FREE SUGARS DETERMINATION BY HPLC IN PINEAPPLE PRODUCTS

Free sugars have been determined by HPLC in fresh pineapple fruit, fre shly extracted pineapple juice (home-made), pineapple juice concentrat e (for industrial use), commercial pineapple juices and nectars. In na tural samples, intermediate products and commercial juices the dominan t sugar was sucrose, followed by fructose and glucose, both of which w ere found in similar concentrations. However, the sugar content of nec tars analyzed was highly variable. The presence of maltose in nectar s amples is a clear indication of the addition of sugars from corn syrup . We have found a fructose/glucose ratio close to 1, and the coefficie nt fructose plus glucose/sucrose close to 1, both of which are a good index of authenticity of pineapple juices.