Chapter 16 - Chemical sensing of food phenolics and antioxidant capacity

Abstract

In the past years the field of phenolics and their antioxidant properties have inspired different food and health disciplines such as nutrition, biochemistry, pharmacology, physiology, food processing, and analytical chemistry. The increased interest in this direction has led to the necessity of taking conventional analysis studies to the next stage. This has also made the use of sensors and sensing strategies as strong alternative methods due to their clear advantages. Polyphenols present a large group of structurally related chemical compounds widely distributed in the plant kingdom. These molecules are secondary metabolites of plants and characterized by at least two phenyl rings and one or more hydroxyl substituents. Polyphenols can act as metal ion chelators and free radical scavengers neutralizing dangerous reactive oxygen species by donating an electron. Both these activities are responsible for antioxidant properties, which can be helpful in the evaluation of food quality as well as realizing beneficial features of the products. A variety of nanostructures have been used in electrochemical sensing of food phenolics to provide enhanced detection, protection from passivation, and as immobilization matrices for biomolecules such as carbon black, carbon nanotubes, and graphene. In this chapter, we aim to provide a critical and upto-date overview of the most recently developed chemical sensing approaches for phenolics determination. We have also covered the mechanisms of conventional methods and highlighted the most recent optical and electrochemical methodologies for the detection of total phenolics and antioxidant capacity in various matrices. We comprehensively review novel methods with their advantages and disadvantages and provide a comparison with conventional methods.