棕榈油基甘油二酯的性质研究及其塑性脂肪贮藏稳定性的评价
发布时间：2018-09-10 09:01
【摘要】：甘油二酯(DAG)油脂不仅具有减轻体重和降低餐后血脂等健康的生理功能,还具有独特的理化性质,因而备受关注,利用这些特性可以将富含DAG的脂肪加工成各种类型且具有减肥作用的塑性脂肪产品。因此,本文以棕榈硬脂(PS)、棕榈中间分提物(PMF)、棕榈油(PO)、棕榈软脂(POL)和低芥酸菜籽油(RSO)为试验对象,通过系统研究不同棕榈油基DAG油脂分子组成、熔化结晶性质、晶体形态、流变性质、质构特性,并研究棕榈油基DAG的结晶机理,不同富含DAG油脂之间相互作用后对油脂体系相关性质的影响以及富含甘油二酯塑性脂肪的贮藏稳定性,探索用富含DAG的油脂替代普通油脂制备棕榈油基塑性脂肪的可行性,为推广DAG功能性食用油提供科学的理论依据。主要研究结果如下所示:(1)选择Lipozyme TL IM固定化脂肪酶作为催化剂,在叔丁醇体系进行甘油解反应,脂肪酶的添加量为底物油的5%(w/w),反应温度为70℃,其中棕榈油基油脂的叔丁醇与底物油的体积比为4:1,底物与甘油的摩尔浓度比为1:2,PMF和PO甘油解的反应时间为36h,PS和POL为24h,RSO的叔丁醇与底物油的体积比为3:1、底物与甘油的摩尔浓度比1:3,反应时间为36h,在此条件下,TAG转化率较高,也能得到高含量的DAG。通过分子蒸馏纯化后,PS、PMF、PO、POL、RSO中的DAG含量分别为89.45%、92.61%、90.43%、89.87%、92.67%。(2)棕榈油基油脂转为甘油二酯后,脂肪酸构成未发生变化,各组分含量变化不显著,滑动熔点升高,塑性范围变宽,晶型由β′型为主变为β型为主。熔化结晶性质发生明显改变,结晶曲线和熔化曲线均向高温区偏移,并且在高温区出现了新的吸热峰和放热峰。在相同的温度下,棕榈油基DAG油脂的成核和结晶速率明显快于其相应原油,而且其成核机制对温度的敏感度较低。震荡流变结果表明,棕榈油基DAG油脂的|G*|曲线和δ曲线达到平衡时的时间跨度较小,且曲线变化趋势更陡峭。棕榈油基DAG油脂的晶体网络结构是由细小的针状晶体聚集而成的,与其相应原油相比,晶体尺寸更细小,网络结构更紧致,填充度较高。(3)1,3-PO,1,3-OO和1,3-PP的同质多晶型均表现为β型,其滑动熔点分别为37.6℃、22.1℃和68.7℃。通过结晶和熔化DSC曲线构建的动力学相图均表明二元体系1,3-PO/1,3-OO和1,3-PP/1,3-PO存在共晶现象,1,3-PP/1,3-OO则表现为偏晶行为。1,3-PO/1,3-OO和1,3-PP/1,3-PO的液相边界模拟分析结果表明,在1℃/min和10℃/min两种冷却速率条件下,当0≤X_(1,3-PP)≤X_e时,体系的非线性参数ρ均为负值,意味着异分子间的相互作用占优势,趋向于形成1,3-PO-1,3-OO和1,3-PP-1,3-PO体系。1,3-PO/1,3-OO,1,3-PP/1,3-OO和1,3-PP/1,3-PO的微观晶体结构的研究表明,添加的组分对其微观晶体形态影响显著,尤其是在接近共晶点附近尤为明显。(4)与原油体系相比,二元体系PO-DAGE/POL-DAGE和PO-DAGE/PS-DAGE的相容性较得到了显著的改善,并伴有微弱的共晶作用,熔化和结晶性质差异极其显著,富含DAG油脂的二元体系结晶速率更为迅速,且在结晶过程中无球形晶体生长,形成的晶体网络结构更为致密有序。三元体系PO-/POL-/RSO-DAGE、PO-/PS-/RSO-DAGE、PO-/PS-/POL-DAGE均具有良好的相容性。最后通过相容性、SFC以及同质多晶型的研究确定了比较适用于典型焙烤起酥油的基料油配方分别为:PO-/POL-/RSO-DAGE(45:45:10)、PO-/PS-/POL-DAGE(45:10:45)、PO-/PS-/POL-DAGE(10:10:80)、PO-DAGE/POL-DAGE(90:10)、PO-DAGE/POL-DAGE(70:30)、PO-DAGE/PS-DAGE(90:10)。(5)在恒温和波动温度两种条件下贮藏3个月,无论是PDAGE-起酥油还是其对照组以及市售起酥油的POV值和甘油酯组分均未发生明显改变(P0.05)。与其相应的原油对照组相比,PDAGE-起酥油A和B的SFC对温度的敏感度明显较低,而且硬度下降较为平缓。在贮藏期间,PDAGE-起酥油A和B粘弹性较为稳定,对温度和时间变化的敏感度较低,且变化幅度明显较弱。恒温5℃存储时,时间对PDAGE-起酥油A和B的焓值影响不显著,恒温贮藏温度升高,时间对二者焓值影响相对显著。波动温度贮藏时,时间对PDAGE-起酥油A和B的焓值影响比在恒温时显著,但是对温度和时间的敏感程度均明显弱于其对照A和对照B以及市售起酥油。PDAGE-起酥油A和PDAGE-起酥油B的晶型衍变速率比其相应的对照A和B以及市售起酥油明显缓慢,在贮藏3个月后,样品依然存在一部分β′型晶体。而且在贮藏过程中富含DAG油脂的起酥油晶体的生长和迁移聚集过程较为缓慢,不及其棕榈原油对照样品明显,且不易聚集生成较大的颗粒状晶体或大脂肪块。
[Abstract]:Diethylene glycerol (DAG) lipids not only have the physiological functions of reducing body weight and postprandial blood lipids, but also have unique physical and chemical properties, which have attracted much attention. Using these properties, DAG-rich fats can be processed into various types of plastic fat products with weight-reducing effect. Extracts (PMF), palm oil (PO), palm soft fat (POL) and low erucic acid rapeseed oil (RSO) were used to study the molecular composition, melting and crystallization properties, crystal morphology, rheological properties and texture characteristics of different palm oil-based DAG oils. The crystallization mechanism of palm oil-based DAG and the interaction between different DAG-rich oils were also studied. The main results are as follows: (1) Lipozyme TL IM was selected as the immobilized lipase for lipase immobilization. As a catalyst, glycerolysis was carried out in tert-butanol system. The addition of lipase was 5% (w/w) of substrate oil, and the reaction temperature was 70 ~C. The volume ratio of tert-butanol to substrate oil of palm oil was 4:1, the molar concentration ratio of substrate to glycerol was 1:2, the reaction time of PMF and PO glycerolysis was 36 h, PS and POL was 24 h, RSO was