MAJOR milling oat buyer Uncle Tobys is looking at segregation for varieties with superior milling and nutritional attributes.

Uncle Tobys uses 30,000 tonnes of oats a year for flavoured and plain porridge, and other products, including health-food bars.

Quality engineer Phillip Nickson said mitika, the new dwarf, milling variety might be binned separately this coming harvest.

"We want more control on how we segregate grain lots on variety, with certain varieties being binned together to suit our milling processes," he said.

The Riverina's oat crop harvest began a fortnight ago, with Uncle Tobys expecting all grower contracts to be fulfilled.

Mr Nickson said the mill yield, or the difference between oat hull and kernel, was important to processors.

"The greater percentage of kernel to hull is better for us as the hull is a waste-product," he said.

"Kiln-drying hulled oats change the character of the oat kernel, imparting a nutty flavour by cooking it."

Mr Nickson said the way a kernel rolled out flat was important.

The oats are rolled to a thickness ranging from 0.35 to 1mm.

Mr Nickson said yarram oats were no longer used to produce muesli bars due to problems with rolling thickness.

"We get too much variation in grain size with the older varieties and encourage people to grow the newer varieties," he said.

"Various grain sizes make it difficult for us to handle them in the milling process."

When it comes to nutrition, Mr Nickson said the beta-glucan (fibre) concentration in a kernel affected the level of cholesterol reabsorption by the consumer.

Varieties were sought for their high anti-oxidant levels and were also rated on their ability to satisfy a person's hunger.

"This is important for people wanting to lose weight," he said.

Uncle Tobys has a collaborative research project with the South Australian Research and Development Institute.

Oats from the national breeding program are processed by Uncle Tobys into porridge for sensory testing.

South Australian oat breeder Dr Pamela Zwer said mitika was bred for improved groat percentage, which directly related to milling yield.

Groat yield is the percentage of the whole oat after the husk is removed.