DETERMINATION OF FREE AND TOTAL CARBOHYDRATE PROFILE IN SOLUBLE COFFEE

A liquid chromatographic (LC) method was evaluated for the determinati on of free and total carbohydrates in soluble coffee, Samples are solu bilized in water for free carbohydrates or hydrolyzed with 1.00N hydro chloric acid for total carbohydrates. An aliquot of the sample solutio n is analyzed on a pellicular anion-exchange polystyrene-divinyl benze ne column using pure water as the mobile phase, Carbohydrates are quan titated by a pulsed amperometric detector, All major carbohydrates fou nd in soluble coffee are determined in a single run, The technique all owed the detection of fraudulent addition of coffee husks or parchment s as well as cereals or caramelized sugar for the 63 commercial produc ts analyzed, High levels of free mannitol, free fructose, free glucose , sucrose, total glucose, and total xylose are a good indication of ad ulteration. Data were compared with those obtained from separate enzym atic determinations and from a different LC procedure, A close agreeme nt among the methods was observed, However, the original method was su perior in precision and was the only procedure that enabled the quanti tation of all major carbohydrates, The technique is, therefore, a very powerful tool for routine analysis and for purity assessment of solub le coffee.