Rye (Secale Cereale L.) has been playing an important agronomic,nutritional and social role throughout human civilization. In the last 50 years, rye grain yields have increased but not enough to offset the decrease in cropping area to maintain production. While rye may be considered a minor crop in terms of production, contributions to research in cereal genomics have been substantial. The importance of rye has continued to increase due to high yield, resilient agronomic performance, and stable, good grain quality. It has the remarkable capability to grow in a wide range of environments including cold temperatures, semi-arid and high altitude zones, and marginal soils.
GLOBAL PRODUCTION
According to FAOSTAT in 2018 around 11.27 million tonnes of rye grain was harvested globally, out of which 81% was grown in Europe and 13% in Asia.
Climate change is a global driver of farmers’ interest in growing hybrid rye varieties because of their tolerance to marginal soils and diseases. The expenditures for fertilizers and plant protection chemicals on rye cultivation are lower than for other cereals.
Winter rye is of great importance in the world economy and food traditions of those seven countries, where the crop is grown on more than 90 thousand hectares (Belarus, Denmark, Germany, Poland, Russian Federation, Spain, and Ukraine). In recent years, China, Canada, and the United States have begun to cultivate increasing amounts of rye.
NUTRITIONAL COMPOSITION
Rye grain is used to bake bread and other products through the sourdough process that confers a unique taste with specific nutritional benefits and market opportunities. Rye-derived products benefit from reduced gluten compared to wheat.
Rye contains starch, dietary fiber, protein, and minerals like manganese, copper, magnesium, phosphorus, B-complex vitamins, and phenolic antioxidant compounds.
The health effects of rye can be associated not only with fiber content, but also with the so-called “rye fiber complex”, which is a mixture of various biologically active compounds including arabinoxylans, oligosaccharides, lignans, phytates, and phenolic acids. The rye fiber complex has 73% insoluble and 27% soluble fiber.
From a nutritional approach, rye proteins are recognized to be superior to those of wheat and other cereal grains because of their better composition of essential amino acids.
Scientific evidence shows that rye contains a mixture of biologically active substances and possesses a wide range of protective properties in the prevention and treatment of metabolic syndrome, including cardiovascular diseases and type 2 diabetes as well as intestinal health and certain types of cancer. The studies have shown that rye helps reduce development of childhood asthma, promotes weight loss, helps to prevent ulcers and stones in the gallbladder, and can improve the metabolic parameters of cells.
AGRICULTURAL RELEVANCE
Rye is an ideal crop for agricultural biogas production in regions with low fertility and sandy soils. Rye biomass is increasingly being used as a renewable raw material for biogas production. Bioethanol and biogas production may be a growing market for rye.
Rye is the most common and reliable cover crop in the Midwest and Northeast of the United States and in Canada, as it is one of the few cover crops that can be successfully established when planting in autumn after harvesting corn or soybeans. It is winter hardy throughout the region and accumulates significant amounts of biomass before spring planting of other crops. As a cover crop, rye is multifunctional in no-till agroecosystems. This is the most effective way to reduce nitrogen and phosphorus losses.
The deep root system of rye, especially rye hybrids, captures excess nitrogen and prevents it from entering groundwater or leaching. These nutrients are stored and then made available in the residual biomass for the next harvest. In general, fertilizer costs are decreased and labor is distributed evenly throughout the year, ie it is a regenerative crop.
Owing to all of the above, it’s a grain which is highly relevant in human nutrition and agriculturally given the extreme climate variability faced by farmers globally.
RESEARCH RELEVANCE
Our search in the Scopus international database, as per January 2021, revealed only 15,411 publications included rye as a keyword in contrast to over 150,000 publications on wheat.
As the only outcrossing Triticeae species, rye is of considerable interest both from an evolutionary and a genetic perspective, especially in comparative genomic studies with other grains species.
Genome sequences of Triticeae species are critical resources for understanding the biology and evolution of these species through comparative genomic approaches and for associating phenotypic traits with underlying genes.
Rye, a close relative of wheat (Triticum aestivum L.), which is the economically most important cereal, is providing a vast and largely untapped reservoir of genetic variation for traits such as stress tolerance, biomass, yield, and photosynthetic potential, not only for the commercial crop triticale, but also for wheat.
RYE GRAIN FLOUR TERMINOLOGY
Even though there are many grade of rye flour exist out there, just like grades of wheat flour. We at Three One Farms associate 'Dark Rye' with whole rye grain flour, and 'Light Rye' with a sifted one. Check it out here.
