Research on malting technology of hulless barley used for brewing hulless barley beer

Malt and Grains Session
Guangtian Zhou, School of Food and Bio-engineering, Shandong Institute of Light Industry, 250353, Jinan, Shandong, China
Co-author(s): Song Wang, and Naibin Zhang, School of Food and Bio-engineering, Shandong Institute of Light Industry, Jinan, China; Zhihong Xu, Process and Equipment Engineering, Pöyry Shandong Engineering Consulting Co., Ltd. Jinan, China

ABSTRACT: Hulless barley (Hordeum vulgare subsp. vulgare) is a particular grain crop produced in Tibet, China. It has a wealth of dietary fiber, and every 100 g of barley flour contains: 0.32 mg of VB1, 0.21 mg of VB2, 3.6 mg of Vpp, and 0.25 mg of VE. It is also rich in mineral elements, such as calcium, phosphorus, iron, copper, zinc, and selenium. These materials play a vital role in promoting human health. Research found that hulless barley contains the highest beta-glucan in barley and wheat crops with an average content of 6.57%. A good variety of hulless barley, No. 25, is even running at 8.6%. Beta-glucan is a polysaccharide that has special physiological functions. It can significantly improve cardiovascular function and also has a good curative effect in the treatment of diabetes. However, beta-glucan has a high viscosity. If hulless barley is used to brew beer, wort separation will be extremely difficult, and the stability of the finished beer will also be affected. Therefore, the purpose of this study was to obtain high quality hulless barley malt through the improvement of the malting process. A high-quality hulless barley variety, Zangqing No. 85, and normal barley were used as a test and control, respectively. The results showed that during malting, under the same conditions, hulless barley hydrated quickly, developed rootlets easily, and germinated vigorously and malting loss was relatively large. Meanwhile, the content of beta-glucan in hulless barley was changed too. Further research has studied the effect of different germination parameters on beta-glucan content, such as temperature, time, and the amount of gibberellin (GA3) added. We optimized the germination parameters of hulless barley by the corresponding surface methodology. Results showed that under the precondition of minimum beta-glucan content (3.1 g/L, in comparison the content of beta-glucan in Australian barley Baudin malt is 2.0 g/L) the best germination conditions were as follows: germination temperature at 16.6°C, germination time of 101.5 hr, and GA3 addition at 0.085 mg/L. The beta-glucan content was greatly reduced in this process. With 30% of the proportion of the hulless barley malt as adjunct, beta-glucan content of the wort was 272.8 mg/L, alpha-amino nitrogen was 260.7 mg/L, viscosity of the wort was 1.573 mPa·sec, and pH value was 6.42. Thus, the separation of wort becomes easier and so is brewing performance. Hulless barley beer is designed so the beer is brewed with top-fermenting yeast, somewhat similar to wheat beer. The finished hulless barley beer has a unique taste and harmonious flavor. The beer also has a lot of advantages in terms of health benefits, due to the higher content of beta-glucan.

Guangtian Zhou received his B.S. degree in bioengineering from Shandong Institute of Light Industry, Jinan, China, in 1982. He was then employed with the Jinan Beer Group as a brewer. Guangtian studied in Doemens Akademie, Munich, Germany, from August 1987 until November 1988. After graduation, he became chief brewer of the Jinan Beer Group. Since July 1994, Guangtian has functioned as professor, tutor of M.S. degree students, and the director of the China-Germany Beer Technology Center in the School of Food and Bio-engineering, Shandong Institute of Light Industry, teaching and researching beer production. At present, he serves as an editor of China Brewing and a council member of Shandong Society for Microbiology.