FitNESS partners at the Institute Agro Dijon investigate the merits of polysaccharides as an alternative material in food packaging; finds strong ability as oxygen barriers; most polysaccharides exhibited stability over year-long storage time
The mounting environmental concerns linked to plastic packaging have ignited an expanding interest in seeking more eco-conscious options. Among the contenders for a greener approach, biopolymers have emerged as a potential substitute for conventional fossil-based plastics. Against this backdrop, Scientists from the FitNESS partners at the Institute Agro Dijon explored the potential of polysaccharides in addressing food packaging challenges. Their findings were published in June this year in a two-part publication in the peer-reviewed journal Food Hydrocolloids.
The primary objective of this research endeavor was to investigate the attributes of different polysaccharide films in terms of their ability to act as barriers against oxygen and water vapor, as well as their mechanical strength and optical properties such as transparency and UV-blocking capacity. Nine distinct polysaccharides were assessed in the form of films: hydroxypropyl methylcellulose, methylcellulose, hydroxypropyl cellulose, low-methoxyl pectin, cationic starch, sodium alginate, kappa-carrageenan, chitosan, and pullulan.
Due to their hydrophilic nature, all polysaccharides displayed limited capacity to block water vapor (with water vapor permeance ranging from 10-6 to 10-8 mol.m-2.s-1.Pa-1). However, chitosan, low-methoxyl pectin, kappa-carrageenan, pullulan, cationic starch, and sodium alginate demonstrated medium to very high oxygen barrier capabilities under both semi-dry (50% relative humidity) and humid (80% relative humidity) conditions. This was in stark contrast to cellulose derivatives, which showed lower effectiveness in impeding oxygen (with oxygen permeance greater than 10-12 mol.m-2.s-1.Pa-1).
These findings point towards the potential of polysaccharides as effective oxygen barrier materials.
One of the key concerns when using materials derived from natural sources is their stability over time. This is addressed in the second part of the publication by the same scientists from Institute Agro Dijon, where they conducted an in-depth assessment of how storage duration influences the functional attributes of films made from popular polysaccharides.
The researchers investigated the same nine promising polysaccharides. These polysaccharide films were subjected to testing after being stored for 6 and 12 months at 50% relative humidity and 25°C. The resulting data were then compared to the initial properties of the materials right after their production.
Most of the polysaccharide films demonstrated stability over the year-long storage period indicating that these materials could maintain their performance characteristics over time. However, some minor alterations were observed, particularly in the optical properties of the chitosan films. These films exhibited changes in color that were indicative of the Maillard reaction, a chemical process that occurs between amino acids and reducing sugars, often leading to changes in color and flavor in food products. Additionally, alterations in the UV-visible spectrum were observed, particularly in the 280–350 nm range, resulting in reduced light transmittance.
After the 12-month storage period, all polysaccharide films experienced a reduction in glycerol content by 4–60%. However, this reduction did not significantly impact the mechanical strength or the barrier properties of the films.
In essence, this research delves into the potential of polysaccharides as a component in sustainable and effective food packaging options. Not only do these materials exhibit promising barrier properties against oxygen, but their ability to maintain their integrity over time adds another layer of appeal to their candidacy for environmentally friendly packaging applications.
References
Ureña, M., Phùng, T. T., Gerometta, M., De Siqueira Oliveira, L., Chanut, J., Domenek, S., Dole, P., Roudaut, G., Lagorce, A., & Karbowiak, T. (2023). Potential of polysaccharides for food packaging applications an experimental review of the functional properties of polysaccharide coatings: Part 1/2. Food Hydrocolloids, 108955. https://doi.org/10.1016/j.foodhyd.2023.108955
Ureña, M., Fournier, P., Phùng, T. T., Lagorce, A., & Karbowiak, T. (2023). Potential of polysaccharides for food packaging applications an experimental review of the effect of aging conditions on the functional properties of polysaccharide films: Part 2/2. Food Hydrocolloids, 108954. https://doi.org/10.1016/j.foodhyd.2023.108954