TY - JOUR
T1 - Processing Has Differential Effects on Microbiota-Accessible Carbohydrates in Whole Grains during In Vitro Fermentation
AU - Smith, Caroline
AU - Van Haute, Mallory J.
AU - Rose, Devin J.
N1 - Funding Information:
We gratefully acknowledge funding from the Nebraska Agricultural Experiment Station Hatch Multistate Research capacity funding program (accession number 224073) and from the Nebraska Food for Health Center.
PY - 2020/11
Y1 - 2020/11
N2 - Whole grains are generally low in nondigestible carbohydrates that are available for fermentation by the gut microbiota, or microbiota-accessible carbohydrates (MAC). However, there is potential to increase MAC in whole grains through food processing. Five processing methods: boiling, extrusion, sourdough bread, unleavened bread, and yeast bread, were applied to whole wheat flour and then subjected to in vitro digestion followed by fermentation using fecal microbiomes from 10 subjects. The microbiomes separated into 2 groups: those that showed high carbohydrate utilization (CU) and those that ex-hibited low CU. The former exhibited not only enhanced CU but also increased butyrate production (MAC, 31.1 ±1.1% versus 19.3 ±1.2%, P< 0.001; butyrate, 5.26 ± 0.26 mM versus 3.17 ± 0.27 mM, P< 0.001). Only the microbiomes in the high-CU group showed significant differences among processing methods: extru-sion and sourdough bread led to dichotomous results for MAC and short-chain fatty acid production, where extrusion resulted in high MAC but low butyrate production while sourdough bread resulted in low MAC but high butyrate pro-duction. Extrusion led to a noticeable decrease in α-diversity and some members of the families Ruminococcaceae and Lachnospiraceae, with increases in Acineto-bacter, Enterococcus, and Staphylococcaceae. This study demonstrated that only microbiomes that exhibited high CU responded to the effects of processing by showing significant differences among processing methods. In these micro-biomes, extrusion was able to increase accessibility of the cell wall polysaccha-rides but did not increase butyrate production. In contrast, sourdough bread led to high butyrate production by supporting important butyrate-producers in the families Lachnospiraceae and Ruminococcaceae.
AB - Whole grains are generally low in nondigestible carbohydrates that are available for fermentation by the gut microbiota, or microbiota-accessible carbohydrates (MAC). However, there is potential to increase MAC in whole grains through food processing. Five processing methods: boiling, extrusion, sourdough bread, unleavened bread, and yeast bread, were applied to whole wheat flour and then subjected to in vitro digestion followed by fermentation using fecal microbiomes from 10 subjects. The microbiomes separated into 2 groups: those that showed high carbohydrate utilization (CU) and those that ex-hibited low CU. The former exhibited not only enhanced CU but also increased butyrate production (MAC, 31.1 ±1.1% versus 19.3 ±1.2%, P< 0.001; butyrate, 5.26 ± 0.26 mM versus 3.17 ± 0.27 mM, P< 0.001). Only the microbiomes in the high-CU group showed significant differences among processing methods: extru-sion and sourdough bread led to dichotomous results for MAC and short-chain fatty acid production, where extrusion resulted in high MAC but low butyrate production while sourdough bread resulted in low MAC but high butyrate pro-duction. Extrusion led to a noticeable decrease in α-diversity and some members of the families Ruminococcaceae and Lachnospiraceae, with increases in Acineto-bacter, Enterococcus, and Staphylococcaceae. This study demonstrated that only microbiomes that exhibited high CU responded to the effects of processing by showing significant differences among processing methods. In these micro-biomes, extrusion was able to increase accessibility of the cell wall polysaccha-rides but did not increase butyrate production. In contrast, sourdough bread led to high butyrate production by supporting important butyrate-producers in the families Lachnospiraceae and Ruminococcaceae.
KW - butyrate
KW - dietary fiber
KW - Lachnospiraceae
KW - Ruminococcaceae
KW - wheat
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U2 - 10.1128/AEM.01705-20
DO - 10.1128/AEM.01705-20
M3 - Article
C2 - 32859598
AN - SCOPUS:85093539189
VL - 86
SP - 1
EP - 16
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
SN - 0099-2240
IS - 21
ER -