As starch is an inexpensive, filmogenic, easily processable and a widely available material, it is a material that can be utilized in the creation of biodegradable films and containers, presenting as a viable alternative to polymers derived from petrol. Moreover, starch could also be used to create edible coatings for fresh foods in order to extend shelf life. As such, wheat starch films with two glycerol contents were formulated to mimic the effects of compounds currently used to coat fruit. Their structural and functional properties were characterized. This study found that the transfer properties of starch films containing 33% of plasticizer was less effective than film comprised of 50% glycerol. Water diffusivity, oxygen permeability, and water vapor permeability at two different humidity gradients, surface tension, works of surface adhesion and cohesion, and moisture sorption were tested. Glycerol content does not play a significant role on the color or mechanical properties. This work shows that glycerol can strongly affect the functional properties of starch-based coatings and films.

In order to extend the shelf life of the fruit, improve appearance, and to keep all nutrition properties of the plum from diminishing, edible coatings comprised of wheat starch and wheat starch–whey protein isolate (in ratio 80/20) were created. Stand-alone films were produced to assess properties which helped to understand the phenomena occurring on the surface level of coated plums. The properties of coatings based on starch are similar to starch coatings containing oil because the natural epicuticular wax layer of plums merges with coating materials. Adding oil doubled the contact angle value and the dispersive component of the surface tension. The workings of adhesion and cohesion, spreading coefficient, water absorption, water content, and solubility in water of the films decreased. Similar processes were observed on the fruits’ surface. In appearance, the coating process is similar to polishing the plum surface for removing crystalline wax. The color parameters of coated fruits did not significantly change. Newly formed bonds or interactions established between starch, whey proteins, water, glycerol, and oil are displayed by Fourier transform infrared (FTIR) analysis. This work revealed how the interactions between the epicuticular wax on the fruit’s surface and the hydrocolloid-based coatings affect the efficiency of the coatings.

Edible starch-based materials have shown a positive impact on quality parameters. In this study, plums (Prunus domestica cv. Jojo) were divided into five groups: a control, two coating treatments (starch and starch-whey protein (80–20%), and two film systems (starch and starch-whey protein (80–20%). Biodegradable packaging, particularly the coating treatment, had no negative effect on color parameters. After 28 days of performed tests, firmness was boosted with starch and starch-whey protein (80–20%) films. With the coated materials, there was no significant difference compared to control group. The lowest transpiration velocity was of plums wrapped in starch films. In the case of respiration rate, no significant difference was observed between the packaging and control samples. After the conducted trials, the weight loss of untreated plums was at 10%, while 5% of weight loss was noticed for plums wrapped in starch materials, and around 6% was noticed for the other materials. Oxygen permeability was higher for S-WP films, the thickness of S and S-WP films were comparable and thickness of starch coating was around 60% higher than S-WP. Both films have an affinity to water and both show typical behavior of water vapor sensitive hydrophilic biopolymers. The starch film with the addition of 20% of proteins increased the resistance of gas exchanges, which represents one of its great benefits.

Today the packaging design and production is vastly driven by the aspect of sustainability, which is not merely a consumer trend, but a necessity to meet the goals of sustainable growth, as well as the legal demands imposed by EU regulations. Packaging manufacturers are challenged to continuously seek new ways of providing products compliant with modern demands. Ecolure is an example of a sustainable paper packaging solution that is recyclable and compostable while still maintaining the metallized shine of a traditional PET-laminated board.