NIR-HSI for the non-destructive monitoring of in-bag hazelnut oxidation

Abstract

This study explores the application of Near-Infrared Hyperspectral Imaging (NIR-HSI) as a non-destructive method for monitoring the oxidation of hazelnuts (Corylus avellana) stored under different atmospheric conditions (air, nitrogen, and vacuum) and light exposures, directly inside plastic bags, without the need for packaging removal nor sample preparation. Hazelnuts were imaged over a 78-day storage period, and data were analysed using ANOVA-Simultaneous Component Analysis (ASCA) to quantify the effects of time, atmosphere, and light on oxidation. Individual hazelnuts within each bag were segmented for analysis to study inter-hazelnut variability. Images were studied individually to detect oxidation patterns on the surface. Results indicate that time is the primary driver of oxidation, as expected, with atmosphere and light significantly impacting oxidation rates. Vacuum storage was most effective at reducing oxidation, while light exposure under ambient conditions accelerated oxidation via photooxidation. Sensory analysis confirmed that spectroscopic indicators of oxidation corresponded to perceptible sensory changes, validating NIR-HSI as a reliable tool for assessing hazelnut quality. This study underscores the potential of NIR-HSI and chemometrics for quality control and shelf-life assessment in hazelnuts and other oxidation-prone food products.