The solid fat content (SFC) at different temperatures is an important characteristic of fat phases because it correlates to functionality in product applications. Consequently, this characteristic is also used to specify fat compositions in trade. Of three methods applicable, pulsed nuclear magnetic resonance (pMNR) is predominantly applied. Dilatometry and differential scanning calorimetry (DSC) find much less application. Handling with glass vials and high equipment costs make the search for alternatives to pNMR a useful endeavor. Optical refractometry is evaluated with respect to its potential to determine SFC values. Since refractometry is in the first place not suited for suspensions the positive results found are surprising. Applying temperature modulated optical refractometry (TMOR), isothermal optical refractometry with a superimposed temperature undulation yields repeatable results that are highly comparable to pNMR data. For the system studied (palm oil, coconut oil, partially hydrogenated palm oil), TMOR clearly outperforms DSC when pNMR is considered the method of reference. The key finding that refractive index is suitable to determine properties of suspensions is accompanied by the indications that refractometry has the potential to enable competitive methods within the fat technology. Practical Applications: The observation that refractometry can deliver quantitative data on fat suspensions enables the development of an array of new analytical methods. Next to SFC values and melting point, studies on the characterization of polymorphism can be envisioned. Since the device is robust and affordable, it could be in product development and quality control.

The phase behavior of fats is mainly determined using DSC. Here, the application of temperature modulated optical refractometry (TMOR) is examined to monitor the phase transitions of palm oil with different degrees of saturation.Studying the phase behavior by both methods revealed systematic differences. At identical scan rates, TMOR yielded up to 2 °C higher crystallization temperatures and identified consistently lower temperatures for melting phenomena. Because the prism serves as heating surface and defines the sample volume considered for the measurement a more direct heat transfer with TMOR is assumed. The sample depth above the prism relevant for the determination is only one micron. Hence, a direct heat transfer is ensured and thermal lag is practically eliminated causing the above‐mentioned differences.Because the TMOR signal is averaged over a defined prism surface area data for inhomogeneous samples can be generated. Although actual values for thermal expansion coefficients appear meaningless the combination of the TMOR signals allows to accurately determine the relevant phase transitions. The identification of different polymorphic forms and levels of solids in palm oil will be studied prospectively building on the promising results reported to identify if TMOR can become a valuable extension of the fat technologists' toolbox.Practical Applications: The new temperature modulated optical refractometry can extend the mainly used differential scanning calorimetry. It works highly accurate at small scan rates (<5 °C min−1) in comparison to the DSC. The new method can provide a deeper insight into samples during heating and cooling due to additional temperature undulation as well as the possibility to perform quasi‐isothermal measurements.It is possible to investigate the crystallization and melting behavior of fats with the new temperature modulated optical refractometry (TMOR). An undulated temperature is applied and the time‐delayed answer of the refractive index is measured. Subsequently, the real and imaginary part of the thermal expansion coefficient α are calculated based on the refractive index of the sample and the occurring phase shift. A plot of the real and imaginary part against the temperature leads to peaks at the phase transition temperatures and a resulting thermogram for the sample.

Chapter 3 Molecular Interactions and Mixing Phase Behavior of Lipid Crystals Eckhard Floeter, Eckhard FloeterSearch for more papers by this authorMichaela Haeupler, Michaela HaeuplerSearch for more papers by this authorKiyotaka Sato, Kiyotaka SatoSearch for more papers by this author Eckhard Floeter, Eckhard FloeterSearch for more papers by this authorMichaela Haeupler, Michaela HaeuplerSearch for more papers by this authorKiyotaka Sato, Kiyotaka SatoSearch for more papers by this author Book Editor(s):Kiyotaka Sato, Kiyotaka Sato Hiroshima University, Higashi-Hiroshima, JapanSearch for more papers by this author First published: 26 January 2018 https://doi.org/10.1002/9781118593882.ch3Citations: 5 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary This chapter discusses the mixing behavior in solid phases and considers first the phase behavior of highly asymmetric systems. It also discusses the modeling of the solid and liquid phase states briefly to facilitate its application for the purpose of interpretation of observations. The chapter also discusses the phase behavior of the binary mixtures of principal fatty acids. It focuses on the mixing behavior of simple binary triacyglycerol (TAG) mixtures, illustrating that basically the systematic order found for the evolution of phase behavior in n-alkane and fatty-acid systems is also present in TAG systems. The chapter outlines the solid-liquid phase behavior of lipid aliphatic chain-based molecules and its underlying principles up to the relevance in industrial applications. Even though manufacturing processes often involve high cooling rates and significant shear rates, it should be noted that these crystallization conditions primarily apply for the creation of the first metastable solid phase. Citing Literature Crystallization of Lipids: Fundamentals and Applications in Food, Cosmetics, and Pharmaceuticals RelatedInformation

