Optical analysis of nanoencapsulated food ingredients by color measurement

Nanoencapsulation is widely used in the food industry and the currently there is a focus on the processing and formulation of food ingredients to form nanostructures. For example, nanocarriers can deliver functional food ingredients to the target organ in the human body; new food products are made with nanobiotechnology by synthetic and recombinant methods; nanoparticles, nanoemulsions, and nanocomposites can be used to develop new packaging materials to improve barrier properties. On the other hand, a colorimeter can measure the color of food in many applications. Optical properties of materials include transmissivity, reflectivity, and absorptivity. Besides, the appearance of surface gloss, color, and opacity play an important role in optical properties of nanoencapsulated food ingredients. According to the optical characteristics, food products can be classified into three categories: opaque foods, translucent foods, and transparent foods. Transparency is measured by the transmission principle; opacity and translucence are measured by the reflection principle. Different colorimeters are suitable for different types of foods. Colorimetry and spectrophotometry are usually employed in color measurement. Hence, the main aim of this chapter is to outline the current state of knowledge on analysis and application of color measurement in different categories of nanoencapsulated food ingredients. In addition, the relationship between optical properties and other food characteristics will be discussed. Finally, future trends and concerns will be mentioned.