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1.
Effect of DAG on milk fat TAG crystallization 总被引:1,自引:0,他引:1
Amanda J. Wright Alejandro G. Marangoni 《Journal of the American Oil Chemists' Society》2002,79(4):395-402
The effect of milk fat and standard DAG on the crystallization behavior of milk fat TAG (MF-TAG) was investigated. When milk
fat DAG were added to MF-TAG at the 0.1 wt% level, crystallization was delayed. Racemic purity was shown to be an important
factor in the ability of DAG to influence TAG crystallization. Only sn-1,2 isomers of blends of MF-TAG with 0.1 wt% of the racemic mixtures of dipalmitin and diolein increased the activation free
energy barrier to MF-TAG nucleation (ΔG
c
) and delayed the subsequent crystallization process by increasing the crystallization induction time (τSFC) determined from solid fat content-time measurements. Although crystallization kinetics were affected, the properties of
the resulting network structures remained unchanged upon addition of milk fat minor components at the 0.1 wt% level 相似文献
2.
Guanghui Li Jiazi Chen Jia Yang Shaolin Wang Ning Liu Chaoying Qiu Yong Wang 《European Journal of Lipid Science and Technology》2020,122(8)
The effects of diacylglycerols rich in medium‐ and long‐chain fatty acids (MLCD) on the crystallization of hydrogenated palm oil (HPO) and formation of 10% water‐in‐oil (W/O) emulsion are studied, and compared with the common surfactants monostearoylglycerol (MSG) and polyglycerol polyricinoleate (PGPR). Polarized light microscopy reveals that emulsions made with MLCD form crystals around dispersed water droplets and promotes HPO crystallization at the oil‐water interface. Similar behavior is also observed in MSG‐stabilized emulsions, but is absent from emulsions made with PGPR. The large deformation yield value of the test W/O emulsion is increased four‐fold versus those stabilized via PGPR due to interfacial crystallization of HPO. However, there are no large differences in droplet size, solid fat content (SFC), thermal behavior or polymorphism to account for these substantial changes, implying that the spatial distribution of the HPO crystals within the crystal network is the driving factor responsible for the observed textural differences. MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals to enhance the rigidity of emulsion. This study provides new insights regarding the use of MLCD in W/O emulsions as template for interfacial crystallization and the possibility of tailoring their large deformation behavior. Practical Applications: MLCD is applied in preparing W/O emulsion. It is found that MLCD forms unique interfacial Pickering crystals around water droplets, which promote the surface‐inactive HPO nucleation at the oil‐water interface. Thus MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals, which can greatly enhance the rigidity of emulsion. This observation would provide a theoretical reference and practical basis for the application of the MLCD with appreciable nutritional properties in lipid‐rich products such as whipped cream, shortenings margarine, butter and ice cream, so as to substitute hydrogenated oil. MLCD‐stabilized emulsions can also be explored for the development of novel confectionery products, lipsticks, or controlled release matrices. 相似文献
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Dr. Jessica S. Kelsey Dr. Tamas Geczy Nancy E. Lewin Dr. Noemi Kedei Colin S. Hill Julia S. Selezneva Christopher J. Valle Wonhee Woo Dr. Inna Gorshkova Dr. Peter M. Blumberg 《Chembiochem : a European journal of chemical biology》2014,15(8):1131-1144
The C1 domain, which represents the recognition motif on protein kinase C for the lipophilic second messenger diacylglycerol and its ultrapotent analogues, the phorbol esters, has emerged as a promising therapeutic target for cancer and other indications. Potential target selectivity is markedly enhanced both because binding reflects ternary complex formation between the ligand, C1 domain, and phospholipid, and because binding drives membrane insertion of the C1 domain, permitting aspects of the C1 domain surface outside the binding site, per se, to influence binding energetics. Here, focusing on charged residues identified in atypical C1 domains which contribute to their loss of ligand binding activity, we showed that increasing charge along the rim of the binding cleft of the protein kinase C δ C1 b domain raises the requirement for anionic phospholipids. Correspondingly, it shifts the selectivity of C1 domain translocation to the plasma membrane, which is more negatively charged than internal membranes. This change in localization is most pronounced in the case of more hydrophilic ligands, which provide weaker membrane stabilization than do the more hydrophobic ligands and thus contributes an element to the structure–activity relations for C1 domain ligands. Coexpressing pairs of C1‐containing constructs with differing charges each expressing a distinct fluorescent tag provided a powerful tool to demonstrate the effect of increasing charge in the C1 domain. 相似文献
5.
