The microencapsulation of flavor, oil, or functional compounds is the technology of converting liquid materials into easy-to-handle solids. It also provides protection against degradative reactions and prevents the loss of the compounds. Among them, spray drying is the most popular method of producing food powders, which presents the challenge of removing water by vaporization while retaining the functional compounds. The relaxation behaviors of spray-dried powder during spray-drying and the flavor release at storage are reviewed in the research of spray-dried powder. Especially, the estimation of diffusion coefficient of water or flavor in matrix was discussed. The flavor release behaviors could be well correlated with Avrami equation. The morphology of spray-dried powder affected the release and oxidation of flavor. It is pointed out that the morphology of spray-dried powder is important properties in the relaxation behaviors of spray-dried powder.
Fluorescence fingerprints (FF) of 137 Japanese taro samples and 23 Chinese ones, harvested in 2008, were measured in the excitation and emission wavelengths ranging from 200 to 900 nm at 10 nm intervals after grinding and homogenization. The obtained data set was split into calibration and validation data sets. Canonical discriminant analysis was applied to the former to develop a model for the prediction of the country of origin from its FF. Then the model was applied to the validation set to test the model accuracy, which resulted in the misclassification rate of 9.4%. The area under the curve (AUC) of the receiver operating characteristics for the FF method was equivalent to those for inorganic elements composition and the combination of inorganic elements composition and the Sr isotopic ratio. These results showed the potential of FF as a quick and accurate method to determine the geographic origin of taros.