Nondestructive Hardness Assessment of Kiwi-Fruit Using Near-Infrared Spectroscopy

Abstract

To study the relationship between the hardness of kiwi-fruit and its near infrared diffuse reflectance spectroscopy, using near infrared diffuse reflectance spectroscopy and chemical analysis method. And establish a method to realize the nondestructive assessment of hardness, which at room temperature (24 degrees ±2 degrees) conditions, using near infrared spectroscopy (4000~10000cm-1) to test different parts of kiwifruit samples in the equatorial region for the original spectral data acquisition. And using processing method based on the smoothing, normalization of combined processing method to preprocess the original spectral data. Then using partial least squares (PLS), principal component regression (PCR) and multiple linear regression (MLR), which can be establish the positive model for the hardness and assessment. The experimental results showed that the accuracy of the calibration model established by the combination of pretreatment method and PLS method is the highest. And the calibrating correlation coefficient (Rc) and correlation coefficient of prediction set (Rp) reached 0.9765 and 0.9462 respectively, RMSEC and RMSEP reached 0.5483 and 0.6127 respectively which is verified the feasibility of the method.