ONLINE MEASUREMENT OF THE MICROBIAL IMPACTS ON THE GERMINATION OF BARLEY DURING MALTING

During germination, the metabolic activity of sterile barley was more pronounced than the activity of barley contaminated by its endogenous microbial population. CO2 and heat production profiles showed higher p eak values when microbial activity was eliminated. Moreover, the maxim a in the profiles appeared sooner than with barley in the presence of its natural microflora. More intensive growth of the acrospire was obs erved with sterile barley and a malt was obtained with a higher and mo re homogeneous modification. Reverse effects were noticed when sterile barley was inoculated with an Erwinia sp. strain and germination was evaluated. The results provide clear evidence for the strong interacti on between microbial and plant metabolism, even for non dormant and no n water sensitive barley. The ratio of CO2 production to heat producti on levels was a useful tool for on-line monitoring of microbial activi ty during germination. In this way, the effects of the microbial activ ity can be taken into account in the development of a more effective c ontrol of the malting process. All experiments were performed using a specially designed solid-state reactor.