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Influence of extrusion on the health benefits of soluble fibre in oat cereal products S. M. TOSH (1). (1) Agriculture and Agri-Food Canada, Guelph, ON, Canada Breakfast cereals and snack foods are commonly consumed extruded products. During extrusion, a combination of heat, moisture and pressure are used to denature protein and gelatinize starch. This causes changes in the flavour, texture and physical appearance of the cereals. Human clinical trials have shown that extruded oat cereals maintain beneficial health effects during processing. Extruded oat cereal (3 g of oat β-glucan per day) was shown to lower serum LDL-cholesterol by 5.5 ± 0.2% compared to a wheat bran cereal with equivalent fibre content. The β-glucan appeared to function by increasing viscosity in the gut and reducing cholesterol absorbed during digestion. The same cereal was found to elicit low blood glucose responses after a meal containing 8 g of β-glucan soluble fibre. The extruded oat bran cereal with milk produced a glycemic response 39% lower than the response to white bread. Reduction in the molecular weight of the β-glucan in the cereal, caused by increasing the temperature and shear rate in the extruder while decreasing the water, resulted in increased blood glucose concentrations after a meal. However, oat bran cereals (58 – 60g per serving) with β-glucan molecular weights ranging from 326 000 to 2 180 000 all had low relative glycemic responses ranging from 34 ± 4 to 45 ± 4% of the response to white bread. The extent of changes to the microstructure and physicochemical characteristics of macronutrients occurring during extrusion is dependent on the temperature, moisture content and shear rate in the extruder. The integrity of cell walls can be disrupted making starch more bioaccessible. The energy input can also increase the soluble fibre content. Careful control of the extrusion process can maintain or even enhance the beneficial nutrients in extruded breakfast while improving taste and texture. View Presentation