Short spacings and polymorphic forms of natural and commercial solid fats: A review

Abstract

Short spacings refer to the cross sectional packing of the hydrocarbon chains. They are independent of chain length. Short spacings are widely used for characterizing the various polymorphic forms. Fats can crystallize into four polymorphic forms, i.e., sub-a, a, fl" and 8. These polymorphic forms differ in their chain packing and thermal stability. The fl' form is also known to exhibit several intermediate polymorphic forms. The nomenclature for the polymorphic forms has generated a great deal of confusion over the years. Several researchers have reported on the polymorphic forms of pure triglycerides. Similar polymorphs have sometimes been described by different names. Currently, the nomenclature proposed by Larsson [Larsson, K., Acta Chem. Scand. 20:2256 (1966)] is being widely used. Much of the earlier work on polymorphism has been obtained by studying simple purified substances. The listing of short spacings for natural and commercial fats presented in this paper will be beneficial to researchers working in this field.

Blending of mango kernel fat and palm oil mid-fraction to obtain cocoa butter equivalent

“…The two peaks showed the strongest scattering intensity, implying that β′ was the predominant polymorph for MKF solidified under these conditions. The diffraction peak at 4.38 Å was close to that of pseudo-β′ form as reported by Gibon et al (1986) whilst the one at 3.60 Å could be associated with the sub-β structure (D'Souza et al 1990). The 4.55 Å peak was a typical main diffraction peak in WAXS of the β structure of fats (Larsson 1966).…”

“…Unlike MKF, when CBE started to crystallize at~10 min of the crystallization time, only one diffraction peak appeared in WAXS at 4.19 Å. Although this signal could be linked to either α or β′ structures of fats (D'Souza et al 1990), the fact that no any other signature peaks of β′ appeared during the first 30 min implies that the fat crystallized into α form first. After 30 min, more diffraction peaks began to emerge at 3.60 Å (sub-β′), 3.88 Å (β′), 4.38 Å (Pseudo-β′) and 4.55 Å (β′).…”

Lauric Fat Cocoa Butter Replacer from Krabok (<i>Irvingia Malayana</i>) Seed Fat and Coconut Oil

“…The 4.04 Å peak was close to peak range of β 3.70-4.00 Å reported by Ghotra et al 20 . The peak at 4.41 Å matched one of the diffraction peaks of pseudo-β structure reported by D Souza et al 19 and O Brien 21 . It can be seen here that, under the same crystallization conditions, the polymorphic behavior of R-LCBR was the same as C-LCBR.…”

“…Additionally, there was a small diffraction peak at 4.15 Å 2 which could be related to either α structure 18 or pseudo-β structure 19 . Similarly, the R-LCBR exhibited mainly β structure with two main diffraction peak at 3.84 Å 1 and 4.24 Å 3 17 .…”

Characterization of Coconut Oil Fractions Obtained from Solvent Fractionation Using Acetone

“…No further changes in WAXD and SAXD peak shape or spacing were observed during the experimental timeframe. The peaks at 3.82 and 4.17 Å were close to 3.80 Å and 4.2 Å which are typical diffraction WAXD β polymorph patterns 23 . The 4.29 Å peak was also related to β structure of lipid 24 .…”