鲢鱼糜凝胶体系的挤压式三维打印研究

发布时间：2018-06-20 19:54

本文选题：葡萄糖酸内酯 + 鱼糜凝胶　；参考：《江南大学》2017年博士论文

【摘要】：近年来,随着科技的进步以及经济的快速增长,人们对社会的需求逐渐增加,食品加工行业的高度工业化水平不断提升。三维打印技术是基于增材制造法原理的一种高新技术,是快速成型技术的延续与发展,其以制造技术和信息技术深度融合为特征的现代智能制造模式,为我国食品加工行业的发展提供了不同于传统制造技术的新思路。打印材料是三维打印技术发展的重要基础,也是制约三维打印技术获得广泛应用的瓶颈。对于广泛应用于食品加工领域的挤压式三维打印技术,其对食品物料有着准确严格的要求:应具备一定的流动性、成型性,并具有合格的物理、化学性质。鱼糜凝胶体系具有一定的凝胶强度、黏度和流变特性,因此本论文以葡萄糖酸内酯(GDL)诱导形成的鱼糜凝胶体系为挤压式三维打印食品材料,通过辅料添加改善凝胶体系的力学特性以适用于三维打印技术。在此基础之上,研究挤压式三维打印工艺参数对鱼糜凝胶体系打印品质及精度的影响。并进一步研究贮藏条件对鱼糜打印特性的影响,探究贮藏过程中脂肪过氧化产物对鱼糜凝胶打印效果的影响,探究鱼糜肌原纤维蛋白氧化聚形成的内在机制。以期深入阐明加工及贮藏过程中食品物料结构状态、打印特性与打印工艺三者之间的关系。本研究对于了解肉制品凝胶体系在挤压式三维打印技术中的应用奠定了理论依据和实际运用基础。首先初步研究了葡萄糖酸内酯(GDL)诱导鲢鱼糜凝胶体系的形成过程。通过分析不同GDL浓度对鱼糜凝胶的持水性、质构特性及水分分布的影响。进一步通过GDL作用于鱼肉肌原纤维蛋白(MP),研究GDL诱导鱼糜凝胶化过程中分子间作用力的变化。结果表明,促进鱼糜凝胶体系建立的GDL最佳浓度为1.5%。在此条件下,鱼糜凝胶化4 h内,鱼糜pH值快速降至4.5左右。GDL可改变鱼肉蛋白结构。随着GDL浓度的增加,蛋白结构展开,α-螺旋转化为β-折叠或无规则卷曲,疏水基团外露促进蛋白发生交联形成凝胶,凝胶强度及持水性提高。而过量的GDL添加反而会降低鱼糜凝胶的凝胶特性,导致凝胶劣化。低浓度的GDL诱导肌原纤维蛋白凝胶形成的作用力主要是疏水作用和共价二硫键,而当GDL浓度进一步增加时,出现疏水作用降低的现象。通过添加NaCl和固体脂肪改善鱼糜凝胶体系的松弛应力、蠕变特性、表观粘度以及动态学流变等打印特性,以期得到可用于三维打印的鱼糜凝胶体系。结果表明NaCl添加能够显著提高鱼糜凝胶的松弛应力、蠕变特性及动态学流变特性,有利于提高打印线条的抗压力,改善鱼糜凝胶的成型性,同时表观粘度的提高也有利于挤压式三维打印出料系统供料顺畅。10.0%的脂肪能够显著提高鱼糜凝胶的松弛应力、蠕变特性及动态流变学特性,但表观粘度呈逐渐下降的趋势。当加入过量的脂肪,鱼糜凝胶体系的粘度降低,不利于打印系统出料,并且打印完成后,样品结构容易塌陷变形。通过工艺参数试验研究了层高值、打印速率、喷嘴直径、出料速率及打印温度等参数对挤出成型质量的影响,并确定了关键工艺参数之间的相互制约关系。结果表明:层高值1.5 mm、打印高度5.0 mm,喷嘴直径2.0 mm、打印速率28 mm/s、打印温度45°C以及出料速率0.003 cm3/s条件下,打印鱼糜凝胶样品的成型质量较好,成型件表面光滑没有突起,层层之间结合较为紧密,没有缺口,搭接的量较少。其中,出料速率Vd、打印速率Vn与喷嘴直径Dn三个打印参数之间存在着一定的制约关系,因此在打印过程中应综合调控这三个参数,以提高打印精度。另外,对三维打印螺杆挤压出料的过程中螺杆转速与打印速率的关系进行建模及数值分析,并设计简单打印模型验证数值分析的结果。结果显示利用此模型,螺杆转速与打印速率更加匹配,挤出物料过程的稳定性显著提高,减少了打印误差,有效的提高了打印精度。考察了鱼糜在不同贮藏温度下脂肪氧化、蛋白氧化、鱼糜持水性、凝胶强度及三维打印相关特性的变化规律,结果表明随着贮藏时间的延长,鱼糜肌肉蛋白氧化增加和脂肪氧化加速,整体新鲜度会下降。同时持水性、凝胶强度、凝胶弹性、松弛应力、蠕变特性及表观粘度显著性降低。三种贮藏温度下,各指标整体变化趋势相似,而在相对较高温度下较长时间贮藏,会加速氧化劣变的发生,脂肪氧化与蛋白氧化具有一定的相关性,脂肪氧化能够促进蛋白氧化的发生。另外,建立基于整体稳定性指数法(GSI)预测不同温度贮藏下鱼糜凝胶的蛋白氧化程度及打印特性变化的数学模型,GSI=1-5.6161texp(-20.9159/RT),该模型能够准确有效地预测贮藏鲢鱼糜解冻后的基本品质及三维打印特性的变化规律。建立亚油酸(OLA)与丙二醛(MDA)脂质过氧化物氧化体系并作用于鱼糜凝胶,通过对肌原纤维蛋白结构变化的影响及促进肌原纤维蛋白氧化程度的研究,阐明贮藏过程中脂肪氧化对鱼糜凝胶打印效果的影响机制。并以MDA作用于肌原纤维蛋白,通过测定蛋白凝胶强度、持水力、水分状态及微观结构等研究蛋白氧化聚集形成凝胶的过程。研究表明脂质过氧化物OLA和和MDA可提高鱼糜的表观粘度、屈服应力以及动态流变特性,表现了一定的凝胶黏弹特性,从而促进鱼糜浆料顺利出料,减小出丝断条的几率。MDA诱导蛋白凝胶化的效果要明显高于OLA体系,当MDA浓度达到0.03%时,鱼糜在短时间内就可表现出固态特性,在料斗剪切进料时发生凝胶大分子聚集,并且提高剪切速度仍无法使浆料均匀进料,在螺杆缝隙极易出现堵塞的现象,导致打印无法正常进行。OLA和和MDA引起了肌原纤维蛋白的结构变化,即蛋白溶解度下降,蛋白羰基值、表面疏水性呈先增加后缓慢下降的趋势,肌原纤维蛋白内源荧光强度下降并且出峰位置发生蓝移。NMR结果显示MDA作用于鱼肉肌原纤维蛋白可促进蛋白结构舒展,随着MDA浓度的增大,MDA-MP形成刚性的凝胶结构,蛋白中不易流动水发生蓝移,自由水比例降低。加热作用结合适量的共价键有利于加固凝胶结构,使得多余的自由水排除在凝胶结构之外。
[Abstract]:In recent years, with the progress of science and technology and the rapid growth of economy, the demand for society is increasing gradually. The high level of industrialization in the food processing industry is increasing. The three-dimensional printing technology is a new and high technology based on the principle of material increasing manufacturing. It is the continuation and development of rapid prototyping technology, and its manufacturing technology and information technology are deep. The modern intelligent manufacturing mode characterized by degree fusion provides a new idea different from the traditional manufacturing technology for the development of the food processing industry in China. Printing material is an important basis for the development of 3D printing technology, and also a bottleneck restricting the wide application of three-dimensional printing technology. For the extrusion type three widely used in the field of food processing. It has a precise and strict requirement for food materials: it should have certain fluidity, formability and qualified physical and chemical properties. The gelatin gel system has a certain gel strength, viscosity and rheological properties. Therefore, the gelatin gel system induced by gluconate (GDL) in this paper is a three dimensional extrusion. To print the food materials, the mechanical properties of the gel system were added to improve the mechanical properties of the gel system to apply to the three-dimensional printing