饲料限水糊化动力学及其颗粒结构特性的表征  

Characterization of gelatinization kinetics and particle structure of feed under limited moisture condition

作　　者：金楠[1] 李腾飞 王红英[1] 方鹏[1] 段恩泽[1] 陈计远 Jin Nan;Li Tengfei;Wang Hongying;Fang Peng;Duan Enze;Chen Jiyuan(College of Engineering,China Agricultural University,Beijing 100083,China;Beijing 3D Printing Research Institute,Beijing City University,Beijing 100083,China)

机构地区：[1]中国农业大学工学院,北京100083 [2]北京城市学院北京3D打印研究院,北京100083

出　　处：《农业工程学报》2020年第16期293-299,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划项目“畜禽养殖绿色安全饲料饲养新技术研发”(2018YFD0500600)。

摘　　要：饲料的糊化作为一种功能特性广泛存在于饲料的热加工中,水分、温度和时间是影响饲料糊化的重要工艺参数。为探究饲料在水热处理过程中的糊化动力学参数及饲料颗粒结构的内在变化,该研究基于均匀板加热法,将25%和30%水分的育肥猪配合饲料,分别在75、80、85、90和95℃温度下,进行0.5、1、3、5、7和10 min加热时间的热处理,分析热处理后饲料样品的糊化程度、糊化动力学参数、结晶特性、双折射特性和微观形貌等理化性质。结果显示,水分是饲料糊化的第一限制性因素,25%和30%水分饲料的最大糊化度分别为0.3206±0.0162和0.6688±0.0150,饲料的糊化过程遵循非线性一级动力学模型,且在热处理时长达到3 min左右时,糊化度趋向糊化终端的渐进值;由Arrhenius公式回归得到的25%和30%水分饲料糊化活化能分别为11356.58和52705.59 J/mol,是限制水分条件下的“不完全糊化活化能”。具有不同双折射消失程度的颗粒共存于同一热处理样品体系中,淀粉颗粒双折射性的消失从颗粒中心开始,热处理样品微观结构的变化主要表现为颗粒中心无定形区的优先破坏,中心结构的破坏导致颗粒表面塌陷,并促进了存在于淀粉颗粒无定形区直链淀粉的浸出;经过热处理样品的结晶图谱由A型转变为V型;晶体结构的破坏和重组同时发生但程度不同,样品的相对结晶度表现为先降低,并在特征温度明显回升后再次下降。研究结果为饲料热加工中原料的相互作用及变化机制提供了基础数据,对饲料调质和膨化工艺的优化具有潜在的应用价值。The gelatinization of starch in feedstuffs as a functional property is applied extensively in feed thermal processing,and the moisture,temperature and time are the important technological parameters affecting the gelatinization of feed.In order to explore the gelatinization kinetic parameters and intraparticle structural changes in formula feed during the process of hydrothermal treatment,the heat treatment of formula feed for finishing pigs(moisture-adjusted to 25%and 30%)was carried out at different temperature,i.e.75,80,85,90 and 95℃,for different heating time,i.e.0.5,1,3,5,7 and 10 min,respectively,based on the homogeneous plate heating method.The degree of feed gelatinization was quantified by enzymatic method,and polarized light microscopy,X-ray diffractometry,scanning electron microscope were used to characterize the physical and chemical properties of samples after heat treatment,such as,gelatinization kinetic parameters,crystallization characteristics,birefringence and micro morphology.The results showed that full gelatinization did not occur even at high enough temperature under limited moisture condition.The maximum gelatinization degree of feed with 25%and 30%moisture were 0.3206±0.0162 and 0.6688±0.0150,respectively.The gelatinization process of feed followed nonlinear first order kinetics model.The gelatinization degree tended to the asymptotic value of terminal extent of gelatinization,when the heat time reached about 3 min.Compared with the gelatinization activation energy of natural starch in the previous study,the gelatinization activation energy of feed with 25%and 30%moisture in this research,11356.58 and 52705.59 J/mol,obtained from regression of Arrhenius formula was relatively low,and it could only be regarded as“incomplete gelatinization activation energy”under limited moisture condition.Granules with different disappearance degree of birefringence coexisted in the same heat-treated sample system,and the birefringence lost from the center of some granules,indicating that the main m

关 键 词：饲料 热处理 糊化动力学 颗粒结构 低水分 

分 类 号：S816.9[农业科学—饲料科学]