Effect of dry-heat treatments on the nutritional value of maize germ

Maize germ is a by-product of the maize milling process that is characterised by a high nutritional value. Currently, heat treatments are employed to prevent full-fat maize germ from spoilage. The aim of this research was to study the effect of five dry-heat treatments on the nutritional value of full-fat maize germ. The results confirmed that after each dry-heat treatment, the lipase activity decreases but the use of high temperatures could be detrimental for phytosterol and thiamine concentrations. The main negative effects have been observed after treatments at 140 °C for 30 min and 160 °C for 10 min. No significant difference has been observed for protein, ash or fatty acid contents. The treatment at 140 °C for 20 min resulted an optimal combination between temperature and heating time to inactivate lipase without altering deeply the nutritional value and the colour of maize germ.