AN-NIR-132
2025-10
Almond analysis with near-infrared (NIR) spectroscopy
Multiparameter determination of moisture, fat, and protein.
Summary
Almonds are nutritious edible nuts from the almond tree and can be eaten whole or processed in other foods. During processing, quality control (QC) parameters like moisture levels are checked to ensure that the correct percentage is reached before moving on to other stages (e.g., grinding or packaging). When determining almond quality, destructive analytical techniques are helpful but can involve extensive sample preparation and solvent extractions. These traditional techniques are also slow and expensive. Nondestructive near-infrared spectroscopy (NIRS) is a great alternative because it is fast, simple, and cost effective [1]. In this study, almond moisture content (water content), protein content, and fat have been measured using NIRS. NIR spectroscopy offers the rapid and reliable prediction of several quality parameters in seconds without any sample preparation.
Experimental Equipment
60 samples of ground almonds and 60 samples of whole almonds were measured on a Metrohm NIR Analyzer. All measurements were performed in reflection mode (1000–2250 nm) using the large cup accessory. The samples were measured in rotation to collect spectral data from diverse areas. Spectral averaging of signals from several spots helped to reduce sample inhomogeneity. Metrohm software was used for all data acquisition and prediction model development.
Result
The obtained NIR spectra of whole almonds
(Figure 1) and ground almonds (Figure 2) were used to create prediction models for the quantification of protein, fat, and moisture content. The quality of the prediction models was evaluated using correlation diagrams (Figures 3–8) which display a very high correlation between the NIR prediction and the reference values. The respective figures of merit (FOM) display the expected precision of a prediction during routine analysis.