Evolution of Physicochemical Properties and Volatile Compounds in Potatoes during Boiling

To systematically investigate the dynamic changes and underlying mechanisms of physicochemical properties and volatile compounds in potatoes during cooking, samples subjected to five cooking durations were comprehensively characterized using multidimensional techniques, including texture analyzers, rheometers, low-field nuclear magnetic resonance (LF-NMR), gas chromatography-ion mobility spectrometry (GC-IMS), and scanning electron microscopy (SEM), to assess texture properties, water migration, microstructure, and volatile profiles. It was revealed that cooking time had no significant effect on total moisture content (P>0.05). However, a decrease in the transverse relaxation time (T2) at the core was observed, indicating partial conversion of bound water to free water. Chromaticity parameters (L*, a*, b*) were significantly reduced (PPP>0.05). Rheological studies revealed that the viscosity versus frequency trends became increasingly similar for samples boiled between 18.5 min and 24.5 min, and the curves for 22.5 min and 24.5 min almost completely overlapped. Microstructural examination revealed that starch granules underwent swelling, rupture, and fragmentation, accompanied by progressive disintegration of the core matrix. Additionally, 67 volatile compounds were identified, among which aldehydes and pyrazines were enhanced by cooking. Prolonged cooking (>20.5 min) led to the formation of off-flavor compounds (e.g., 1-propanethiol, propanol, butyric acid, nonanoic acid). A critical threshold was identified at 20.5 min of boiling, with stabilized color parameters, water distribution, textural properties, and rheological characteristics, accompanied by elevated levels of characteristic flavor compounds and superior overall quality.