Bifidogenic effect from consumption of fresh and oven-dried Jerusalem artichoke (Helianthus tuberosus L.) in Thai subjects

Recently, Jerusalem artichoke ( Helianthus tuberosus L.) has been introduced to Thailand and promoted as a potential health food because of its high inulin content. However, the effect of daily intake of fresh (FJA) or oven-dried (OJA) Jerusalem artichoke on intestinal Bifidobacterium has not yet been investigated. To evaluate the bifidogenic effect of FJA and OJA intake, 77 volunteers received 150 g/d of FJA (containing 29.1 g of inulin) and 55 volunteers consumed 32 g/d of OJA (prepared from 150 g fresh weight) for 4 wk. Fresh stool samples were collected on days 0 and 28. During the experimental period, a daily intake of FJA or OJA was recorded. At the end of the study, 46 and 30 volunteers completely consumed the FJA and OJA daily for 4 wk, respectively. Quantitative analysis of fecal Bifidobacterium by a real-time polymerase chain reaction (PCR) technique targeting a xylulose-5-phosphate/fructose-6-phosphate phosphoketolase gene ( xfp ) revealed that the numbers of volunteers with increased fecal Bifidobacterium were significantly higher than those with decreased levels in both experimental groups ( P < 0.001). In addition, the total numbers of fecal Bifidobacterium after both interventions were significantly increased ( p <0.001). Moreover, there was no significant difference in the changes of fecal Bifidobacterium numbers between FJA and OJA dietary groups ( P = 0.314). In conclusion, the consumption of both FJA and OJA was effective in increasing intestinal Bifidobacterium , indicating that Jerusalem artichoke could be promoted as an alternative health food. Keywords:     Bifidobacterium ,  Inulin,  Prebiotics,  Probiotics