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Food Science and Biotechnology
→ Food Science and Biotechnology 2017 ; 26(5): 1227-1233
Enhancing the hydrolysis of corn starch using optimal amylases in a high-adjunct-ratio malt mashing process
Linjiang Zhu1,2, Ting Ma1, Yiming Mei3, Qi Li1
1The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, No. 1800 Lihu Avenue, Wuxi 214122, Jiangsu, China, 2Institute of Fermentation Engineering, College of Biotechnology and Bioengineering, Zhejiang University of Technology, No. 18 Chaowang Road, Hangzhou 310014, China, 3Novozymes (China) Investment Co. Ltd, No. 14 Xinrin Road, Shangdi Zone, Haidian District, Beijing 10086, China
ABSTRACT
Incompletely degraded corn starch particles often seriously inhibit wort filtration and decrease a brewery’s beer productivity. Herein, the inhibiting factors of starch hydrolysis and the application of amylases to degrade residual starch were evaluated. The results showed that resistant starch and the amylopectin of corn starch were not the inhibiting factors. Almost all residual starch left in the spent grain layer was proved to be degradable by amylases. Mesophilic α-amylase was selected through a comparison of nine amylases, which increased the wort filtration rate by 44%. However,>6% of corn starch was still left after mashing when a high ratio of corn starch to water (>1:3.5) was used in liquefaction. The low water content in liquefaction was proved to be the key inhibiting factor. Considering the existing equipment and brewing technology, the application of mesophilic α-amylases should be a simple and effective method for enhancing the hydrolysis of corn starch and accelerating the wort lautering process during a high-adjunct-ratio beer brewing process.
KEYWORD
Amylase, Beer brewing, Corn starch, High-gravity, fermentation, Low-water-content liquefaction
Food Science and Biotechnology 2017 ; 26(5): 1227-1233
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