Relation of fat bloom in chocolate to polymorphic transition of cocoa butter

A special chocolate with spray-dried sugar (50:50 w/w sucrose/20 Dextrose Equivalent corn syrup solids) was made to study the polymorphic changes in cocoa butter crystals using X-ray diffraction. Anhydrous milk fat (AMF) and high-, middle-, and low-melting milk fat fractions were used to replace 2% (w/w) of cocoa butter. Chocolates were tempered, and the consistency of temper among chocolate samples was verified by a temper meter. Chocolates were cycled between 19 and 29°C at 6-h intervals to induce fat bloom. The special chocolates were analyzed by X-ray spectroscopy and colormeter. X-ray analysis on the special chocolates showed polymorphic transition from the βV to the βVI form of cocoa butter. After a lag phase, the percentage of the βVI form rapidly increased. However, the sample made with the high-melting milk fat fraction transformed slowly to βVI. Visual bloom appeared rapidly on the special chocolates made with AMF, middle- and low-melting fractions, whereas visual bloom was very slow to appear on the special chocolates made with high-melting milk fat fraction and on the cocoa butter control. The commercial chocolate responded consistently; the control bloomed rapidly, the AMF exhibited some bloom resistance, and the high-melting fraction inhibited bloom. Despite the βV to βVI transition, the control chocolates with amorphous sugar did not bloom. Since the only difference in the chocolates was sugar microstructure, differences in bloom formation were caused by the microstructure, not the polymorphic transition.     

Determination of milk fat in chocolates by gas-liquid chromatography of triglycerides and fatty acids

The combination of two routine methods is proposed to determine the content of milk fat (MF) in chocolates, which is applicable even in the presence of lauric fats or others. The content of MF is obtained from the sum of C₄₀, C₄₂, and C₄₄ medium-chain triglycerides, determined by capillary gas-liquid chromatography (GLC). A new method, based on methyl esters of lauric acid and on minor acids situated between myristic and palmitic, is proposed. It enables detection and estimation of potential lauric fats, as well as the determination of the actual content of MF. The influence of other vegetable and animal fats is discussed. We analyzed 45 MF samples extracted from industrial milk powders and from pure or fractionated MF for chocolate manufacturing or pastry by GLC of triglycerides. We also analyzed by capillary GLC the methyl esters from 22 of those fats. Mixtures of these 22 MF samples with a cocoa butter also were used for chromatographic analyses of methyl esters and triglyceride. Results from the various analytical methods have been presented.     

Stabilisierung von Kakaobutterersatzfetten

Stabilization of Cocoa Butter Substitute Fats There is an increasing interest in cocoa butter substitute fats, mainly in cocoa butter exchange fats (also called CBE-cocoa butter equivalent). The industry for chocolates and sweets depends on substitute fats of highest quality. The quality estimation of CBE depends on its stability and mixability with cocoa butter (similarities of physical and chemical properties). The stability of cocoa butter substitute fats can be increased to the level of cocoa butter by the ingrediences as tocopherol and lecithine, admitted in the industry for chocolates.     

The interpretation of GLC triglyceride data for the determination of cocoa butter equivalents in chocolate: A new approach

A new approach to interpret triglyceride data obtained by gas liquid chromatography (GLC) in order to determine cocoa butter equivalents (CBE) in chocolate is described. The approach is based on the known straight line relationship which exists between the C₅₀ and C₅₄ triglycerides of cocoa butter of different origins and the realization that, for currently available CBE conforming to CAOBISCO’s criteria, a similar band relationship exists. The technique described enables the quantity of unspecified CBE in a chocolate containing an unknown cocoa butter to be determined to an accuracy of ±1.5% when present in chocolate at the 5% level. Nut oils (almond, walnut or hazelnut) are sometimes present in mainland European chocolates and, should CBE also be present, it is possible to calculate the combined percentages of nut oil and CBE in the chocolate. The method of interpretation described is not dependent on a particular GLC technique for determining triglycerides. Interpretation of other laboratories’ results obtained using different GLC instruments and procedures has shown that the method enables any CBE present in the fat under examination to be determined accurately. The method compensates for variations in the composition of CBE and for the differences between cocoa butters of different origin. A detailed knowledge of CBE compositions is not required and only a few cocoa butter/CBE standards are necessary. The method described is graphical, enabling small laboratories not equipped with microcomputers to utilize the method. The calculation can, however, be programmed for a computer.     

