select for desired grain quality during cultivar development. However, the different values for amylose content for the same variety reported in different publications, and the different methods used for measuring amylose found in different research papers suggest confusion about measuring amylose at the international level. The International Network for Quality Rice (INQR) carried out a survey involving 27 quality evaluation laboratories from every rice-growing region of the world to determine: ways that amylose is measured; reproducibility between laboratories; and sources of variation. Each laboratory measured the amylose content of a set of 17 varieties of rice. The data show that repeatability was high within laboratories but reproducibility between laboratories was low. The major sources of variability were the way the standard curve was constructed and the sources of the potato amylose standards for constructing the standard curves. New research avenues for quantifying the real amount of amylose in rice grains are presented.

Technical Abstract: Amylose content is a parameter that correlates with the cooking behaviour of rice. It is measured at the earliest possible stages of rice improvement programs to enable breeders to build the foundations of appropriate grain quality during cultivar development. Amylose is usually quantified by absorbance of the amylose-iodine complex. The International Network for Quality Rice (INQR) carried out a survey to determine: ways that amylose is measured; reproducibility between laboratories; and sources of variation. Each laboratory measured the amylose content of a set of 17 varieties of rice. The study shows that five different versions of the iodine binding method are in operation. The data show that repeatability was high within laboratories but reproducibility between laboratories was low. The major sources of variability were the way the standard curve was constructed and the iodine binding capacity of the potato amylose. When laboratories are separated by type of standard curve, reproducibility is much lower between laboratories that used a standard curve of potato amylose alone compared with those who used calibrated rice varieties. We, as heads of most of the world’s rice quality programs, present new research avenues for quantifying the real amount of amylose in rice grains.