Optimization of Preparation Technology of Crystallized Malt by Response Surface Methodology

In order to improve the quality and crystallization rate of crystalline malt, this study optimized the pre-saccharification and kilning processes in the preparation of crystalline malt through single factor and response surface experiments. The free amino nitrogen content and reducing sugar content were used as indices to study the effect of pre-saccharification process on crystalline malt. At the same time, the coking process was optimized with moisture content, crystallization rate and color as indices. The results showed that the green malt with a germination time of 72 h was selected, the protein was rested at 45 ℃ for 1.5 h, and the saccharification was carried out at pH = 6.0 and temperature of 66.4 ℃ for 2.0 h. Under these conditions, the reducing sugar content was the highest and the saccharification effect was the best. Further the malt was baked at 127 °C for 27 min to obtain a crystalline malt with a moisture content of 3.75%, a chromaticity of (158.9 ± 1.19) EBC, and a crystallization rate of 99%. Compared with commercially available crystalline malt, the crystalline malt can be completely crystallized inside, the crystalline quality is better, and other quality indicators have been significantly optimized.