Colour Transition Dynamics of Commercial Plant- and Animal-Based Meat Analogues

The inferior visual sensory attributes, particularly colour, of plant-based burgers, remain a barrier to enhancing consumer acceptance and uptake in the global market. This study aimed to comprehensively profile the colour transition dynamics at varying internal temperatures (uncooked, 35 °C, 55 °C, 75 °C, and 85 °C) of four distinct commercial plant-based (PB) and six animal-based (AB) burgers, and to identify key "colour gaps" for improvement. Raw beef burgers appeared red with higher positive a* values (redness), whereas v2food, vEEF, and Beyond burgers showed comparatively higher b* (yellowness) and c* (chroma) values both externally and internally. The sample Impossible PB burgers had the lowest colour differences (∆a*, ∆b*, ∆c*, and ∆E*), showing a beef-like colour transition in both raw and cooked states. Chicken and pork+beef burgers exhibited lower redness in the processed visual images attributed to higher L* values owing to lower myoglobin content. In AB burgers, a* was negatively correlated with L* and h°, while PB burgers positively correlated with b* and c*. The browning intensity observed in both AB and PB burgers is influenced by their internal structural characteristics, which respond dynamically to changes in internal temperature. Mapping the colour transition during the cooking of AB and PB burgers is a critical first step toward identifying gaps in PB product development. Enhancement of visual sensory attributes can be achieved through the modelling of suitable natural colour combinations to target specific dimensions in the colour space.