Effect of temperature and pH on the degradation of fructo-oligosaccharides

The degradation process of fructo-oligosaccharides has been studied in buffered solution affected by temperature and pH. The system has been incubated at 60, 70, 80, 90 and 100 oC; pH has been varied between 2.7 and 3.3. The carbohydrate compositions of the solution-samples have been analyzed by an accurate analytical method for oligosaccharide determination (HPLC with differential refractometric detection). Under acidic condition the hydrolysis of fructo-oligosaccharides is insignificant at 60 oC; however, already at 70–80 oC it is so considerable, that the amount of them could be bisected in 1–2 h. Meanwhile, all of the oligomers are degraded in 1–1.5 h at 90–100 oC. The increase of proton concentration of the solution makes degradation faster; however, there is a slighter effect of pH on the rate of hydrolysis than of temperature in the studied range. The rate of the changes in the value of average degree of polymerisation (DP_a) significantly depends on the temperature and pH.