Different Oat Ingredients Stimulate Specific Microbial Metabolites in the Gut Microbiome of Three Human Individuals in Vitro

Abstract

We used a standardized in vitro simulation of the intestinal environment of three human donors to investigate the effect of six oat ingredients, which were produced by the application of different processing techniques, on the gut microbial community. Fructooligosaccharide was used as the positive control. Consistent changes in pH and gas production, on average −0.4 pH units and +32 kPa, indicated the high fermentability of the oat ingredients, and the resulting increased production of metabolites that are considered as beneficial for human health. These metabolites included acetate and lactate, but mostly propionate (+13.6 mM on average). All oat ingredients resulted in increased bifidobacteria levels with an average increase of 0.73 log. Moreover, a decreased production of proteolytic markers was observed, including branched short-chain fatty acids and ammonium. The results were donor-specific and product-specific. The results suggested an association between the total amounts of dietary fiber and the prebiotic potentials of different ingredients. Furthermore, as mechanical processing of oat products has previously been linked to increased extractability of dietary fibers, the obtained results suggest that different processing techniques might have impacted the potential functional properties of the final ingredients.

Impact of processing degree on fermentation profile and chemopreventive effects of oat and waxy barley in LT97 colon adenoma cells

“…starch) [20,21,32], which might affect the digestibility and fermentability of oat and barley products. But until now, studies investigating the impact of processing such as flaking on the fermentation profile [12,13] and resulting consequences for their chemopreventive potential are rare. In recent studies, we investigated the impact of heat treatment (roasting) on fermentation characteristics and chemopreventive effects of oat and barley flakes [10,11] in separate fermentation experiments.…”

“…The aim of the present study was to examine the impact of the processing degree of oat and barley (beta®barley) on end points of fermentation and chemoprevention. Until now, only a few studies have investigated similar effects of differentially processed oat samples regarding fermentation profiles such as SCFA formation [11][12][13]. But, there is no sufficient information available on how processing, such as flaking, affects the chemopreventive effects of oat and barley products.…”

Comparison of the Bifidogenic Effects of Goat and Cow Milk-Based Infant Formulas to Human Breast Milk in an in vitro Gut Model for 3-Month-Old Infants

“…The general reactor setup was adapted from the SHIME R , representing the GIT of the human adult as described by Molly et al (25), to the digestive conditions of 3-month-old infants. Similar as how van den Abbeele et al (26) adapted model parameters for human adult simulations, operational parameters for infants were adapted from the international consensus method of the INFOGEST consortium (27) that was recently extended for young infants (28). All three test products (cow IF, goat IF and human milk) were first subjected to upper gastrointestinal digestive and absorptive processes, after which they underwent colonic incubations (Figure 1).…”

“…Except for the oral phase, which was omitted to simulate infant feeding condition, the residence times in the gastric and small intestinal incubations were similar to human adult conditions (26). .…”

“…Hence, the 3.5 kDa membrane was chosen as the best compromise to minimize absorption of non-digestible carbohydrates and maximize removal of lactose and proteins to best reflect in vivo conditions. During a pre-test, the dialysis via a 3.5 kDa cut-off membrane, as described previously by van den Abbeele et al (26), was validated by using two reference molecules (lactose and FOS), while using same volumes and refreshment procedures as outlined above.…”