2D excitation-emission fluorescence mapping analysis of plant food pigments

Homogeneous dispersion of plant food pigments is indispensable to study their characteristic fluorescence features for non-destructive rapid monitoring of food systems. However, it is highly challenging to obtain such optical grade homogenized stable dispersion of various plant pigments in aqueous media for tracing their precise fluorescence signatures. Herein, we demonstrate a unique strategy to disperse various pigments, such as chlorophylls, carotenoids and phenolic compounds by the high-speed shear-force mixing of fresh green and red bell peppers (Capsicum annuum) in an aqueous medium with followed centrifugation and filtration. An advanced FLuorescence Excitation-emission (FLE) mapping and optical absorption analysis from the optical grade aqueous bell peppers dispersion allow simultaneous probing of chlorophylls, phenolic compounds and carotenoids by their characteristic electronic transitions. The demonstrated sampling protocols and spectroscopic analysis will be highly beneficial to obtain advanced spectroscopic databases from different food materials for rapid food analysis and quality control.