Abstract
In this study, we aimed to develop a simple measurement method for estimating the firmness of foods, based on spatially resolved diffuse reflectance measurement. Apples stored for different periods were measured, and the gradient of the intensity profiles was shown to gradually decrease with storage. To estimate apple firmness from the intensity profiles, the coefficients of the theoretical formula and the gradients of the intensity profiles calculated at 1.0 mm intervals were used. As a result, the firmness could be estimated at a practical level with RMSE less than 1.5 N, which was more precise than sensory evaluation. Compared to other non-destructive methods used for texture estimation, the method proposed in this study is advantageous in terms of easy implementation.
