Bioactive Multilayer Polylactide Films with Controlled Release Capacity of Gallic Acid Accomplished by Incorporating Electrospun Nanostructured Coatings and Interlayers

Luis Quiles-Carrillo,Rafael Balart,Sergio Torres-Giner,Nestor Montanes,José Lagaron

doi:10.3390/app9030533

Abstract

The present research reports on the development of bi- and multilayer polylactide (PLA) films by the incorporation of electrospun nanostructured PLA coatings and interlayers containing the antioxidant gallic acid (GA) at 40 wt% onto cast-extruded PLA films. To achieve the bilayer structures, submicron GA-loaded PLA fibers were applied on 200-µm cast PLA films in the form of coatings by electrospinning for 1, 2, and 3 h. For the multilayers, the cast PLA films were first coated on one side by electrospinning, then sandwiched with 10-µm PLA film on the other side, and the resultant whole structure was finally thermally post-treated at 150 °C without pressure. Whereas the bilayer PLA films easily delaminated and lacked transparency, the multilayers showed sufficient adhesion between layers and high transparency for deposition times during electrospinning of up to 2 h. The incorporation of GA positively contributed to delaying the thermal degradation of PLA for approximately 10 °C, as all films were thermally stable up to 345 °C. The in vitro release studies performed in saline medium indicated that the GA released from the bilayer PLA films rapidly increased during the first 5 h of immersion while it stabilized after 45–250 h. Interestingly, the PLA multilayers offered a high sustained release of GA, having the capacity to deliver the bioactive for over 1000 h. In addition, in the whole tested period, the GA released from the PLA films retained most of its antioxidant functionality. Thus, during the first days, the bilayer PLA films can perform as potent vehicles to deliver GA while the multilayer PLA films are able to show a sustained release of the natural antioxidant for extended periods.

Highlights

The development of novel “functional foods” is a great opportunity to improve the quality of foods available to consumers to benefit their health and well-being in most modern societies
The determination of these parameters is certainly relevant to explain the behavior of each biopolymer solution during electrospinning and a combined optimization of them is needed to tune the fiber into the required form [19]
The addition of gallic acid (GA) to the PLA solution mainly induced an increase in conductivity as well as a slight decrease in viscosity and a negligible effect on the surface tension

Summary

Introduction

The development of novel “functional foods” is a great opportunity to improve the quality of foods available to consumers to benefit their health and well-being in most modern societies. The majority of commercial functional foods are presented with the bioactive components contained within compatible foods. This aspect imposes to the food industry a number of limitations and difficulties during processing and storage such as the loss of product functionality, the development of undesirable flavors, or the modification of the food product texture [3]. The so-called bioactive packaging differs from the well-known active packaging technologies in the fact that while active packaging primarily deals with maintaining or increasing quality and safety of packaged foods (e.g., antimicrobial and antioxidant packaging), bioactive packaging provides a direct impact on the health of the consumer by generating healthier packaged foods

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Results

Conclusion