Browsing by Subject "raffinoosiryhmän oligosakkaridit (RFO)"

The literature review deals with carbohydrates in faba bean and other legumes. Analytical methods for determining different carbohydrates was introduced. Particular emphasis was given to α-galactosides in faba bean which are raffinose family oligosaccharides (RFO) raffinose, stachyose and verbascose, those are associated with flatulence. The aim of the experimental work was to develop an HPAEC-PAD-method (high-performance-anion-exhange-chromatography-pulse-amperomeric-detector) to determine low molecular weight carbohydrates (LMWC) in faba bean, focusing on RFO-compounds. The best extraction method for oligosaccharide separation from faba bean matrix was investigated. HPAEC-PAD-methods for monosaccharide and oligosaccharide analysis were tested and the most suitable was chosen for quantitative RFO-analysis. In addition, LMWC contents in faba bean were investigated and variation among different cultivars and annual harvests were compared. Lupin and lentil were used as comparison samples. The chosen extraction method was following: faba bean flour was homogenised for 1 min with 70 % EtOH-solution. Extraction was carried out three times. Samples were centrifuged between extractions and the supernatant, where oligosaccharides were dissolved, was separated. The HPAEC-PAD-method was used with a Carbopac PA1-column and gradient elution. The eluent was dilute NaOH solution at the beginning of the elution time and stronger at the end. The validated method gave reliable results for RFO-compounds in faba bean. The main oligosaccharides in faba bean cultivar Kontu from 2012 (Kontu2012) were verbascose (13.2 mg/g) and stachyose (7.88 mg/g). The amount of raffinose (2.42 mg/g) was close to melibiose (1.78 mg/g), which is one of the disaccharides. The main disaccharide in Kontu2012 was sucrose (23.1 mg/g). The monosaccharides galactose and glucose were present at trace amounts (< 400 mg/g) and fructose was not detected. Results were calculated by dry weight. No statistically significant difference was observed between different cultivars of faba bean, whereas growth factors influenced greatly. A statistically significant difference was also observed between different legumes (faba bean, lupin and lentil) among all the compounds investigated in this study.