Physicochemical and functional properties of cross-linked banana resistant starch. effect of pressure cooking

A resistant starch (RS)-rich powder was prepared from phosphate cross-linked banana starch. Serial autoclaving and cooling treatments of this cross-linked material were also made. The powders were evaluated for chemical composition, resistant starch content, thermal characteristics, as well as for swelling and solubility properties. The parental cross-linked starch had similar lipid and protein contents than its autoclaved counterpart, but the ash content decreased after autoclaving, a pattern that is in agreement with the low phosphorus index and degree of substitution recorded in the autoclaved preparation. Although the RS content in the autoclaved cross-linked product was lower than in the non-autoclaved starch, the autoclaved product still exhibited a remarkable indigestibility. The peak temperatures of gelatinization were 86.6 and 68.5°C for cross-linked and autoclaved cross-linked starch, respectively. At low temperatures the autoclaved modified starch exhibited greater swelling values than its cross-linked counterpart. The pattern of solubility values resembled the swelling behavior of both samples. The autoclaved cross-linked banana starch appears suitable for the formulation of foods requiring none or moderate further heat treatment.