Using nano-filtering technology could assist in the recovery and purification of bioactive ingredients such as phenolic compounds from fruit wastes.
The study investigated the performance of nano-filtration membranes in the treatment of by-products of citrus processing.
The team tested four different nano membranes to assess the potential for separating sugars and bioactive compounds from concentrated ‘liquors’ made from orange peels – revealing that the membranes effectively separated phenolic compounds and sugars.
Alfredo Cassano of University of Calabria, Italy, said: “Citrus by-products are enriched in bioactive compounds, such as flavonoids and phenolic acids, recognised for their beneficial implications in human health due to their antioxidant activity and free radical scavenging ability.
“The recovery of these compounds offers new opportunities for the formulation of products of interest in food (dietary supplements and functional foods production, pharmaceutical (products with antibacterial, antiviral, anti-inflammatory, antiallergic and vasodilatory action) and cosmetic industry”.
Cassano and his team evaluated the potential of a nanofiltration (NF) process for the separation and concentration of phenolic compounds from press liquors obtained by pigmented orange peels.
Four different spiral-wound NF membrans, characterised by different molecular weight cut-off (MWCO) )250, 300, 400 and 1000Da) and polymeric material (polyamide, polypiperazine amide and polyethersulphone), were investigated.
The research team said: “The obtained results indicated a reduction of the average rejection towards sugars by increasing the molecular weight cut-off (MWCO) of the selected membranes, while the rejection towards anthocyanins remained higher than 89% for all the NF membranes investigated”.
The team revealed that a NFPES10 membrane gave the lowest average rejection towards sugar compounds and high rejections towards both anthocyanins (89.2%) and flavonoids (70%).
The research team added: “The use of NF PES10 membrane for concentrating press liquor allows recovery of some sugars in the permeate stream, yielding the best separation of phenolic compounds from sugars”.
