Volatile Retention in Microwave Freeze-Dried Model Foods

Pregelatinized corn starch solutions (8% solids) were mixed with 500 ppm each of 1-hexanol, 1-decanol and D-limonene, and subjected to three treatments: control or null treatment, addition of 4%β-cyclodextrin, and addition of 4% sucrose. Samples were frozen at ?15°C, ?60°C or ?198°C, and freeze-dried at a microwave power of 10W and a cavity pressure of 1 or 2 torr. Results showed that sample composition was significant in both drying rate and volatile retention. Samples containing β-cyclodextrin had higher levels of volatile retention than other treatments, probably due to inclusion complex formation and shorter drying times. In general, samples frozen at ?15°C had higher levels of volatile retention. Freeze-drying of samples at 1 torr resulted in higher final moisture contents than at 2 torr, but no appreciable differences in volatiles.