Screening and identification of saccharifying strains in the highland barley kojiand process optimization for degrading barley starch
WANG Xiaoyan1, WANG Rongfu1, ZHANG Haoyu1, YUAN Zhenzhen1,2,3, CAO Xiaohai1,3, WANG Shulin1,2,3*, Du Yan2
1(College of Agriculture and Animal Husbandry, Qinghai University,Xining 810016, China) 2(Qinghai Province Highland Barley Resources Comprehensive Utilization Engineering Technology Research Center,Xining 810016, China) 3(United Laboratory of Food Research and Testing of Qinghai-Gansu Province, Xining 810016, China)
Abstract: In order to reduce the content of starch in highland barley, the saccharification fungus was screened from barley koji and the liquid fermentation process was optimized. Low-sugar barley powder was produced by saccharification fungus fermentation and solid-liquid separation technologies. The dominant saccharification strain with saccharification efficiency of 359.62 μg/(g·h) was screened using saccharification efficiency as the index. It was further identified as Aspergillus oryzae by morphological and molecular biological identification. The optimum growth temperature and pH of this strain were 40 ℃ and 4.0, respectively. The saccharide strain had a certain ability to resist sodium ions. The growth curve of Aspergillus oryzae at 35 ℃ showed that 0-3 days was the growth retardation period, 3-5 days was the logarithmic period, and 6-7 days was the stable period. Starch in highland barley was degraded by fermentation with this screened strain. The Box-Behnken center combination design was carried out based on the single factor tests. The optimal fermentation time was 2.8 days under 37.6 ℃, and the inoculum size was 6.6%. The results showed that microbial degradation of starch in highland barley is an efficient method and the results have important value and significance for the development and utilization of low sugar highland barley products.
王晓燕,王蓉福,张昊宇,等. 青稞酒曲中糖化菌的筛选鉴定及降低青稞淀粉工艺优化[J]. 食品与发酵工业, 2020, 46(5): 160-165.
WANG Xiaoyan,WANG Rongfu,ZHANG Haoyu,et al. Screening and identification of saccharifying strains in the highland barley kojiand process optimization for degrading barley starch[J]. Food and Fermentation Industries, 2020, 46(5): 160-165.