Polyphenol-containing water-soluble bio-composite films as alternative food packaging materials
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Date
2025-06-29
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Plovdiv University Press "Paisii Hilendarski"
Abstract
Historically, the development of better food preservation techniques has been one of the main factors in the prosperity and health of any human population, and with the exponential rise in food demand leads science in search of eco-friendlier solutions. One such path is the development of water-soluble biodegradable coatings based on easily accessible and abundant natural polymer materials. As a common byproduct of the food industry, corn zein is one of the most promising biopolymers for food packaging, offering excellent barrier properties. Its main drawback – poor mechanical strength – can be mitigated with the addition of other biodegradable polymers that would result in the creation of bio-composite materials with controllable properties. Further improvements of such biopolymer coatings can be achieved with the addition of other materials, such as different polyphenols, that may improve their antioxidant properties. The presented paper investigates water-soluble bio-composite films, created by
dissolving equal parts zein and hydroxypropyl methylcellulose in ethanol solution (70:30 ethanol to water ratio). Polyethylene glycol was used as plasticiser in all samples. Two different polyphenols (quercetin and curcumin) were incorporated in the bio-composites at a concentration of 2 mg/cm2. The mechanical properties of the created films were studied with a use of Universal Testing Machine (Lloyd Instrument). The surface morphology was investigated with scanning electron microscopy and the surface free energy was determined with the use of the sessile drop method. The dependence of the normalized surface potentials on the storage time
of the charged substrates was studied. Parameters, important for food preservation, such as water vapor permeability, were investigated.
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Keywords
food packaging, biopolymer, polyphenols