# Preserving Pomelo Quality: Sodium Alginate Coating Containing Bacillus subtilis for Sustained Antifungal Activity

## TL;DR

A sodium alginate coating with Bacillus subtilis is shown to preserve pomelo quality by delaying decay and extending storage life.

## Contribution

A novel bio-based coating combining sodium alginate and Bacillus subtilis is developed for postharvest pomelo preservation.

## Key findings

- The B. subtilis/SA coating effectively inhibits P. digitatum and P. italicum fungi.
- The coating maintains bacterial viability and film properties while delaying fruit deterioration.
- The treatment enhances flavonoid accumulation and antioxidant enzyme activity, extending storage life to 90 days.

## Abstract

Wendan pomelo (Citrus maxima), valued for its unique quality and high nutritional value, is susceptible to postharvest decay caused by mechanical damage and fungal infection. This study developed a bio-based preservation strategy by incorporating Bacillus subtilis (B. subtilis) into a sodium alginate (SA)-based coating. An antagonistic B. subtilis strain, isolated from the pomelo growth environment, demonstrated effective inhibition against the pathogenic fungi P. digitatum and P. italicum. The B. subtilis/SA (2.0%) coating maintained high bacterial viability without adversely affecting the viscosity, gas barrier properties, or mechanical strength of the film. The application of the B. subtilis/SA coating significantly delayed fruit appearance deterioration, pulp softening, and decay in pomelo. Furthermore, the treatment enhanced flavonoid accumulation and increased the activity of antioxidant enzymes, thereby maintaining quality and extending storage life to 90 d. This study provides an effective bio-preservation strategy for the postharvest management of pomelo.