Nanoencapsulation of roasted coffee bean oil in whey protein wall system through nanospray drying

Roasted coffee bean oil is an important by-product obtained from the coffee industry. In this study, roasted coffee bean oil was nanoencapsulated in whey protein wall system, using nanospray drying (NSD). The structural properties and thermal behavior of the resultant encapsulate were studied in comparison with that obtained through conventional spray drying. From the dynamic light scattering-based particle size measurement, the mean particle diameter of the nanospray-dried encapsulates was found to be 304.9 +/- 99.4 nm. Further, image analysis showed that the nanoencapsulates were about 11-fold smaller than the microencapsulates. NSD resulted in a more uniform particle size distribution of the coffee oil nanoencapsulates than its microencapsulated counterpart. Study of morphology by scanning electron microscopy revealed nanosized, smooth, and spherical particles of the nanospray-dried encapsulate. Whereas, microencapsulates showed both smooth-spherical and cap-shaped, dented particles. Thermal stability analysis by differential scanning calorimetry indicated the protective effect of encapsulation on coffee oil constituents. Practical applications The results of this study established the nanospray-drying process as a potential technique for the nanoencapsulation for roasted coffee oil. The inferences from this research work would be useful to the food, ingredient, and flavoring industries.