This study was conducted to examine if the new temperature modulated optical refractometry (TMOR) method is applicable to study the phase behavior of alkyl-based components. n-Hexadecane, palmitic acid, and glycerol tripalmitate were used as model components. TMOR was benchmarked against differential scanning calorimetry (DSC) and polarized light microscopy (PLM). For all substances, a good agreement of the DSC data with TMOR was found. For n-hexadecane, a difference of 2.2 °C for the crystallization and 2.6 °C for the melting temperature was found. Considering palmitic acid, the crystallization temperature differed by 3.3 °C while the melting varied by 2.8 °C. The crystallization temperature of tripalmitate identified by TMOR was 2.7 °C higher, and the melting temperature 2.3 °C was lower compared to the DSC. The crystallization temperature for TMOR was always higher, and the melting temperature was always lower if related to DSC. This leads to the conclusion that TMOR is more accurate and direct. In addition, the transition peaks identified by TMOR were narrower compared to the DSC peaks. This is due to slower heating and cooling rates leading to a smaller temperature range of phase transition and less thermal lag. The study showed that TMOR is an appropriate method to determine the phase transition temperatures for the three examined substances. The results were comparable to the DSC data in both melting and crystallization behavior. Since the accuracy of TMOR is better at lower heating and cooling rates, it could be a reasonable extension of the well-known DSC method in the studies of melting and crystallization.

Collagen can be modified by the addition of co-gelling proteins. The extrusion of these gels might lead to collagen films with new functionalities, e.g. microstructure and texture. An amount of 4% (w/w), 2.75% (w/w) telopeptide-poor or native collagen and 2.75% (w/w) of both collagen types containing 125% (w/w) soy protein isolate, blood plasma or gluten were extruded utilizing a laboratory nozzle extruder system to form films. Gels and films were analyzed using rheology, tensile tests and microscopy. Results indicated that co-gelling proteins are more prone to incorporation in highly crosslinked native collagen gels, as indicated by a maximal consistency index k* of 2.00 10(-3) Pa s(-n)*, rather than cluster-like telopeptide-poor collagen gels, as indicated by a maximal consistency index value of 0.50 10(-3) Pa s(-n)*. However, the film forming ability of collagen could not be matched by any other protein, as shown by decreased complex viscosities when co-gelling proteins were added. The addition of gluten to telopeptide-poor collagen impaired the film strength due to phase separation leading to lumps. Both collagen types featured comparable tensile strengths, ranging from 0.42 to 1.70 kPa, suggesting that the ionic bonds caused by precipitation determine the film strength, rather than initial covalent crosslinks. The 4% (w/w) pure collagen gels of either type yielded the thinnest films, however, with the highest tensile strength and complex viscosity. Results thus suggest that addition of co-gelling proteins presents a suitable approach to modify the gel strength in order to create collagen films with altered elasticity or tensile strength, leading to sausages with modified sensory attributes, e.g. bite or snap. (C) 2015 Elsevier Ltd. All rights reserved.

Collagen gels were modified by addition of co-gelling proteins to obtain gels with new functionalities. Microstructure and rheology of these mixed telopeptide-poor collagen gels were assessed. It was assumed that proteins with a low molecular weight strengthen the collagen structure by embedding themselves in the matrix, while high molecular weight proteins weaken the structure by interfering with the assembly of the network.Different combinations of collagen (2.8-5.19% (w/w)) and co-gelling protein concentrations (0.36-2.14% (w/w)) were applied. Blood plasma protein, soy protein isolate, whey protein isolate, and gluten were used as co-gelling proteins. The storage modulus was measured as an indicator of the gel strength. Frequency sweeps (0.1-10 Hz) at 1% strain were conducted in the linear viscoelastic region. The position of the co-gelling proteins in the collagen matrix was examined via both confocal laser scanning and scanning electron microscopy.The results showed weakening effects for whey protein isolate. The addition of blood plasma protein did not affect the rheology, but the microstructure was influenced, featuring more fibrillar structures in the pores compared to the reference gels. Gluten seemed to lead to phase separation, forming a separate layer without interacting with the collagen matrix. The greatest impact was found for soy protein isolate, with a strengthening effect indicated by increased storage moduli and well distributed and embedded soy protein isolate in the collagen network.In conclusion, co-gelling proteins display a suitable approach to modify collagen strength in order to create matrices with new functionalities, such as co-extruded sausage casings with modified knack or snap. (C) 2015 Elsevier Ltd. All rights reserved.

Differences between tempered and untempered cocoa butter were investigated by an ultrasonic signal “chirp” generated by contact transducers. Polarized light microscopy and powder X-ray diffraction were used to characterize the morphology and polymorphism of tempered and untempered cocoa butter, whereas pulsed nuclear magnetic resonance was used to determine the amount of crystalline solids present. Ultrasonic wave velocity and attenuation data were collected simultaneously throughout the 5-h crystallization process for cocoa butter. Ultrasonic velocity and attenuation changed at the different solid fat contents (SFC): 4, 8, and 11 %. Untempered cocoa butter showed an attenuation of 3 dB/cm at 1.7 MHz and 4 % SFC, whereas tempered cocoa butter showed an attenuation of 4.5 dB/cm at 1.7 MHz and 4 % SFC. At 3 MHz, the attenuation was 2 dB/cm for untempered and 6 dB/cm for tempered cocoa butter. Under these conditions (4 % SFC, 3 MHz), the chirp wave of tempered sample showed a phase angle change of 0.5 rad, whereas the untempered sample showed −0.5 rad relative to the canola oil that was taken as 0. The study suggests that an ultrasonic chirp can be effectively used to detect differences between tempered and untempered cocoa butter when measuring attenuation and ultrasonic wave phase angle changes as a function of frequency. The in-line characterization of chocolate “temper” using such nondestructive ultrasonic measurements could be applied to industrial chocolate manufacturing.