Effect of the addition of hardfats on the physical properties of cocoa butter

Fully hydrogenated oils, also known as hardfats, are currently employed in a limited number of applications in the food and chemical industries. The use of these compounds has been proposed for the improvement or standardization of the physical properties of lipid systems, showing great potential for use in the production of chocolate, confectionery, and similar products. This work evaluated the addition of different hardfats on the physicochemical properties of cocoa butter (CB). Fully hydrogenated oils with significantly different chemical composition, obtained from palm kernel oil (FHPKO), palm oil (FHPO), cottonseed oil (FHCO), soybean oil (FHSO), and crambe oil (FHCrO), were evaluated for their fatty acid and triacylglycerol compositions. Blends of CB/hardfats, at concentrations of 1, 3, and 5% w/w were studied by determining the melting point, solid fat profiles, microstructure, and consistency. Hardfats FHPO, FHCO, FHSO e FHCrO proved to be effective additives to modulate the physical properties of CB. Major changes on the physical properties of CB were performed by the FHSO. FHPKO was found unsatisfactory as a modifier of the CB. Practical applications : The use of hardfats as crystallization additives in products containing CB is here recommended for technological adjustments of CB formulations in relation to attributes like heat resistance and hardness, often necessary when commercialized in regions of warm climates or with large variation in temperature. The hardfats may act as potential modulators of CB crystallization, aiming to obtain higher quality products and significant cost reduction of industrial processing.     

Impact of Limonene on the Physical Properties of Reduced Fat Chocolate

The addition of limonene, a low molecular weight hydrophobic compound, to chocolate was reported to decrease the hardness and the viscosity of chocolate, facilitating the production and improving the eating quality of reduced fat chocolate. The objective of this study is to understand the functionality of limonene in decreasing the viscosity and the hardness of chocolate, a fat (cocoa butter)-based particulate suspension. This study shows that chocolate hardness was decreased because limonene mixes with cocoa butter, affects its crystallization pattern and decreases its solid fat content. After checking that limonene does not significantly affect the continuous phase volume fraction, we show that limonene decreases chocolate viscosity by decreasing the viscosity of the continuous phase, cocoa butter. The addition of low quantities of limonene in cocoa butter leads to a great decrease in the liquid fat viscosity. The dependence of the viscosity on the ratio of cocoa butter to limonene analyzed using Kay’s equation seems to indicate that limonene mixes with and within the cocoa butter triglycerides, diluting the fat and leading to a decrease in the overall fat viscosity.     

Impacts of Bleaching and Packed Column Steam Refining on Cocoa Butter Properties

Natural and alkalized cocoa butters were bleached and subsequently steam refined in a continuous packed column at temperatures ranging between 160 and 220 °C. None of the processes evaluated gave rise to any detectable formation of trans fatty acids, interesterification or polymerization. For the pressures and steam injection rates used, packed-column steam refining required a minimum temperature of 170 °C to achieve acceptable taste. Bleaching was highly effective in preventing darkening at high steam-refining temperatures, as well as in removing alkaloids, such as theobromine and caffeine, before steam refining. The impacts on the crystallization properties of cocoa butter were studied using DSC and P-NMR. The more significant changes in crystallization kinetics and equilibrium values can be reliably predicted on the basis of FFA removal from the butter.     

Real-time X-ray powder diffraction investigations on cocoa butter. II. The relationship between melting behavior and composition of β-cocoa butter

The melting behavior of twelve different cocoa butter samples, in the β-phase, has been investigated with real-time X-ray powder diffraction. The melting trajectory of each sample is characterized by three temperature values: a starting point, a point of maximum melting, and a point of complete melting. These points are determined by an analysis of the subsequent X-ray diffraction patterns. A least-squares analysis has been developed which allows the observed melting points to be related to the composition of the cocoa butter. This analysis shows that the melting behavior of cocoa butter can be described as a function of certain binary combinations of its major components.     

Negative Pressure Induced Cavity Formation During Cocoa Butter Crystallization

Negative pressure effects appear to play an important role during crystallization of complex TAG mixtures such as cocoa butter. Crystallization conditions influence the final macroscopic sample density and the resulting gaseous phase void structure. Well-tempered cocoa butter had a relatively smooth surface, higher macroscopic density, and a closed-pore void structure. In contrast, over-tempered samples were rougher, less dense, and contained large continuous gas-filled pores. Under-tempered cocoa butter had properties between these two treatments, with a continuous, yet very fine pore structure. Since cocoa butter is the continuous phase in chocolate, negative pressure phenomena will likely have a significant influence on chocolate density and thus how it de-molds during processing.     

