Storage-Driven Flavor Deterioration in Goji berry Pulp: Unraveling Evolution Patterns and Underlying Chemical Mechanisms via a Multi-Technology Approach

Storage-driven flavor deterioration of goji berry pulp was systematically elucidated by integrating sensory evaluation, electronic nose (E-nose) and gas chromatography-ion mobility spectrometry (GC-IMS). Seven storage time points (0,2, 4, 6, 8, 10 and 12 months) were monitored under 25 °C. Sensory analysis revealed that the overall liking score declined significantly from 7.29 to 4.05 ( p < 0.001), accompanied by a monotonic increase in undesirable yeast-like and grassy off-odors. E-nose differentiated all storage stages with 92.7% accuracy. GC-IMS identified 47 volatile compounds, with aldehydes and ketones being predominant in fresh pulp, while acids and furans accumulated during storage. After 6 months, the total abundance of fruity ketones and aldehydes dropped by 1571.56 μg/kg, coinciding with the first detection of 2-pentyl-furan and trimethylamine (TMA). A total of 23 key markers (VIP > 1), including 6 aldehydes, 4 ketones, 3 alcohols, 4 carboxylic acids, 3 esters and 3 other compounds, that correlated strongly with sensory decline (r = -0.9759) were identified. 1-Octen-3-ol (ROAV = 19.78) and TMA (ROAV = 21.77) were confirmed the main contributors to off-odor after 6 months. The multivariate approach establishes 6 months as the critical sensory turning point and provides a rapid E-nose+TMA/1-octen-3-ol dual-marker strategy for real-time shelf-life control of goji pulp.