0000000000349059
AUTHOR
Jaime Salcedo
showing 5 related works from this author
Determination of sialic acid and gangliosides in biological samples and dairy products: A review
2009
Gangliosides are sphingolipids containing one or more moieties of sialic acid in their structure. Both gangliosides and sialic acid are bioactive compounds related to animal physiology. Due to their biological relevance, analytical methods adapted to each type of matrix have been developed over time. The present study reviews the main methods applied to the analysis of sialic acid and gangliosides in biological samples and dairy products.
Comparison of spectrophotometric and HPLC methods for determining sialic acid in infant formulas
2011
Abstract Two methods for determining sialic acid in infant formulas – spectrophotometry and HPLC with fluorescence detection – have been optimised and validated, the first one allows to determine total sialic acid while the second allows to differentiate the two main forms of sialic acid (N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc)). A common sample preparation procedure (hydrolysis and purification) for both methods has been proposed. The linearity (from 6 to 150 μg of total sialic acid in the assay for spectrophotometry, and from 12.5 to 250 ng and 1 to 5 ng of Neu5Ac and Neu5Gc, respectively, for HPLC) is adequate. The detection and quantification limits (0.29…
Effect of simulated gastrointestinal digestion on sialic acid and gangliosides present in human milk and infant formulas.
2011
The effects of simulated gastrointestinal digestion upon sialic acid and gangliosides in infant and follow-on formulas and human milk, as well as their bioaccessibility, have been evaluated. The gastric stage is the step that causes a greater decrease in sialic acid and ganglioside contents. The intestinal stage only decreases the total and individual contents of gangliosides. After gastrointestinal digestion, neither sialic acid nor gangliosides were found in the nonbioaccessible fraction. The highest bioaccessibility (100 × content in soluble fraction after gastrointestinal digestion/total content) of sialic acid is found in human milk (87%), followed by infant formula (77%) and follow-on…
Gangliosides and sialic acid effects upon newborn pathogenic bacteria adhesion: An in vitro study
2012
The effect of the main gangliosides (GM(1), GM(3), GD(3)) and free sialic acid (Neu5Ac) upon the adhesion of pathogenic bacteria implicated in infant diarrhoea is assessed in vitro using the Caco-2 cell line. Concentrations of the bioactive compounds found in the bioaccessible (soluble) fraction of infant formula and human milk are employed. Bacterial adhesion behaviour included enterotoxigenic Escherichia coli (ETEC), enteropathogenic E.coli (EPEC), Listeria monocytogenes, Salmonella entericaserovartyphi, Shigella sonnei, Campylobacter jejuni and Helicobacter pylori. Three different approaches were assayed: pre-incubation of bacteria and compounds before addition to cells (competition); pr…
Sialic acid (N-acetyl and N-glycolylneuraminic acid) and ganglioside in whey protein concentrates and infant formulae
2011
Abstract Sialic acid and gangliosides content and profiles were analyzed in infant formulae, whey protein concentrates and human milk. In infant formulae, N-acetylneuraminic (Neu5Ac) and N-glycolylneuraminic (Neu5Gc) acid ranged from 147.6–199.7 to 3.3–8.3 mg L −1 , in whey protein concentrate from 1.6–2.4 g 100 g −1 to 2.8–20.2 mg 100 g −1 and in human milk from 299.9 to 2.1 mg L −1 . Gangliosides ranged from 0.25 to 2.29 mg lipid-bound sialic acid L −1 in reconstituted infant formula, the main gangliosides being GD 3 (73.3–55.5%), GM 3 (3.5–36.6%) and GT 3 (1.4–14.1%) and O-acetyl-GD 3 (5.3–18.9%). In whey protein concentrates, 0.7–55.6 mg lipid-bound sialic acid 100 g −1 were found with …