Rye and barley contain numerous less ̶ known bioactive compounds ̶ good sources for example mämmi and beer

​Press release from University of Turku 3rd August

The aim of these studies was to increase our knowledge of the minor components in cereals and cereal products. Although their amounts in cereals are low, they might act as beneficial health promoting compounds in our body. Pihlava studied the quantities of these compounds in rye, oats, barley and wheat grains and in food products containing them, such as flakes, breads and beers.

– The results could be useful for example in the development of a new type cereal-based food products, says Mr. Pihlava who is working as a scientist in Natural Resources Institute Finland (Luke).

In his dissertation Mr. Pihlava focused on avenathramides in oats, hordatines in barley and benzoxazinoids in rye and wheat. Of a special interest were various flavonoids in rye grain and rye products, since these have not been widely studied previously. In addition he with his colleagues, determined the content of alkylresorcinols and phenolic acids in rye, wheat and barley and lignans in rye.

– It is interesting that most of these studied secondary metabolites act in plant´s defense system against for example fungal diseases or herbivores, and in the same time while being part of our diet act as beneficial compounds. These compounds can have antioxidative, anti-inflammatoric or anticarcinogenic properties, Mr. Pihlava explains.

Beer is an intriguing example of much studied cereal food product, which still can offer surprises. Some 15 years ago Japanese scientist found that certain hordatines in beer stimulated gastrointestinal motility and thus at least in theory prevent constipation. Until 2014 only a few basic stuctures of hordatines were know, then two independently done studies showed that the number of the basic structures can be high as 12 and that certain hodatine glycosides in beer can have even nine sugar residues.

In addition of identifying new hordatines and their precursors, Mr. Pihlava and his team analyzed total hordatines contents in over 200 beers

– With the exception of the group of wheat and rye beers, the amount of total hordatine content correlates to the alcohol by volume (ABV). It is noteworthy that quite high total hordatine contents were also found in non- or low-alcoholic beers. There is some indication again by Japanese studies that hordatines may contribute to the flavor of beer by being bitter and astringent compounds, Mr. Pihlava continues.

As a new interesting finding were the various forms of benzoxazinoids in wheat- and ryemalt beers. Their amounts can be considerable even in non- or low-alcoholic beers. There are some indications that these compounds may have anticarcinogenic properties. However, it must be emphasized that direct conclusions that wheat or rye beer could prevent cancer cannot be made.

– Variation of benzoxazinoid content in wheat- and ryemalt beers was high and more research would be needed in order to find out the most efficient way to transfer benzoxazinoids from malt to wort and to maintain their amounts in beer or other beverages, outlines Mr. Pihlava.

According to Mr. Pihlava, in addition to wheat- and ryemalt beers other good sources of benzoxazinoids are sourdough rye breads, rye crisp breads, organic mämmi, and especially rye malt flour. Rye grains and rye products contain also a wide range of flavonoids, although their quantities compared to berries, fruits and vegetables are low.

– Because these compounds were also found in sourdough rye bread, rye crisp bread, rye malts and mämmi ,it can be concluded that these compounds can at least partly withstand quite harsh food processing conditions, Pihlava continues.

More information: Juha-Matti Pihlava p. +358 29 532 6439, juha-matti.pihlava(a)luke.fi

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