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.
Het boekje ‘Thermoharders: kort & bondig’ van het Saxion Kenniscentrum Design en Technologie beschrijft de onderzoeksresultaten van het project Materialen in Ontwerp 1, deelproject Thermoharder. Het boekje is geschreven om meer informatie te geven over thermoharders. Het produceren van thermoharder producten is een arbeidsintensief proces. Daarom wordt het steeds lastiger om te kunnen concurreren met thermoplasten. De thermoharderindustrie richt zich steeds meer op niche markten. Hier kunnen de specifieke eigenschappen van thermoharders goed benut worden. Helaas is kennis over thermoharders geen algemeen goed meer. Vaak weet men te vertellen dat de thermoharders over het algemeen beter tegen hitte kunnen dan thermoplasten, maar daar houdt het vaak op. Door het gebrek aan kennis over thermoharders wordt het materiaal vaak niet als productmateriaal in overwegingen meegenomen, terwijl het materiaal uitstekend aansluit bij sommige specificaties van nichemarktproducten. Om deze kans te benutten, geeft dit boekje een uiteenzetting van typische materiaaleigenschappen, thermoharders in composieten, verschillende productietechnieken en verschillende toepassingen.
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