Scientists involved in a US Department of Agriculture study were able to use the materials to produce the composite films. The films showed an increase in stiffness and strength and a decrease in water solubility and water vapor transmission rate, in comparison with films cast from pectin alone.
The development could provide a new way to use food waste to produce biodegradable packaging for the industry. Food processors are also demanding more biodegradable packaging in a bid to meet pollution and waste regulations.
"The composite films inherited the elastic nature of proteins, thus being more flexible than the pure pectin films," they said in reporting on their work in a paper published in the current issue of the Journal of Agricultural and Food Chemistry.
The composite films were biodegradable and possessed moderate mechanical properties and a low water vapor transmission rate, they reported.
"Therefore, the films are considered to have potential applications as packaging or coating materials for food or drug industries," said the four scientists involved in the study.
The US fruit juice and sugar beet processing industries produce about 108 tons of orange peel and sugar beet pulp annually.
The scientists estimate that the waste residues from these industry segments could generate about 106 tons of purified pectic polysaccharides a year.
However, only about 0.1 per cent of the potential pectin is produced, and most of it is used in the food industry
"The development of nonfood applications for pectin presents a new strategy to profitably use these underutilized carbohydrates," they write. "Recent work in our laboratory has shown that pectin can be used to prepare delivery systems for controlled drug release, for implantable cell carriers in tissue engineering, and for prebiotics."
Studies have shown that pectin-starch films swell upon exposure to moisture and dissolve in contact with water.
The studies have also showed that pectin-derived films or gels appeared to be effective in food protection with low-moisture foods, but were poor moisture
Pectin has been used as a means of producing films for food packaging. However poor processing endurance and high water susceptibility have been obstacles limiting the expansion of pectin film use by the industry.