Application of Natural Frequencies for Prediction of Apple Texture Based on Partial Least Squares Regression

Experimental modal analysis was performed to identify natural frequencies to predict the texture of inhomogeneous tissues of apple ( Malus domestina cv. ‘Golden Delicious’). Partial least squares calibration models based on natural frequencies with or without weight and density were created for predicting apple texture representing by yield gradient and initial modulus. The prediction models shown good prediction ability for texture of skin but impossible for flesh (all determination coefficients for skin models were more than 0.5 while for flesh models less than 0.5). A nondestructive and rapid method was provided to evaluate the fruit texture.