Abstract: Crude chickpea extract was obtained from chickpea seeds by extraction with 50% ethanol aqueous solution by shaking and purified by medium-pressure activated carbon-diatomite column chromatography to obtain  chickpea α-galactooligosacchardies (α-GOS) with different purities. The prebiotic function of α-GOS was evaluated by anaerobic fermentation method in vitro against human fecal bacteria and fluorescence in situ hybridization (FISH). The results demonstrated that α-GOS in chickpea was an efficient proliferation factor to beneficial bacteria such as Bifidobacterium spp. and Lactobacillus-Enterococcus spp., and an inhibitory factor to harmful bacteria such as Bacteroides prevotella group and Clostridium histolyticum group. During the anaerobic fermentation in vitro, the bacterial composition was affected by the addition of chickpea α-GOS. However, total bacterial number had no difference. In addition, the sample with the highest content of α-GOS (＞90%) showed the highest prebiotic index (PI, 2.00). The PI of samples containingα-GOS at the content of 70%—80% and 80%—90% and crude chickpea extract were 1.39, 1.73 and 0.89, respectively, while the PI of the control sample without saccharide addition was －0.29. Therefore, α-GOS in chickpea had an excellent prebiotic function.

Key words: chickpea, α-galactooligosaccharide, prebiotic function, fluorescence in situ hybridization, fermentation in vitro