Optimization and Characterization of Centrifugally Spun Gelatin-Based Fibers Incorporated with Bay Laurel (Laurus nobilis L.) Leaf Essential Oil

Centrifugal spinning serves as a new method that can produce fibers to be used in active packaging. The primary objective of this study was to design and to characterize centrifugally spun fibers containing bay laurel leaf essential oil (BLLEO). In addition, it was aimed to optimize flow rate and fiber composition based on fiber diameter, antioxidant activity, and total phenolic content. In this aspect, different flow rates of solution (10, 15, and 20 mL/h), concentrations of gelatin (20%, 25%), and concentrations of BLLEO (1%, 3%, and 5%) were studied. Optimization of fibers was conducted by multiple regression analysis, and characterization experiments such as morphological analysis, antioxidant activity, total phenolic content, encapsulation efficiency, water vapor permeability, Fourier transform infrared spectroscopy (FTIR), thermal analysis, and antimicrobial activity were performed with the different BLLEO concentrations (1%, 3%, and 5%) of selected optimum fiber to understand the effect of BLLEO concentration. Fiber with 20% gelatin concentration and 5% BLLEO concentration at a flow rate of 20 mL/h was determined as the optimum in terms of fiber diameter, total phenolic content, and antioxidant activity. Addition of BLLEO did not affect the homogenous morphology of fiber, and notably, antioxidant activity and total phenolic content of fibers increased with BLLEO addition. Encapsulation efficiency of fibers ranged between 94.77 and 54.70%, with a decreasing trend by enhancing the BLLEO concentration. Fibers with BLLEO showed antimicrobial activity and also ability to reduce lipid oxidation. Therefore, BLLEO incorporated gelatin-based centrifugally spun fibers might be a promising active packaging material due to its antioxidant and antimicrobial activities.