ABSTRACT Crystallization in fats is of fundamental importance in the production and consumption o... more ABSTRACT Crystallization in fats is of fundamental importance in the production and consumption of fats per se and of food and home and personal care (HPC) products in which fats form a major part. While crystallization of fats as such has been extensively reviewed over the past decade there has been less emphasis on the role of minor components. A review by Smith et al. [1] redressed this; this article is based on that review.
ABSTRACT Shea stearin is widely used in cocoa butter equivalents to provide enhanced solidity and... more ABSTRACT Shea stearin is widely used in cocoa butter equivalents to provide enhanced solidity and crystallization characteristics to chocolate. Although it is predominantly composed of triacylglycerols, a small amount of diacylglycerols is also naturally present in the fat. This can affect its crystallization. To determine the extent of these effects shea stearin and shea stearin that has been treated with silica to remove diacylglycerol have been compared.
Journal of the American Oil Chemists' Society, 2011
... Although not entirely correct, the words ''lecithin&amp... more ... Although not entirely correct, the words ''lecithin'' and ''phospholipid'' are often used interchangeably. In reality, lecithin is a mixture of phospholipids, such as phosphatidylinositol (PI), lyso-phosphatidylcholine (LPC) and phosphatidylcholine (PC). J Am Oil Chem Soc 123 ...
European Journal of Lipid Science and Technology, 2012
ABSTRACT TAGs play an important role in determining the functional properties of fat-based food p... more ABSTRACT TAGs play an important role in determining the functional properties of fat-based food products such as margarines, chocolate, and spreads. Nowadays, special attention is given to the role of the TAG structure and how it affects functional properties such as mouth feel, texture, and plasticity. Key to this research is the need to develop more healthy fats with a reduced level of trans and saturated fatty acids (SFAs), while maintaining the desired properties. In this study, fat blends with identical levels of SFA (50%) but differing in the ratio asymmetric/symmetric blends were evaluated by pulsed NMR and texturometry as a function of storage time and storage temperature. A higher trisaturated TAG content gave rise to a higher solid fat content (SFC) at higher temperature and a lower SFC at lower temperature for both palmitic and stearic based blends. On the other hand, the effect of symmetry on the SFC-profile of the blends was only clear for the stearic based blends. At lower temperatures, the SFC of symmetric TAG based blend (blend SM) was markedly lower than that of asymmetric TAG based blend (blend iS). However, from 30°C onwards, the SFC of blend SM was clearly higher than that of blend iS. The microscopic analyses revealed a denser crystal network for a higher degree of trisaturated TAG and for symmetric stearic based blends. Moreover, some blends showed a clear evolution of the microstructure during storage with smaller crystals transforming into larger ones. Finally, texture analyses demonstrated the importance of the crystallization and storage temperature on the hardness of the blends.
European Journal of Lipid Science and Technology, 2013
ABSTRACT The crystallization of shea stearin was investigated both before and after pre-treatment... more ABSTRACT The crystallization of shea stearin was investigated both before and after pre-treatment with silica to remove a small amount (0.7 wt%) of diacylglycerols (DAGs) and oxidized material. NMR (for solid fat content), X-ray diffraction (XRD), polarized light microscopy, confocal Raman microscopy, and non-isothermal, isothermal and “stop-and-return” differential scanning calorimetry (DSC) techniques were used. Four major polymorphs previously found with 1,3-distearoyl-2-oleoyl-sn-glycerol (StOSt) were detected: α, γ, β′, and β; whilst evidence for a further (δ) polymorph was found by DSC and possibly XRD but not Raman spectroscopy. Isothermal crystallization of shea stearins by DSC at 20°C produced α and δ forms within 5 min which then transformed to γ. Microscope images showed that after 1 day these had transformed into β′ with a few crystals of β, with further conversion to β after one week. Silica treated samples showed a faster initial crystallization, with faster transformation or direct crystallization into δ and then γ and β′ forms. Non-isothermal DSC also showed a faster transformation into γ from α on the subsequent remelt. However, further transformation into β appeared to occur at reasonably similar rates for both types, suggesting that DAGs have less influence on this transformation and may be excluded from higher forms.Practical applications: This paper has two main practical applications: (i) Provides knowledge and understanding of the crystallization and polymorphic behavior of commercial shea stearin, which is a widely used fat in the confectionery, cosmetic, and pharmaceutical industries. (ii) The presence of small amounts of DAGs significantly delays the crystallization process of shea stearin, particularly of the lower polymorphs.
