Dietary fibers are at the forefront of nutritional research because they positively contribute to human health. Much of our processed foods contain, however, only small quantities of dietary fiber, because their addition often negatively affects the taste, texture, and mouth feel. There is thus an urge for novel types of dietary fibers that do not cause unwanted sensory effects when applied as ingredient, while still positively contributing to the health of consumers. Here, we report the generation and characterization of a novel type of soluble dietary fiber with prebiotic properties, derived from starch via enzymatic modification,yielding isomalto/malto-polysaccharides (IMMPs), which consist of linear (α1 → 6)-glucan chains attached to the nonreducing ends of starch fragments. The applied Lactobacillus reuteri 121 GTFB 4,6-α-lucanotransferase enzyme synthesizes these molecules by transferring the nonreducing glucose moiety of an (α1 → 4)-glucan chain to the nonreducing end of another (α1 → 4)-α-glucan chain, forming an (α1 → 6)-glycosidic linkage. Once elongated in this way, the molecule becomes a better acceptor substrate and is then further elongated with (α1 → 6)-linked glucose residues in a linear way. Comparison of 30 starches, maltodextrins, and α-glucans of various botanical sources, demonstrated that substrates with long and linear (α1 → 4)- glucan chains deliver products with the highest percentage of (α1 → 6) linkages, up to 92%. In vitro experiments, serving as model of the digestive power of the gastrointestinal tract, revealed that the IMMPs, or more precisely the IMMP fraction rich in (α1 → 6) linkages, will largely pass the small intestine undigested and therefore end up in the large intestine. IMMPs are a novel type of dietary fiber that may have health promoting activity.
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Muscle fiber-type specific expression of UCP3-protein is reported here for the firts time, using immunofluorescence microscopy
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Background/Objectives: Personalized and self-initiated dietary adjustments have been shown to alleviate mental and somatic complaints. Here, we investigated the potential role of gut microbiome alterations underlying these effects. Methods: For this purpose, participants (n = 185) underwent a four-week self-initiated dietary intervention and filled out weekly questionnaires on their dietary intake, somatic and mental symptoms, and physical activity. Results: Overall, the participants lost weight, had alleviated mental and somatic complaints, reduced their total caloric and percentual carbohydrate intake, and ate less processed, party-type, and traditional Dutch food items, but ate more Pescatarian type food items, while keeping their fiber intake unaltered. Baseline and endpoint gut microbiota analyses using 16S rRNA gene sequencing revealed an overall increase in Gemmiger formicilis and reductions in Peptostreptococcaceae and Ruminococcus bromii over the four-week dietary intervention. While these bacterial alterations were considered to be beneficial for the host, they were not individually correlated with alterations in, or endpoint levels of, somatic and/or mental complaints. Instead, individual increases in Ruminococcus bicirculans (a well-known utilizer of plant cell wall polysaccharides) were strongly correlated with reductions in mental complaints, even though overall R. bicirculans remained unaltered over the course of the four-week self-initiated dierary intervention. Conclusions: Our results suggest that overall altered versus individually correlated microbiota abundances and their relations with host health characteristics over the course of a self-chosen dietary intervention may represent different levels of regulation, which remain to be further untangled.
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