This article was written by Jorge Luis Alonso G., an information consultant specializing
in the potato crop.
Have you ever wondered what happens to the tons of potato peels left over after making your favorite crispy fries or mashed potatoes? While they may seem like a waste, these humble peels are now revolutionizing the processed food industry in ways you never imagined. From reducing food waste to adding flavor and nutrients, potato peels are becoming the star ingredient of many popular food products. This article explores how potato peels are changing the food industry and the thinking about food waste.
Potato peels produced by the processing industry
The world’s potato production is usually eaten fresh as a traditional ingredient in many dishes and is thus traded as a commodity. The world’s potato production is usually eaten fresh as a traditional ingredient in many dishes and is thus traded as a commodity. However, an estimated 50 percent of the world’s total potato production is used after processing in four forms: freezing, drying, cooking/preserving and potato starch.
In general, potato processing begins with peeling of the tubers, which includes a steam peel, caustic peel, and abrasive peel, the latter of which is used in the potato chip industry. Value-added processed products such as French fries, crisps, hash browns, purées and frozen foods generate potato peeling waste. Depending on the peeling process, this waste can range from 15% to 40% of the original fresh weight.
The potato starch, flour and canning industries are also responsible for large amounts of peel waste, the disposal of which is a major environmental concern. These industries produce between 70 and 140 thousand tons of potato peel per year worldwide. Most of it is either disposed of in landfills, which pollutes the environment, or used as animal feed, which adds no value to the production process.
To overcome this global problem, the utilization of these residues into value-added products can thus be of interest not only to the food industry but also to government agencies and policymakers, thus reducing the environmental impact of the potato processing industry.
According to a study by the Instituto Politecnico de Braganca (Portugal, 2020), there is an urgent need to return by-products and waste to the food supply chain and related industries in the context of the circular economy and the increasing environmental impact of the agricultural industry.
For them, several studies have highlighted the great potential for extracting bioactive compounds and antioxidants from potato peels that can serve as antimicrobial agents or as functional ingredients in foods and dietary supplements.
Given the unwieldy nature of potato peels, they say, future research must focus on facilitating the industrial use of this promising material with efficient green protocols, as well as exploring alternative uses to increase the value of this important crop.
Exploring the Versatility and Nutritional Benefits of Potato Peels
ICAR-Central Potato Research Institute (India) published a book in 2020 titled Potato. Nutrition and Food Security. One of its chapters, Potato Peel Composition and Utilization, explains the health benefits and various food uses of potato peel. Below is a summary of this chapter.
Fiber is a broad term that includes various carbohydrates such as cellulose, hemicelluloses, lignins, pectins, gums, etc. It is known as a bulking agent that increases intestinal mobility and hydrates feces. The skin of potatoes contains insoluble fiber that binds to bile acids, giving it the ability to lower plasma cholesterol.
A high fiber intake also affects bowel movement and gastric emptying time, which further affects the absorption of glucose in the body. This has a positive effect on blood glucose levels.
Dietary fiber is known to protect against mutagenesis and carcinogenesis by binding mutagenic and carcinogenic agents, decreasing transit time in the intestine, increasing water absorption and stool volume, and decreasing stool pH through fermentation by intestinal microorganisms.
The main contributors to the antioxidant properties of potato peel are the phenolic compounds. The skin contains both bound and free phenolics, the most important of which is ferulic acid. They are present throughout the potato tuber, with the highest concentration in the peel (50%) and decreasing concentration toward the center of the tuber. The presence of these active compounds in the human diet prevents inflammation and degenerative diseases.
A Source of Dietary Fibre
To replace wheat flour in bakery products, various sources of dietary fiber have been used. In the 1970s, work began on incorporating potato peels into bakery products as a source of fiber.
Some authors have reported that potato peel is superior to wheat bran in total fiber content, water retention, and low starch content. When incorporated into bread, potato peel increased crumb darkening and reduced loaf volume. Others have reported a musty smell in bread with potato peels, which could be reduced by extruding the potato peels before incorporation.
Potato peels offer bakers the opportunity to extend shelf life while increasing fiber content, especially extruded peels with reduced glycoalkaloid levels.
A Source of Natural Antioxidants
Antioxidants inhibit the oxidation of lipids in foods. The consumption of high concentrations of synthetic antioxidants has a carcinogenic effect on the human body. Natural antioxidants, therefore, have gained considerable interest in recent years for their role in preventing the auto-oxidation of fats, oils and fat-containing food products.
The dominant phenolic compounds of potato peel extracts are chlorogenic and gallic acids. In comparison with mature potatoes, young potato peel is an excellent source of bioactive phytochemicals with good antioxidant potential.
Several studies have illustrated that potato peel extract exhibits very strong antioxidant activity which is almost equal to synthetic antioxidants although when applied at a higher amount. Therefore, potato peel extract in oils, fats and other food products can be used as a natural antioxidant to suppress lipid oxidation.
In comparison with synthetic preservatives potato peel extract as an antioxidant is non-carcinogenic and non-mutagenic.
Potato peels, which were once considered waste, are now revolutionizing the food industry in many ways. The potential to extract bioactive compounds and antioxidants from potato peels has led to the development of functional ingredients for food and dietary supplements.
The fiber content in potato peels has been found to have various health benefits, such as reducing plasma cholesterol and blood glucose levels, protecting against mutagenesis and carcinogenesis, and preventing inflammation and degenerative diseases. Potato peels are also being used as a source of natural antioxidants to inhibit the oxidation of lipids in food products.
By upgrading potato peel waste into value-added products, the food industry can reduce its environmental impact and contribute to a circular economy. It is important to continue exploring the industrial use of potato peels with efficient green protocols and alternative uses to increase the value of this crop.
Author: Jorge Luis Alonso G. is an information consultant specializing in the potato crop. He writes marketing materials for Ag-Tech companies.
Cover photo: Credit Thomas G. from Pixabay