Freshness Assessment of Sweetpotatoes Based on Physicochemical Properties and VOCs Using HS-GC-IMS Combined With HS-SPME-GC-MS Analyses

Abstract

This study investigates the dynamic changes of volatile organic compounds (VOCs) during the storage of sweetpotatoes and their correlation with freshness, providing guidance for quality evaluation. The physicochemical indicators of sweetpotatoes stored at 15°C and 90% relative humidity were analyzed, followed by cluster analysis based on these indicators. VOCs during storage were measured using headspace–gas chromatography–ion mobility spectroscopy (HS-GC-IMS) and headspace–solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) techniques. The results showed that the physicochemical properties of sweetpotatoes changed regularly with storage time, allowing for the classification of freshness into three stages. Both HS-GC-IMS and HS-SPME-GC-MS results indicated significant changes in VOCs during storage, with orthogonal partial least squares discriminant analysis (OPLS-DA) effectively distinguishing between different freshness stages. Further multivariate statistical analysis of the HS-SPME-GC-MS data identified benzaldehyde, β-cyclocitral, β-cyclohomocitral, methyl phenylacetate, ethyl phenylacetate, eugenol, and β-ionone as indicators of freshness changes. A prediction model for the freshness variation of sweetpotatoes was constructed based on these VOCs, providing an important reference for analyzing freshness changes by measuring the VOCs released during storage.