The Antioxidant Capacity of Different Fruit Peels

Fruits are some of the most important foods in the human diet.

They’re abundant in all the necessary vitamins and minerals, and they’re also a source of soluble fiber while being low in calories.

The health benefits of having a diet high in fruits are numerous, including protection from chronic diseases.

Many types of fruit are naturally high in antioxidants, which gives them a superpower.

But, what about fruit peels?

Fruit juice industries discard tons of fruit waste, including fruit peels.

This waste is often poorly managed, resulting in emissions of unnecessary gasses, which lead to secondary waste, like the release of pollutants that can cause not only environmental damage but also health issues.

Having said that, finding a better solution for this type of waste is imperative.

Some fruit peels are often recycled into agricultural compost or biofuel, however, it’s important to note that just like fruit, fruit peels are also full of nutrients.

They are an excellent source of carbohydrates, fiber, proteins, and phytochemicals, especially polyphenols that have a high antioxidant capacity.

There are many creative ways of how fruit peels could be used more effectively, as food ingredients, animal feed, or nutraceutical products.

A recent study, published in the journal Foods has examined the antioxidant capacities of fruit peels, and we’ll give you the highlights.

What’s Important

Polyphenols are a large group of micronutrients naturally present in plant-based foods.

They’re packed with different types of antioxidants, including phenolics, flavonoids, and tannins.

They protect the body and help it to regulate cellular activity and neutralize free radicals that cause oxidative stress to cells and tissues.

Oxidative stress is an imbalance between free radicals and antioxidants in the body.

Free radicals are molecules naturally produced in the body during normal metabolic processes.

However, the body also naturally produces antioxidants that fight off the free radicals in order to re-establish balance in the body.

Otherwise, damage to cells, proteins, and DNA may occur, which is why antioxidants are so important.

The Details

The study focused on discovering the total content of phenolics, flavonoids, and tannins in 20 different fruit peel samples, as well as examining their total antioxidant capacity and free radical scavenging ability.

The fruit varieties used were: apple, apricot, avocado, banana, custard apple, dragon fruit, grapefruit, kiwi, mango, lime, melon, nectarine, orange, papaya, passionfruit, peach, pear, pineapple, plum, and pomegranate.

Here’s what they discovered:

Mango, grapefruit, and lime peel had the highest phenolic content;

Dragon fruit, nectarine, and passion fruit peels had the lowest phenolic content;

Avocado peel had the highest tannic content, followed by mango, lime, and custard apple peels;

Dragon fruit, melon, nectarine, passion fruit, peach, and pear peels were found to have a low tannin content;

Grapefruit, avocado, and mango peels showed the highest free-radical scavenging activity, respectively;

Grapefruit peel had the highest total antioxidant capacity, followed by mango, avocado, and apple peels.

In Conclusion

Fruit peels have high contents of nutrients that can be made use of in a way that’s better for both human health and the environment.

This study is another step further towards finding a way to turn seemingly disposable food waste into something beneficial.

Resource: Suleria, H.A.R.; Barrow, C.J.; Dunshea, F.R. Screening and Characterization of Phenolic Compounds and Their Antioxidant Capacity in Different Fruit Peels. Foods 2020, 9, 1206. doi:https://doi.org/10.3390/foods9091206