How fructophilic lactic acid bacteria may reduce the FODMAPs content in wheat-derived baked goods: a proof of concept

Abstract

Background: FODMAPs (Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) intake is associated with the onset of irritable bowel syndrome symptoms. FODMAPs in wheat-derived baked goods may be reduced via bioprocessing by endogenous enzymes and/or microbial fermentation. Because of the inherent enzyme activities, bread made by baker's yeast and sourdough may result in decreased levels of FODMAPs, whose values are, however, not enough low for people sensitive to FODMAPs.

Results: Our study investigated the complementary capability of targeted commercial enzymes and metabolically strictly fructophilic lactic acid bacteria (FLAB) to hydrolyze fructans and deplete fructose during wheat dough fermentation. FLAB strains displayed higher fructose consumption rate compared to conventional sourdough lactic acid bacteria. Fructose metabolism by FLAB was faster than glucose. The catabolism of mannitol with the goal of its reuse by FLAB was also investigated. Under sourdough conditions, higher fructans breakdown occurred in FLAB inoculated doughs compared to conventional sourdough bacteria. Preliminary trials allowed selecting Apilactobacillus kunkeei B23I and Fructobacillus fructosus MBIII5 as starter candidates, which were successfully applied in synergy with commercial invertase for low FODMAPs baking.

Conclusions: Results of this study clearly demonstrated the potential of selected strictly FLAB to strongly reduce FODMAPs in wheat dough, especially under liquid-dough and high oxygenation conditions.

Keywords: Bread; FODMAP; Fructans; Fructophilic lactic acid bacteria; IBS; Wheat flour.

Fig. 1

Mannitol (white bars) and lactic (black bars) and acetic (grey bars) acids level (g L⁻¹). Fructobacillus fructosus MBIII5 was grown in Mannitol Yeast extract Peptone (MYP) broth at 30 °C for 72 h under aerobic condition in shaking (200 rpm) flasks with baffles. For each compound, bars with different superscript letters (a–c) are significantly different (P < 0.05)

Fig. 2

Total fructans, fructose, glucose, and mannitol level (mg per 100 g of flour) in doughs. Wheat doughs (DY 160) were fermented with Apilactobacillus kunkeei B23I (green bars), Fructobacillus fructosus MBIII5 (yellow bars), A. kunkeei B23I + Fructo. fructosus MBIII5 (red bars), Lactiplantibacillus plantarum DC400 (blue bars) or Fructilactobacillus sanfranciscensis SD8 (cyan bars) at 30 °C for 24 h. A control dough without bacterial inoculum was incubated under the same conditions (black bars). Bars with different superscript letters (a–g) are significant different (P < 0.05)

Fig. 3

FODMAPs (mg per 100 g of flour) in firm (DY 160) doughs. Wheat doughs were added with invertase (EC 3.2.1.26) and fermented at 35 °C for 3 h with Apilactobacillus kunkeei B23I (Treatment 1, T1), or Fructobacillus fructosus MBIII5 (Treatment 2, T2), or with a mixed starter composed by A. kunkeei B23I and Fructo. fructosus MBIII5 (Treatment 3, T3), or Lactiplantibacillus plantarum DC400 and Fructilactobacillus sanfranciscensis SD8 (Control treatment, CT). Unstarted dough was also analyzed. Total fructans, red bars; galactosyl-sucrose oligosaccharides, yellow bars; fructose in excess of glucose, blue bars; mannitol, green bars. Bars with different superscript letters (a–d) are significant different (P < 0.05)

Fig. 4

FODMAPs (mg per 100 g of flour) in liquid (DY 280) doughs. Wheat doughs were added with invertase (EC 3.2.1.26) and fermented at 35 °C for 3 h under aerobic condition (in shaking [200 rpm] flasks with baffles) with Apilactobacillus kunkeei B23I (Treatment 1, T1), or Fructobacillus fructosus MBIII5 (Treatment 2, T2), or with a mixed starter composed by A. kunkeei B23I and Fructo. fructosus MBIII5 (Treatment 3, T3), or Lactiplantibacillus plantarum DC400 and Fructilactobacillus sanfranciscensis SD8 (Control treatment, CT). Unstarted dough was also analyzed. Total fructans, red bars; galactosyl-sucrose oligosaccharides, yellow bars; fructose in excess of glucose, blue bars; mannitol, green bars. Bars with different superscript letters (a-d) are significant different (P < 0.05)