Fabrication and characterization of starch-based bigels under phase control: Structural, physicochemical and 3D printing properties

Abstract

Edible bigels are being developed to replace plastic fats in the food industry due to their ability to form semi-solids with controllable properties. In this study, biopolymer hydrogels were formed using modified corn starch with chitosan, betaine, and vanillin, whereas oleogels were formed from insect wax in soybean oil. The impact of varying the hydrogel-to-oleogel ratio on the properties of bigels was then examined. The rheological, oil-binding capacity (OBC), water-oil distribution, structural, and 3D printing characteristics of the bigels were evaluated. Higher hydrogel-to-oleogel ratios resulted in improved rheological properties of bigels. Hydrogen bonding, electrostatic interactions, and covalent Schiff base bonds played an important role in the formation and properties of the hydrogels. In contrast, the mechanical strength of the oleogels was mainly attributed to van der Waals attraction between the insect wax crystals. The optimized bigels had good OBC and mechanical strength. Furthermore, increasing the hydrogel-to-oleogel ratio induced a transition from W/O to O/W type structure in the bigels. A study of the potential application of the bigels as edible inks showed that bigels with a high hydrogel-to-oleogel ratio had better 3D printing characteristics. The findings of this study suggest that bigels can be successfully used as solid fat substitutes.