Browsing by Author "Oliveira, Diana"
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- Milk oligosaccharides: a reviewPublication . Oliveira, Diana; Wilbey, R. Andrew; Grandison, A. S.; Roseiro, Luisa B.Milk oligosaccharides (OSs) confer unique health benefits to the neonate. Although human digestive enzymes cannot degrade these sugars, they support specific commensal microbes and act as decoys to prevent the adhesion of pathogenic micro-organisms to gastrointestinal cells. The limited availability of human milk oligosaccharides (HMOs) impedes research into these molecules and their potential applications in functional food formulations. Recent studies show that complex OSs with fucose and N-acetyl neuraminic acid (key structural elements of HMO bioactivity) also exist in caprine milk, suggesting a potential source of bioactive milk OSs suitable as a functional food ingredient.
- Natural caprine whey oligosaccharides separated by membrane technology and profile evaluation by capillary electrophoresisPublication . Oliveira, Diana; Wilbey, R. Andrew; Grandison, A. S.; Roseiro, Luisa B.The functional food market is growing rapidly and membrane processing offers several advantages over conventional methods for separation, fractionation and recovery of bioactive components. The aim of the present studywas to select a process that could be implemented easily on an industrial scale for the isolation of natural lactose-derived oligosaccharides (OS) from caprine whey, enabling the development of functional foods for clinical and infant nutrition. The most efficient process was the combination of a pre-treatment to eliminate proteins and fat, using an ultrafiltration (UF) membrane of 25-kDa molecular weight cutoff (MWCO), followed by a tighter UF membrane with 1-kDaMWCO. circa 90% of the carbohydrates recovered in the final retentate were OS. Capillary electrophoresis was used to evaluate the OS profile in this retentate. The combined membrane-processing system is thus a promising technique for obtaining natural concentrated OS from whey.
- Separation of oligosaccharides from caprine milk whey, prior to prebiotic evaluationPublication . Oliveira, Diana; Wilbey, R. Andrew; Grandison, A. S.; Duarte, Luís C.; Roseiro, Luisa B.Milk oligosaccharides are believed to have beneficial biological properties. Caprine milk has a relatively high concentration of oligosaccharides in comparison with other ruminant milks and has the oligosaccharide profile closest to that of human milk. The first stage in recovering oligosaccharides from caprine milk whey, a by-product of cheese making, was accomplished by ultrafiltration to remove proteins and fat globules, leaving more than 97% of the initial carbohydrates, mainly lactose, in the permeate. The ultrafiltered permeate was further processed using a 1 kDa ‘tight’ ultrafiltration membrane, which retained less than 7% of the remaining lactose. The final retentate was fractionated by preparative scale molecular size exclusion chromatography to yield 28 fractions; oligosaccharide-rich fractions that were suitable for functionality and gut health promotion testing were detected between fractions 9/10 to 16/17. All fractions were evaluated for their oligosaccharide and carbohydrate profiles using three complementary analytical methods.