Chlorophyll encapsulation by complex coacervation and vibration nozzle technology: Characterization and stability study

Abstract

Soy protein isolate (SPI) and chitosan were used as carriers to encapsulate chlorophyll. Optimization conditions utilizing the Box-Behnken design used 1:7 (wet basis) mass ratio of chitosan to SPI, 1:14.8 (wet basis) mass ratio of chlorophyll to SPI, and pH 6.91. Under this condition, the predicted and experimental encapsulation efficiency was 97.95% and 96.21% respectively. Using complex coacervation and vibration nozzle technology, different chlorophyll-loaded nanoparticles were obtained with acceptable green colour, satisfactory encapsulation efficiency (94.9–96.1%) and loading capacity (3.32–4.22%). Z-average diameter, SEM, and TEM showed nanoparticle sizes were nano-sized (273–373 nm), porous and largely spherical with good dispersibility. FTIR, Raman, and DSC analyses confirmed significant interaction between chlorophyll molecules and carriers. Furthermore, chlorophyll retention of nanoparticles after 21 days of exposure to sunlight at room temperature ranged from 58.3–62.3%. At pH 2.5, chlorophyll retention ranged from 59.4–69.5%. In weak acid condition (pH 4.5 and 6.5), nearly all (97.7–100%) chlorophylls remained. Industrial relevanceThe burgeoning awareness of consumers on the negative health implications of synthetic food colorants has stimulated the need to seek for healthier alternatives. Chlorophyll, a natural pigment found in many green vegetables is highly valued due to its chemo-preventive effects. Despite the huge health benefits, the exposure of chlorophyll to external factors such as heat, light, oxygen, and acid during processing and storage limit the gains associated with this pigment. An optimized encapsulation process has the benefit of minimizing chlorophyll degradation under these conditions while also maintaining product integrity.