Improvement of 3D printability of buckwheat starch-pectin system via synergistic Ca2+-microwave pretreatment

Synergistic calcium chloride and microwave heating treatment was applied to improve the rheological properties and printability of a model buckwheat starch-high-methoxy pectin (BP) gel system. Rheological property results suggested that sole microwave heating significantly improved the plasticity, while synergetic treatment significantly decreased the viscosity of the gel. Microwave heating weakened the hydrogen bonding within the gel. On the other hand, synergistic treatment caused an aggregation through cross-linkage between Ca2+ and amide group within the gel; this in turn resulted in the discharge of part of water bound to gel matrix and hence the lower viscosity of the gel. Printing experiments revealed that synergistic pretreatment for 30 s could significantly improve the printing precision of the gel when compared with that of the gel sample steamed for 30 min.