Volatiles as an indicator of fungal activity and differentiation between species, and the potential use of electronic nose technology for early detection of grain spoilage

There is significant interest in methods for the early detection of quality changes in cereal grains. The development of electronic nose technology in recent years has stimulated interest in the use of characteristic volatile s and odours as a rapid, early indication of deterioration in grain quality . This review details the current status of this area of research. The rang e of volatiles produced by spoilage fungi in vitro and on grain are describ ed, and the key volatile groups indicative of spoilage are identified, The relationship between current grain quality descriptors and the general clas ses of off-odours as defined in the literature, e.g. sour, musty, are not v ery accurate and the possible correlation between these for wheat, maize an d other cereals, and volatiles are detailed. Examples of differentiation of spoilage moulds and between grain types using an electronic nose instrumen t are described. The potential for rapid and remote grain classification an d future prospects for the use of such technology as a major descriptor of quality are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.