Real-time X-ray powder diffraction investigations on cocoa butter. I. temperature-dependent crystallization behavior

The crystallization behavior of cocoa butter has been investigated by means of real-time X-ray powder diffraction. Two procedures have been followed: cooling from 60°C at a constant rate until maximum solidification has taken place; and cooling from 60°C in 2 min to a constant solidification temperature. It appears that all polymorphic forms of cocoa butter, with the exception of the β form, can be formed from liquid. The solidification temperature appears to be the most important crystallization parameter.     

Influence of Brazilian Geographic Region and Organic Agriculture on the Composition and Crystallization Properties of Cocoa Butter

Cocoa butter (CB) is the most important ingredient in chocolate and represents the biggest share in the continuous phase of this product. The accurate composition of CB depends, among other factors, on the genetic characteristics of the cocoa tree, its agricultural handling and the farming region's climate. The influences of the cocoa‐producing region in Brazil and the agricultural cultivation method on the composition and crystallization properties of CB are presented in this article. Raw CB was extracted from fruits cultivated in six main Brazilian states using two agricultural methods, organic and conventional. The samples were evaluated according to fatty acids, triacylglycerol composition, solid fat content, consistency, melting behavior and isothermal crystallization. The wide range of cocoa‐producing regions in Brazil causes the distinct characteristics of the chemical composition and crystallization behavior of the CB, attributes that affect the quality of products using this raw material. Differences in consistency, hardness and crystallization parameters, among others, were observed. The results showed the great potential of using Brazilian CB with similar features to those of African and Asian origin, considered more appropriate for use in chocolates. However, no clear tendency concerning the agricultural method was found.     

Real-time X-ray powder diffraction investigations on cocoa butter. III. Direct β-crystallization of cocoa butter: Occurrence of a memory effect

Direct β-crystallization of different samples of cocoa butter has been investigated. The influence of the thermal history of cocoa butter on its phase behavior is defined as a memory effect. The chemical composition of cocoa butter has been related to the occurrence of the short-term β-memory effectvia statistical analysis of the results. We explain how this effect can be attributed mainly to stearic acid and its related triacylglycerols. The total phase behavior of cocoa butter is discussed on the basis of the results obtained from the series of three papers of which this is the last.     

Phase behavior and extended phase scheme of static cocoa butter investigated with real-time X-ray powder diffraction

A complete isothermal phase-transition scheme of cocoa butter under static conditions is presented, based on time-resolved X-ray powder diffraction experiments. In contrast to what is known from literature, not only β V, but also β VI can be obtained directly through transformation from β′. Another remarkable result is that β′ exists as a phase range rather than as two separate phases. Within this β′ phase range no isothermal phase transitions have been observed. More detailed information concerning the observed cocoa butter polymorphs was obtained by determination of melting ranges, using time-resolved X-ray powder diffraction. Also standard X-ray powder diffraction patterns of the γ, the α, and the two β phases and parts of the β′ phase range have been recorded. The observed phase behavior of cocoa butter has been explained based on the concept of individual crystallite phase behavior of cocoa butter     

Crystallization Kinetics of Cocoa Fat Systems: Experiments and Modeling

Isothermal crystallization kinetics of unseeded and seeded cocoa butter and milk chocolate is experimentally investigated under quiescent conditions at different temperatures in terms of the temporal increase in the solid fat content. The theoretical equations of Avrami based on one-, two- and three-dimensional crystal growth are tested with the experimental data. The equation for one-dimensional crystal growth represents well the kinetics of unseeded cocoa butter crystallization of form α and β′. This is also true for cocoa butter crystal seeded milk chocolate. The sterical hindrance due to high solids content in chocolate restricts crystallization to lineal growth. In contrast, the equation for two-dimensional crystal growth fits best the seeded cocoa butter crystallization kinetics. However, a transition from three- to one-dimensional growth kinetics seems to occur. Published data on crystallization of a single component involving spherulite crystals are represented well by Avrami’s three-dimensional theoretical equation. The theoretical equations enable the determination of the fundamental crystallization parameters such as the probability of nucleation and the number density of nuclei based on the measured crystal growth rate. This is not possible with Avrami’s approximate equation although it fits the experimental data well. The crystallization can be reasonably well defined for single component systems. However, there is no model which fits the multicomponent crystallization processes as observed in fat systems.     

