Use of hemicellulose for the production of green packaging systems.
Due to increased global awareness of environmental issues, combined with the possibility of a decrease in the availability and consequent increase in the cost of traditional fossil-based plastics, the interest of the food industry in green materials is constantly increasing. In this context, in a recent study, carried out by a group of Chinese researchers (Zhao et al., 2020), highlights the main progress made in the development of hemicellulose film for use in food packaging.
According to the study, the origin, extraction and modification of hemicellulose are parameters that can influence the chemical-physical properties of films. The main problems limiting the spread of these packaging materials are their poor mechanical characteristics and significant sensitivity to water.
To overcome these limitations, several approaches involving the combined use of physical and chemical modifications have been proposed. Among the possible future developments, the study mentions the identification of plasticizers or fillers compatible with the hemicellulosic matrix and able to improve its mechanical performance.
As far as chemical modifications are concerned, the main problem is the possible degradation of hemicellulose as a result of the action of undesirable reaction by-products. In conclusion, the authors point out that, due to their excellent barrier properties, hemicellulose films can be used successfully in cases where the mechanical properties of the packaging are not particularly important (as in the case of food film rolls).
Application of electro-spinning for the production of active packaging systems
A recent study, conducted by a group of international researchers (Topuz & Uyar, 2020), summarises the main advances made in the development of active packaging systems through the application of the electro-spinning technology. According to the authors, this technology allows different solutions to be developed using biopolymers, biocompatible synthetic polymers and their nanocomposites.
The large surface-to-volume rations of these systems enables the incorporation of large amounts of active agents as nutraceuticals, antioxidants, antimicrobial or antifungal agents. Among the main problems which still limit the application of electro-spinning technology, the study mentions: an insufficient availability of non-toxic solvents to be used for the solubilization of different polymers and a low barrier property due to the high porosity of the materials thus obtained.
Research should be directed toward the selection of suitable GRAS (generally recognized as safe) solvents and molecules that absorb water and oxygen, and their encapsulation for their use as active food packaging materials. Finally, among future developments, the study calls for the application of electro-spinning also in the production of so-called intelligent packaging, citing, as an example, the possibility of incorporating phase-changing materials (PCM), obtaining a system capable of providing thermal protection to the packaged product during its storage.
References: Zhao et al., Polymers, 12, 2020, 1-14; Topuz & T. Uyar, Food Research International, 130, 2020, 108927