_Applied_  
_sciences_  
_Apticle_  
_Bioactive Multilayer Polylactide Films with Controlled Release Capacity of Gallic Acid_  
_Accomplished by Incorporating Electrospun_  
_Nanostructured Coatings and Interlayers_  
**[PERSON] \({}^{\text{1}}\)\({}^{\text{\textregistered}}\)**, **[PERSON] \({}^{\text{1}}\)**, **[PERSON] \({}^{\text{2}}\)\({}^{\text{\textregistered}}\)**, **[PERSON] \({}^{\text{1}}\)\({}^{\text{\textregistered}}\)**  
**and [PERSON] \({}^{\text{2,*}}\)\({}^{\text{\textregistered}}\)**  
Received: 7 January 2019; Accepted: 31 January 2019; Published: 5 February 2019  
**Featured Application: The electrospinning coating technology is herein proposed to develop multilayer polylactide (PLA) films with controlled release rates of gallic acid (GA), a natural antioxidant, into saline medium. The bioactivity of the PLA films described here is based on their potential capacity to incorporate a large amount of GA into the packaging structure until its eventual release into the food product either through fast release, by means of coatings, or sustained release, in the form of interlayers, during storage. Therefore, their application in bioactive packaging for both short- and long-term storage of food products can advantageously permit the development of functional food, enhancing the food impact over the consumer's health.**  
**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-\(\upmu\)m 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-\(\upmu\)m PLA film on the other side, and the resultant whole structure was finally thermally post-treated at 150 \({}^{\circ}\)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 \({}^{\circ}\)C, as all films were thermally stable up to 345 \({}^{\circ}\)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.**  
**Keywords: PLA; GA; electrospinning; multilayer films; bioactive packaging**