Pulsed NMR Method for Solid Fat Content Determination in Tempering Fats Part II: Cocoa Butters and Equivalents in Blends with Milk Fat

Earlier, in part I of this paper, a method for Solid Fat Content (SFC) determination with pulsed NMR has been described for cocoa butters and cocoa butter equivalents. The present work (part II) is a continuation with these fats together with 10 to 30% milk fat. These fat blends need a modified pretreatment before NMR analysis. Crystallisation of the melted fat should be done at 0° C for 150 min and subsequent tempering performed at 19.0° C for 40 h. No other deviations from the earlier reported method have been carried out. Also SFC determination for chocolate has been described and used as a tool for the development of a proper NMR method, giving SFC on a pure fat blend more or less equal to SFC in corresponding milk chocolate. Different pretreatments (i.e. tempering temperatures) have given very different SFC results. A crystallographic understanding of these were achieved using X-ray, microscope and thermal analysis techniques. The chosen tempering temperature 19.0° C gave a single solid solution, which is essential in chocolate if the right properties of the fat are to be reached. Differences in SFC on pure fat blends by different tempering temperatures could, in the same way, be found in milk chocolates stored at corresponding temperatures. Storage temperature can, to a certain degree, be chosen in order to optimize and control the SFC (i.e. properties) in a chocolate product. The choice of initial temperature especially will strongly influence the SFC in chocolate and the crystal lattice remains virtually unaffected by changes in storage temperature.     

Analytical platforms to assess the authenticity of cocoa butter

This paper reviews strategies to detect and analyse cocoa butter equivalents added to genuine cocoa butter or to chocolate products. The legal background of the issue is that current European legislation allows the addition of vegetable fats other than cocoa butter to chocolate up to a level of 5% of the product weight, provided that the addition is correctly indicated on the label. However, the Directive fails to specify a method of analysis to enforce compliance. The principal themes highlight compositional data (triglyceride and fatty acid composition, components of the unsaponifiable matter) of cocoa butter from different origins and suitable raw materials used for the formulation of cocoa butter equivalents, and explains how analytical techniques (gas‐liquid chromatography, high‐performance liquid chromatography, infrared spectroscopy, pyrolysis mass spectrometry) make use of subtle differences between the two commodities to detect commingling.     

Effect of fat composition on texture and bloom of lauric compound chocolate

Cocoa butter (CB) and milk fat (MF) contents were varied and their effects on the textural property and bloom formation of lauric cocoa butter substitutes (CBS)‐based compound chocolates was investigated. Compositional parameters for CBS compound chocolates were two types of CBS (hydrogenated palm kernel olein (HPKO) and hydrogenated palm kernel sterin (HPKS)), CB (0, 5, 10, and 15%) and MF (0, 3, and 6%) contents. Addition of CB or MF significantly (p<0.001) influenced the hardness of compound chocolates but the effects were less pronounced at higher fat content. Addition of MF or CB accelerated the bloom formation compared with the control samples, but in combination they delayed the bloom formation, suggesting that the mechanisms of bloom formation were different in the CBS compound chocolate made with different fat mixtures. Practical applications This study deals with the effect of fat composition on both texture and bloom of lauric‐based compound chocolates. CB and MF can be used in lauric‐based compound chocolates to improve the flavor, but eutectic and dilution effects appear when these fats are added separately. However, there are few studies on the interactions of ternary mixtures and the physical properties such as hardness of corresponding compound chocolates. In order to be able to predict the bloom formation, it is important to study how these fats affect the physical properties of the compound chocolates.     

