# Structural Characterization and Stability Evaluation of Melanin from Liquidambar formosana Hance Leaves: A Potential Natural Pigment for Food Applications

## TL;DR

This study characterizes and evaluates the stability of melanin from Liquidambar formosana leaves, showing it could be a stable natural pigment for black-colored foods.

## Contribution

The study identifies the structural composition and stability of LHM, suggesting its potential as a functional food pigment.

## Key findings

- P-LHM has a yield of 3.47% and contains eumelanin, pheomelanin, and associated bioactive compounds.
- P-LHM retains >90% stability under various environmental and chemical conditions.
- The presence of phenolic compounds supports its use as a functional colorant in food.

## Abstract

In this study, purified Liquidambar formosana Hance melanin (P-LHM) was structurally characterized and evaluated for stability. The yield of P-LHM was approximately 3.47%. Analytical results revealed P-LHM is a melanin-rich complex where eumelanin and pheomelanin polymers are intimately associated with specific flavonoids, phenolic acids, and terpenoids. The condensation molecular formula of P-LHM might be ([C24H29NO9]n). The stability evaluation showed that under specific conditions (natural light, darkness, pH = 7–11, 25–100 °C, Na+, Al3+, Fe2+ solution, and low concentrations of reducing agents), the retention rate of P-LHM was >90%. Given its excellent stability, LHM may be used as a new type of food ingredient in the processing of black-colored foods. Meanwhile, the rich phenolic compounds provide a theoretical basis for the development of functional colorants, enhancing the functional value of food colorants.