Sustainable food packaging made from pomace

What if packaging that could significantly reduce the environmental impact were made from a by-product of food processing, pomace?

It is one of the ongoing projects in the Sustainable food processing and packaging laboratory on the Oregon State University campus under the supervision of Yanyun Zhao, professor in the Department of Food Science and Technology. Holder of a doctorate in food engineering – she studied modified atmosphere packaging for her doctoral thesis – Zhao specializes in the development of sustainable packaging.

For several key projects under his leadership, the raw material is pomace, the pulpy by-product that remains after juicing apples, wine grapes and other fruits or vegetables. In one example, the whole pomace is used to make compostable packaging. In another, the pomace extract is used to produce edible films.

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Fruit and wine grape pomace is an abundant resource of dietary fiber, phenolic compounds and other bioactive compounds, Zhao points out. While some companies have extracted bioactive compounds from the pomace, “there is still a huge amount of bulk material … my research aims to use 100% of this fiber-rich by-product to create environmentally friendly packaging,” explains she does. Packaging condensate.

According to Zhao, fruit and vegetable pomace has a high amount of phenolic compounds, which provide good antioxidant and antimicrobial effects. Edible pomace films protect food products and provide additional antioxidant and antimicrobial benefits to packaged foods.

While the research involves theoretical and fundamental studies, it also involves working closely with industry partners.

“It targets the commercial needs of the market and thus develops materials with specific functionalities to meet targeted applications,” explains Zhao.

The marc is provided free of charge by local juice processors. “They were very supportive of our research,” she adds.

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Edible Fruit Leather Wrapping Film is made of cranberry pomace extract with the natural color of cranberry juice.

In other research, the lab is producing edible films using food polymers to replace single-use plastic for food. Some applications studied in Zhao’s lab include a sachet of edible oil and single-use seasonings; an edible muffin pan (shown below); an edible package produced from pomace extract for fruit leather; and edible films that can be interleaved to wrap stacks of cheese or sliced ​​meat for packaging.

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In a side project, whole pomace is used to create compostable molded pulp packaging products. This research has been ongoing for years with a granted patent, “but requires additional research and development to create packaging products that meet specific criteria for given food packaging applications,” Zhao notes.

Coatings for products.

In addition, the laboratory has developed patented coating techniques to protect and preserve food products, especially fruit crops throughout the supply chain. These coatings could potentially replace wax coatings typically used for products, for example carnauba (derived from nature) or shellac. A video showing the shelf life of bananas with and without a coating can be seen here.

“Today in the United States, approximately 52% of fruits and vegetables are lost, of which 20% in production and 15% in post-harvest handling, storage, distribution and retailing.” , she emphasizes. Zhao’s laboratory has developed new food coatings to protect and preserve certain fruit crops throughout the supply chain. The objective is to create a barrier against both oxygen and humidity, the enemies of the shelf life of fresh produce.

Zhao was invited to present the edible coating research at the USDA Food Loss and Waste Innovation Show held on May 26, 2021. She notes that “our research was just on the target, in particular for fresh fruits and vegetables “.

One of the main advantages of coatings is that they work as secret packaging versus using plastic wrap that is obvious to everyone, including those who would consider it unnecessary versus packaging. Coatings perform a similar function in a much more durable and natural way.

“Coating is like waterproof packaging when it is made with the right properties,” Zhao explains. “Additionally, an antimicrobial agent can be incorporated into the coatings and released during storage to further extend the shelf life of a coated food. This requires a good understanding of the coating itself as well as the physiological property of this specific food… a banana behaves very differently from a blueberry.

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The work is further complicated by the fact that to ensure the effective application of the coating, it is necessary to study the surface morphology of the product.

Due to the different applications with different functional requirements between coatings and films, the exact formulations may be different, which is under study, ”Zhao explains.

There is also the improvement in the production efficiency of coating application over packaging film applied using semi-automatic or automated film packaging equipment. Fruit and vegetable packers have for years used coatings for citrus fruits, apples and pears, which are applied by brush, followed by drying via a controlled heat air tunnel or something similar.

All of the ingredients in patented fruit coatings are generally recognized as safe (GRAS), with the exception of fibrillated cellulosic materials. “Studies on the safety of fibrillated cellulose are ongoing and a GRAS petition request on fibrillated cellulose is underway by our industrial licensee,” she said.

Zhao’s research was funded by the USDA National Institute of Food and Agriculture (NIFA) grant, the Oregon Department of Agriculture Specialty Crop Block Grant, and industrial sponsors.

For now, Zhao will focus R&D “on coatings, edible films and compostable packaging products in order to improve the performance of a given application and extend the applications of our sustainable packaging techniques to more. of food products ”.

Zhao can be contacted via OSU website.

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