Structure of the low-melting phase of petroselinic acid

Kaneko, F.; Kobayashi, Masanori; Kitagawa, Y.; Matsuura, Yoshiki; Sato, K.; Suzuki, Mamoru

doi:10.1107/s0108270191012921

Cited by 21 publications

(26 citation statements)

References 4 publications

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“…Furthermore, there is no reversible orderdisorder-type phase transition in petroselinic acid. In the previous paper, we showed that the LM phase forms a characteristic crystal structure considerably different from the crystal structures of other previously determined cis-unsaturated fatty acids (Kaneko, Kobayashi, Kitagawa, Matsuura, Sato & Suzuki, 1992). Two bimolecular layers form a double-layered polytype structure (Orth II), in which the crystallographic repeating unit along the stacking direction of the layers is twice the thickness of one layer (Kobayashi, Kobayashi, Itoh & Sato, 1984), and the polymethylene chains at both sides of the cis-olefin groups are packed in the orthorhombic subcell with perpendicular skeletal (O_t_) planes (Abrahamsson, Dahlrn, Lrfgren & Pascher, 1978).…”

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confidence: 58%

“…Both characteristics have not been reported previously in cis-unsaturated lipid-related compounds. A preliminary study using vibrational spectroscopic and X-ray diffraction methods on the HM phase (Kaneko, 1989) suggested that this phase also has a unique crystal structure with the asymmetric unit containing two independent molecules. An understanding of the detailed structure of the HM phase is of fundamental importance for studies of polymorphism in cis-unsaturated fats and lipids.…”

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confidence: 99%

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Structure of the high-melting phase of petroselinic acid

Kaneko¹,

Kobayashi²,

Kitagawa³

et al. 1992

Acta Crystallogr C

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confidence: 58%

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confidence: 99%

Structure of the high-melting phase of petroselinic acid

Kaneko¹,

Kobayashi²,

Kitagawa³

et al. 1992

Acta Crystallogr C

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“…It is quite interesting to elucidate precise subcell packing and conformation, configuration of olefinic group, glycerol structures, and methyl end packing. With regard to the con- figuration of the olefinic group, it is notable to remember that the diversity of molecular structures of cis-unsaturated fatty acids has been revealed in oleic acid (25), erucic acid (26), and petroselinic acid (27). The diversity may be seen in the subcell structures of saturated-oleoyl mixed-acid TAG in pure systems and their mixtures systems.…”

Section: Resultsmentioning

confidence: 95%

Thermal and structural properties of sn‐1,3‐dipalmitoyl‐2‐oleoylglycerol and sn‐1,3‐dioleoyl‐2‐palmitoylglycerol binary mixtures examined with synchrotron radiation X‐ray diffraction

Minato

Ueno

Yano

et al. 1997

J Americ Oil Chem Soc

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Thermodynamic and polymorphic behavior of POP (sn-1,3-dipalmitoyl-2-oleoylglycerol) and OPO (sn-1,3-dioleoyl-2-palmitoylglycerol) binary mixtures was examined using differential scanning calorimetry and conventional and synchrotron radiation X-ray diffraction. A molecular compound, β C , was formed at the 1:1 (w/w) concentration ratio of POP and OPO, giving rise to two monotectic phases of POP/compound and compound/OPO in juxtaposition. β C has a long-spacing value of 4.2 nm with a double chainlength structure and the melting point of 31.9°C. A structural model of the POP-OPO compound is proposed, involving the separation of palmitoyl and oleoyl chain leaflets in the double chainlength structure. In the polymorphic occurrence of the POP-OPO mixtures, the POP fraction transformed from α to β′ with no passage through γ, then transformed to β. The presence of OPO in POP promoted the β′-β transformation of POP during the melt-mediated crystallization. JAOCS 74, 1213-1220 (1997).KEY WORDS: Binary mixture, differential scanning calorimetry, phase behavior, polymorphism, synchrotron radiation X-ray diffraction, triacylglycerol.Triacylglycerols (TAG) are employed in oils, margarine, cream, chocolate, and other edible fats products, and the fat structures are the major factors to determine their physical properties, such as texture, plasticity, morphology, and so on (1-4). Polymorphism is of the highest importance in the physical properties of TAG. Polymorphism of TAG has been elucidated at a molecular level for pure systems (5-7). In the practical systems, however, the fats are present in multicomponent states consisting of different types of TAG species. The first step in approaching the multicomponent systems is to study the binary systems of major TAG components, which reveal the nature of molecular interactions between the component materials at macroscopic and microscopic dimensions.Various types of phase diagrams of the binary mixtures of TAG were reviewed by Small (8), Knoester et al. (9), Timms (10), and Rossell (11). As a typical mixture system, tristearin-tripalmitin (SSS-PPP) mixtures have been studied by many researchers (11-13), where metastable α and β′ forms exhibited continuous solid solutions, yet eutectic nature was revealed in the most stable β form. The formation of the molecular compound was suggested in the mixture of sn-1,3-dipalmitoyl-2-oleoylglycerol and sn-1,3-dioleoyl-2-palmitoylglycerol (POP-OPO) (P, palmitoyl; O, oleoyl) by Moran (14) who indicated two binary systems, in juxtaposition, of POP/compound and compound/OPO. In this mixture, the compound was estimated to form at an equal concentration ratio. Most recently, Engstrom (15), Koyano et al. (16), and Minato et al. (17) reported precise analyses of the mixture systems of sn-1,3-distearoyl-2-oleoylglycerol and 1,2-distearoyl-3-oleoylglycerol (SOS/SSO) (S, stearoyl), sn-1,3-distearoyl-2-oleoylglycerol and sn-1,3-dioleoyl-2-stearoylglycerol (SOS/OSO), and sn-1,3-dipalmitoyl-2-oleoylglycerol and 1,2-dipalmitoyl-3-oleoylglycerol (POP/PPO), r...

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“…Polytypism has been found in some long-chain compounds such as n-alkanes [4][5][6][7][8], nalcohols [9,10], n-fatty acids [11][12][13], and cismonounsaturated fatty acids [14]. The researches on the polytypism in fatty acids have revealed that polytypism significantly affects the thermodynamic 11.242 and mechanical properties [8,[15][16][17], and solid-solid phase transition mechanisms [18,19].…”

Section: Introductionmentioning

confidence: 99%