Barley is macerated, malted, and roasted to make malt, which is the main ingredient in beer brewing. The malting of barley, the hydrolysis of macromolecules and the corresponding malt quality play a crucial role in the production of beer. In order to obtain better germination performance and malt quality, various malting additives are added in the malt production process. Gibberellin can break seed dormancy, promote seed germination and shorten germination time, so it is widely used in the malting industry. But gibberellins may lead to excessive root formation, excessive macromolecular hydrolysis and darkening of wort. Therefore, it is very important for the malting industry to find an efficient, safe and environmentally friendly malting additive.
Alginate Oligosaccharide is chemically or enzymatically degraded by sodium alginate, and has the advantages of strong solubility, good stability, and easy absorption by the body. Studies have found that Alginate Oligosaccharide can significantly improve the germination index and vigor index of seeds, and significantly accelerate the germination rate of seeds. Dalian University of Technology applied Alginate Oligosaccharide to the malting industry as a malting additive to study its effect on barley germination and malt quality.
The effects of adding Alginate Oligosaccharide in the immersion stage on barley germination ability and germination rate, hydrolase activity and malt quality during barley germination were studied experimentally. The results showed that when adding 50mg/LAlginate Oligosaccharide, the germination ability and germination rate of barley increased by 46.4% and 12.0%, respectively, compared with the control group. Alginate Oligosaccharide can significantly increase the activities of α-amylase, β-amylase, protease and β-glucanase during barley germination. At the end of germination, the activities of α-amylase, β-amylase, protease and β-glucanase added with 50mg/LAlginate Oligosaccharide increased by 43.5%, 22.9%, 20.6% and 20.5%, respectively, compared with the control group. Alginate Oligosaccharide can also improve the quality of malt. Compared with the control group, when adding 50mg/LAlginate Oligosaccharide, the brittleness, extract mass fraction, α-amino nitrogen mass fraction, Courbach value and saccharification power of malt increased by 6.1% respectively. , 8.0%, 21.2%, 7.3% and 8.6%, the β-glucan mass fraction and viscosity of malt decreased by 29.2% and 15.4%, respectively.
Alginate Oligosaccharide can promote barley to overcome dormancy, stimulate barley germination, accelerate barley germination rate and improve germination ability, which indicates that Alginate Oligosaccharide is an elicitor that can promote the germination of grain seeds. The results of this study show that in the process of barley germination, the addition of Alginate Oligosaccharide in the process of soaking can promote the improvement of hydrolase activity, thereby significantly improving the solubility of malt, shortening the malting cycle, and significantly improving malt quality and wort yield.