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Gregersen S.B.,University of Aarhus | Andersen M.D.,AarhusKarlsHamn Denmark A S | Hammershoj M.,University of Aarhus | Wiking L.,University of Aarhus
Food Chemistry | Year: 2017

This study demonstrates a strong interaction between triacylglycerol (TAG) composition and effects of shear rate on the microstructure and texture of fats. Cocoa butter alternatives with similar saturated fat content, but different major TAGs (PPO-, PSO-, SSO-, POP- and SOS-rich blends) were evaluated. Results show how shear can create a harder texture in fat blends based on symmetric monounsaturated TAGs (up to ∼200%), primarily due to reduction in crystal size, whereas shear has little effect on hardness of asymmetric monounsaturated TAGs. Such differences could not be ascribed to differences in the degree of supercooling, but was found to be a consequence of differences in the crystallisation behaviour of different TAGs. The fractal dimension was evaluated by dimensional detrended fluctuation analysis and Fourier transformation of microscopy images. However, the concept of fractal patterns was found to be insufficient to describe microstructural changes of fat blends with high solid fat content. © 2016 Elsevier Ltd


Gregersen S.B.,University of Aarhus | Miller R.L.,AarhusKarlshamn Denmark A S | Andersen M.D.,AarhusKarlshamn Denmark A S | Hammershoj M.,University of Aarhus | Wiking L.,University of Aarhus
European Journal of Lipid Science and Technology | Year: 2015

In this study, the degree of inhomogeneity in crystallized fat samples was evaluated in terms of texture, solid fat content, microstructure, and triacylglycerol (TAG) composition. Four different cocoa butter alternatives based on symmetric or asymmetric monounsaturated TAGs and with different contents of palmitic acid (a POP-rich fat and a PPO-rich fat) and steric acid (a SOS-rich fat and a PSO-rich fat) were studied. Significant differences (P<0.001) in hardness between top and bottom was observed for all fats except the PSO-rich fat. The inhomogeneous consistency was shown to be a consequence of microstructural variation within the crystallized fats. No differences in solid to liquid ratio, melting points, or polymorphic behavior between top and bottom of fats were found. Sedimentation during the crystallization process could explain the observed inhomogeneity. Although sedimentation most likely is limited to the early stages of the crystallization process due to network formation, sedimented crystals influence the crystallization kinetics and thus introduce microstructural variations. This hypothesis is supported by findings of a higher amount of trisaturated TAGs in the bottom compared with the top of crystallized fats. The PSO-rich fat crystallizes fast compared with the other evaluated fats, which explains the more homogeneous texture of the PSO-rich fat compared with the other evaluated fats. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gregersen S.B.,University of Aarhus | Povey M.J.W.,University of Leeds | Kidmose U.,University of Aarhus | Andersen M.D.,AarhusKarlshamn Denmark A S | And 2 more authors.
Food Research International | Year: 2015

In this study, the correlation between sensory attributes and the mechanical and acoustic properties of cocoa butter alternatives was elucidated. Needle penetration, cone penetration and compression tests were used to characterise mechanical properties and acoustic properties were evaluated by simultaneous texture and sound analyses. Results were correlated with a descriptive sensory evaluation. A significant correlation was found between hardness (needle penetration) and sensory hardness evaluated upon biting (r = 0.91, p <. 0.05) and between Hencky strain (compression test) and the sensory toughness (r = 0.94, p <. 0.05). In contrast, no significant correlation was found between brittleness (cone penetration) and the sensory brittleness. The use of different mechanical methods shed light on a complex rheological behaviour of fat which demonstrates the importance of not simply relying on results from penetration tests when evaluating fat texture. For instance, a hard fat was perceived very differently depending on the degree of elasticity. A significant correlation was found between sound pressure level (simultaneous sound and texture analyses) and the sensory evaluation of the sound intensity upon breakage (r = 0.96 and 0.97, p <. 0.05). Both hardness and elasticity were found to be of great importance for the intensity of the sound emission i.e. a hard texture with a low degree of flexibility (less elastic) is more likely to provide a rapid energy release upon breakage and thus a high intensity sound emission. © 2015 Elsevier Ltd.


Gregersen S.B.,University of Aarhus | Miller R.L.,AarhusKarlsHamn Denmark A S | Hammershoj M.,University of Aarhus | Andersen M.D.,AarhusKarlsHamn Denmark A S | Wiking L.,University of Aarhus
Food Structure | Year: 2015

In this study, the effect of cooling rate on cocoa butter replacers with similar content of saturated fat but different types of saturated fatty acids was evaluated. Two fats with a high content of monounsaturated asymmetric triacylglycerol were studied (62.1% and 70.9%, respectively); one with a high content of palmitic acid (P-rich) and one with a high content of stearic acid (S-rich). Different cooling rates (0.1, 0.5 and 2. °C/min) were applied during crystallization and samples were stored at different times (0. h, 1 day and 7 days) prior to analysis by pNMR, texture analysis, oscillatory rheometry and microscopy. For the S-rich fat, cooling rate influenced brittleness to a higher extent compared with storage modulus and hardness whereas for the P-rich fat cooling rate influenced hardness and storage modulus to a higher extent compared with brittleness. For the S-rich fat, an increase in brittleness around 75% and an increase in storage modulus around 25% were observed for faster cooling whereas no significant effect of cooling rate on hardness was observed after 1 week of storage. An increase in hardness and storage modulus around 30% and 50%, respective, and no significant increase in brittleness was observed for faster cooling of the P-rich fat.The different behaviour depended on the relative inter- and intraparticle links in the fat crystal network. For the S-rich fat, faster cooling provided stronger interparticle links, most likely as a result of formation of solid bridges, which lead to a more brittle texture. For the P-rich fat, faster cooling provided stronger intraparticle links and an increase in the sum of weak interparticle links resulting in a harder but not brittle texture. The results contribute to clarify the mechanisms behind effects of cooling rate on different textural characteristics of fat and show the importance of understanding effects on the relative strength of inter- and intraparticle links in the fat crystal network to be able to tailor the textural properties of fats. © 2015 Elsevier Ltd.


