Structure and digestibility of endosperm water-soluble α-glucans from different sugary maize mutants

The structure and digestibility of endosperm water-soluble α-glucans from different sugary-1 maize mutants (Zhongtian 8#, Zhongtian 2# and Pintian 8#) were investigated. The yield of pure glucan was in the range of 25.91-34.38%. The α-glucan belonged to a typical native nano-scale particle and the average particle size was in the following order: Zhongtian 8# >Pintian 8# >Zhongtian 2#. The weight-average molar mass of glucans ranged from 1.69 to 2.08 × 107 g/mol. The branch densities and α-1,6 linkages of Zhongtian 8#, Zhongtian 2# and Pintian 8#, were 8.60%, 8.77% and 9.51%, 7.71%, 6.58% and 6.81%, respectively. The resistant starch (10.06%) of Pintian 8# was lower than other two cultivars. The study showed that water-soluble glucan exhibited α-1,4-linked backbone with α-1,6 branch sites and digestibility was influenced by granule size, ratio of α-1,4 to α-1,6 linkages, molecular fine structure in this set of sugary maize mutants.