Abstract: In order to study the difference in the encapsulation capacity of different microcapsule wall materials for volatile flavor substances, microcapsules were prepared with seven common wall materials by ultrasonic spray-freeze drying technology and their morphology, encapsulation and slow release capacity for 32 volatiles were evaluated by cold field emission scanning electron microscopy (CFE-SEM), electronic nose (EN), and gas chromatography-mass spectrometry (GC-MS). These results showed that the encapsulation capacity of different wall materials exhibited selectivity for different volatiles. In general, β-cyclodextrin had a stronger encapsulation capacity for the volatile compounds, with a higher encapsulation and release efficiency, so it was an ideal wall material. After 30 minutes of heating, the release profile of volatiles encapsulated by β-cyclodextrin in the EN radar plot was similar to that of free volatiles, indicating that the microcapsules prepared in this study had good slow-release performance. These results provide a theoretical basis for the utilization of microencapsulated products for flavor enhancement and flavor stability improvement in the food field.

Key words: ultrasonic spray-freeze drying; slow-release microcapsules; microcapsule wall; gas chromatography-mass spectrometry; flavor compounds