Effect of PPG-PEG-PPG on the Tocopherol-Controlled Release from Films Intended for Food-Packaging Applications

Abstract

The feasibility of novel controlled release systems for the delivery of active substances from films intended for food packaging was investigated. Because polyolefins are used highly for food-packaging applications, the reported high retention degree of antioxidants has limited their use for active packaging. Thus, in this study, PP films modified with different chain extenders have been developed to favor and control the release rates of the low molecular weight antioxidant tocopherol. The use of different chain extenders as polymer modifiers (PE-PEG M(w), 575; and PPG-PEG-PPG M(w), 2000) has caused significant changes in tocopherol-specific release properties. High-performance liquid chromatography coupled to PDA-FL and PDA-MS was used to test tocopherol and chain extender migration, respectively. The release of tocopherol from the prepared films with two chain extenders into two food simulants was studied. Different temperatures and storage times were also tested. Varying the structural features of the films with the incorporation of different levels of PPG-PEG-PPG, the release of tocopherol (food-packaging additive) into different ethanolic simulants could be clearly controlled. The effect of the temperature and storage time on the release of the antioxidant has been outstanding as their values increased. The migration of the chain extender, also tested, was well below the limits set by European legislation.

Preparation of antioxidant active films based on chitosan: diffusivity study of α-tocopherol into food simulants

“…Siró et al (2006) reported a diffusion coefficient of 1.68 9 10 -12 cm 2 /s for a-tocopherol forming complexes with beta-cyclodextrin from LDPE polymer into 95 % EtOH (v/v) at 7°C, and a value of D one order of magnitude lower (1.53 9 10 -11 cm 2 /s) for the non-complexed form. D values ranging from 6.58 9 10 -12 to 4.60 9 10 -10 cm 2 /s were obtained for a LDPE/ polypropylene (PP) blend films-95 % EtOH (v/v) system (Zhu et al 2012). Castro López et al (2012 evaluated the release of a-tocopherol from polypropylene (PP) film modified with poly(propyleneglycol)-block-poly(ethylene glycol)-block-poly(propyleneglycol) (PPG-PEG-PPG) into the food simulant 50 % EtOH (v/v) at 40°C and reported values were between 2.4 9 10 -12 and 2.0 9 10 -11 cm 2 /s.…”

Antioxidant Microemulsion-based Ethylene Vinyl Acetate Film Containing Mangiferin and Surfactants

“…Mangiferin (96% purity) was obtained from Changsha Huir Biological-Tech Co., Ltd., China. Ethylene vinyl acetate (12,18, 25, 40%VA), Sorbitan monolaurate (Span ® 20) and PEG-PPG-PEG (Pluronic ® Pí123) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) were obtained from Sigma Aldrich. All reagents used in this study were of analytical grade.…”

“…According to the results from the previous section, mangiferin-Span ® 20 emulsion was incorporated into the EVA solutions containing different vinyl acetate contents (12,18,25, and 40% VA). The film was prepared by pouring a polymer solution a ceramic plate and the solvent was evaporated in hot oven at 90°C.…”

“…The melting point (T m ), heat of fusion and degree of crystallinity of the EVA films with varying VA contents (12,18, 25 and 40) incorporated with mangiferin were analyzed using a differential scanning calorimeter (DSC model 883, Mettle Toledo, Ohio, USA). Approximately 20 mg of a sample film was placed in an aluminum pan.…”

“…Results from the present study showed the effects of Span Other studies also reported that surfactants increased the release rate of active substances from the polymer matrices. For example, sorbitan sesquioleate (Span ® 83) increased the release of metoprolol tartrate from the EVA containing 40% VA [11] and poly(ethylene)-block-poly(ethylene glycol) (PE-PEG) increased the release of tocopherol from the polypropylene matrix [12].…”