Document Detail

Development of new antioxidant active packaging films based on EVOH and green tea extract.
MedLine Citation:
PMID:  21682295     Owner:  NLM     Status:  Publisher    
Ethylene vinyl alcohol copolymer (EVOH) films containing green tea extract were successfully produced by extrusion. The films were brown and translucent and the addition of the extract increased the water and oxygen barrier at low RH but increased the water sensitivity, increased the glass transition temperature and the crystallinity of the films and improved their thermal resistance. An analysis by HPLC revealed that the antioxidant components of the extract suffered partial degradation during extrusion, reducing the content of catechin gallates and increasing the concentration of free gallic acid. Exposure of the films to various food simulants showed that the liquid simulants increased their capacity to reduce DPPH• and ABTS•+ radicals. The release of green tea extract components into the simulant monitored by HPLC showed that all compounds present in the green tea extract were partially released, although the extent and kinetics of release were dependent on the type of food. In aqueous food simulants, gallic acid was the main antioxidant component released with partition coefficient values ca. 200. In 95% ethanol (fatty food simulant) K value for gallic acid decreased to 8 and there is a substantial contribution of catechins (K in the 1000 range) greatly increased antioxidant efficiency. Kinetically, gallic acid was released faster than catechins, owing to its faster diffusivity in the polymer matrix as a consequence of its smaller molecular size, although the most relevant effect is the plasticization of the matrix by alcohol, increasing the diffusion coefficient more than 10 folds. Therefore, the materials here developed with the combination of antioxidant substances which constitute the green tea extract could be used in the design of antioxidant active packaging of all type of foods, from aqueous to fatty products, being the compounds responsible for the protection those with the higher compatibility with the packaged product.
Carol Lopez de Dicastillo; Cristina Nerin; Pilar Alfaro; Ramón Catalá; Rafael Gavara; Pilar Hernandez-Muñoz
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-6-17
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  -     ISSN:  1520-5118     ISO Abbreviation:  -     Publication Date:  2011 Jun 
Date Detail:
Created Date:  2011-6-20     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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