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  • Kesya Hanna Rosalie

Edible Wrapper for Longer-Lives Crop

At the grocery store, most foods come wrapped in plastic packaging. Not only does this create a lot of waste, but thin plastic films are also inefficient at preventing spoilage. To solve these difficulties, scientists are currently working on an alginate-based coating that could spell the end of your standard packaging.

Edible protective coatings (source:/https://www.packaging-360.com/)


The Great Combo

The idea of edible packaging has been around for a while, but the time is now ripe for it to take hold in the food industry with this coating. Coating serves a few purposes, but the most important is preventing water loss, thus protecting food from hungry fungi and bacteria. Some probably do not know but fruits and vegetables produce breath and sweat too by letting out carbon dioxide, water, and heat through their skin. Even after they're picked, fruits and vegetables are still very much alive, which eventually leads to them shriveling and spoiling.


Many coatings nowadays are supercharged. Not only do they slow down spoilage and fight off fungi, but they also add shine (and we humans sure do love our shiny things). The great news is this new alginate-based coating can do it all. It is not just one substance; it is a cocktail of three major components. Alginates in food packaging are preferred due to their inherent antimicrobial and UV-barrier qualities. The Chemistry Department of Cairo University's Faculty of Science aims to build smart alginate-based coatings for active food packaging through the combination of aloe vera (AV) and garlic oil (GO).


Alginates are an important raw material made from refined seaweed which is used in a wide array of medical and clinical applications. The addition of AV and GO increased thermal and mechanical qualities. The presence of these two had no effect on the transparency of alginate films. The films exhibited a significant UV-shielding to all UV regions. GO possesses excellent antioxidant and anticancer properties along with the regulation of some biological processes in human cells. Furthermore, GO-enriched edible coatings may help prevent microbial infection. On the other hand, the AV gel is a promising additive for the improvement of the UV-protecting and antimicrobial properties of edible coatings. Many active components, including phenolic compounds, minerals, and organic acids, are known to be present in AV.

The preparation of alginate-AV-GO edible films (source: https://doi.org/10.1016/j.ijbiomac.2021.09.031)


The interactions between alginate, AV, and GO were validated using FTIR and XRD, indicating the successful fabrication of their films. FTIR spectra are studied to detect the interactions between the film constituents. XRD may be utilized to discover interactions between alginate, AV, and GO through the examination of crystallinity changes.


No Wrinkling, No Mushy

The process used an applicator which is a spray tool that's going to help protect the surrounding skin from any excessive moisture. Experiments show that the shelf-life of tomatoes (Solanum lycopersicum L.) was extended when covered with the film. The coated tomato did not show any surface spoilage, but the uncoated tomato began to spoil after 6 days of storage. Due to the presence of AV, spotting of the coated tomatoes was not seen. Furthermore, the spoilage due to microbial growth was constrained for the coated tomato due to the synergetic strong antimicrobial potencies of AV and GO.


The uncoated tomato had a significant percentage of mass loss after 16 days of storage, losing nearly 47% of its mass. This is due to it losing a lot of water and fluids to the environment. The mass loss for the coated tomato, on the other hand, was considerably lower, with just around 8% of its mass lost after 16 days of storage. So, there's obviously no washing involved and nothing needs to be thrown out in order to keep your tomatoes fresh.

After selected storage periods for coated (above) and uncoated tomatoes (under) (source: https://doi.org/10.1016/j.ijbiomac.2021.09.031)


Next Challenge

The growing interest from consumers toward healthy and nutritious products and their benefits for health has increased for food preservation development. Edible coatings or films have been used for decades in the food industry to preserve food so this is not a new preservation technique. For example, waxing on fruits and vegetables and cellulose coating in meat casings. Chitosan has proven able to control numerous pre and postharvest diseases of fresh fruits and extend the shelf life by minimizing the rate of respiration and reducing water loss. Milk proteins have good tensile strength, act as good oxygen barriers, retard moisture loss, and are flexible, and generally have no taste or flavor. In this way, smart packaging based on natural materials has emerged and evolved throughout the years. Now, alginate has also proven successful.


The ability of the selected materials in extending the shelf life of food without reducing the sensory and nutritional characteristics are the main challenges in the edible coating techniques. The materials selection plays a key role in determining its effectiveness and consumer's acceptability. This demands attention for further research. Now we know that wrappers can function with different types of intelligence. So there's a real opportunity for us to step ahead and meet what people need.


 

References:

Abdel Aziz, M.S. & Salama, H.E., 2021. Developing multifunctional edible coatings based on alginate for active food packaging. International Journal of Biological Macromolecules, 190, pp.837–844.


Salama, H.E. & Abdel Aziz, M.S., 2020. Optimized carboxymethyl cellulose and guanidinylated chitosan enriched with titanium oxide nanoparticles of improved uv-barrier properties for the active packaging of green bell pepper. International Journal of Biological Macromolecules, 165, pp.1187–1197.


Senturk Parreidt, T., Müller, K. & Schmid, M., 2018. Alginate-based edible films and coatings for food packaging applications. Foods, 7(10), p.170.

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