In this study, autolysis was induced by incubating cell suspensions of spent brewer's yeast at elevated temperatures of 45, 50, 55 and 60 degrees C with a reaction time ranging from 8 to 72 h. Contents and yields of solid, a-amino nitrogen, protein and carbohydrate were determined. It can be said that optimum temperature and time for the production of yeast extract was 50 degrees C for 24 h on the basis of a-amino nitrogen and protein contents. Sensory analysis was also done by yeast extract powder and control and samples with the addition of 0.5 and 1.0% yeast extract had the highest overall acceptance. (C) 2007 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.