A A C C   2 0 0 0   A n n u a l   M e e t i n g

Oligosaccharides of the raffinose series are major components in many grain legumes and are implicated in causing flatulance and diarrhea for both humans and livestock as they are not hydrolyzed in the upper gut due to the absence of alpha-galactosidase enzyme. The most widely used method for the determination of carbohydrates in food products involve the separation on an ion exclusion column in the hydrogen or calcium form using water mobile phase and refractive index detection. Although, suitable for many applications, since this approach uses RI detection and size based separation, it suffers from poor sensitivity and selectivity. We present here the development of a rapid ion chromatographic method for the simultaneous determination of sucrose, stachyose and raffinose in soy beans using pulsed amperometric detection. The ground samples after defatting with chloroform are extracted with EtOH/water mixture and were directly analyzed by anion exchange chromatography on a Dionex Carbopac 1 column using 150 mM NaOH as mobile phase in isocratic mode. All the three sugars are baseline resolved and separated in under 12 min. The advantages of this approach include not only greater selectivity but also enhanced sensitivity compared to the RI detection by almost two orders of magnitude. This technique is ideally suited for the analysis of single or partial seeds and for the screening of elite germplasm lines.