Climate-adaptable grain could be key to human health

Dr Stuart Johnson from Curtin’s School of Public Health and International Institute of Agri-Food Security is heading up a team running field and glasshouse trials on coloured sorghum grain varieties.

Together with Dr Sarita Bennett, Dr Sue Low and Dr Roger Mandel from Curtin’s Department of Environment and Agriculture, he is investigating the potential role of the unusually high level of antioxidants in black sorghum for the production of health-protective human food and supplements, as well as its potential to be grown in the Australian agricultural industry.

Black sorghum bran can have higher levels of antioxidants than blueberries, however, somewhat ironically, this grain is not considered that suitable for pig and poultry feed because of its slow digestibility of starch and hence reduced energy available for production.

“We are nicknaming this project ‘The Reverse Pig Paradigm’ as, although farmers want their pigs to gain weight as quickly as possible by feeding a low antioxidant white-grained sorghum variety, we are looking at ways to do the opposite in humans with the high antioxidant dark sorghum varieties,” Dr Johnson said.

“Black sorghum has potential to develop foods with a higher antioxidant concentration than foods currently on the market. It also has potential for development of foods with a low glycemic index and high appetite suppression properties – a perfect combination for protection against development of obesity and related chronic diseases such as type 2 diabetes and cardiovascular disease.

“Also, as rainfall patterns continue to change and higher temperatures are being recorded, the resilient sorghum may be well-suited to food grain production. Unlike wheat that will die-off when drought-stressed, sorghum will go dormant, and come alive again with the next rain.”

A small 100-gram sample of black sorghum donated by the Department of Agriculture, Fisheries and Forestry Queensland was all the team had to start off the growing program, but this year they managed to produce 20 kilograms of the seed on site at Curtin, enough to perform rigorous research studies.  

Dr Johnson said he was not only looking at black sorghum grain but other coloured varieties, aiming to design food products such as baked goods, breakfast cereals, pasta and snack foods that were both tasty and could deliver long-term health benefits.

“The problem with sorghum is the difficulty to process as there is no gluten in it, so this limits the type of food products that can be produced,” Dr Johnson said.

“We have to think of novel ways to add texture to the products to make them more acceptable to consumers, like with a popcorn or puffing-type process.”

The Curtin-led project is the first to involve large human clinical trials on coloured sorghum to substantiate health-related physiological benefits from eating them.

Notes to Editor
About Sorghum:
Sorghum is a summer-growing cereal crop native to Africa, and is the fifth most important cereal crop grown in the world, produced in large quantities in the USA, China, India and Africa. It is also a major crop in S.E Queensland and northern NSW. Sorghum grows in harsh environments where other crops do not grow well.

For centuries, sorghum has been one of the most important staple foods for millions of people of Asia and Africa, remaining a principal source of energy and protein. In developed countries, the predominant use of sorghum is as fodder for poultry and cattle. Interest is now on  the potential  of sorghum as a grain for healthy human foods.

Media Contact: 
Dr Stuart Johnson,
School  of Public Health, Curtin University
Tel: 08 9266 9486, Email: [email protected]

Megan Meates, Public Relations, Curtin University
Tel: 08 9266 4241; Mobile: 0401 103 755; Email: [email protected]