tert-butanol. The ratio of DAG to substrate oil was 3:1, the molar concentration ratio of substrate to glycerol was 1:3, and the reaction time was 36 h. Under these conditions, the conversion of TAG was higher and the content of DAG was higher. After purification by molecular distillation, the content of DAG in PS, PMF, PO, POL and RSO was 89.45%, 92.61%, 90.43%, 89.87%, 92.67% respectively. The composition of fatty acids remained unchanged, the content of each component remained unchanged, the sliding melting point increased, the plastic range widened, and the crystalline form changed from beta'-type to beta-type. The results of oscillatory rheology show that the | G * | and | delta curves of palm oil-based DAG oils reach equilibrium with a shorter time span and a steeper change trend. The network structure is composed of fine acicular crystals. Compared with the corresponding crude oil, the crystal size is smaller, the network structure is more compact, and the filling degree is higher. Phase diagrams show that the binary system 1,3-PO/1,3-OO and 1,3-PP/1,3-PO have eutectic phenomena, while 1,3-PP/1,3-OO exhibit monotectic behavior. The liquid-phase boundary simulation results of 1,3-PO/1,3-OO and 1,3-PP/1,3-PO show that the nonlinear parameters of the system are negative when the cooling rates are 0 < X_ (1,3-PP) < X_e at 1,3-PP/min and 10 < X_e. It means that the intermolecular interactions are predominant, and tend to form 1,3-PO-1,3-OO and 1,3-PP-1,3-PO systems. The compatibility of the binary system PO-DAGE/POL-DAGE and PO-DAGE/PS-DAGE was improved remarkably, accompanied by weak eutectic effect. The difference of melting and crystallization properties between the binary system was extremely significant. The binary system rich in DAG oil had a faster crystallization rate, and no spherical crystals grew during the crystallization process. The crystal network structure was more compact. The ternary systems PO-/POL-/RSO-DAGE, PO-/PS-/RSO-DAGE, PO-/PS-/POL-DAGE, PO-/PS-/POL-DAGE have good compatibility. Finally, through compatibility, SFC and homogeneous polymorphism, the formulations of base oils suitable for typical baking shortening are PO-/POL-/RSO-DAGE (45:45:10), PO-/PS-/POL-DAGE (45:10:45), PO-/PS-/POL-DAGE (1:1:45), PO-/PS-/POL-DAGE (1:1:1). PO-DAGE/POL-DAGE (90:10), PO-DAGE/POL-DAGE (70:30), PO-DAGE/PS-DAGE (90:10). (5) The POV value and glyceride composition of PDAGE-shortening, its control group and commercial shortening did not change significantly (P 0.05) after 3 months storage at constant and fluctuating temperatures. During storage, PDAGE-shortening A and B were more stable in viscoelasticity, less sensitive to temperature and time changes, and the range of change was significantly weaker. The effect of storage time on the enthalpy values of PDAGE-shortening A and B is more significant than that of isothermal storage, but the sensitivity to temperature and time is weaker than that of control A and control B, and the crystal type derivative ratio of PDAGE-shortening A and PDAGE-shortening B. The corresponding control A and B as well as the commercial butter were obviously slow. After 3 months storage, there were still some beta'-type crystals in the samples, and the growth, migration and aggregation process of the butter crystals rich in DAG oil during storage was slower than that of the palm crude oil, and it was not easy to aggregate into larger granules. Crystals or large fat blocks.
