Effect of Different Wall Materials on the Preparation of Sustained-Release Aroma Microcapsules by Ultrasonic Spray-Freeze Drying

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.

Keywords

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