Impact of roasting and grinding on coffee polysaccharide structure and derived melanoidins: Influence on cholesterol solubilization by bile salt micelles.

Coffee roasting and grinding can modulate dietary fiber content, influencing bioactivities such as cholesterol solubility at intestinal lumen. Light- and dark-roasted coffee beans were ground to fine and coarse particle sizes, and the carbohydrate composition of coffee brews and fractionated high-molecular-weight compounds-galactomannans, arabinogalactans, and melanoidins-was characterized. Roasting promoted arabinogalactan debranching, while finer grinding increased soluble high-molecular-weight material in the brews. The effect of coffee brews and respective fractions on cholesterol solubility was evaluated by quantitative 13C NMR using an in vitro intestinal lumen model containing glycodeoxycholic bile acid micelles. Coffee brews lower cholesterol solubility by 36-50%, whereas melanoidin-rich fractions showed the strongest effect (35-45% decrease), followed by galactomannan-rich (18-30%) and arabinogalactan-rich (16-29%) fractions. Cholesterol solubility decrease did not correlate with bile acid depletion, suggesting mechanisms beyond bile salt sequestration. These findings highlight structure-function relationships relevant to carbohydrate-based cholesterol management strategies.