Bringing food chemistry to life

The Spring meeting of the American Chemical Society (ACS) has highlighted a bunch of interesting studies related to food.

The first one to grab my interest was the report by scientists Dr Iain Brownlee and Prof Jeff Pearson of Newcastle University about the potential of alginates to reduce fat uptake by up to 75% !!! They used an artificial gut to do the experiments and the artificial gut gained no weight during the experiment. For the life of me I can’t think of a specific reason why alginates may be better at reducing fat absorption than other polysaccharides.  If it is charge there are LM pectins, chitosan, and carrageenans that may also be effective. If it is size & viscosity, then barley and oat beta-glucans  should be effective. Brownlee and co-workers wrote in a 2005 review**

“Evidence suggests that the intake of dietary alginates results in a number of potentially beneficial physiological effects, such as reduced intestinal absorption, increased satiety, reduced damaging potential of GI luminal contents, modulation of colonic microflora, and elevation of colonic barrier function. Alginates have all these properties, whereas other fiber types have previously been reported to have some but not all of these effects. Similar effects have also been noted for other dietary fibers. A direct comparison of the physiological effects of alginate to those of other dietary fibers is not always possible, since relatively few studies have considered the potential of alginate as a dietary fiber”.

The press release is certainly short on specifics, particularly on the mechanism. I cannot find yet a refereed article on this specific study, I await it with relish, thickened of course with alginate!

Alginate is a co-polymer mannuronic and glucuronic acid residues – here is the structure courtesy of the FAO

“Dark-roasted coffee may be easier on the tummy“

In another presentation at the ACS meeting Veronika Somoza, Ph.D. from the University of Vienna in Austria, and Thomas Hofmann, Ph.D. from the Technische Universität München in Germany, reported the that an increase in N-methylpyridium in darker roasted coffee was associated with reduced acid production by stomach mucosal cells.  In their words…

“Our data show, for the first time, that caffeine, catechols and N-alkanoly-5-hydroxytryptamides are those coffee components that stimulate molecular mechanisms of stomach acid secretion in human stomach cells… We found out there’s no single, key irritant. It is a mixture of compounds that seem to cause the irritant effect of coffee.”

“…one of the coffee components, N-methylpyridium (NMP), seems to block the ability of the stomach cells to produce hydrochloric acid and could provide a way to reduce or avoid stomach irritation. Since NMP is generated only upon roasting and not found in raw coffee beans, darker-roasted coffees contain higher amounts of this stomach-friendly coffee ingredient. Dark- roasted coffee can potentially contain up to twice as much of the ingredient as light-roasted coffees, but its levels can vary widely…”.

The scientists who conducted study are self-confessed coffee-lovers and were reported to be “very excited about this research.”

I think the press release may have the compound name wrong N-methylpyridinium is a known roasting product of the degradation of trigonelline [which is in green beans]. The other main outcome of roasting trigonelline is the production of nicotinic acid. The peak for N-methylpyridinium comes at higher roast temperatures as shown by Stadler et al in 2002***.

***Alkylpyridiniums. 1. Formation in Model Systems via Thermal Degradation of Trigonelline. Richard H. Stadler,, Natalia Varga,, Jörg Hau,, Francia Arce Vera, and, Dieter H. Welti. Journal of Agricultural and Food Chemistry 2002 50 (5), 1192-1199.

Figure with permission ACS