# Nitrogen Fertilization Optimizes the Physicochemical Properties of Cactus Mucilage and the Biopolymeric Films Produced

## TL;DR

This study shows that using low nitrogen fertilization on cactus plants improves the quality of mucilage and the biopolymer films made from it, making them suitable for sustainable packaging.

## Contribution

The study demonstrates how nitrogen fertilization affects mucilage composition and film properties for sustainable packaging.

## Key findings

- Low nitrogen fertilization increases cladode yield and improves mucilage quality with higher phenolic content and lower conductivity.
- Films made from low nitrogen mucilage show better transparency, stiffness, and moisture resistance.
- XRD and SEM analyses confirm improved crystallinity and mechanical resistance in low nitrogen films.

## Abstract

In recent decades, increasing environmental concerns
have driven
interest in sustainable polymers, such as the mucilage derived from
forage cactus (Opuntia stricta), which
shows significant potential for food applications and the production
of biopolymeric films. To expand its industrial use, improvements
in synthesis methods, additive incorporation, and agronomic practices
are necessary. However, studies on the use of O. stricta in films produced under nitrogen fertilization remain scarce, underscoring
the need for further research to fully explore its potential in the
bioplastics industry. Cladodes of O. stricta fertilized with 50, 150, 300, and 450 kg N ha–1 were washed, peeled, and ground with ethanol (99.8% P.A.) at a 2:3
ratio (parenchyma/alcohol), resulting in a dried mucilage powder used
for analysis and film formulation. Lower nitrogen supply resulted
in the highest cladode yield and produced mucilage with lower electrical
conductivity, reduced sodium and potassium content, and a higher concentration
of phenolic compounds, making it more suitable for antioxidant food
applications. Films made from this mucilage demonstrated greater transparency,
higher luminosity, increased stiffness, and reduced moisture content
and water solubility. XRD and SEM analyses revealed a more crystalline
and homogeneous structure, resulting in improved mechanical resistance.
These outcomes indicate that nitrogen availability directly modulates
mucilage composition and, consequently, the structural integrity and
barrier properties of the films. The findings identify low nitrogen
fertilization as a cost-effective and environmentally favorable strategy
for producing consistent, high-quality biopolymeric films with potential
applications in sustainable packaging.