Effect of methocel™, maltodextrin, sodium chloride, and pH on foaming properties and foam-mat drying of aqueous pandan (Pandanus amaryllifolius) leaves extract

Abstract

The pandan (Pandanus amaryllifolius) leaf is commonly used as a food coloring and flavoring agent. Aqueous pandan leaf extract has no foaming properties and deteriorates quickly. Finding the appropriate foaming agent and stabilizer during drying is a challenge. The objective of this research was to investigate the effect of Methocel™, maltodextrin, sodium chloride (NaCl), and pH on foaming properties and foam-mat drying of aqueous pandan leaf extract. Foaming properties of an aqueous extract from fresh pandan leaves were elucidated using Methocel™ K4M (1 and 1.5% w/w) as a foaming agent, maltodextrin (0, 5, 10 and 15% w/w) as a stabilizer, and NaCl (0, 3, and 5% w/w) as a foam improver. The foamed pandan leaf extract was dried using a batch-type cabinet dryer. The results showed that the appropriate concentrations of Methocel K4M™, maltodextrin, and NaCl were 1% or 1.5%, 15%, and 5% (w/w), respectively. Increasing the maltodextrin concentration in combination with NaCl significantly affected the foam density, foam overrun, and foam drainage volume of the pandan leaf extract (p < 0.05). Adjusting the pH of the foam solution to 6.2-7.2 maintained the chlorophyll content during drying better than the control (p < 0.05).