Effects of Preheating and Storage Temperatures on Aroma Profile and Physical Properties of Citrus-Oil Emulsions.

Citrus oils are used as good carrier oil for emulsion fabrication due to their special flavor and various health-promoting functions. In this study, the effects of preheating temperature (30, 40, 50, 60, and 70 °C) and storage temperature (4, 25, and 37 °C) on aroma profiles and physical properties of three citrus-oil (i.e., mandarin, sweet orange, and bergamot oils) emulsions were systematically investigated for the first time. The results demonstrated the significant impact of temperature on aroma profile and physical properties. The abundance of d-limonene was found to be the main factor determining the aroma of the three citrus-oil emulsions at different preheating and storage temperatures, while β-linalool and linalyl acetate were important for the aroma of bergamot oil emulsion. Preheating temperature showed a profound impact on the aroma of citrus-oil emulsions, and the aroma of different citrus oil emulsions showed different sensitivity to preheating temperature. Storage temperature was also able to alter the properties of citrus oil emulsions. The higher was the storage temperature, the more alteration of aroma and more instability of the emulsions there was, which could be attributed to the alteration of the oil components and the properties of emulsions. Among all three emulsions, bergamot-oil emulsion was the most stable and exhibited the most potent ability to preserve the aroma against high temperature. Our results would facilitate the application of citrus-oil emulsions in functional foods and beverages.