Influence of the drying process on the composition of brewer's dried grains

The effect of temperatures ranging from 80–200°C and overdrying times of 0, 3 and 6 min was studied. Protein content of brewer's dried grains was not significantly altered, even under the most extreme conditions (200°C and 6 min overdrying time). Nevertheless, total-nitrogen percentage in the ADF fraction increased from 120°C (0 and 3 min overdrying time) and 160°C (6 min). After 6 min overdrying, this percentage was much higher, even at low temperatures. Dry-matter losses rose continuously as temperature increased, but variations were not significant when there was no overdrying. The fibrous fraction was not modified under 130°C, but increased at higher temperatures; the longer the overdrying time, the larger the fibrous fraction obtained. It was concluded that unless the temperature exceeded 120–130°C and the overdrying time 3 min, there was no deleterious effect on the composition of brewer's dried grains.