Incorporating phenolic compounds opens a new perspective to use zein films as flexible bioactive packaging materials

Abstract

To eliminate their classical brittleness and flexibility problems zein films were plasticized by incorporation of different phenolic acids (gallic acid (GA), p-hydroxy benzoic acid (HBA) or ferulic acids (FA)) or flavonoids (catechin (CAT), flavone (FLA) or quercetin (QU)). The use of GA, CAT, FA and HBA at 3 mg/cm 2 eliminated the brittleness of films and gave highly flexible films showing elongations between 135% and 189%, while FLA and QU caused no considerable effect on film elongation. The films containing FA and HBA showed extreme swelling and lost their structural integrity when hydrated in distilled water. In contrast, CAT and GA containing films maintained their integrity following hydration. Most of the GA (up to 93%) and a considerable portion of CAT (up to 60%) in the films existed in soluble form. Therefore, the films showed antioxidant and/or antimicrobial activity. The TEACs of soluble phenolic compounds in 3 mg/cm 2 CAT and GA containing films were 21.0 and 86.2 μmol trolox/cm 2 , respectively. The GA containing films showed antimicrobial activity on Listeria monocytogenes and Campylobacter jejuni, while CAT showed no antimicrobial activity on these bacteria at the studied concentration. This work opens a new perspective for using zein in flexible bioactive packaging.

Synthesis, characterization and antibacterial activity of biodegradable films prepared from Schiff bases of zein

“…Whereas, the opposite mechanical behavior was noticed for all Schiff bases-based films which showed lower tensile strength with higher elongation comparing with zein-based films. These results agree with those of Arcan and Yemenicioğlu (2010), when phenolic compounds incorporated within zein film matrices. Thus, such Schiff bases films based either on CA, BA or DMABA prepared at various temperatures for different times exhibited lower tensile strength and higher elongation percentage than zein based films.…”

“…Moreover, The Schiff bases reaction conditions can affect on lutein that has an obvious role in maintaining zein polypeptide conformation. Changes in this conformation can lead to change the exposing functional groups of these polypeptides and subsequently alter the nature and types of forces forming between these polypeptide chains (Soliman et al 2009;Arcan and Yemenicioğlu 2010).…”

Antioxidants extraction from Pinhão ( Araucaria angustifolia (Bertol.) Kuntze) coats and application to zein films

“…This difference may be attributed to the CW extract composition, which was rich in phenolic acids and flavonoids (Table 3). According to Arcan and Yemenicioğlu (2011), the increased flexibility of zein films by the addition of phenolic compounds probably results from the binding of phenolic compounds to the surface of the zein proteins, which leads to an increase in the free volume of the film matrix. Also, a decrease in the hydrophobic interactions among zein molecules may occur due to the action of the hydrophilic groups of the phenolic compounds that contribute to an increase in polymeric chain mobility, eliminating film brittleness.…”

“…Zein films may serve as carriers for antioxidant compound in food packaging applications (Arcan & Yemenicioğlu, 2011;Forato, Britto, Scramin, Colnago, & Assis, 2013;Park et al, 2012). In zein films, for instance, the addition of gallic acid, p-hydroxy benzoic acid, ferulic acid, flavone, (+)-catechin, and quercetin (Arcan and Yemenicioğlu, 2011), butylated hydroxyanisole and butylated hydroxytoluene (Kleen, Pauda, & Engeseth, 2002), green tea extract (Lee, Lee, & Song, 2004), gallic acid (Neo et al, 2013), and ferulic acid and gallic acid (Cheng et al, 2015) have been reported.…”

“…In zein films, for instance, the addition of gallic acid, p-hydroxy benzoic acid, ferulic acid, flavone, (+)-catechin, and quercetin (Arcan and Yemenicioğlu, 2011), butylated hydroxyanisole and butylated hydroxytoluene (Kleen, Pauda, & Engeseth, 2002), green tea extract (Lee, Lee, & Song, 2004), gallic acid (Neo et al, 2013), and ferulic acid and gallic acid (Cheng et al, 2015) have been reported. However, to the best of our knowledge polyphenolic compounds from pinhão extracts have not yet been applied in films formulation as a carrier of antioxidant substances.…”