Development of complete hydrolysis of pectins from apple pomace

Enzymatically extracted pectins have a more complex structure than those obtained by conventional methods. As a result, they are less susceptible to hydrolysis, which makes the precise determination of their composition difficult. The aim of the study was to develop a method of complete hydrolysis of enzymatically extracted apple pectins. Substrates were pectins isolated from apple pomace by the use of xylanase and multicatalytic preparation Celluclast and apple pomace. Hydrolysis was performed by a chemical method with 2 M TFA at 100 °C and 120 °C and a combined acidic/enzymatic method. After hydrolysis, the contents of galacturonic acid and neutral sugars were measured by HPLC. Complete hydrolysis of polygalacturonic acid occurred after 2.5 h incubation with 2 M TFA at 120 °C. The efficient hydrolysis of neutral sugars in pectins was performed with 2 M TFA at 100 °C for 2.5 h. Monomers most susceptible to concentrated acid were rhamnose, mannose and arabinose.