Classification by bitterness of intact almonds analysed in bulk using NIR spectroscopy

摘要

Near infrared (NIR) spectroscopy can be a fast and reliable candidate for the non-destructive and in-situ classification of almonds by bitterness, when analysed in bulk. With that purpose, in-shell and shelled sweet and bitter almonds were analysed using a handheld diode array NIR spectrophotometer (950-1650 nm). Models were constructed using partial least squares-discriminant analysis (PLS-DA) and the optimum threshold value was set up using the Receiver Operating Characteristic (ROC) curves. The models correctly classified 95 % of in-shell and 100 % of shelled samples belonging to the external validation sets. The excellent performances obtained for the classification models of the in-shell and shelled almonds analysed in bulk will enable to remove bitter almonds from the sweet almond batches and, with it, to avoid selling those batches containing bitter almonds that could lead to product depreciation.