Upcycled ingredients from melon peels show functional properties

Melons could provide a healthy, sustainable, and inexpensive source for certain functional ingredients. According to research published in Food Chemistry (DOI: https://doi.org/10.1016/j.foodchem.2020.127579), the chemical profile of melon peels is full of bioactive compounds and antioxidants.

Researchers from Portugal and Mexico analysed the chemical properties of the melon Cucumis melo peels (Inodorus cultivar)—noted to be the most common fruit cultivated in tropical countries globally. They looked at the melon peels’ nutritional index, bioactive compounds and antioxidant properties. The studied melon peels were processed into three fractions: solid, liquid and pellet.

Researchers found in the melon by-products 15 polyphenols (mainly hydroxybenzoic and hydroxycinnamic acids and flavonous acids) and four carotenoids (mainly β-carotene and β-cryptoxanthin). They noted these to be “responsible for diverse biological activities (antimicrobial, provitamin A, antioxidant activity, among others) with health promotion.”

Interestingly, researchers found the solid fraction of the melon peel to offer the most benefits related to fibre—cellulose, hemicellulose and lignin-richness: "This fraction can be directly used as a source of dietary fibre (flour) that has contributed to the modulation of intestinal microbiota, such as Bifidobacterium, which has been associated with the prevention of colon, stomach, breast and prostate cancer.”

The liquid fraction had the highest level of antioxidant activity due to its high quantity of available polyphenols; it also had fibre and proteins. Researchers highlighted, “This fraction can be used as an additional ingredient (juice powder) for human health promotion as polyphenols exhibit good inhibition of digestive enzymes (lipase, amylase and glucosidase), minimising hyperglycaemia, which is also strongly associated with diabetes and obesity disorders.”

When looking at the pellet fraction, researchers found it the fraction with the highest levels of chlorophylls, carotenoids, and proteins. "This fraction can be used as colouring and food additives (powder)," they added.