Effect of foaming agents on process conditions, characteristics, and stability of foam-mat freeze-dried pandan (Pandanus amaryllifolius) powder

摘要

Foam-mat freeze-drying (F-FD) of aqueous pandan extract with various foaming agents (egg white protein, sodium caseinate, and METHOCEL) was carried out to improve the process conditions, physicochemical properties, and stability of pandan powder. The foamed pandan solution with egg white protein (F-EW) provided the most stable foam structure and shortened drying time to 6 hr, while the control took 24 hr to dry at the same sample thickness. The F-EW freeze-dried pandan powder (FDPP) had the highest hue angle, the highest greenness (a* value), the lowest bulk density, and high solubility. The reaction rate constants for the physicochemical changes in foamed-freeze-dried pandan powders were lower than those of the control and the highest color stability was recorded for F-EW FDPP when stored at high temperature (37°C) for 12 weeks. Egg white at a concentration of 10% w/w is an appropriate foaming agent for producing pandan powder via the F-FD.