Comparison of physicochemical properties and in vitro digestibility of starches from seven banana cultivars in China

Lots of bananas were wasted before commercialization. It is necessary to search potential industrial applications of banana. In the present study, starches from seven banana cultivars (labeled as A-G) were isolated and then characterized. These starches presented different and irregular shapes, such as sphere, long spheroid and polygonal granules. The distribution of size and analyses of average molecular weight showed more small granules in samples B, D, F and G than other samples. The amylose content varied from 22.59% to 38.40%. The crystal types of these starches were a mixture of B-type and C-type, and the relative crystallinity varied greatly. The differential scanning calorimetry (DSC) results showed that the onset temperature of gelatinization increased as follows: A < B < E < C ≈ D < F. The maximum viscosity of banana starch decreased as follows: G > C > D > F > E = B > A. The in vitro digestibility test showed that the content of resistant starch was very high in banana starches. These results would be useful to the application of those starches in food and nonfood industries.