FLUIDIZED BED DRYING PROCESS OF MINIFLAKES BANANA (Musa acuminata)

Abstract

The influence of pre-treatment and drying conditions on physical characteristics (moisture content, water activity, net colour difference, shrinking and effective diffusivity) of banana miniflakes during fluidized bed drying was investigated. Banana miniflakes in physiological state (diameters 1.0 - 2.0 cm) were pre-treated with citric acid solution (0-1 % w/w) before to be submitted to the drying process. Drying process (air temperature 50-70 oC) timed 90 min and was monitored every 5 min. A surface response model was used in order to analyse the effect of factors. Citric acid solution (1 % w/w) decrease colour difference since a minor difference of 2.72 was obtained. Banana miniflakes showed aw<0.2 after 60 min treatment, supposing a microbiological stable product. Miniflakes shrinking turned out to be independent of diameter, then, values from 20-25 % were achieved for the whole samples. It was found an inverse function between diffusivity coefficient (E-10) and diameter sample. Drying of banana miniflakes was influenced by pre-treatment, drying temperature and miniflakes diameter.