technology. On this basis, the influence of the extrusion parameters on the printing quality and precision of the surimi gel system was studied. The effects of storage conditions on the printing characteristics of the surimi were further studied and the fat in the storage process was explored. The effect of peroxide products on the printing effect of surimi gel, and to explore the internal mechanism of the formation of the oxidative polymerization of myofibrillar protein of surimi, in order to clarify the relationship between the structure state of the food materials and the relationship between the printing characteristics and the printing process in the process of processing and storage. This study is to understand the three-dimensional printing technique of the meat gel system in the extrusion type. The application in the operation laid a theoretical basis and practical basis. First, the formation process of gluconate (GDL) induced silver carp surimi gel system was first studied. The effects of different GDL concentrations on the water holding, texture and water distribution of the surimi gel were analyzed. The effect of GDL on fish myofibrillar protein (MP) was further studied. GDL induced changes in the intermolecular force during the gelation of fish surimi. The results showed that the optimum concentration of GDL to promote the surimi gel system was 1.5%. under this condition. The gelation of surimi was 4 h, and the pH value of surimi decreased rapidly to about 4.5.GDL to change the structure of fish protein. With the increase of GDL concentration, the structure of protein was expanded and the alpha helix was transformed into beta. Folding or irregular curling, hydrophobic group exposure promotes protein crosslinking to form gelatin, gel strength and water holding capacity increases. But excessive GDL addition can reduce gel properties of surimi gel and lead to gel deterioration. Low concentration of GDL induced myofibrillar gel formation force is mainly hydrophobic and covalent two sulfur bond, When the concentration of GDL is further increased, the hydrophobicity is reduced. By adding NaCl and solid fat to improve the relaxation stress, creep property, apparent viscosity and dynamic rheological properties of the surimi gel system, it is expected that the fish chyle gel system can be used for three-dimensional printing. The results show that the addition of NaCl can improve the fish significantly. The relaxation stress, creep properties and dynamic rheological properties of the chygels are beneficial to improve the pressure resistance of the printing lines and improve the formability of the surimi gel. At the same time, the increase of apparent viscosity is also beneficial to the smooth.10.0% fat of the extruded three dimensional printing and discharging system, which can significantly raise the relaxation stress, creep properties and dynamics of the fish surimi gel. The rheological properties, but the apparent viscosity decreases gradually. When the excess fat is added, the viscosity of the surimi gel system decreases, which is not conducive to the printing of the system. After the printing is completed, the structure of the sample is easily collapsed and deformed. Through the process parameter test, the layer height, the printing rate, the nozzle diameter, the feed rate and printing temperature are studied. The influence of the number on the quality of the extrusion molding was determined and the interaction between the key technological parameters was determined. The results showed that the molding quality of the printed surimi gel samples was better and the surface light of the molded parts was better under the conditions of the height of 1.5 mm, the printing height of 5 mm, the diameter of the nozzle 2 mm, the printing rate 28 mm/s, the printing temperature 45 degree C and the feed rate 0.003 cm3/s. There is no protruding, there is no gap between the layers, there is no gap, and the amount of lap joint is less. Among them, there is