120 yrs of wheat protein
A recent article in J. Agric. Food Chem., reviewed at phys.org, caught my eye because it reports on protein/gluten content of wheat varieties going back to 1891. I thought it might help explain Red Fife's disappointing performance in recent doughs chez nous. But only German varieties were studied. Still interesting, esp. the part about the strong influence of harvest year weather on protein composition. Here's the abstract:
Epidemiologic studies suggest an increasing prevalence of celiac disease and non-celiac gluten/wheat sensitivity. With wheat proteins being the main triggers, changes in wheat protein composition are discussed as a potential cause. The goals of breeding toward increased yield and resistance might have inadvertently contributed to a higher immunostimulatory potential of modern wheat cultivars compared to old wheat cultivars. Therefore, agronomic characteristics, protein content, and gluten composition of 60 German winter wheat cultivars first registered between 1891 and 2010 grown in 3 years were analyzed. While plant height and spike density decreased over time, yield and harvest index increased. The protein and gliadin contents showed a decreasing trend, whereas glutenin contents increased, but there were no changes in albumin/globulin and gluten contents. Overall, the harvest year had a more significant effect on protein composition than the cultivar. At the protein level, we found no evidence to support an increased immunostimulatory potential of modern winter wheat.
Tom
So would you say this study tends to discredit the "Franken-wheat" claim?
I've sometimes wondered if we have _over-hybridized_ our wheat and corn.
Also, am I correct in my understanding that no GMO wheat is currently extant in the US? I read that a few years ago, but I wonder if it is still true.
I'm not familiar with "the Franken-wheat claim" but it doesn't sound like a hypothesis that academic plant researchers would care (or be able to obtain funding) to test.
imho, modern breeders' hybridization efforts are a drop in the bucket compared to millions of years of pre-human plant hybridization. I'm not sure what "over-hybridization" would mean. Obsessive directional selection - now that's something we're really good at. Ask any Pekinese dog.
I'm not familiar enough with wheat breeding or the US wheat crop to know if GMO wheat is in commerce. Everything else, including the turfgrass of your neighbor's lawn, is Roundup-Ready, so I wouldn't be surprised if there's Roundup-Ready wheat too. But then again, a grower can't uniformly kill down his crop before harvest by spraying it with Roundup if the crop is resistant.
Tom
that gluten content has remained relatively constant over the years, while glutenin content has risen. Do you mean that the disappointing performance of Red Fife (widely cultivated in Canada before 1990, if I get it right) might be attributed to the higher gliadin to glutenin ratio? I personally don't observe a noticeable difference in dough performance between modern hard red wheat and Red Fife wheat. Yet, that does seem to explain your observation. Though it is uncertain if the findings apply to non-German wheat. Mentioned the discussion part, "In contrast to our findings, a Canadian study reported an increase of protein contents in 36 red spring wheat cultivars first registered between 1860 and 2000."
No surprise that climatic factors (precipitation to be specific) play a role in crude protein content. Though I'm enthralled by its insignificant influence on the relative proportions of protein fractions. Thanks for sharing the paper.
While glutenins have increased, about 25%, gliadins have fallen, about 18%. That's behind the slight fall in total protein over the 120 years.More extensible, less elastic.
Some people have asserted that gliadins are the more reactive proteins, allergenically, which further suggests that any increase in "gluten intolerance" is probably not the result of wheat breeding for proteins.
Glutenins are the elastic proteins that provide resistance while gliadins provide viscosity and extensibility. So one expect increased tenacity and lack of extensibility where glutenins have increased and gliadins have decreased.
I believe it is generally the α-gliadins that are known to be a problem for those with coeliac disease.
Yes that is correct it is the gliadins that are the problem for those with celiac disease. When patients with celiac disease ingest gliadin, an immunologically mediated inflammatory response occurs that damages the mucosa of their intestines, resulting in maldigestion and malabsorption of food nutrients.
Hi Elsie,
My Red Fife doughs have invariably displayed evidence of glutenin, if not overall gluten, deficiency. The RF acts like pastry flour. Reducing overall hydration restores some loft and profile but at the cost of accelerated staling. Perhaps I need to exercise it more than I routinely do. For now, I’ll shelve it until temp and humidity moderate in a few weeks.
Tom