Effect of oleo-disaturated triacylglycerol content on properties of palm mid fraction,sal stearin and borneo tallow blends

Binary blends of palm mid fraction (PMF) with Borneo tallow (IP) and PMF with sal stearin (SLs) showed eutectic behavior. To produce a cocoa butter extender with steep melting profiles and containing not less than 70% solid fat at 20°C, the maximum amount of PMF1 (IV=49.2) and PMF2 (IV=39.8) that could be added to IP in PMF:IP binary systems were about 10% and 33%; whereas the amount of PMF2 that could be added to SLsl (IV=33.4), SLs2 (IV=31.7) and SLs3 (IV=30.3) in PMF2:SLs binary systems were about 7%, 10% and 38%, respectively. Blends of any PMF with an iodine value of 37 or lower with IP could fulfill the above specifications at any blend ratio.     

Cocoa butter extenders from Kokum (Garcinia indica) and Phulwara (Madhuca butyracea) butter

Cocoa butter extenders, suitable for use in chocolate and confectionery, were prepared from Kokum fat and a Phulwara butter fraction. The latter fraction was prepared from Phulwara butter by two-stage dry fractionation and blended with Kokum fat in selected proportions to obtain a series of hard butters with different melting profiles. The blends with higher proportions of Kokum fat were harder and hence may find application in warm climates. The blends with higher proportions of Kokum fat were harder and hence may find application in warm climates. The blends had solidification properties, fatty acid and triacylglycerol compositions similar to those of cocoa butter. In addition, they had narrow melting ranges like cocoa butter, and they were compatible with cocoa butter and have tolerance toward milk fat.     

Effect of temperature on recrystallization behavior of cocoa butter

Crystallization of cocoa butter in the β phase directly from the melt is only possible by employing the memory effect of cocoa butter. Cocoa butter crystallized in the β phase, heated to the so-called maximal temperature (just above its melting end point), recrystallizes in the β phase after cooling to a crystallization temperature. The influence of the maximal and crystallization temperatures on the recrystallization behavior has been investigated for two cocoa butters. Rapid-starting recrystallization into the β(VI) phase and slow-starting recrystallization into the β(V) have been observed. It is concluded that rapid-starting recrystallization is induced by high-melting 1,3-distearoyl-2-oleoyl-glycerol (SOS)-rich crystals. The two β phases were identified by X-ray powder diffraction and melting ranges. However, the X-ray powder diffraction patterns for the β phases depended on the composition of the cocoa butter and on the crystallization method used. Therefore, it was not possible to take any particular β(VI) X-ray powder diffraction pattern as a standard for the β(VI) phase of all cocoa butters.     

Structure evolution and bloom formation in tempered cocoa butter during long‐term storage

Structural evolution in tempered cocoa butter (CB) and CB mixed with a cocoa butter equivalent (CBE) was examined during 26 wk of storage (at 25 °C) using atomic force microscopy, X‐ray powder diffraction, colorimetry and pulsed nuclear magnetic resonance. The form V‐to‐VI polymorphic transition in CB started after 1 week of storage. However, fat bloom was not detected until week 3 when large crystals started to appear on the CB surface. Changes in surface topography coincided with an increase in the surface whiteness index. Addition of CBE delayed bloom development by 1–2 wk. The solid fat content (SFC) of both CB and CB + CBE increased gradually during the early wk of storage before reaching a summit and then decreasing slowly with time (at 25 °C). Concurrently, the surface roughened and the whiteness index increased for both CB and CB + CBE. We postulate that, upon bloom formation, parallel phenomena took place: (i) There was exclusion of triglyceride molecules from the CB and CB + CBE fat crystal networks due to continued contraction, and (ii) less stable crystals melted due to the heat release from the (re)crystallization of liquid fat onto existing surface crystals and from the ongoing form V → VI polymorphic transition. These events resulted in the gradual decrease in SFC seen at longer storage times. In conclusion, this study demonstrated that kinetic and thermodynamic phenomena take place in CB long after it has been tempered.