Reference Number: 143
BACKGROUND: Wheat grains are a rich source of dietary fibres, particularly in the western human diet. Many of the health effects attributed to dietary fibres are believed to be related to their microbial fermentation in the gut. This study evaluated the ability of two potentially probiotic strains, Lactobacillus plantarum L12 and Bifidobacterium pseudocatenulatum B7003, to ferment soluble dietary fibres (SDFs) from modern and ancient durum-type wheat grains.
RESULTS: Fibre microbial utilisation was highly variable and dependent on the strain. SDFs from the varieties Svevo and Solex supported the growth of L. plantarum L12 the best, whereas those from the varieties Anco Marzio, Solex and Kamut? Khorasan were good carbohydrate substrates for B. pseudocatenulatum B7003. The highest prebiotic activity scores (describing the extent to which prebiotics support selective growth of probiotics) for B7003 were obtained with SDFs from the varieties Solex (0.57), Kamut? Khorasan (0.56) and Iride (0.55), whereas for L12 the highest scores were achieved with the varieties Orobel (0.63), Kamut? Khorasan (0.56) and Solex (0.53).
CONCLUSION: The present study has identified some SDFs from durum-type wheat grains as suitable prebiotic substrates for the selective proliferation of B. pseudocatenulatum B7003 and L. plantarum L12 in vitro. The results provide the basis for the potential utilisation of wheat-based prebiotics as a component of synbiotic formulations.
SIGNIFICANCE OF THIS STUDY
The current study quotes Gibson et al. who defined a prebiotic as ‘a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microbiota that confers benefits upon host well-being and health’. The human gut is populated by an array of bacterial species and the interaction between nutrients introduced with the diet that help the survival and growth of beneficial gut micro-organisms contribute to overall health and wellbeing. The current paper focusses in particular on Bidifobacterium species. and Lactobacillus species that are known to breakdown non-digestible fibres coming from food sources such as wholegrain wheat. In general, the breakdown of dietary fibre also called as microbial fermentation of dietary fibres in the large intestine is believed to be strictly linked to many of the health effects (i.e release of health promoting short chain fatty acids) attributed to cereal dietary fibres. In general, both soluble and insoluble dietary fibre can be degraded by intestinal bacteria, but soluble fibre is more easily, rapidly and completely fermented than insoluble fibre. The aim of the current study was to the influence of different wheat varieties on the growth and proliferation of selective health promoting bacterial species and the extent to which these strains (Bidifobacterium pseudocatenulatum and Lactobacillus plantarum) ferment the soluble fibre fraction of different durum-type wheat varieties. The study was conducted using specific assays on cell cultures of the two main strains of bacteria. The present study identified soluble dietary fraction (SDF) fibres from durum-type wheat grains as potential prebiotic substrates for the selective proliferation of B. pseudocatenulatum and L. plantarum in cell cultures. Among tested wheat SDF fractions, the ancient grain Kamut Khorasan and the modern variety Solex had the most promising potential to promote the growth of both tested strains in the gastrointestinal tract. However, the study concluded that carbohydrate degradation/fermentation in the colon is almost certainly a cooperative process involving a consortium of bacterial species and not solely carried out by these specific bacterial strains.