Hrastar R.,Slovenian Institute of Hop Research and Brewing | Hrastar R.,University of Aarhus | Cheong L.-Z.,University of Aarhus | Xu X.,University of Aarhus | And 4 more authors.
European Journal of Lipid Science and Technology | Year: 2011

Camelina sativa oil (CO) is characterized by a high content (up to 40 wt %) of essential α-linolenic acid and characteristic odour and flavour. Deodorization of highly unsaturated oils requires great attention as the refining process involves thermal treatment which affects oil integrity. In the present study RSM and principal component analysis (PCA) were used to optimize bench-scale deodorization of CO. Mathematical models were generated through multiple regressions with backward elimination, describing the effects of process parameters (temperature, steam flow, time) on oil quality indicators [peroxide value (PV), p-anisidine value (p-AV), γ-tocopherol (γ-T) and oxidative stability (OS)]. Additionally, sensory evaluation was performed. RSM analysis showed a significant effect of deodorization temperature and to a lesser extent, deodorization steam flow and time on removal of oxidative compounds, flavour and odour. PCA of chemical and sensory results showed that deodorization temperature affected the sensory properties in the samples. The best conditions for removing undesirable flavour and odour were achieved by using a deodorization temperature of 195-210°C. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Hrastar R.,Slovenian Institute of Hop Research and Brewing | Hrastar R.,University of Aarhus | Cheong L.-Z.,University of Aarhus | Xu X.,University of Aarhus | And 2 more authors.
JAOCS, Journal of the American Oil Chemists' Society | Year: 2011

Camelina sativa oil is characterized by its high content (up to 40 wt%) of α-linolenic acid and its unique flavor. It is considered to have beneficial health properties and is suitable for food and cosmetic uses. In the present study, response surface methodology was used to optimize processing parameters for bench-scale deodorization of camelina oil. The mathematical models generated described the effects of process parameters (temperature, steam flow, time) on several deodorization quality indicators: free fatty acids (FFA), trans fatty acids (TFA), color, and polymerized triglycerides (PTG). These newly established models can be used as a tool to identify optimum deodorization process conditions within chosen constraints. Based on the optimization of minimum retained FFA with the constraint of a maximum allowable TFA, deodorization parameters can be defined. At a constant steam flow rate of 42 ml/h, a temperature range of 210-220 °C, and deodorization time of 70-120 min were defined. 220 °C appears to be a critical upper temperature limit; above this temperature, isomerization rates significantly increase. © 2010 AOCS.


PubMed | University of Aarhus and AarhusKarlsHamn Denmark A S
Type: | Journal: Food chemistry | Year: 2016

This study demonstrates a strong interaction between triacylglycerol (TAG) composition and effects of shear rate on the microstructure and texture of fats. Cocoa butter alternatives with similar saturated fat content, but different major TAGs (PPO-, PSO-, SSO-, POP- and SOS-rich blends) were evaluated. Results show how shear can create a harder texture in fat blends based on symmetric monounsaturated TAGs (up to 200%), primarily due to reduction in crystal size, whereas shear has little effect on hardness of asymmetric monounsaturated TAGs. Such differences could not be ascribed to differences in the degree of supercooling, but was found to be a consequence of differences in the crystallisation behaviour of different TAGs. The fractal dimension was evaluated by dimensional detrended fluctuation analysis and Fourier transformation of microscopy images. However, the concept of fractal patterns was found to be insufficient to describe microstructural changes of fat blends with high solid fat content.


Trademark
Aarhuskarlshamn Denmark A S | Date: 2012-07-03

Edible vegetable fat which is whippable and only used for further processing in the foodstuff industry.


Patent
Aarhuskarlshamn Denmark A S | Date: 2011-04-14

The invention relates to a bloom retarding fat composition comprising a component A and a component B; said component A being present in an amount of 40-95% (w/w) of said bloom retarding fat composition, and said component B being present in an amount of 5-60% (w/w) of said bloom retarding fat composition; wherein said component A comprising a fat composition having a content of SatOSat TAGs of 60% (w/w) or higher; and wherein said component B comprising a fat composition having a content of saturated fatty acids of 30% (w/w) or less, and a total content of Sat2U TAGs of 18% (w/w) or less, and a content Sat3 TAGs of 8% (w/w) or less; with the proviso that if the content of SatSatU TAGs in component B is 1% (w/w) or more, then the molar ratio of SatSatU: SatUSat TAGs is 1 or higher; and wherein Sat is a CI 6-20 saturated fatty acid, and wherein O stands for oleic acids; U stands for unsaturated fatty acids, including oleic acid. Furthermore, the invention relates to various applications of such a bloom retarding fat composition.

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