Improving 3D/4D printing characteristics of natural food gels by novel additives: A review

3D printing technology and its extension 4D printing technology have been extensively developed since it was proposed and applied to many industries, including aerospace, biomedical, and food fields. However, there are material limitations for 3D/4D food printing, as some natural food gels cannot be directly applied to 3D/4D food printing, and most natural food gels tend to have poor printing characteristics, which are difficult or impossible to print. Additives in food have a long history of application, which can change some properties of natural food gels. Suitable rheological property is the primary condition of 3D/4D food printing, most of the research is about improving the rheological property of ink, while the research on improving the thermal property, electrostatic property, nutritional property and sensory quality of ink (especially electrostatic property and nutritional property) is still insufficient. This article discusses the printing characteristics (rheological properties, thermal properties, electrostatic properties, nutritional properties, and sensory qualities) of natural food gels that are improved by additives in 3D/4D food printing, mainly from three types of additives: lipids, hydrocolloids, and carbohydrates.