Quantitative Analysis of Debranched Amylopectin by HPAEC-PAD with a Postcolumn Enzyme Reactor

Abstract

The chain-length distribution of debranched amylopectin was analyzed by using high performance anion-exchange chromatography with an amyloglucosidase (AMG) reactor and a pulsed amperometric detector (HPAEC-ENZ-PAD). The effects of reactor length, reactor temperature, and additional a-amylase reactor were studied. Results showed that a 2 mm i.d. x 23 mm AMG reactor at 25%°C was sufficient to convert HPAEC-separated amylodextrins to glucose; the PAD response for the hydrolyzed amylodextrins of different chain-length was consistent, and quantitative results were achieved. With this enzymatic treatment, amylodextrin with DP up to 77 was detected for a debranched tapioca amylopectin sample. The chain-length distribution profile of debranched tapioca amylopectin showed three fractions with peak DPs 48± 1 (Fl), 19 (F2a), and 12 (F2b).