Active zein coatings carry antimicrobials, antioxidants to preserve products.
With an eye toward sustainable development, there have been increasing efforts to develop biodegradable polymers obtained from renewable resources.
In addition, the strong demand by consumers for high-quality, safe, minimally processed foods that are free of synthetic additives has promoted the use of active packaging technologies combined with naturally occurring antimicrobial and antioxidant compounds.
The design of green active packaging systems that are capable of extending the microbiological shelf life of products and increasing the quality of processed foods is a new challenge for the food and packaging industries.
Spanish scientists studied the effectiveness of zein proteins as carriers and release systems of a combination of natural antimicrobial and antioxidant compounds. They also investigated the design of a bilayer system employing zein as a coating on polylactic acid (PLA) film. They found that zein can be effectively incorporated in the design of active packaging systems to preserve refrigerated foods with extended shelf life.
An aqueous ethanol solution of zein was prepared using glycerol as the plasticizer. Then, antimicrobial ethyl lauroyl arginate (LAE) at 10% and the antioxidant catechin at 5% were incorporated by the researchers, who obtained films by casting.
The scientists evaluated the antimicrobial activity of the films in vitro in a liquid medium against Listeria monocytogenes and Salmonella enterica. The antioxidant activity of the film was assayed with 2,2-diphenyl-1-picrylhydrazyl--DPPH. The effectiveness of the films was tested in vivo by packaging fresh orange juice inoculated with L. monocytogenes in PLA bags coated with the active zein.
In vitro results demonstrated that the zein films were effective against both pathogenic microorganisms, most notably against L. monocytogenes, and retained relevant antioxidant activity. Bacterial counts of L. monocytogenes in the fresh orange juice packed with the active bags showed a significant decrease on the third day of storage at refrigeration temperatures. The antioxidant activity of the orange juice packaged in the active bags slightly increased compared with the control.
Further information. Rafael Gavara, Instituto de Agroquimica y Tecnologia de Alimentos, IATA-CSIC, Avda. Catedratico Agustin Escardino, 7, 46980 Paterna, Valencia, Spain; phone: +34 963 900 022; fax: +34 963 636 301; email: email@example.com.
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|Publication:||Emerging Food R&D Report|
|Date:||Sep 1, 2016|
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