The physicochemical properties and molecular structure of Maori potato (Taewa) starch

Abstract

The properties of starch, the resultant purified amylopectin, and beta-limit dextrins from five Maori potato (Taewa) cultivars (Kowiniwini, Moemoe, Tutaekuri, Huakaroro, Karuparera) were investigated to determine whether differences exist between the different starch and to determine possible relationships between starch properties, including physicochemical characteristics, granule morphology, thermal and pasting properties, rheological capacity, and enzyme susceptibility. It was found that there were no significant differences between the properties in Taewa starch and the starch of current cultivars of potato (Red potato). Normal maize starch, used as a comparison for differences in botanical origin, exhibited more remarkable differences in the properties. Taewa starch exhibited typical characteristics of Group 3 starch, according to the internal unit chain length profile of their beta-limit dextrins, where the highest amount of B3- and B2- chains were located. The Moemoe and Tueakuri starch showed obvious differences in various properties. Moemoe starch, with the lowest phosphorus content, exhibited the highest enthalpy requirement during gelatinization and enzyme susceptibility compared to other Taewa cultivars. Tueakuri had the highest amylose content, contributing to the highest measured transition temperature when gelatinized and the hardest gel texture among the samples tested. The isolated starch from Taewa cultivars have more similar physicochemical properties, granular structure, thermal and rheology properties, and molecular structure compared to starch of other Taewa cultivars than to starch from modern cultivar (Red potato). However, regardless, there are differences in the properties between the starches of different Taewa cultivars.