Accelerated storage of ground coffee: Merging of analytical techniques to assess sensitivity to oxygen and moisture exposure

This study investigates the effectiveness of analytical techniques-electronic nose (e-nose), headspace (HS) analysis by solid phase micro extraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and Fourier-transform near-infrared (FT-NIR) spectroscopy-in detecting quality changes in ground coffee exposed to accelerated conditions, including elevated oxygen levels, relative humidity, and temperature. The goal is to assess how these techniques could be complementary to sensory analysis to provide a comprehensive evaluation of coffee aging and quality deterioration. Sensory analysis revealed a decline in attributes such as body, odor intensity, aftertaste, and aroma intensity over time and at higher temperatures, while oxidative notes and astringency increased. Bitterness and acidity were also intensified under accelerated aging. HS-SPME-GC-MS analysis showed a reduction in volatile compounds during storage, with high temperatures accelerating this loss. E-nose data reflected a rapid decline in sensor signals for aromatic and sulphur-containing compounds, indicating significant aroma degradation. FT-NIR analysis identified variations in moisture, carbohydrate, and lipid content between fresh and aged samples. Principal component analysis (PCA) of combined sensory and instrumental data revealed that fresh samples were associated with higher volatile levels and more favourable sensory characteristics, whereas aged samples exhibited greater bitterness, acidity, and oxidation. Mid-level data fusion confirmed consistent trends across techniques, enhancing the interpretation of quality changes. These findings underscore the complementarity of instrumental and sensory methods to monitor the aging process of ground coffee and ensure product quality over time.