Determination of Apparent Amylose Content in Japanese Milled Rice Using Near-Infrared Transmittance Spectroscopy

抄録

The objective of the present study was to develop a method to analyze apparent amylose content (AAC) of Japanese milled rices using near-infrared transmittance spectroscopy (NIT). Samples (n=110, varieties=37), harvested in 1996, were collected at various sites throughout Japan. Whole-grain milled rice was scanned using a near-infrared range (833-1050 nm with 8 nm steps and 27 wavelengths) transmittance filter type spectrometer. The AACs of samples were in the range of 13.1% to 20.7% (SD: 1.53). The wide range AAC (0-35.3%) partial least squares (PLS) model was found to be inadequate for accurate prediction of the narrow AAC range (13.2-20.7%) of the rice samples. The statistical performance of PLS modeling (11 factors) for narrow range AAC analyses gave a standard error of cross-validation (SECv) of 0.78 and square of regression coefficient (R²) of 0.74. The AAC model was applied to 20 unknown samples of products from different crop year (1997), and gave a standard error of prediction (SEP) of 1.25, R² of 0.49 on the validation set. These results suggested that this model based on NIT spectroscopy could be applied for rapid and nondestructive measurement of narrow range AAC of Japanese milled rices.