Abstract:

This study was conducted aiming to evaluate and compare the effects of six drying methods including hot-air drying,
vacuum freeze drying, explosion puffing drying, traditional frying, vacuum drying, microwave vacuum drying on nutritional
components, microstructure, sensory evaluation, aroma composition, and manufacture cycle of dried banana products. Physical and
chemical analyses were carried out for nutrient contents, sensory evaluation was performed using scoring test, and microstructure
was observed by scanning electron microscopy (SEM). Solid phase micro-extraction and gas chromatography mass spectrometry
analysis were used to detect flavor components. Furthermore, comprehensive evaluation was implemented by the coefficient of
variation method. The results showed that all the six drying methods could significantly change nutritional contents of banana;
explosion puffing drying and vacuum freeze drying provided better retention of various nutrients; as observed by SEM,
explosion puffing drying showed the maximum intercellular gaps in dried products and the dried product had the highest
sensory score and contained different classes of unique flavor components. Frying and vacuum freeze drying gave better
retention of esters in fresh banana. Comprehensive evaluation results followed the decreasing order of vacuum freeze
drying > explosion puffing drying > fried puffed drying > vacuum drying > microwave vacuum drying > hot-air drying.
However, vacuum freeze drying needed large investment and long production cycle. Explosion puffing drying produced a
dried product with a loose and porous structure characterized by the largest intercellular spaces. Taken together, it can be
concluded that explosion puffing drying is suitable for dried banana products.

Key words: bananas, drying method, nutritional component, microstructure, aroma component, coefficient of variation