The synergistic effects of amylose and phosphorus on rheological, thermal and nutritional properties of potato starch and gel

Abstract

► Higher phosphorus content enhanced re-crystallisation of amylopectin in a concentrated starch gel system. ► More rigid gel can be obtained from higher phosphorus content of starch. ► Phosphorus content was positively correlated to the resistant starch content in raw starch. ► Phosphorus content was positively correlated to the slowly digestible starch in starch gel. This study investigated synergistic impact of amylose and phosphorus on the rheological, thermal, structural and nutritional properties of native potato starch, dry starch gel and freshly cooked gel. The results indicated that starch with a high amylose level and higher phosphorus content showed enhanced retrogradation extent, associated with a well-formed and rigid gel structure and more ordered structure, compared to starch with a lower phosphorus content. Phosphorus content in starch was positively correlated to resistant starch content in native starch ( p < 0.001) and to the slowly digestible starch content in the starch gel ( p < 0.05). Amylose content alone appeared not to be a good indicator of the starch digestibility. Phosphorus content played a dominant role in some physicochemical properties of starch when the amylose content was above a threshold level. The temperature ramp test appeared to be a sensitive method to detect the re-crystallisation of starch molecules during the early stages of retrogradation.