Changes in Physicochemical Properties and Volatile Flavors of Abalone Muscle during Drying Process

The patterns of changes in the physicochemical properties and volatile flavors of abalone muscle during drying at 50 ℃ and 65% relative humidity were investigated in this study. With an increase in drying time, the browning intensity and fluorescence intensity of both surface and internal muscles of abalone increased gradually, which started to decrease after reaching a peak on the 90th day. The contents of reducing sugar and lysine in the surface muscle were 3.11 mg/g and 2.60% after pretreatment, and decreased to 1.95 mg/g and 1.61% after 120 days of drying, respectively. High molecular mass polymers were observed in the electrophoretic pattern of abalone muscle after 30 days of drying. Fourier transform infrared spectra showed that the intensity of the characteristic absorption peaks (1 403 and 1 026 cm-1) of glycoproteins gradually enhanced with increasing drying time. The response values of the electronic nose sensors W1W (sulfides) and W2S (alcohols, aldehydes and ketones) increased, and the content of 1-octen-3-ol decreased while the contents of linalool and (E,E)-2,4-decadienal increased after 30 days of drying, as determined by gas chromatography-mass spectrometry (GC-MS). At the same drying time, the intensity of Maillard reaction in the surface muscle was weaker than that in the internal muscle.