Markierung von Butterfett mit seltenen Erden und deren quantitativer Nachweis in Fettmischungen und Schokoladen

Labelling of Butter Fat with Rare-Earth Elements and the Quantitative Determination of these Elements in Fat Mixtures and Chocolates The studies described below have shown the three lanthanides Eu, Tm, and Yb to be suitable markers for butter fat and fat mixtures. As palmitates, prepared from the oxides, the elements could be mixed homogeneously in the ppb range with fats and were determined quantitatively with high sensitivity by atomic absorption spectrometry. 0.5 ppb of Yb were measured reliably in butter fat and mixtures of butter fat and cocoa butter. The lanthanides could be extracted from solutions of the fats in organic solvents by dilute aqueous HCl/NaCl. Such solutions could be directly injected into a graphite furnace atomiser. The AAS instrument was calibrated with standards dissolved in aqueous HCl/NaCl of the same strength as that used for extracting the fat samples. If fats labelled with lanthanides are to be determined quantitatively in an other matrix, e.g. in chocolate, the matrix must be ashed and the determination must be carried out by the standard addition method because calibration with aqueous solutions of the elements is no longer possible. Because of the dilution by the matrix the element content of the supplementary labelled fat must be large enough to be assayed in the final product. Yb proved to be unsuitable as a marker for chocolate because this matrix contains by nature measurable and variable amounts of this element. Yb enters chocolates with plant components whereas Eu and Tm have not been detected. As Yb is present in many kinds of plant material it will not be suitable for labelling fats or fat mixtures for food containing ingredients of plant origin. In the case of Eu and Tm there should be practically no restrictions.     

Crystallization Behavior and Kinetics of Chocolate-Lauric Fat Blends and Model Systems

Binary mixtures of cocoa butter and lauric fats have widespread use in chocolates and confections, yet incompatibilities between these fats can present formulation and processing constraints. This study examined the phase behavior and crystallization kinetics of cocoa butter-lauric fat model systems and chocolate-lauric fat blends. Solid fat content (SFC) profiles and isosolid diagrams confirmed eutectic and diluent interactions, indicating a softening of cocoa butter by lauric fat addition. Crystallization kinetics of model systems adhered to an exponential growth model. High lauric fat levels delayed crystal growth and reduced equilibrium SFC of cocoa butter. Coconut and palm kernel oils altered the solidification mechanisms of cocoa butter to a greater extent than fractionated palm kernel oil. Chocolate systems displayed multi-step crystal growth that contrasted with the exponential growth observed in the model systems. At high lauric fat levels (30%), crystallization onset was significantly lengthened. Blends with high lauric fat contents showed low \(G_{{\text {max}} }^{\prime }\) and did not achieve final equilibrium after 60 min of cooling, indicating incomplete crystallization.     

Confectionery fats from palm oil and lauric oil

In the search for economical cocoa butter alternatives, palm and lauric oils have emerged as important source oils in the development of hard butters. Based on the method presented for categorizing hard butters, the lauric oils, primarily palm kernel and coconut, can be modified by interesterification and hydrogenated to yield lauric cocoa butter substitutes (CBS) which are both good eating and inexpensive. Fractionation, although adding to the cost of production, can provide lauric hard butter with eating qualities virtually identical to cocoa butter. Unfortunately, one factor identified with the lauric oils is their very low tolerance for cocoa butter. Palm oil, on the other hand, has been identified as a valuable component in all types of cocoa butter alternatives. It is a source of symmetrical triglycerides vital in the formulation of a cocoa butter equivalent (CBE). It can be hydrogenated or hydrogenated and fractionated to yield hard butters with a limited degree of compatibility with cocoa butter, allowing some chocolate liquor to be included in a coating for flavor enhancement. Palm oil is used with lauric oils as a minor component in interesterified lauric hard butters, as well as functioning as a crystal promoter in coatings formulated with a fractionated lauric CBS. While palm oil’s importance and flexibility have been duly noted, some important concerns remain from a market perspective. The fact that the CBE fats are very expensive suggests they offer limited cost savings compared to cocoa butter. The potential for CBE products is still questionable in those countries where chocolate labeling standards preclude the use of vegetable fats other than cocoa butter. The nonlauric CBS products, while cheaper than the CBE types and able to tolerate limited levels of cocoa butter, do not exhibit the level of eating quality characteristics present in the lauric hard butters. Some challenges remain for today’s oil chemists. An economical nonlauric CBS, made predominantly from palm oil, possessing the eating quality of a fractionated lauric CBS and exhibiting good compatibility with cocoa butter would be met with considerable interest by the chocolate and confectionery industries. As for the lauric oils, it would seem reasonable to assume that greater cocoa butter compatibility, if attainable, could enhance their potential for gaining even greater acceptance by confectionery manufacturers currently using pure chocolate. As for the CBE products, the major issue is cost. If the cost of a CBE could be reduced to a level which would allow a CBE to compete with the nonlauric and lauric cocoa butter substitutes, a major advancement in the evolution of cocoa butter alternative fats will have been achieved.     

