Amino-dealkoxylation of hm citruc pectin with n-alkylamines: a kinetic study

Abstract

Pectins are plant polysaccharides that are widely used in food industry. Chemical modification of pectins influences their technological properties. Amidated pectins are important pectin derivatives with good gelling properties at low-sugar conditions. The common method of pectin amidation is ammonolysis of methyl ester groups of highly methoxylated (HM) pectins in heterogeneous reaction with ammonia in methanol. Aminodealkoxylation (aminolysis) of HM pectin with primary amines leads to the formation of N-alkylpectinamides. The reaction yield of aminolysis depends on reaction time, temperature and the pectin/alkylamine ratio. The reaction of HM citrus pectin (type XSS, Danisco) with five chosen n-alkylamines (n-butylamine, n-hexylamine, n-octylamine, n-dodecylamine and n-octadecylamine) was carried out in N,N-dimethylformamide at 20°C (n-butylamine, n-hexylamine, n-octylamine) and at 50°C (all the amines) for 1-9 days. Obtained results can be applied to prepare N-alkylpectinamides of predicted DA varying the reaction time at the same reaction conditions (temperature, pectin/alkylamine ratio).

Keywords

• n-alkylpektinamides
• hm citrus pectin
• amino-dealkoxylation (aminolysis)