Optimizing the Appearance of plant-based Foods: Impact of Pigment and Droplet Characteristics on Optical Properties of Model oil-in-water Emulsions

Abstract

Plant-based foods should mimic the appearance of the animal-based ones they are designed to replace, such meat, seafood, egg, milk, and their products. Each food is required to have specific optical properties, such as color and opacity, which depend on the selective absorption and scattering of light. In this study, oil-in-water emulsions containing plant-derived pigments were used as model plant-based foods. The pigments were selected to represent the three primary colors: turmeric (yellow), red beet (red), and butterfly pea flower (blue). We then investigated the impact of pigment and oil droplet characteristics on the optical properties of the model emulsions, including pigment type and concentration, and droplet size and concentration. Reflectance spectroscopy and colorimetry (L*, a*, b* values) were used to quantify the impact of these parameters on the optical properties of the emulsions. The chromaticness of the emulsions increased with increasing colorant concentration, increasing droplet size, and decreasing droplet concentration due to greater light absorption. The lightness of the emulsions increased with decreasing colorant concentration, decreasing droplet size, and increasing droplet concentration due to greater light scattering. This study provides a better understanding of the factors influencing the optical properties of plant-based foods, which could be used to optimize their appearances, thereby increasing consumer acceptance.