【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】：TS221
，
本文编号：2233987
[Abstract]:Diethylene glycerol (DAG) lipids not only have the physiological functions of reducing body weight and postprandial blood lipids, but also have unique physical and chemical properties, which have attracted much attention. Using these properties, DAG-rich fats can be processed into various types of plastic fat products with weight-reducing effect. Extracts (PMF), palm oil (PO), palm soft fat (POL) and low erucic acid rapeseed oil (RSO) were used to study the molecular composition, melting and crystallization properties, crystal morphology, rheological properties and texture characteristics of different palm oil-based DAG oils. The crystallization mechanism of palm oil-based DAG and the interaction between different DAG-rich oils were also studied. The main results are as follows: (1) Lipozyme TL IM was selected as the immobilized lipase for lipase immobilization. As a catalyst, glycerolysis was carried out in tert-butanol system. The addition of lipase was 5% (w/w) of substrate oil, and the reaction temperature was 70 ~C. The volume ratio of tert-butanol to substrate oil of palm oil was 4:1, the molar concentration ratio of substrate to glycerol was 1:2, the reaction time of PMF and PO glycerolysis was 36 h, PS and POL was 24 h, RSO was tert-butanol. The ratio of DAG to substrate oil was 3:1, the molar concentration ratio of substrate to glycerol was 1:3, and the reaction time was 36 h. Under these conditions, the conversion of TAG was higher and the content of DAG was higher. After purification by molecular distillation, the content of DAG in PS, PMF, PO, POL and RSO was 89.45%, 92.61%, 90.43%, 89.87%, 92.67% respectively. The composition of fatty acids remained unchanged, the content of each component remained unchanged, the sliding melting point increased, the plastic range widened, and the crystalline form changed from beta'-type to beta-type. The results of oscillatory rheology show that the | G * | and | delta curves of palm oil-based DAG oils reach equilibrium with a shorter time span and a steeper change trend. The network structure is composed of fine acicular crystals. Compared with the corresponding crude oil, the crystal size is smaller, the network structure is more compact, and the filling degree is higher. Phase diagrams show that the binary system 1,3-PO/1,3-OO and 1,3-PP/1,3-PO have eutectic phenomena, while 1,3-PP/1,3-OO exhibit monotectic behavior. The liquid-phase boundary simulation results of 1,3-PO/1,3-OO and 1,3-PP/1,3-PO show that the nonlinear parameters of the system are negative when the cooling rates are 0 < X_ (1,3-PP) < X_e at 1,3-PP/min and 10 < X_e. It means that the intermolecular interactions are predominant, and tend to form 1,3-PO-1,3-OO and 1,3-PP-1,3-PO systems. The compatibility of the binary system PO-DAGE/POL-DAGE and PO-DAGE/PS-DAGE was improved remarkably, accompanied by weak eutectic effect. The difference of melting and crystallization properties between the binary system was extremely significant. The binary system rich in DAG oil had a faster crystallization rate, and no spherical crystals grew during the crystallization process. The crystal network structure was more compact. The ternary systems PO-/POL-/RSO-DAGE, PO-/PS-/RSO-DAGE, PO-/PS-/POL-DAGE, PO-/PS-/POL-DAGE have good compatibility. Finally, through compatibility, SFC and homogeneous polymorphism, the formulations of base oils suitable for typical baking shortening are PO-/POL-/RSO-DAGE (45:45:10), PO-/PS-/POL-DAGE (45:10:45), PO-/PS-/POL-DAGE (1:1:45), PO-/PS-/POL-DAGE (1:1:1). PO-DAGE/POL-DAGE (90:10), PO-DAGE/POL-DAGE (70:30), PO-DAGE/PS-DAGE (90:10). (5) The POV value and glyceride composition of PDAGE-shortening, its control group and commercial shortening did not change significantly (P 0.05) after 3 months storage at constant and fluctuating temperatures. During storage, PDAGE-shortening A and B were more stable in viscoelasticity, less sensitive to temperature and time changes, and the range of change was significantly weaker. The effect of storage time on the enthalpy values of PDAGE-shortening A and B is more significant than that of isothermal storage, but the sensitivity to temperature and time is weaker than that of control A and control B, and the crystal type derivative ratio of PDAGE-shortening A and PDAGE-shortening B. The corresponding control A and B as well as the commercial butter were obviously slow. After 3 months storage, there were still some beta'-type crystals in the samples, and the growth, migration and aggregation process of the butter crystals rich in DAG oil during storage was slower than that of the palm crude oil, and it was not easy to aggregate into larger granules. Crystals or large fat blocks.
【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】：TS221
，
本文编号：2233987
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