摘要
传统的玉米干燥工艺效率低,干燥后的玉米品质不好,在加工过程中,玉米会产生破损。进行了玉米自然干燥、热风干燥和热风-真空复合干燥,考察了3种干燥方式下的玉米力学特性和表观形态。力学特性测试结果发现,50℃热风+45℃真空复合干燥的玉米应变最大。自然干燥中,应力松弛曲线达到的最大应力为0.0455 MPa,三元件Maxwell模型能很好地拟合应力松弛测试结果,决定系数均达到0.977以上。玉米籽粒储能模量和损耗模量均随频率增大而增大,储能模量大于损耗模量,意味着干燥后的玉米表现出的弹性大于粘性。表观形态测试结果发现,相比于热风干燥,复合工艺干燥的玉米籽粒中淀粉颗粒更为饱满,玉米品质更好。干燥后的玉米结晶形态均为A形模式。热风-真空复合工艺干燥玉米的力学特性研究,可以为玉米加工、储藏等相关设备的研制提供实验基础。
The efficiency of traditional maize drying is low and the quality of dried maize kernel is not good.Maize will be damaged during processing.Natural drying,hot-air drying and hot-air-vacuum combined drying of maize kernel were carried out,and the mechanical properties and apparent morphology of maize kernel dried by three methods were investigated.The test results of mechanical properties showed that the maize kernel dried by 50℃hot-air+45℃vacuum had the largest deformation.In hot-air drying,the creep curve of maize kernel dried at 65℃was the highest,and that of maize kernels dried at 75℃was the lowest.Among three drying methods,the stress achieved by the stress relaxation curve of natural drying was the largest,and its value was 0.0455 MPa.In compound drying,the stress achieved by the stress relaxation curve of 50℃hot-air+65℃vacuum was the largest,and its value was 0.0414 MPa.The three-element Maxwell model could fit the stress relaxation test results well,and the coefficients of determination were all above 0.977.Both the storage modulus(G′)and loss modulus(G″)of maize kernel were increased with the increase of frequency.The storage modulus was greater than loss modulus,and the dominant position was occupied by elasticity.The elasticity of dried maize kernel was greater than its viscosity.The results of the apparent morphology test showed that the starch granules in maize kernels dried at high temperature were relatively drier and shriveled,while those in maize kernels dried at low temperature were rounder and plumper.At the same temperature,the starch granules dried by compound process were plumper than those dried by hot-air.The quality of the maize kernel dried by compound process was better.The maize kernel structure exhibited A-type crystalline pattern.The characteristic peaks of maize kernel dried by hot-air appeared at about 13.7°,15.7°,16.4°and 21.5°(2θ).Among them,single peaks appeared at 13.7°and 21.5°,and double peaks appeared at 15.7°and 16.4°.In compound drying,only 50℃hot-air+55℃vacuum and 50℃hot-air+65℃vacuum were basically the same as natural drying.Their characteristic maize peaks appeared at about 14.8°,16.9°,17.8°and 22.8°(2θ).The mechanical properties of maize kernel dried by hot-air-vacuum compound process could provide an experimental basis for the development of maize processing and storage related equipment.
作者
盛韶阳
吴敏
胡纯秋
王国秀
陈文军
SHENG Shaoyang;WU Min;HU Chunqiu;WANG Guoxiu;CHEN Wenjun(School of Public Health,Anhui Medical University,Heifei 230032,China;College of Engineering,China Agricultural University,Beijing 100083,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2020年第S01期476-482,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家重点研发计划项目(2016YFD0701801)
安徽医科大学博士科研资助项目(XJ201623)
安徽医科大学校科研基金项目(2017xkj009)。
关键词
玉米
热风-真空干燥
力学特性
表观形态
maize
hot-air-vacuum drying
mechanical properties
morphology
