Development of Nitrate Content Prediction Technique of Aloe Vera Leaves using Nondestructive Technique by Near Infrared Spectroscopy

Abstract

This study examined the use of near-infrared spectroscopy to assess nitrate concentration of freshly harvested aloe vera leaves. Equations for predicting nitrate concentration of aloe vera leaves were developed in this work, based on the analysis of 80 samples. The NIR spectra were collected from different positions on the outer rind, specifically the apex, center, and base. Subsequently, the outer layer of the corresponding sites was removed and the concentration of nitrate in the aloe vera gel was examined by nitrate ion meter. The partial least squares regression (PLSR) method was employed to create a prediction equation for the nitrate content. The equation derived from the spectra obtained at the central position demonstrated the highest accuracy, as indicated by a correlation coefficient of prediction of 0.98 and root mean squared error of prediction of 3.50 ppm. The regression coefficients of the nitrate prediction equations were dominated at the wavelengths of 957, 1104 and 1154 nm. Therefore, it is possible to use the NIRS technique to predict the nitrate content of aloe vera leaves without destroying the sample. This technique will allow a quick and accurate measurement of the nitrate content in aloe vera leaves.