# Foam-Porous Alginate-Bentonite Beads Coated with Gamma-Irradiated Chitosan for Selective Chlorophyll Removal with Preservation of Plant Bioactives

## TL;DR

Researchers created a new biocomposite material that effectively removes chlorophyll from plant extracts without harming beneficial compounds, offering a sustainable solution for food and cosmetic industries.

## Contribution

The development of foam-porous alginate-bentonite beads coated with gamma-irradiated chitosan for selective chlorophyll removal while preserving plant bioactives.

## Key findings

- The beads achieved 88.4% chlorophyll removal in 30 minutes with minimal impact on bioactives.
- The material maintained over 85% efficiency through five reuse cycles with structural stability.
- The process followed pseudo-second-order kinetics, indicating chemisorption via electrostatic interactions.

## Abstract

Excess chlorophyll in plant ethanol extracts can compromise
analytical
accuracy and restrict industrial applications in food, herbal, and
cosmetic formulations. This study developed foam-porous alginate-bentonite
beads coated with gamma-irradiated chitosan (FP-Alg/Bent-gCS) as a
selective, reusable biocomposite adsorbent for chlorophyll removal
while preserving plant bioactives. The beads were created using CO2 foaming, cross-linked with CaCl2, reinforced with
bentonite, and coated with gamma-irradiated chitosan (0.5%, pH 5.5).
The resulting beads demonstrated a high surface area (75.6 m2·g–1) and pore volume (0.096 cm3·g–1), as confirmed by BET analysis. FTIR
spectra indicated the presence of hydrogen bonding and electrostatic
interactions among hydroxyl, carboxyl, and amino groups. Additionally,
XRD and HRTEM confirmed the formation of a semicrystalline foam-like
structure. When applied to kale extract in 50% ethanol (25 mL), the
beads achieved an impressive 88.4% total chlorophyll removal in just
30 min at a dosage of 5 g. This process followed pseudo-second-order
kinetics, suggesting chemisorption via electrostatic attraction between
−NH3
+ groups and chlorophyll molecules.
Colorimetric assays for total phenolic content (TPC) and total flavonoid
content (TFC) revealed no significant reduction in polyphenols or
flavonoids, confirming that the removal of pigments was selective
and did not lead to loss of bioactives. The beads maintained over
85% removal efficiency through five reuse cycles, with only minor
surface deformation observed after the sixth cycle, consistent with
XRD and EDS analyses that showed structural stability. In conclusion,
the FP-Alg/Bent-gCS beads represent a low-cost, environmentally friendly,
and sustainable method for selectively removing chlorophyll while
preserving bioactives. They present a promising material for green
extraction and purification processes in the food, herbal, and cosmetic
industries.