The Science of Landrace Grains Nutrition and Flavor
Comprehensive studies comparing the nutritional values of pre-hybridized landrace and other heritage grains with modern wheat and barley varieties has only recently been undertaken by scientists. For many years large-scale commodity production of crops has focused on increasing yield, but increasing interest from health-conscious consumers has stirred interest in grains in order to improve nutrition and health. Depending on growing conditions and grain variety, important macro-minerals like calcium, magnesium, and potassium, and such micro-minerals as iron, copper, and selenium are found in grain kernels. These are distributed throughout the aleurone layer (55%), endosperm (20%), pericarp (10%), scutellum and testa (10%), and embryo (5%).
In recent studies at the Swedish University of Agricultural Sciences in Alnarp, cereal researchers conducted chemical analysis using plasma mass and atomic emission spectrometry on 321 spring and winter wheats. These were divided into several groups including primitive hulled grains, landraces and old variety selections, old cultivars (1900-1960s releases/hybrids), and new cultivars released since 1970. (The researchers defined old variety selections as wheats that have been selected for organic cultivation from such “old material” as durum and bread wheat breeding lines.) The results shown in the chart below show that heritage grains have higher mineral rates compared to modern hybrid varieties, and that the more highly refined the flour, the lower the nutritive value.
The grains were grown at several locations and under controlled conditions in order to provide comparative results without influence of synthetic soil amendments, herbicides, or pesticides. Results of the study were published in “Mineral Composition of Organically Grown Wheat Genotypes” in the International Journal of Environmental Research and Public Health (September, 2010) and indicate substantial variation among the groups. Primitive grains, landraces, and old variety selections were found to have significant concentrations of the most minerals including iron, manganese, calcium, phosphorus, and selenium. The primitive grains einkorn and emmer showed the highest level of zinc compared to others, while spelts were highest in sulfur.
The Alnarp research and similar investigations conducted elsewhere suggests that the negative correlation between modern cultivars and mineral density is likely due to the shallow root systems of hybridized varieties and a nutrient dilution effect given the increased yield of many modern grains. These studies indicate that grain mineral levels depend on absorption in the soil by the plant’s root system and subsequent redistribution to the kernels through vegetative tissues which is also influenced by photosynthesis. Higher chlorophyll content, for example, is positively correlated to iron concentration, as is availability of nitrogen which facilitates photosynthesis. The Alnarp study also indicates that grain variety is more influential than geographic location for mineral content in primitive and landrace grains. Finally, growing environments significantly contribute to variations for others, and high organic matter and increased soil pH also favor mineral concentration.
Wheat and other grains are important sources of minerals for maintaining human health, and 200 grams of flour per day from many wheat types can contribute nearly 100% of recommended daily requirements. Levels are dependent on the part of the grain that is used, with whole grain flour the most nutritious given the high concentration of minerals in the aleurone level. Microelement malnutrition is a significant global problem as some three billion people today suffer from such “hidden hunger” that can cause high premature infant mortality rates, permanent cognitive impairment, and lower workplace efficiency. Grains represents an important renewable resource to alleviate these problems and are much more available and affordable than other sources like fish, fruits, and vegetables. Summarized below are some of these essential minerals and their important roles to maintain health.
Magnesium: Contributes to efficient metabolism as well as proper muscle and nerve functioning; also shown to reduce diabetes and metabolic ailments.
Calcium: An essential component for development of the musculoskeletal, cardiovascular, and nervous systems, and promotes overall physiological performance.
Phosphorus: Necessary for proper functioning of kidneys and heart muscle, contributes to bone and dental strength, and regulates protein reactions.
Potassium: Contributes to proper heart muscle contraction, neural impulse transmission, and fluid system balance.
Copper: Facilitates the functions of C-oxidase enzymes, promotes connective tissue development, and iron metabolism.
Selenium: Inhibits some types of cancer cell formation and promotes essential antioxidant reactions.
Iron: Synthesizes hemoglobin and produces energy.
Zinc: Regulates the function of many enzymes, glucose, and insulin, and synthesizes proteins.
Minerals in grains also contribute significantly to food flavor since taste bud receptors are sensitive to many metal and hydrogen ions as well as protein compounds. Selection of grain variety and the milling process affects mineral content since it is reduced through heat, extended exposure to processing and bleaching, and removal of the kernel’s outer level. Moderating these factors can lead to a wider range and deeper intensity of flavors that has led some agronomists and artisan bakers to speak of grains and farming regions in ways akin to noble wine grapes and terroir.
Acclaimed Wales & Johnson University baker-instructor Peter Reinhart writes in Bread Revolution: World Class Baking with Sprouted Grains, Heirloom Flours & Fresh Techniques (2014) of “the full potential to unlock the flavor trapped in the grain” as a mission of craft and quality. He cites the work of Dr. Stephen Jones, director of the Washington State University’s Bread Lab at Mt. Vernon, Washington, who has championed a national effort to study and promote grains with distinct flavors and nutritional profiles that are disease resistant and adaptable to particular soil and climatic conditions.
The subtitle of Maine farmer David Buchanan’s recent book, Taste, Memory: Forgotten Foods, Lost Flavors, and Whey They Matter (2012), suggests that healthy food systems involve a balance of culinary traditions and biodiversity with a context of sustainable and economically efficient agriculture. The Slow Food USA organizer explored industrial and craft milling operations across the country and tasted vegetables, fruits, and grains in foods from the Southwest to the Northeast. Through Glenn Roberts, founder of Anson Mills in Columbia, South Carolina, Buchanan experienced the unique flavors of such heritage wheats as soft winter Red May, soft white spring Sonora, and hard Turkey Red, and their distinctive suitability for variousfoods. Turkey Red made dark, earthy yeast breads of “excellent flavor,” while the flatbreads and muffins of Sonora he found “light, nutty, and nearly free of gluten.” Sounding more like a sommelier, Roberts spoke of Sonora’s “lingering sweetness on the back palate… and a haunting minerality,” which has also been characterized as “a rich buttery earthiness.”
James Beard Outstanding American Chef Dan Barber of the Rockefeller Stone Barns Center Blue Hill Restaurant in New York is a grateful beneficiary of such research which he describes in The Third Plate: Field Notes on the Future of Food (2014). Barber points out the relevance of heritage grains not only for improved quality of breads and other bakery products, but also for malting barleys that impart distinctive tastes in a new generation of craft brews that can be paired with fine food like premium wines.