Das physikalische Verhalten und die chemischen Zusammensetzung von Schokolade,Kakaobutter und einigen Kakaobutter-Austauschfetten

Physical Behaviour and Chemical Composition of Chocolate, Cocoa Butter and Some Cocoa Butter Substitutes Cocoa butter, which forms the continuous phase in the dispersed system of chocolate, is responsible for the most important properties of the latter. Such properties and methods for determining the same are treated exhaustively. Physical properties of cocoa butter and its substitutes, as well as the relationship between their physical behaviour and chemical composition are discussed. Fats that can replace cocoa butter satisfactorily, have a chemical composition which is similar to that of cocoa butter, Such substitutes are available and fairly good quality chocolates can be prepared from them. Determination of fatty acid composition and aniline point are adequate for ascertaining, whether a fat is suitable as cocoa butter substitute.     

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.     

Confectionery fats. II. Characterization of products prepared by interesterification and fractionation

Several cocoa butter-like fats, which had been prepared by fractional crystallization of the reaction product obtained on interesterifying highly-hydrogenated cottonseed oil and a triolein product or olive oil, were characterized and compared with cocoa butter. The fats, as obtained by fractional crystallization from acetone solutions, contained varying amounts of glycerides melting above 37°C., an undesirable feature which caused the fats to thicken too much when used in chocolate type compositions under the same conditions employed with cocoa butter. The higher-melting glycerides could be removed by filtration, or their proportions could be decreased by changing the fractionation temperatures. The fats melted mostly over the same temperature range associated with cocoa butter, and the best of the fats resembled cocoa butter closely over the temperature range 0° to 30°C. The cocoa butter-like fats resembled cocoa butter in hardness at all test temperatures. The fats were reasonably compatible with cocoa butter, that is, in mixtures of the two, one did not cause extensive premelting of the other. According to their cooling curves, the cocoa butter-like fats did not supercool as cocoa butter does. The former contain not only the 2-oleodisaturated glycerides of cocoa butter but also positional isomers of these glycerides. When the fats were molded under the same conditions employed with cocoa butter, linear shrinkage was only about one-third that of cocoa butter.     

Fats and processes used in manufacturing chocolate and confectionery coatings

The basic requirements of the confectioner for fats to be used in chocolate are briefly reviewed. The melting properties of the polymorphs of cocoa butter and variation in them are outlined together with methods of measuring them. These properties govern two important steps in the manufacture of chocolate—tempering and cooling. The tempering process and methods for determining the state of temper in a sample are noted. The main types of chocolate in common use are described along with two main processes used for their manufacture. The polymorphic forms commonly found in commercial operations are discussed. The discussion on chocolate and cocoa butter leads to reasons for the interest of confectioners in so-called coating fats or cocoa butter substitutes. The various classes of fat which have been tried so far for this use are briefly reviewed along with their limitations from the viewpoint of the confectioner and his consumers. Desirable specifications for a coating fat and possible future developments in their use in the candy industry are discussed briefly. One of seven papers presented in the symposium “Fats and Oils in the Food Industry,” Atlantic City, October 1971.     

