Production of pectin-derived oligosaccharides from lemon peels by extraction, enzymatic hydrolysis and membrane filtration

BACKGROUND: There is growing interest in the search for new prebiotics with improved functional properties. In this field, pectin-derived oligosaccharides (POS) have been identified as promising prebiotics. Lemon peels (an abundant agro-industrial by-product) can be used as a raw material for manufacturing a variety of POS, whose prebiotic properties depend on their chemical structure and composition. This work deals with the production of POS by partial enzymatic hydrolysis under a variety of operational conditions, with their purification by membrane filtration and detailed chemical characterisation. RESULTS: As a result of a three-stage process (water extraction, enzymatic hydrolysis and membrane filtration), two POS refined concentrates were obtained after 7.5 or 24 h of enzymatic hydrolysis (the contents of the non-volatile impurities were 5.8 and 11.8wt%, respectively), mainly made up of oligogalacturonides with different molar mass distribution and degree of methylation (43.4 and 37.4%, respectively) and degree of acetylation (5.5 and 8.6%, respectively) at yields of 13.1 and 10.8 g 100 g(-1) dry lemon peel wastes, respectively. CONCLUSION: A high-yield process (based on simple and scalable technologies) enabled the production of two POS mixtures with different chemical characteristics, fulfilling the compositional requirements to be used as prebiotics. (C) 2014 Society of Chemical Industry