Using tannins as active compounds to develop antioxidant and antimicrobial chitosan and cellulose based films

Three tannin extracts from different sources (white peel grape (W), red (R) and oak bark (O)) have been used to obtain active films based on polysaccharides: chitosan (CH), methylcellulose (MC) hydroxypropylmethylcellulose (HPMC). Tannin-rich were obtained by casting as monolayers (by blending all the components) bilayers (one polysaccharide layer plus one applied a coating). Microstructural physicochemical properties (water solubility, water vapor permeability, mechanical optical properties), well antioxidant antimicrobial activities of films, analysed. Tannins, regardless their origin, acted crosslinking agents when incorporated into CH or MC due establishment specific associations, mainly hydrogen bonds hydrophobic interactions. Thus, these tannin-rich turned less soluble, mechanically stiffer stretchable. In contrast, tannins provoke precipitation in HPMC film-forming solutions application onto film surface gave rise weakened network local HPMC-tannin complexes. The greatest capacity was found both mono bilayer food simulants, line with release polymer matrix. also exhibited bacteriostatic activity against E.Coli L. innocua. So, could represent good alternative coatings packaging material so prevent occurrence oxidative reactions sensitive products control bacterial growth.