On the base of equipment constitutions and working principle of thin slab continuous casting,the cause of pendulum shear top cutting malfunction was analyzed from four sides.They cover the control functions of pendulum shear cycle cutting,frame swing,hold-down roll and horizontal roll.And measures were taken to improve the malfunction as well.
ABSTRACTThis study monitored the physical, chemical, and sensory quality of raw Pacific white shrimp (Litopenaeus vannamei) and the evolution of microbial flora under modified atmosphere packaging (MAP) with varying concentrations of CO2 (95% CO2/5% O2; 80% CO2/15% N2/5% O2; 65% CO2/30% N2/5% O2) at 4°C during 10-day storage. Plate counts on selective agars indicated that MAP had a strong inhibitory effect on psychrotrophic bacteria, mesophilic bacteria, Enterobacteriaceae, and H2S-producing bacteria. Analyses with molecular techniques (denaturing gradient gel electrophoresis, DGGE) by extracting bacterial DNA from shrimp samples showed that Vibrio spp. and Aeromonas spp. were predominant in fresh MAP samples. Shewanella putrefaciens, which dominated in samples stored in air, were found sporadically in MAP samples. Interestingly, lactic acid bacteria were not predominant in MAP samples, whose pH values were high (6.66 to 8.14) during storage. The content of total volatile basic nitrogen in MAP samples was about 10 mg N/g lower than the control at the end of storage. Higher lightness values and sensory scores were also observed in samples under MAP. However, MAP with CO2 concentrations higher than 80% did not enhance the inhibitory effect on bacterial growth but induced more severe reddening and sensory quality loss.KEYWORDS: Litopenaeus vannameimodified atmosphere packagingdenaturing gradient gel electrophoresismicrobiota FundingFunding was provided from the National Natural Science Foundation of China (Grant No. 31501551), the National "Twelfth Five-Year" Plan for Science and Technology Support (Grant No. 2013BAD19B06), Shanghai Engineering Research Center Construction Special from Shanghai Municipal Science and Technology Commission (Grant No. 11DZ2280300), Leading Academic Discipline Project of Shanghai Municipal Education Commission (Grant No. J50704), and Excellent Thesis Grant from Shanghai Ocean University.Additional informationFundingFunding was provided from the National Natural Science Foundation of China (Grant No. 31501551), the National "Twelfth Five-Year" Plan for Science and Technology Support (Grant No. 2013BAD19B06), Shanghai Engineering Research Center Construction Special from Shanghai Municipal Science and Technology Commission (Grant No. 11DZ2280300), Leading Academic Discipline Project of Shanghai Municipal Education Commission (Grant No. J50704), and Excellent Thesis Grant from Shanghai Ocean University.
The applied trained in undergraduate college is to face the industries and enterprises,to conform to the trend of the economic development and to have strong practical abilities. So it is required that in the process of training applied talents,we should focus on serving the local economy,taking the initiative to integrate into the society,building close cooperation with enterprises,closing up to the market demand. Schools and enterprises should share the benign and interactive development in the concept of innovation,the government leading,information exchange,mechanism innovation,project promotion and culture aspects,etc.
[Objective] In order to reduce the production cost,further domestication and screening of aspergillus strains CO827 were done by means of selective conditions,and efficient aspergillus strains gotten would be used in practical production. [Method]10% acid tablet domestication,breeding,and preliminary screening shaking were used to produce high acid strain primarily,and 15% acid tablet domestication and shaking culture were used to reselect,finally aspergillus Niger strain CO827-0515-7 producing high acid was gotten,which has been used in production through subculture. [Result]The result showed that on the base of intrinsic quality and flavor of Citric acid products,the fermentation level has been improved and the fermentation producing cost has been reduced by about RMB 82. 59 per ton( clear liquid),which equals the total cost of citric acid product can be lowered by RMB 76. 60 per ton. [Conclusion] By gradient acid type flat screen has acid conversion CO827-0515-7 strains which had the characteristics of high acid,high sugar,and was successfully applied to the production process.
Abstract The importance of spoilage‐related bacteria in fresh Pacific white shrimp ( Litopenaeus vannamei ) under different modified atmospheres (MAs) at 4 °C and the effect of O 2 were demonstrated in the current study. The changes of bacterial communities in MA‐packed shrimp during cold storage were studied by a combined method of plate counts with isolation and identification. Three gas mixtures were applied: 80% CO 2 /5% O 2 /15% N 2 , 80% CO 2 /10% O 2 /10% N 2 and 80% CO 2 /20% O 2 , and unsealed packages of shrimp were used as the control. In addition, the TVB‐N, pH, whiteness index, and sensory scores were also determined to evaluate the quality changes of shrimp. MA packaging effectively inhibited the increase of total psychrotrophic bacteria counts and H 2 S‐producing bacteria counts by about 1.7 and 2.1 log cycles, respectively. The growth of Gram‐negative spoilage bacteria in shrimp, including Shewanella spp., Aeromonas spp., and Pseudomonas spp., was inhibited by MA packaging, but the growth rate of Gram‐positive bacteria such as lactic acid bacteria (LAB) and Brochothrix spp. were less affected by MA as effectively as Gram‐negative bacteria. In comparison with the MA‐packaged samples, the counts of H 2 S producers in shrimp under a CO 2 ‐enriched atmosphere with 20% O 2 were slightly lower than the count in samples under an atmosphere with 5% O 2 . However, MA with 20% O 2 led to higher concentrations of TVB‐N, and lower whiteness values and sensory scores. The shelf life of shrimp under 80% CO 2 /10% O 2 /10% N 2 has been prolonged by > 6 d in comparison with the control according to the sensory scores.
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