X-ray micro computed tomography investigation of microstructure and its relations with physicochemical properties of heterogeneous food product during hot air drying

X-ray micro computed tomography (μCT) is a non-invasive measuring technique that can be used to reveal the microstructural information of food product. In this work, μCT was applied to obtain the microstructural information (porosity, pore size, pore size distribution and relative solid volume) on drying behavior of plantain samples subjected to hot air drying at 50, 60 and 70 o C. The μCT results showed that at the end of drying, there was 51.59, 54.11 and 113.60% increase in the porosity of plantain samples dried at 50, 60 and 70 o C, respectively. Whereas there was 18.31, 19.06 and 37.29% decrease in the relative solid volume at 50, 60 and 70 o C, respectively. The μCT also revealed cell rupturing of the sample as drying progressed. The pore size distribution indicated that the pore sizes increased as drying progressed and at high temperature. The correlation analysis showed that at 70 o C, vitamin C had a significant (p<0.05, p<0.01) strong negative correlation with pore size (-0.88) and porosity (-0.93), respectively, while carotenoid had a significant (p<0.05) strong positive correlation with pore size (0.89) and porosity (0.91). The information can be used in the modelling and design of an efficient drying system for a heterogeneous food material. • Non-invasive measurement of microstructural properties of dried plantain by X-ray micro computed tomography (μCT) • Cell rupturing was visualized by μCT • Porosity increased by 51.59, 54.11 and 113.60% for samples dried at 50, 60 and 70 o C, respectively. • Solid volume decreased by 18.31, 19.06 and 37.29% for samples dried at 50, 60 and 70 o C, respectively. • At 70 o C, pore size had a significant (p<0.05) strong negative correlation (-0.88) and positive correlation (0.89) for vitamin C and carotenoid, respectively.