THINGS TO KNOW ABOUT RYE WHILE MAKING A RYE BREAD
Properly made rye breads have a rich fullness of aroma, a unique and bold flavor, excellent keeping quality, and a delicious eating quality quite different from wheat breads.
Rye flour is significantly different from wheat flour; in fact, from the growing culture of the grains, to the mixing, fermenting, proofing, steaming, baking, and even in the eating, rye differs from wheat:
RYE FLOUR CONTAINS GLIADIN AS WELL AS THE PROTEIN GLUTELIN (which is similar to glutenin). However, due to the presence of pentosans, gluten formation is not possible, hence rye breads will always have a denser structure than wheat breads.
RYE FLOUR IS HIGHER IN BRAN AND FIBER THAN WHEAT, which means rye breads have higher water absorption. The extra water-holding capacity will produce bread with a moist and pasty crumb unless proper care is taken.
THE HIGHER LEVEL OF BRAN AND MINERALS IN RYE has another impact on the bread: As the mineral content of the flour increases, there is a corresponding decrease in bread volume. This is caused because the sharp shape of the bran pieces cuts the gluten network.
RYE HAS MORE SOLUBLE SUGARS THAN WHEAT, and therefore rye doughs ferment more quickly than wheat doughs. This trait, coupled with rye’s inability to form a wheatlike dough structure, means that rye doughs can quickly over-ferment and collapse.
RYE IS HIGH IN A SUBSTANCE CALLED PENTOSANS, a polysaccharide substance found in plants. The pentosan content is higher in rye flour (about 8 percent) than in any other flour. The pentosans contribute to the high water absorption of rye breads, and at the same time compete with the glutelin and gliadin in the flour for moisture. This serves to prevent the development of gluten in rye breads. Further, the pentosans are fragile and easily broken, with a resulting potential for rye doughs to become sticky as the flour unknits. As a consequence of this characteristic, rye doughs must be gently mixed typically at only 25 to 40 rpms in slow mixers.
RYE IS A GRAIN HIGH IN AMYLASE ENZYMES (during humid growing seasons, the amylases can be in an advanced state of activity even before the time of harvest). A thorough understanding of the characteristics of amylases, and their potential to damage crumb structure, is essential for the baker of rye breads. Enzymes have one specific activity, and in the case of amylase, the activity it performs is the conversion of starch into sugar. Starches swell with water during the bake, and eventually form the crumb of the bread. Sugars, on the other hand, do not contribute to the formation of crumb structure; in fact, if they exist in too high a proportion in the dough, they have the effect of causing gumminess in the crumb. During the bake, when the internal dough temperatures are between 122° and 140°F, the starches in the rye begin to expand, absorb water, and gelatinize, and the crumb structure of the loaf begins to form. The amylases, however, are in a state of accelerated activity at these temperatures, and are not destroyed by heat until about 176°F. Therefore, they have an opportunity to wreak considerable havoc by breaking down the starch into sugar, and preventing the starch from forming a well-structured crumb. This is the dreaded “starch attack.” The result (unless the baker uses his or her skill) is bread with a gummy, pasty crumb. The baker of rye breads has one great tool at his disposal to inhibit the decomposing activity of the amylase, and that tool is sourdough. In the presence of acid, the activity of the amylases is slowed down. Therefore, by using sourdough, the baker stabilizes the baking ability of the bread by inhibiting the enzymatic activity that would otherwise result in bread with a gummy crumb.
Sourdough provides the benefits of good eating quality, increased nutrition, good leavening ability, and good keeping quality of the bread.
INDIA AND RYE:
As of date, rye grain is grown in a local villages around Kullu, and locals mostly call it “Neela Jau” and “Russi Gehu”, owing to its color and prevalent geographical production respectively. Some farmers have also been growing it in the upper Himalayan region near Mukteshwar.
Thus, rye is grown at a negligible scale in India at the moment, and is in dire need of reviva owing to its capacity for providing superior nutrition to humans while acting as an excellent regenerative and climate variability resilient crop in the contemporary agricultural ecosystems.
This coming Rabi season we are experimenting with growing a bunch of varieties suited for plains in the semi-arid zones, while strongly committing to our mission of reviving the genetic and biological diversity in Punjab's agricultural landscape.
Resources quoted: Based on 'The Rye Genome' by M. Timothy Rabanus-Wallace & Nils Stein (Editors) published on Springer AND 'Bread - A baker's book of techniques and recipes' by Jeffrey Hamelman.
We hope this was helpful, and you could learn something new about rye. If you have further questions and would love to know anything in specific, please carry on the discussion on our discord channel in #nutritionandrheology thread.
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