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 (DPa) significantly depends on the temperature and pH.