Zein-Curcumin Composite Edible Films for Intelligent Packaging: A Natural pH-Sensing Indicator to Monitor Sea Bream...

Area of Science:

• Food Science and Technology
• Materials Science
• Biochemistry

Background:

• Monitoring fish freshness is crucial for food safety and quality control.
• Current methods for assessing fish spoilage can be time-consuming and require laboratory analysis.
• There is a need for rapid, visual indicators to assess seafood quality.

Purpose of the Study:

• To develop and characterize zein-based edible films incorporating curcumin as natural pH-sensitive indicators.
• To evaluate the physicochemical, mechanical, optical, and antioxidant properties of these films.
• To assess the potential of curcumin-enriched zein films for real-time monitoring of fish freshness.

Main Methods:

• Zein-based edible films were prepared with varying concentrations of curcumin (1-7% wt).
• Films were analyzed for water vapor permeability, contact angle, color, UV barrier properties, antioxidant activity, and mechanical strength.
• Scanning Electron Microscopy (SEM) was used to examine film microstructure.
• The films' pH-sensitivity and colorimetric response were evaluated across a pH range of 3-10.
• The developed films (Z/CR7) were applied to gilthead sea bream fillets stored under refrigeration to monitor freshness over 13 days, assessing TBARS, TVB-N, and microbiological parameters.

Main Results:

• Increasing curcumin content enhanced hydrophilicity, reduced water vapor permeability, and improved UV barrier properties.
• Films showed significant pH-sensitivity, with color changes correlating to pH variations.
• Antioxidant activity and mechanical properties like elongation at break and bursting strength increased with higher curcumin concentrations.
• Zein films with 7% curcumin (Z/CR7) effectively delayed lipid oxidation and spoilage in stored fish, as indicated by lower TBARS and TVB-N values.
• The color changes of the Z/CR7 films correlated with the deterioration of fish freshness, providing a visual cue.

Conclusions:

• Zein-based edible films enriched with curcumin function as effective, natural pH-sensitive indicators for monitoring fish freshness.
• The Z/CR7 films demonstrate potential as intelligent, biodegradable packaging materials for the real-time assessment of seafood quality.
• These films offer a promising visual tool to reduce food waste and ensure consumer safety by indicating spoilage.