In vitro fermentation characteristicsof a mixture of Raftilose and guar gumby human faecal bacteria

SummaryBackground The therapeuticeffects of indigestible carbohydratesin the human colon arewell known. Most fermentationstudies have examined only singlecarbohydrates. Considering theidiosyncratic actions of individualcarbohydrates and the dose required,it is unlikely that any onecarbohydrate will provide idealphysiological actions without havingsome undesirable effects. Littleis known of how mixing non–digestiblecarbohydrates affects theirfermentation. This necessitates fermentationstudies using differentcarbohydrates in mixtures.Aim of the study The aim of this study wasto test the effect of mixing Raftilose™ (R) and guar gum (G) onshort chain fatty acid (SCFA) productionin in vitro cultures of humanfaecal bacteria.Method Thefermentation of the individual carbohydrates(10 mg/ml) was comparedwith that of a 50:50 mixturein anaerobic in vitro cultures of humanfaeces.Results Cultures of R/Gmixtures produced significantlymore n–butyrate than 100 mg Galone at 8 and 24 hours (p < 0.02).There was no significant differencein the production of n–butyrate betweencultures of 100 mg R and theR/G mixture at 8 and 24 hours. R(100 mg) produced a propionic/butyric(p/b) acid ratio of 1.18 comparedwith 3.88 for 100 mg G,whereas R/G mixture produced ap/b ratio of 2.01.Conclusion Thefermentation of R/G mixture wasdifferent compared with 100 mg ofR or G alone. There was no loss ofn–butyrate in the culture containingR/G (50 mg of each) mixturecompared with the 100 mg R culture.