Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2021
Publication Date: 5/31/2021
Citation: Rose, D.J., Poudel, R., Van Haute, M.J., Yang, Q., Wang, L., Singh, M., Liu, S.X. 2021. Pulse processing affects gas production by gut bacteria during in vitro fecal fermentation. Food Research International. 147. Article 110453. https://doi.org/10.1016/j.foodres.2021.110453.
DOI: https://doi.org/10.1016/j.foodres.2021.110453

Interpretive Summary: The research determined the effect of seven processing methods on three types of pulses on the concentration of gas-producing constituents in pulses and the production of gas in the large intestine. Although pulses are known to be nutritious and health-promoting, the perception of pulse consumption causing flatulence and bloating for many people is a barrier to increasing pulse consumption for many people in the U.S. Certain constituents in pulses are widely considered to be the major flatulence causing-compounds in pulses. This study showed that processing can be an effective strategy to reduce flatulence causing compounds and total gas production by the gut from pardina lentils and green peas but not navy beans. Unfortunately, germination, one of the processing methods tested in the study, also resulted in reduction in beneficial gut microbial metabolites. These findings will help the pulse processors and food companies to develop pulse-rich products leading to increasing pulse consumption.

Technical Abstract: One substantial barrier to increasing pulse consumption for many people is flatulence and bloating. Therefore, we examined how processing affects gas production by the microbiome in three classes of pulses. Processing did not affect gas production from Navy beans, but germination and jet-cooking reduced gas production from Pardina lentils (-1.9±0.3 mL/24 h, p<0.001; -0.88±0.34 mL/24 h, p=0.04; respectively) and green peas (-2.3±0.3 mL/24 h, p<0.001; -1.9±0.3 mL/24 h, p<0.001; respectively). Since germination resulted in the greatest reduction in gas production, this processing method was examined for its effect on microbiota composition, non-digestible carbohydrate utilization, and short chain fatty acid production. In Pardina lentils and green peas, germination resulted in diminished non-digestible carbohydrate utilization by the microbiome compared with unprocessed samples (42±1%/24 h versus 47±1%/24 h, p<0.001; 44±1%/24 h versus 56±1%/24 h, p<0.001, respectively). In Pardina lentils germination resulted in reduced abundance of two ASVs from Bacteroides and one from Lachnospiraceae as well as reduced propionate production compared with unprocessed samples. In green peas, germination reduced three ASVs from Lachnospiraceae, including one from Roseburia, with reduced proportion of butyrate production during fermentation. One microbiome had extremely high gas production compared with the others (24.3±0.3 mL/24 h versus 12.9±0.2 mL/24 h, p<0.001). This microbiome had unusually high abundance of an ASV from Megasphaera elsdenii. This study showed that processing can reduce total gas production by the microbiome from Pardina lentils and green peas but not Navy beans. Unfortunately, germination also resulted in reduction in saccharolytic fermentation with reductions in production of beneficial microbial metabolites.