Sorghum has bright future with formulation flexibility, drought tolerance

Sorghum is naturally gluten free, and its variability means growers and formulators have a lot to work with without crossing over into genetic engineering territory, experts say.  And the grain thrives in hot and dry conditions that wither its more well known compatriots, meaning it may be the wave of the future if droughts in grain growing regions that scientists fear may be a potential consequence of global climate change become commonplace.

Sorghum as a food crop is not well known in western societies. The grain is not commonly grown in humid and well-watered Europe, and farmers as they migrated to the New World tended to stick with what they knew—wheat, oats and barley.  And corn, sorghum’s genetic cousin and the superstar of the Americas, came to the fore, with cultivars that delivered spectacular productivity under the right conditions, which include ample water and fertilizer inputs.

But grain sorghum (there is sweet sorghum, too; a related plant that is grown as a source of syrup or for use as an ethanol feedstock) is a staple in many parts of Africa and is grown in India and China, too. As many as 100 million people worldwide consume sorghum daily as the base carbohydrate in their diets.  In much of Africa it is consumed as a stiff porridge forming a vessel for stews, a consumption mode not common in western cuisines.

Mostly a feed crop in US​

In North America sorghum is commonly grown on marginal land as animal feed.  In the US, sorghum is often called milo, and is grown mostly in arid Great Plains states such as Kansas, Texas and Oklahoma.  These states have vast irrigated acreages of wheat and other grains, with sorghum filling in as a viable dry land crop.

But sorghum may be ready to step out of the shadows.  Its importance could rise as the huge aquifers underlying much of the Great Plains, including the Ogallala Aquifer, are depleted, raising irrigation costs as water has to be pumped from ever greater depths.

Genetic diversity​

The grain has a vast amount of natural genetic diversity because of the divergent environments in Africa where it originated, said Earl Roemer, a Kansas farmer and grain wholesaler who has built an entire business called Nu Life Market on the grain.

“The really unique aspect of grain sorghum is its germplasm.  That’s because of the diversity of its genetic lines that comes from 6,000 to 8,000 years of development in Africa,”​ Roemer told FoodNavigator-USA.

Functional attributes​

Roemer has been working with grain for decades as a farmer and as an executive with the Sorghum Checkoff Program, a national research and promotional program funded from fees assessed against the sale of sorghum grain and other products (such as silage).

Some sorghums grown in east Africa developed a light tan color.  This grain yields  a seed with a mild taste and can be ground into a gluten-free white flour that can be a boon to finished product formulators, Roemer said.

“There is a tremendous amount of potential with this.  It is naturally gluten free and a great alternative to rice flour.  You can enhance the nutritional characteristics with more fiber, iron and niacin,”​ he said.

The grain’s utility hasn’t been lost on the market; recently milling giant ADM concluded a deal with US seed company Nuseed Americas to bring a line of flours based on Nuseed’s supply chain to market. Nuseed uses the term Wholis to brand its supply chain of dedicated growers, delivering what the company said will be consistent quality.

“As we promote awareness of sorghum in the food chain, we understand the necessity for food companies to have a consistent supply of grain, bred specifically for use as a good product. The Wholis branded sorghum supply chain ensures a consistent, uniform, gluten-free supply of premium quality sorghum grain,”​ said Nuseed commercial director Tim Birkel.

 “Nuseed sorghum is highly versatile due to its unique light color and neutral flavor,”​ said Brian Forster, general manager of Wheat Starch and Protein for ADM Milling, a subsidiary of ADM based in Overland Park, KS.

In Ethiopia, sorghums in some of the highest elevations developed high levels of anthocyanins​

Other sorghums that developed outside of the traditional East African grain growing regions in countries like Kenya and Tanzania offer additional benefits as functional ingredients, Roemer said.

“In other regions like Ethiopia, sorghums in some of the highest elevations developed high levels of anthocyanins.  That variety has about eight times the amount of antioxidants as found in a blueberry.  It has to protect itself against the high level of UV rays,”​ Roemer said.

No other cereal grain has that kind of natural genetic diversity​

And a burgundy variety that was first cultivated in Sudan developed tannins that are similar in structure to those found in red wine, Roemer said.

“No other cereal grain has that kind of natural genetic diversity,”​ he said.

Mitch Tuinstra, PhD, is a professer at Purdue Univeristy who has been working on sorghum since 1991, including helping to sequence the plant’s genome.  One of the grain’s benefits for formulators lies in the structure of its carbohydrates, he said.  It might offer opportunities to use the grain in products in the blood sugar management category;.

“It often times has a lower glycemic index.  The starches don’t get digested as rapidly.  If you’ve got an issue with diabetes you might consume sorghum,”​ he said.