Secretory IgA (sIgA) purified from colostrum and breast milk obtained from 14 women inhibited the localized adherence of an enteropathogenic Escherichia coli (EPEC) to HEp-2 cells. Inhibition decreased as lactation continued even when the concentration of sIgA was maintained constant at 1 mg/ml. sIgA responded to a 94-kDa plasmid-encoded outer membrane protein implicated as the EPEC adherence factor. An oligosaccharide-enriched fraction (OEF) from these samples also inhibited the attachment of this EPEC. Inhibition by OEFs decreased as lactation continued because of a general reduction in oligosaccharide content. Localized adherence of six other EPEC was also inhibited by sIgA and OEF, whereas attachment of isolates with diffuse or aggregative adherence was not inhibited by these fractions. Experiments with purified oligosaccharide fractions revealed that EPEC attach to HEp-2 cells through a carbohydrate-mediated mechanism based on the preferential recognition of fucosylated residues in human milk.

The factors responsible for the slow digestibility of starch in leguminous seeds have been studied by examining microscopically the cooked seeds after various treatments and by measuring starch digestion in vitro. Starch in leguminous seeds is entrapped in parenchyma cells and swells only partially during cooking. The alpha-amylase cannot easily penetrate within the gelatinized starch granules due to steric hindrance and the physical nature of the leguminous starch. Disruption of the cells, especially before cooking increases the susceptibility of starch to alpha-amylase digestion.

Quantitative determination of all structural families of complex carbohydrate micronutrients was performed on bovine milk samples, milk-based infant formulas, and whey-based manufacturing raw materials. Differences found between formulas depended mainly on their whey: casein ratios. A solvent separation procedure was required for quantitative estimation of the gangliosides and neutral glycolipids within the fat fraction. All infant formulas except one contained slightly more gangliosides than bovine milk. Complex carbohydrates were consistently higher in the nonfat fraction. By gel permeation chromatography, an oligosaccharide subfraction was separated from a glycopeptide one. Oligosaccharide content of infant formulas increased as a function of the whey:casein ratio, and glycopeptides were found only in formulas made with whey components. Neuraminic acids from infant formulas were associated primarily with the glycoprotein fraction, except in hydrolysate-based preparations in which "precipitable" glycoproteins were converted into "soluble" glycopeptides by trypsin treatment. Because whey-based raw materials are very rich in all bovine milk glycoconjugates and oligosaccharides their increased use will result in high contents of these micronutrients in modern formulas.

Various caseinoglycopeptide derivatives prepared from mammalian milk were evaluated as inhibitors of hemagglutinations mediated by Actinomyces viscosus Nyl, Streptococcus sanguis OMZ9, and, for comparative purposes, plant lectins from Arachis hypogaea and Bauhinia purpurea. It was found that recognition of the * Corresponding author.

SummarySugars were separated gas chromatographically on short apolar glass capillary columns by using cold, on-column injection (OCI) techniques. After silylation, oligomers up to the hexasaccharides could be efficiently separated in reasonable retention times. Response factors of silylated sugars were determined as a function of varying sample amounts anld concentrations. The optimum injection amount was found to be 1 pl in heptane as solvent.