A team of researchers from Zhejiang University in China has investigated porous hydrogel packaging for the safe transportation and storage of delicate fruits.
Optimal storage conditions during transportation, storage, and sale are crucial to ensuring that food products meet the quality demands of retail and consumers. Physical damage or imperfections in the surface of soft textured fruits such as berries can make them more vulnerable to fungal growth, causing food safety issues, food waste, and economic loss for companies.
The need to develop soft and reliable fruit packaging materials and technologies that can reduce the damage caused during transit and ensure the quality and shelf-life of soft-bodied fruits is urgent. Ideally, these materials should be economically viable, non-toxic, safe, have good mechanical and physical properties, and enhanced energy dissipation performance.
In the study, the strategy used by the authors involves hydrogels- a well-documented soft advanced material that has been employed in numerous industries. These physically or chemically cross-linked polymer networks are highly absorbent yet maintain their well-defined structure. Hydrogels’ advantageous properties include viscoelasticity, poroelasticity, self-healing, and controllable environmental reactions such as shock absorption and temperature responses.
“The hydrogels in the research were prepared from calcium ion cross-linked alginate networks and soy protein isolates. The isolates produced foams with stable pore properties, which then underwent gelation to fabricate functional hydrogels.
“Mechanical properties were evaluated, along with categorization of the hydrogel’s energy dissipation rate as a function of loading rate and deformation. Cyclic tests were employed to detect energy dissipation rates and modulus. To assess the suitability of the prepared hydrogel, it was used as packaging for strawberries and tested in transportation and free-fall simulations”.
The experiments demonstrated that the novel porous hydrogel provided superior protection for soft-bodied fruits. Strawberries packaged in this material suffered less damage and retained higher sensory values than strawberries packaged in commercially available materials. An additional finding was that the porous hydrogel helps to maintain the low temperatures required for safe transportation and storage of soft-bodied fruits due to its thermal insulating properties.
Other benefits highlighted in the study include the environmental friendliness of the raw materials used in hydrogel preparation, biodegradability, cost-effectiveness, non-toxicity, and the edible nature of the packaging material. In regard to shock-absorbing capabilities, the porous hydrogel dissipated between seventy and seventy-eight percent of the impact energy.
The researchers claim that potential future uses of their novel porous hydrogel can include improved transportation of live organs for the biomedicine and healthcare sectors.
