Non-destructive determination of moisture content and brix value in carrot using Near infrared spectroscopy (NIRS)

One of the most important ways to increase sales and marketability of the agricultural products is the classifying them according to the morphological characteristics and the internal quality. Water content and soluble solid content are two important quality factors of carrot. Although other ways such as image processing can be used for classifying, the spectroscopic method can be a better choice for measuring the internal quality than others. In this research optical method based on near infrared spectroscopy (900-1600 nm) has been used to determine moisture content and brix index in carrot. A total of 60 samples were used for the modeling, whereas 40 samples were used for the calibration set and 20 samples were used for prediction set. Four pre-processing methods, including average smoothing, multiplicative scatter correction (MSC), first and second derivatives, were applied to improve the predictive ability of the models. Then models were developed by partial least squares (PLS). The correlation coefficient (R2) and root mean square error of prediction (RMSEP) were 0.92 and 1.13 for moisture content, whereas 0.96 and 1.07 for SSC., respectively. The results show that NIR can be used as a rapid method to determine soluble solid content and moisture content in carrot.