Predicting the buckwheat flour ratio for commercial dried buckwheat noodles based on the fluorescence fingerprint.

A rapid method for predicting the buckwheat flour ratio of dried buckwheat noodles was developed by using the fluorescence fingerprint and partial least squares regression. Fitting the calibration model to validation datasets showed R(2)=0.78 and SEP=12.4%. The model was refined for a better fit by deleting several samples containing additional ingredients. The best fit was finally obtained (R(2)=0.84 and SEP=10.4%) by deleting the samples containing vinegar, green tea, seaweed, polysaccharide thickener, and yam. This result demonstrates that a calibration model with high accuracy could be constructed based on samples similar in material composition. The developed methodology requires no complex preprocessing, enables rapid measurement with a small sample amount, and would thus be suitable for practical application to the food industry.

[Development and single laboratory validation for thermoluminescence detection of irradiated foods using X-ray irradiation].

The thermoluminescence (TL) method using X-rays was investigated for the purpose of detection of irradiated food, and the method was validated at a single laboratory level. A small X-ray irradiator was developed as an alternative radiation source for normalization, and X-ray irradiation conditions equivalent to gamma-ray irradiation from (60)Co were established. Gamma-ray irradiated spices were used for the method validation. The detection limits (MDL) and lower limit of integrated TL intensities (MDL×10) for the spices were checked and the separation of silicate minerals from the spices was confirmed to be sufficient for TL analysis. There was no significant difference in TL glow ratio obtained using two sets of X-ray irradiation equipment including the newly developed equipment. Repeatability and intermediate precision showed no influence of analysts, X-ray irradiation equipments, or measurement days on the TL ratios. From these results, this detection method was validated in a single laboratory.