a certain restriction relationship between the feeding rate Vd, the printing rate Vn and the three printing parameters of the nozzle diameter Dn. Therefore, in the printing process, the three parameters should be adjusted to improve the printing precision. In addition, the three-dimensional printing screw extruder is used. The relationship between the screw speed and the printing rate is modeled and analyzed, and a simple printing model is designed to verify the results of the numerical analysis. The results show that the screw speed is more matched with the printing rate, the stability of the extrusion material process is greatly improved, the printing error is reduced, and the printing precision is effectively improved. The changes in lipid oxidation, protein oxidation, water retention of surimi, gel strength and three dimensional printing related characteristics were investigated at different storage temperatures. The results showed that with the prolongation of storage time, the muscle protein oxidation and lipid oxidation accelerated, and the whole new freshness decreased. Meanwhile, water holding, gel strength and gel elasticity were also found. Relaxation stress, creep property and apparent viscosity decrease significantly. Under three storage temperatures, the overall change trend of each index is similar, while storage at a relatively high temperature will accelerate the occurrence of oxidative deterioration, fat oxidation and protein oxidation have a certain correlation, fat oxidation can promote the occurrence of protein oxidation. In addition, it is built. Based on the integral stability index method (GSI), a mathematical model for predicting the changes of protein oxidation and printing properties of surimi gel at different temperatures was established. GSI=1-5.6161texp (-20.9159/RT). The model can accurately and effectively predict the basic quality and the three dimensional printing characteristics of silver carp surimi after the storage of silver carp and establish linoleic acid (OLA). The effect of the lipid peroxide oxidation system with malondialdehyde (MDA) on the surimi gel and the influence of the structure of myofibrillar protein and the improvement of the oxidation degree of myofibrillar protein were studied. The effect of lipid oxidation on the printing effect of surimi gel during storage was elucidated, and the effect of MDA on the myofibrillar protein and the determination of the egg was carried out. The results show that the apparent viscosity, yield stress and dynamic rheological properties of the surimi OLA and MDA can increase the apparent viscosity of the gelatin, thus promoting the smooth production of the surimi slurry and reducing the filaments. The effect of.MDA induced protein gelation is obviously higher than that of the OLA system. When the MDA concentration reaches 0.03%, the surimi can show a solid state in a short time. The gelation of the gelatin can occur when the hopper is cut into the material, and the shear speed can not be evenly made into the slurry. The phenomenon of blocking in the screw gap is easy. .OLA and MDA caused the structural change of myofibrillar protein, that is, protein solubility decreased, protein carbonyl value, surface hydrophobicity first increased and then decreased slowly. The endogenous fluorescence intensity of myofibrillar protein decreased and the peak position was blue shift.NMR results showed that MDA acted on the myofibrils of fish flesh. Protein can promote the expansion of protein structure. With the increase of MDA concentration, MDA-MP forms a rigid gel structure. The flow water in the protein is not easy to move blue, and the proportion of free water is reduced. The heating effect combined with a proper covalent bond is beneficial to the strengthening of the gel structure, and the excess free water is excluded from the gel structure.
【学位授予单位】：江南大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TS254.4

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