Binary Phase Behavior of Diacid 1,3‐Diacylglycerols

Candelilla wax (CW) organogelation is a promising method for providing structure to solid‐like fat‐based foods, cosmetics, and drug delivery systems. The main component, n‐hentriacontane (C31), defines, to a large extent, the thermal properties of CW. CW is a complex mixture of n‐alkanes, fatty acids, triterpenic alcohols, and fatty alcohols. In this initial examination of the role of CW components on the phase behavior and structure, CW and binary mixtures of C31 and melissic acid (C30) were studied in bulk and in solutions of vegetable oil. Binary mixtures of C31 and C30 presented a predominantly monotectic phase behavior in which the melting temperature of C31 remained constant independently of the mixture composition. Crystal packing of the pure components and mixtures had an orthorhombic subcell, and the microstructures of the mixtures were extremely different from that of the pure components. In solutions with less than 50 % C31, the order–disorder transition observed in bulk C31 was absent. Organogels of C31, C30, or the mixture were softer than those of CW. The increased strength of CW organogels is associated with the relatively small crystal size of this system.

Section: Resultssupporting

confidence: 80%

Phase Behavior and Structure of Systems Based on Mixtures of n‐Hentriacontane and Melissic Acid

Serrato-Palacios

Toro‐Vázquez

Dibildox‐Alvarado

et al. 2015

“…Phase diagrams were constructed using the onset temperature (T on ) of the lowest melting peak and the peak temperature (T p ) of the highest melting peak to represent an approximation of the onset and completion of the melting process [23]. Phase diagrams were constructed using the onset temperature (T on ) of the lowest melting peak and the peak temperature (T p ) of the highest melting peak to represent an approximation of the onset and completion of the melting process [23].…”

Section: Experimental Pseudo-phase Diagrammentioning

confidence: 99%

“…A phase diagram shows the different phases (solid, liquid, or gas) of materials at equilibrium as a function of temperature and composition, and sometimes of 1 3 pressure. The use of phase and pseudo-phase diagrams in food systems has been reported by several researchers [19][20][21][22][23][24]. Binary phase diagrams are typically constructed by blending different proportions of two pure components.…”

Section: Introductionmentioning

confidence: 99%

“…This diagram helps to determine the total amount of material that can be crystallized under any given condition. Mixtures of pure triacylglycerols [21,25,26], fatty acids [17,20], and monoacylglycerols [23] were studied using phase diagrams, while pseudo-phase diagrams were reported for confectionery fats such as cocoa butter and anhydrous milk fat [19,27]. Natural waxes, however, are mixtures of different molecular entities [17], and phase diagrams constructed for these types of materials are usually referred to as pseudo-phase diagrams [18].…”

Section: Introductionmentioning

confidence: 99%

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Phase Behavior of Binary Blends of Four Different Waxes

Jana

Martini

2016

The objective of this study was to investigate the phase behavior of binary blends of four waxes-beeswax (BW), paraffin wax (PW), sunflower wax (SFW), and rice bran wax (RBW)-using differential scanning calorimetry (DSC) and polarized light microscopy (PLM). Blends of BW/PW, RBW/PW, SFW/PW, SFW/RBW, SFW/BW, and RBW/BW were crystallized in a DSC, and their melting behavior was used to build binary phase diagrams. The microstructure of the crystalline networks formed in these blends was analyzed using PLM. BW/PW, SFW/PW, SFW/ BW, and RBW/BW blends showed eutectic phase behavior, while RBW/SFW showed continuous solid solution and the RBW/PW blend showed monotectic behavior. Results from the box-counting fractal dimension (D b ) measurement of crystal morphology showed higher D b values for the 20 and 80 % wax blends, irrespective of crystallization temperature or wax type. D b values of single waxes decrease as temperature increases.

“…They showed that the number of individual polymorphic forms, molecular structures, melting and crystallization properties and other important polymorphic properties drastically differed from one TAG to others, when the fatty acid moiety at the at the sn-3 position varied. Recently, Craven and Lencki extensively studied mixtures of chiral mixed-acid DAG and TAG, in which varying fatty acid moieties (saturated fatty acids differing in carbon number, and unsaturated fatty acid) are asymmetrically connected to the glycerol [18][19][20][21][22]. They showed that critical differences in the occurrence of the stable polymorphic forms and crystallization behavior were observed between the optical isomers and racemic mixtures.…”

Section: Introductionmentioning

confidence: 99%

Structures and Binary Mixing Characteristics of Enantiomers of 1‐Oleoyl‐2,3‐dipalmitoyl‐sn‐glycerol (S‐OPP) and 1,2‐Dipalmitoyl‐3‐oleoyl‐sn‐glycerol (R‐PPO)

Mizobe¹,

Tanaka

Hatakeyama³

et al. 2013

We performed differential scanning calorimetry (DSC) and synchrotron radiation X‐ray diffraction (SR‐XRD) experiments of polymorphic structures and binary mixing characteristics of the enantiomers of 1‐oleoyl‐2,3‐dipalmitoyl‐sn‐glycerol (S‐OPP) and 1,2‐dipalmitoyl‐3‐oleoyl‐sn‐glycerol (R‐PPO). In the two enantiomers, oleic and palmitic acid moieties are asymmetrically connected at the sn‐1 and sn‐3 positions of the glycerol groups, with palmitic acid moiety at the sn‐2 position. Pure enantiomer samples (>99 %) were synthesized and employed throughout this study. The following results were obtained. (1) A basic feature of the mixture systems of S‐OPP and R‐PPO is of a eutectic nature due to different polymorphic structures of two enantiomers and the racemic compound of PPO (rac‐PPO). (2) Polymorphic behavior of S‐OPP and R‐PPO was quite similar, both having α‐2 and β′‐3, whereas rac‐PPO contained α rac‐3, β′rac‐2, and β′rac‐3. The DSC measurements showed that the melting points of β′‐3 (S‐OPP = 35.3 °C and R‐PPO = 34.9 °C) were higher than that of β′rac‐3 (31.0 °C). β was not crystallized in the pure enantiomers, and rac‐PPO. (3) αrac‐3 was crystallized at low cooling rates (~2 °C/min), whereas α‐2 of the two enantiomers was crystallized only with very rapid cooling (~10 °C/min). (4) Triple‐chain‐length structures were formed in αrac‐3, β′S‐3 (=β′R‐3), and β′rac‐3; α‐2 with a double‐chain‐length structure was formed in both enantiomers. These results indicate the importance of the relationship between subcell packing and glycerol conformation in the polymorphism and mixing characteristics of asymmetric unsaturated–saturated‐saturated mixed‐acid triacylglycerols.