Determination of free and total carbohydrate in instant coffee according to ISO 11292, AOAC 996.04, and DIN 10780

One quality measure for instant coffee is its free and total sugar content. The free content is determined just after dilution of the powder. While the total sugar content requires a hydrolysis step prior to the determination. Sugars of interest are mannitol, fucose, rhamnose, arabinose, galactose, glucose, mannose, xylose, fructose, ribose, and sucrose. The sugars are analyzed on a Metrosep Carb 2 - 250/4.0 column applying pulsed amperometric detection. A high-pressure gradient and post-column addition of NaOH is applied.