Effect of PLA Active Packaging Containing Monoterpene-Cyclodextrin Complexes on Berries Preservation

Area of Science:

• Food Science
• Materials Science
• Microbiology

Background:

• Blackberries and raspberries are highly perishable, limiting their commercial shelf life.
• Active packaging offers a potential solution to extend the shelf life of fresh produce.
• Poly(lactic acid) (PLA) is a biodegradable polymer suitable for food packaging applications.

Purpose of the Study:

• To evaluate the efficacy of biodegradable active packaging incorporating thymol and carvacrol complexed in beta-cyclodextrins (β-CDs) within a PLA matrix.
• To compare the performance of this active packaging against commercial clamshell packaging and a plain PLA control.
• To assess the impact of the active packaging on the physicochemical, microbiological, and sensory quality of blackberries and raspberries.

Main Methods:

• Active packaging films were prepared by incorporating varying concentrations (2.5% and 5.0% wt%) of thymol/carvacrol-β-CD complexes into PLA using melt processing (injection molding).
• Physicochemical analyses included weight loss, color, total phenolic content, and soluble solids.
• Headspace analysis, microbiological counts (yeast and mold), and sensory evaluations were conducted over 21 days of storage at 4 °C.

Main Results:

• PLA packages with thymol and carvacrol significantly maintained berry color, weight, and phenolic content compared to commercial clamshells, showing up to 45% improvement.
• Headspace analysis confirmed the release of thymol and carvacrol, altering the package atmosphere.
• Significant microbial inhibition of yeast and molds was observed, with higher concentrations of thymol and carvacrol leading to greater inhibition (up to 3.5 log units).

Conclusions:

• Biodegradable active packaging based on PLA/β-CD-thymol (5.0%) effectively extended the shelf life of blackberries and raspberries by an additional week at 4 °C.
• The active packaging maintained key quality attributes and provided significant antimicrobial activity without negatively impacting sensory perception.
• This technology presents a promising sustainable alternative for preserving perishable berries.