ABSTRACT Crystallization in fats is of fundamental importance in the production and consumption o... more ABSTRACT Crystallization in fats is of fundamental importance in the production and consumption of fats per se and of food and home and personal care (HPC) products in which fats form a major part. While crystallization of fats as such has been extensively reviewed over the past decade there has been less emphasis on the role of minor components. A review by Smith et al. [1] redressed this; this article is based on that review.
ABSTRACT Shea stearin is widely used in cocoa butter equivalents to provide enhanced solidity and... more ABSTRACT Shea stearin is widely used in cocoa butter equivalents to provide enhanced solidity and crystallization characteristics to chocolate. Although it is predominantly composed of triacylglycerols, a small amount of diacylglycerols is also naturally present in the fat. This can affect its crystallization. To determine the extent of these effects shea stearin and shea stearin that has been treated with silica to remove diacylglycerol have been compared.
Journal of the American Oil Chemists' Society, 2011
... Although not entirely correct, the words ''lecithin&amp... more ... Although not entirely correct, the words ''lecithin'' and ''phospholipid'' are often used interchangeably. In reality, lecithin is a mixture of phospholipids, such as phosphatidylinositol (PI), lyso-phosphatidylcholine (LPC) and phosphatidylcholine (PC). J Am Oil Chem Soc 123 ...
European Journal of Lipid Science and Technology, 2012
ABSTRACT TAGs play an important role in determining the functional properties of fat-based food p... more ABSTRACT TAGs play an important role in determining the functional properties of fat-based food products such as margarines, chocolate, and spreads. Nowadays, special attention is given to the role of the TAG structure and how it affects functional properties such as mouth feel, texture, and plasticity. Key to this research is the need to develop more healthy fats with a reduced level of trans and saturated fatty acids (SFAs), while maintaining the desired properties. In this study, fat blends with identical levels of SFA (50%) but differing in the ratio asymmetric/symmetric blends were evaluated by pulsed NMR and texturometry as a function of storage time and storage temperature. A higher trisaturated TAG content gave rise to a higher solid fat content (SFC) at higher temperature and a lower SFC at lower temperature for both palmitic and stearic based blends. On the other hand, the effect of symmetry on the SFC-profile of the blends was only clear for the stearic based blends. At lower temperatures, the SFC of symmetric TAG based blend (blend SM) was markedly lower than that of asymmetric TAG based blend (blend iS). However, from 30°C onwards, the SFC of blend SM was clearly higher than that of blend iS. The microscopic analyses revealed a denser crystal network for a higher degree of trisaturated TAG and for symmetric stearic based blends. Moreover, some blends showed a clear evolution of the microstructure during storage with smaller crystals transforming into larger ones. Finally, texture analyses demonstrated the importance of the crystallization and storage temperature on the hardness of the blends.
European Journal of Lipid Science and Technology, 2013
ABSTRACT The crystallization of shea stearin was investigated both before and after pre-treatment... more ABSTRACT The crystallization of shea stearin was investigated both before and after pre-treatment with silica to remove a small amount (0.7 wt%) of diacylglycerols (DAGs) and oxidized material. NMR (for solid fat content), X-ray diffraction (XRD), polarized light microscopy, confocal Raman microscopy, and non-isothermal, isothermal and “stop-and-return” differential scanning calorimetry (DSC) techniques were used. Four major polymorphs previously found with 1,3-distearoyl-2-oleoyl-sn-glycerol (StOSt) were detected: α, γ, β′, and β; whilst evidence for a further (δ) polymorph was found by DSC and possibly XRD but not Raman spectroscopy. Isothermal crystallization of shea stearins by DSC at 20°C produced α and δ forms within 5 min which then transformed to γ. Microscope images showed that after 1 day these had transformed into β′ with a few crystals of β, with further conversion to β after one week. Silica treated samples showed a faster initial crystallization, with faster transformation or direct crystallization into δ and then γ and β′ forms. Non-isothermal DSC also showed a faster transformation into γ from α on the subsequent remelt. However, further transformation into β appeared to occur at reasonably similar rates for both types, suggesting that DAGs have less influence on this transformation and may be excluded from higher forms.Practical applications: This paper has two main practical applications: (i) Provides knowledge and understanding of the crystallization and polymorphic behavior of commercial shea stearin, which is a widely used fat in the confectionery, cosmetic, and pharmaceutical industries. (ii) The presence of small amounts of DAGs significantly delays the crystallization process of shea stearin, particularly of the lower polymorphs.
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Papers by Kevin Smith