Enhancing mass transfer and preserving heat-sensitive quality of mango through foam mat drying

Mango puree was foamed using hydroxypropyl methylcellulose to achieve foam densities
ranging from 0.3 to 0.8 g/cm3. Subsequently, these mango foams were dried at temperatures
ranging from 60 to 80 C. The experimental results showed that mango foam drying
was in the falling rate period. The effective moisture diffusivity (Deff) was well described by
the Arrhenius equation, with the pre-exponential factor (D0) and activation energy (Ea)
closely related to the void area fraction in mango foam. This relationship led to higher Deff
and shorter drying times at higher void area fractions. The minimum loss of total phenolics
content (TPC) was observed in mango foams with an initial foam density of 0.3 g/cm3 dried
at 60 C, with only a 7% loss. Increasing drying temperatures to reduce drying time did not
mitigate TPC loss. Similarly, the minimum reductions in antioxidant activities, as measured
by both the 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid and ferric reducing antioxidant
power assays, were observed.