# Physicochemical and Functional Characterization of Cucumis sativus L. (Poona Kheera) Mucilage and Its Application as a Coating to Inhibit Enzymatic Browning in Fresh-Cut Apples

## TL;DR

This study explores using cucumber mucilage as a natural coating to prevent browning in fresh-cut apples, showing promising results for food preservation.

## Contribution

The novel contribution is the characterization and application of Cucumis sativus L. mucilage as an effective edible coating to inhibit enzymatic browning.

## Key findings

- Cucumis sativus L. mucilage delayed enzymatic browning in fresh-cut apples, maintaining brightness and minimizing color change.
- The mucilage exhibited strong antioxidant and anti-inflammatory properties, including tyrosinase inhibition and scavenging activity.
- Characterization revealed a glucose-rich heteropolysaccharide structure with high water and oil retention, emulsifying, and foaming properties.

## Abstract

Enzymatic browning is a major challenge in maintaining the quality and shelf life of fresh-cut fruits, and in this context, plant-derived hydrocolloids are increasingly recognized as sustainable alternatives to synthetic additives due to their ability to retard browning while supporting quality retention. Therefore, in the present study, Cucumis sativus L. mucilage was extracted using microwave irradiation, yielding 24.56% freeze-dried irregular particles with an average size of 194.5 nm and −19.8 mV zeta potential. Various characterization techniques confirmed the amorphous structure and the presence of polysaccharides functional group. The mucilage was primarily composed of glucose (32.27%), along with arabinose, galactose, xylose, mannose, rhamnose, and minor uronic acids, reflecting a glucose-rich heteropolysaccharide. Functionally, the mucilage exhibited notable water retention (8.46 g/g), oil retention (3.21 g/g), foaming capacity (52.13%) with stability (30.46%), emulsifying capacity (90.45%) with stability (91.62%), and solubility (90.14%). Antioxidant assays revealed strong ferric reducing power (5.1 mM FeSO4 at 10 mg/mL), DPPH scavenging (67.50%; IC50 = 1.798 mg/mL), and ABTS scavenging (60.14%, IC50 = 8.038 mg/mL). Anti-inflammatory evaluation indicated enhanced macrophage viability (1.38-fold at 25 mg/mL) with reduced nitric oxide production, while tyrosinase inhibition reached 60.40% (monophenolase) and 68.50% (diphenolase) at 2 mg/mL. Furthermore, when applied as an edible coating on fresh-cut apple slices, Cucumis sativus L. mucilage effectively delayed enzymatic browning in a dose-dependent manner, with 2 mg/mL maintaining apple slice brightness (L* value; 71.08) and minimizing color change (ΔE = 4.54). Overall, these findings highlight Cucumis sativus L. mucilage as a multifunctional biopolymer with promising applications in food systems and edible coatings.