Shape morphing of foods: Mechanism, strategies, and applications

Abstract

The shape of the food is a crucial factor in its acceptability to consumers, as it encompasses visual appearance, texture, bulk properties, and packaging requirements. Leveraging the significance of shape of the food, shape morphing is introduced, a novel technique that can potentially increase the consumer acceptability of custom-designed 4D foods, reduce food packaging waste, and increase food sustainability. However, the current methods for controlling shape morphing in foods are limited, and the information is fragmented. This review aims to provide a detailed shape morphing mechanism in food during food processing. Using this knowledge, innovative strategies are reviewed to achieve this phenomenon with a wide range of potential applications in the food industry. Shape morphing in food occurs naturally and uncontrollably due to the stresses introduced by structural anisotropy or compositional heterogeneity during various food processing conditions such as drying, boiling or frying. Innovative strategies are critically reviewed to achieve the desired shape morphing in food, including stamping, shape constraint materials, and three-dimensional food printing. Grooving is highlighted as a novel morphing strategy to control directional deformation by tuning the grooving features such as depth, orientation, number, gap, and width of the groove. The mechanism highlighted in this review, along with the proposed strategies, has the potential to drive innovation and foster future development in the shape morphing of food.