Release of Cinnamaldehyde and Thymol from PLA/Tilapia Fish Gelatin-Sodium Alginate Bilayer Films to Liquid and Solid Food Simulants, and Japanese Sea Bass: A Comparative Study.

Jingwen Chen,Li Wang,Wenzheng Shi,Hui Zheng,Li Li,Yinxuan Li

doi:10.3390/molecules26237140

Abstract

This study aimed to develop an active biodegradable bilayer film and to investigate the release behaviors of active compounds into different food matrices. Cinnamaldehyde (CI) or thymol (Ty) was encapsulated in β-cyclodextrin (β-CD) to prepare the active β-CD inclusion complex (β-CD-CI/β-CD-Ty). The tilapia fish gelatin-sodium alginate composite (FGSA) containing β-CD-CI or β-CD-Ty was coated on the surface of PLA film to obtain the active bilayer film. Different food simulants including liquid food simulants (water, 3% acetic acid, 10% ethanol, and 95% ethanol), solid dry food simulant (modified polyphenylene oxide (Tenax TA)), and the real food (Japanese sea bass) were selected to investigate the release behaviors of bilayer films into different food matrixes. The results showed that the prepared β-CD inclusion complexes distributed evenly in the cross-linking structure of FGSA and improved the thickness and water contact angle of the bilayer films. Active compounds possessed the lowest release rates in Tenax TA, compared to the release to liquid simulants and sea bass. CI and Ty sustained the release to the sea bass matrix with a similar behavior to the release to 95% ethanol. The bilayer film containing β-CD-Ty exhibited stronger active antibacterial and antioxidant activities, probably due to the higher release efficiency of Ty in test mediums.

Highlights

Active packaging can effectively maintain food quality by controlling microbial growth, enzyme activities, and lipids oxidation, eventually extending the shelf life of the protected foodstuffs [1]
It overcomes the thermo-volatility of essential oils (EOs), and the outer layer of bilayer films can be employed as a waterproof layer to decrease the release loss of active substances from the inner coating layer into the outside environment, and it would be easier to maintain an efficient concentration inside the packaging headspace atmosphere over a long time through slow release
CI or Ty was encapsulated into β-CD inclusion complexes with the drug loading of 11.57% or 9.65%, respectively; and they were added as functional substances into the fish gelatin-sodium alginate composite (FGSA) layer of PLA-based bilayer films to prepare the biodegradable active food packaging films

Summary

Introduction

Active packaging can effectively maintain food quality by controlling microbial growth, enzyme activities, and lipids oxidation, eventually extending the shelf life of the protected foodstuffs [1] It can be developed by incorporating the antimicrobial and/or antioxidant agents into a polymer matrix or to coat such active compounds on the food contact side of packaging [2]. Active β-CD inclusion complexes can be embedded on the only food contact side of packaging materials via a coating to form a bilayer film instead of being incorporated by melt-blending It overcomes the thermo-volatility of EOs, and the outer layer of bilayer films can be employed as a waterproof layer to decrease the release loss of active substances from the inner coating layer into the outside environment, and it would be easier to maintain an efficient concentration inside the packaging headspace atmosphere over a long time through slow release

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Conclusion