The study, published in the journal Food Chemistry , reports the use of acetone to extract the antioxidants from the peel of both ripe and raw mango, and measured the antioxidant activity of the extract, rich in anthocyanins, carotenoids and polyphenols.
"Thus, the mango peel extract exhibited good antioxidant activity in different systems and thus may be used in nutraceutical and functional foods," wrote the authors from the Central Food Technological Research Institute, India.
The main sources of polyphenols on the market today are green tea extracts, like DSM's Teavigo and Taiyo International's Sunphenon, grape seed extracts, like Masquelier's Original OPCs, Anthogenol, and pine bark extracts like Horphag's Pycnogenol.
According to Frost and Sullivan, the European polyphenols market is dominated by grape seed extracts, which account for over 50 per cent of the market.
Green tea extracts account for between 20 to 25 per cent.
The new research taps into the growing trend of sourcing nutraceuticals from by-products of processing.
"During processing of mango, peel is a major by-product.
As peel is not currently utilized for any commercial purpose, it is discarded as a waste and becoming a source of pollution," wrote the authors.
"It has been reported that mango peel contains a number of valuable compounds such as polyphenols, carotenoids, enzymes and dietary fibre," they added.
The researchers measured antioxidant content and activity of two varieties of raw and ripe mango (Raspuri and Badami).
They report that ripe peels contained higher amount of anthocyanins (from 360 to 565 mg/100 g) and carotenoids (from 74 to 436 micrograms per gram of peel) compared to raw peels, but the raw mango peel had high polyphenol content (90 to 110 mg/g peel).
"The mango peel extracts showed a concentration dependent scavenging of DPPH radical," wrote the researchers.
"Raspuri extracts showed low IC50 values (1.83 to 1.98 micrograms of gallic acid equivalents (GAE)) compared to that of Badami peel extracts (3.67 to 4.54 micrograms of GAE)," they added.
Comparison of the free radical scavenging activity of mango peel extracts with the synthetic antioxidant BHA showed that extracts from both raw and ripe Raspuri mango peels were higher than that of BHA.
"The antioxidant potential of mango peels could be due to synergistic actions of bioactive compounds present in them," concluded the researchers.
Waste disposal has increasingly found a place on government agendas recently.
The EU announced at the end of 2005 that reducing the environmental impact of food waste, including cutting down on landfills, would form part of a multi-million euro, five-pronged research project aimed at the food and drink industry.
Source: Food Chemistry (Elsevier) Volume 105, Issue 3, Pages 982-988 "Bioactive compounds and antioxidant potential of mango peel extract" Authors: C.M. Ajila, K.A. Naidu, S.G. Bhat and U.J.S. Prasada Rao