Christian Gertz Hans‐Jochen Fiebig 《European Journal of Lipid Science and Technology》2006,108(12):1066-1069
The “Joint Committee for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GA Fett)” has developed the following method for the determination of isomeric diacylglycerols in virgin olive oils to detect the freshness of oils. It is intended to include this method in Section C, Chapter VI of the German Standard Methods.* 相似文献
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8.
Determination of positional distribution of short-chain fatty acids in bovine milk fat on chiral columns 总被引:4,自引:0,他引:4
Yutaka Itabashi John J. Myher Arnis Kuksis 《Journal of the American Oil Chemists' Society》1993,70(12):1177-1181
The positional distribution of acetic and butyric acids in bovine milk fat triacylglycerols was determined by chiral-phase
high-performance liquid chromatography (HPLC) of the derived diacylglycerols. Enriched fractions of acetic and butyric acid-containing
triacylglycerols were isolated by normal-phase thin-layer chromatography (TLC) from a molecular distillate of butter oil,
and they were fully hydrogenated. Mixedsn-1,2(2,3)- andX-1,3-diacylglycerols of short- and long-chainlength, which were generated by partial Grignard degradation of the hydrogenated
triacylglycerols, were isolated by borate-TLC. The enantiomericsn-1,2-andsn-2,3-diacylglycerols and theX-1,3-diacylglycerols as their 3,5-dinitrophenylurethanes were resolved by HPLC on chiral columns. Both acetic and butyric
acids were exclusively associated with thesn- 2,3- andX-1,3-diacylglycerols of short and long chainlength. These results establish the presence of acetic and butyric acids in thesn-3-position of bovine milk fat triacylglycerols. Other short-and medium-chainlength acids were found in progressively increasing
proportions also in thesn-1- andsn-2-positions. 相似文献
9.
分子蒸馏分离提纯甘二酯中试工艺研究 总被引:1,自引:0,他引:1
研究了中试分子蒸馏分离提纯甘二酯的工艺方法。棕榈油在一定的条件下经过中试分子蒸馏设备蒸馏,得到重相与轻相。轻相主要是甘二酯,重相主要是甘三酯。通过进料量、温度及刮膜转速的控制可以得到纯度70%以上的甘二酯。研究结果表明,在温度220℃、压力0.01 Pa、进料量10 L/h、蒸发器转速200 r/min的条件下,通过脱气,薄膜蒸发与短程蒸馏可以得到纯度较高的甘二酯。用棒状薄层色谱―氢火焰离子化检测器法(TLC–FID)与反相高效液相色谱–蒸发光散射检测法(RP–HPLC–ELSD)分别分析测定了棕榈油以及轻相、重相中甘油酯的含量,并进行了对比;用气相色谱分析了棕榈油以及轻相、重相脂肪酸组成。 相似文献
10.
Waste Frying Oils as Substrate for Enzymatic Lipolysis: Optimization of Reaction Conditions in O/W Emulsion 下载免费PDF全文
Ignacio Moya-Ramírez Alejandro Fernández-Arteaga Encarnación Jurado-Alameda Miguel García-Román 《Journal of the American Oil Chemists' Society》2016,93(11):1487-1497
Waste frying oils (WFO) can be both environmental pollutants and a source of valuable products. In this work we explore the conversion of WFO into surface‐active substances, such as FFA and partial glycerides, through enzymatic hydrolysis in O/W emulsion. Two different WFO and three lipases of different origin were tested. In addition, we optimized the conditions for the production of O/W emulsions to be used as reaction medium as well as several reaction parameters, such as the type of enzyme and its concentration, the pH, and the presence of Ca2+ ions. Gum arabic‐stabilized emulsions with an oil fraction of 0.15 proved to be the most adequate owing to their high interfacial area and short‐term stability. The physicochemical characterization of both WFO revealed the presence of an increased amount of surface‐active matter relative to food‐grade vegetable oils. These substances, mainly FFA, can interfere with lipase action and reduce the reaction rate. However, the extent of hydrolysis was only slightly affected by them, and remained fairly similar to that achieved with a control mixture of food‐grade vegetable oils. The product distribution depended on the enzyme used. Pseudomonas fluorescens lipase was found to be particularly suitable for the production of partial glycerides (mono‐ and diacylglycerols), which are in great demand by the food industry. In any case our results demonstrate that WFO are a good substrate for enzymatic hydrolysis, comparable to food‐grade vegetable oils, providing an alternative route for the valorization of this waste. 相似文献