Crosslinking capacity of tannic acid in plasticized chitosan films

Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films

“…This was unexpected considering the general belief that cross linked films with improved tensile strength are always accompanied by reduced elongation at break values mainly due to the resultant rigid compact structure. Our findings are contrary to observations made by some authors who found that either there were no significant changes in elongation at break or the elongation at break was reduced after chemical crosslinking (Rivero et al 2010;Hernandez-Munoz et al 2004;Orliac et al 2002;Cao et al 2007). The incorporation of oleic acid into the zein films reduced tensile strength (Fig.…”

“…This increase can be attributed to the formation of a strong and compact polymer network as a result of the gallic acid induced cross-linkages as evidenced by the increase in molecular weight (Table 1). Our results are in agreement with findings from other authors who have reported an increase in tensile strength after chemical treatment using different chemical cross linking agents (Rivero et al 2010;Orliac et al 2002;Poole and Church 2015;Ou et al 2005). Elongation at break was not significantly affected though it was increased marginally from 3.7 % for the control samples to 4.2 % for the gallic acid treated films representing an increase of 14 %.…”

“…This reduction can be attributed to the formation of cross-linkages induced by the gallic acid resulting into a more compact film structure restricting water movement. A number of authors have also reported reductions in water vapour permeability after chemical treatments with various cross linking chemical agents (Sun et al 2014;Rivero et al 2010;Hernandez-Munoz et al 2004;Carvalho and Grosso 2004;Carvalho et al 2008;Chiou et al 2008;Pires et al 2013). However, when oleic acid in different concentrations was introduced into the gallic acid treated films, there was an increase in water vapour permeability (Fig.…”

Modified biofunctional p(tannic acid) microgels and their antimicrobial activity

“…The numerous hydroxyl groups can interact with structures and biopolymers such as some proteins, digestive enzymes, carbohydrates, and minerals to provide many intriguing physical and chemical properties of TA-based materials [3,4]. The antibacterial, antioxidant, anticarcinogenic and antimutagenic activities of TA molecules are well known [3][4][5][6].…”

Starch-protein active films for food preservation

“…Nevertheless, the characteristic absorption peak around 1740 cm -1 , corresponding to carbonyl (C=O) stretching vibration, presented a very weak intensity due to the formation of hemiacetal linkage between oxidised and non-oxidised starch residues (Zhang et al, 2007;Zhang et al, 2014). It is remarkable that the absorption peaks in samples with oxidised starch decreased in intensity at a constant wavenumber, as previously described by other authors (Rivero et al (2010) for crosslinked polymer structures, probably associated with the major restrictions for bond vibration. , respectively (Kamoun, 2015), which is reflected in a higher relative intensity of these bands in samples containing this compound.…”