USE OF GLUCOMANNAN FILMS FOR EUGENOL ENCAPSULATION

Abstract

Edible film encapsulated with active compound to improve its functional properties is gaining more attention. The active compounds which are usually encapsulated in edible film are flavors, odors, antioxidant agents, and antimicrobial agents. The purpose of encapsulation is to control the releasing rate and to protect active compounds from the environmental effect. The aim of this study was to analyze the effect of EU incorporation on the structural of KGM film, mechanical, physical, and thermal properties. In addition, the amount of EU remained in the film (encapsulation efficiency, EE) was also studied. The film properties including thickness, tensile strength (TS), elongation at break (EB), Young’s modulus (YM), water vapor permeability (WVP), transparency value, solubility, encapsulation efficiency (EE) of EU, and EU releasing in water were determined. Moreover, cross-section of film was analyzed by scanning electron microscope (SEM). Structural interaction and thermal property of film were studied by Fourier transform infrared spectrometer (FT-IR) and differential scanning calorimeter (DSC), respectively. The changing of thermal stability of the films and EE of EU during storage for 8 months was monitored and reported as thermogravimetric analysis (TGA) thermograph and EE. The results showed that the thickness of film was in a range of 25.80 µm to 51.60 µm. The resistance to break of film increased with increasing KGM, while adding and increasing concentration of EU made the film more stretchable and flexible. These results agree with SEM photographs, FT-IR spectra, and DSC analysis. The results from FT-IR and DSC analysis showed that there was no interaction between KGM and EU. The heterogeneity of the film had the effect to increase WVP and decrease transparent. The solubility of film increased with EU concentration due to the heterogeneous structure but decreased with increasing KGM content. EE of EU encapsulated in KGM film was determined. Amount of EU which could be entrapped in the film depend on the initial EU concentration added in film forming solution. The releasing of EU from film in water reached the equilibrium in 20 - 30 minutes. The amount of EU released depended on the initial EU concentration added. The 0.75% KGM film encapsulated with 1.50% EU was selected to determine the changing of thermal stability of the film and amount of remain EU during storage for 8 months. The pattern of derivative thermogram (DTG) of the films during storage for 60 days were similar but the color of the films changed. In addition, EE (%) of the film decreased 36.90% of initial EE (%) when storage for 8 months. The result showed that KGM could be used for encapsulating EU and preventing the loss of EU to the environment. Moreover, KGM/EU films had high mechanical strength, convenience for use as packaging.