Abstract: In order to investigate the quality changes of specialty malt under different malting conditions, the present study investigated the effect of roasting temperature, roasting time and raw material quality on the color, α-amino nitrogen (α-AN) content, and the contents of 2,5-dimethylpyrazine and furfural in specialty malt. The results showed that the contents of water and α-amino nitrogen in specialty malt decreased significantly with the increase of roasting temperature (P < 0.05). When the temperature reached 160 ℃, the moisture content was lower than 1%, and the content of α-amino nitrogen in specialty malt germinated for 3 days decreased fastest, from 228.157 to 118.427 mg/L. The content of β-glucan in control malt (prepared by the traditional soaking-germination procedure) was the highest. The content of β-glucan decreased gradually with the increase of soaking and germination time. For both control and specialty malt, different raosting temperatures had little effect on the content of β-glucan. The chroma, reducing power, and 2-thiobarbituric acid (TBA) value significantly increased with the increase of roasting temperature (P < 0.05). The malt germinated for 3 days had the fastest growth and the highest reducing power, up to 1.303. Since it is proportional to the severity of beer aging, the TBA value should be reasonably controlled during the malting process. With the increase of roasting temperature, the content of 2,5-dimethylpyrazine decreased firstly and then increased. In contrast, the content of furfural change only marginally with increasing roasting temperature from 80 to 120 ℃, and then began to increase significantly. Both 2,5-dimethylpyrazine and furfural were mainly produced at 120–160 ℃.

Key words: specialty malt, roasting process, color, flavor substances