INVESTIGATING THE EFFECT OF HIGH PRESSURE PROCESSING (HPP) ON MOLECULAR STRUCTURE AND STABILIZATION OF NATURAL HYDROPHILIC COLORANTS

The goal of the proposed study is to investigate the effect of the high pressures process (HPP) on natural colorants' stability. The HPP treatment could restructure the weak associative networks (e.g., hydrogen bonding and hydrophobic associations) between natural colorants and complex-forming polysaccharides/proteins. The HPP treatment is allowing them to be preserved under conditions that typically promote rapid degradation, such as thermal treatment at low pH. Thus, the overall goal of the proposed study is the development and characterization of novel systems for colorant stabilization using HPP in order to broaden the use of natural water-soluble colorants, such as chlorophyllin, betalain, and phycocyanin, within the food industry. Additionally, this research could improve the shelf life extension and clean label promotion in the food industry. To achieve this goal, we have categorized our objectives as follows:Objective 1. Complex the hydrophilic colorants (chlorophyllins, phycocyanins, betalains) with biopolymers, small biomolecules, and metal ions, and reinforce the complexation using HPP.Objective 2. Investigation of the HPP effect on the inter/intra-molecular structure of the complexed colorants using circular dichroism (CD) and quartz crystal microbalance with dissipation (QCM-D).Objective 3. Investigation of the HPP effect on the physicochemical properties of the complexed colorants using UV-Vis spectroscopy, fluorimetry, colorimetry, surface/interfacial tension, particle size and surface charge, and Fourier transform infrared (FTIR) spectroscopy to understand the mechanism of the interactions in the complexes with HPP and without HPP treatments.Objective 4. Investigation of the colorant stability against harsh conditions (e.g., thermal, pH, and light) and the incorporation of stabilized colorants into a model beverage system and evaluation of the physical/organoleptic properties.