Polymorphic changes in mixtures of confectionery fats

The polymorphic behavior of mixtures of cocoa butter and high melting cocoa butter fraction with three types of confectionery fats and mixtures of the confectionery fats with each other were investigated with a differential scanning calorimeter. The confectionery fats were an interesterified-fractionated fat, a hydrogenated-fractionated fat, and a lauric acid fat. The lowered melting point observed in mixtures of confectionery fats with cocoa butter or cocoa butter fraction was related to the proportion of triglycerides dissimilar to the major components in cocoa butter and cocoa butter fraction contained in a particular confectionery fat. The hydrogenated-fractionated fat contained ca. two-thirds 2-oleodisaturated triglycerides similar to the major components of cocoa butter; the interesterified-fractionated fat, ca. one-third 2-oleodisaturated triglycerides. The lauric acid fat contained virtually no triglycerides similar to cocoa butter. The series of mixtures of confectionery fats with cocoa butter and cocoa butter fraction that had the least melting point lowering were those that contained 25% hydrogenated-fractionated fat; the ones that had the greatest lowering of melting point were those that contained 25% lauric acid fat. Mixtures of confectionery fats with cocoa butter possessed considerable amounts of low melting components, whereas similar mixtures with cocoa butter fraction exhibited a narrower melting range and possessed few low melting components. The more highly crystalline confectionery fats can accommodate the addition of fats containing some low melting components. The most compatible of the series of mixtures of confectionery fats with each other was the mixture of interesterified-fractionated fat containing 25% hydrogenated fractionated fat; the least compatible, hydrogenated fractionated fat containing 25% lauric acid fat. Presented at the AOCS Meeting, Mexico City, April 1974.     

Surface bloom on improperly tempered chocolate

The surface composition, in terms of sugar and fat content, on untempered and over‐tempered chocolates was estimated by carefully scraping the surface layer and analyzing fat and sugar melting enthalpies by differential scanning calorimetry. The dull surface of over‐tempered chocolate had a fat and sugar composition similar to the initial chocolate mass, whereas the surface bloom formed on untempered chocolate was nearly depleted of fat, containing primarily sugar and cocoa solids. This was confirmed qualitatively by using polarized light microscopy, where no fat crystals could be observed in the bloom spots. Bloom on untempered chocolate corresponded to a phase separation between fat, sugar and cocoa solids. In contrast, the grey, dull aspect of the surface of over‐tempered chocolate had essentially the same sugar‐to‐fat ratio as the intact chocolate and was due to a diffuse reflection of light on a rough surface, most likely induced by large cocoa butter crystals. Bloom on untempered chocolate developed regardless of the relative humidity of storage (between 0 and 75%). However, bloom developed more quickly and to a greater extent at lower relative humidity. Whiteness was directly related to the number, diameter and growth speed of the white bloom spots.     

Production of cocoa butter-like fats by the lipase-catalyzed interesterification of palm oil and hydrogenated soybean oil

Cocoa butter-like fats were prepared from refined, bleached, and deodorized palm oil (RBD-PO) and fully hydrogenated soybean oil (HSO) by enzymatic interesterification at various weight ratios of substrates. The cocoa butter-like fats were isolated from the crude interesterification mixture by fractional crystallization from acetone. Analysis of these fat products by RP-HPLC in combination with ELSD or MS detection showed that their TAG distributions were similar to that of cocoa butter but that they also contained MAG and DAG, which were removed by silica chromatography. The optimal weight ratio of RBD-PO to HSO found to produce a fat product containing the major TAG component of cocoa butter, namely, 1(3)-palmitoyl-3(1)-stearoyl-2-monoolein (POS), was 1.6∶1. The m.p. of this purified product as determined by DSC was comparable to the m.p. of cocoa butter, and its yield was 45% based on the weight of the original substrates.     

The determination of cocoa butter equivalents in chocolate

A method of determining cocoa butter equivalents in chocolate and cocoa butter is described. The method relies on a new approach for interpreting data obtained by triglyceride gas liquid chromatography (GLC). This technique provides information on the composition of a fat according to the carbon number of the triglycerides (C_n). Examination of the data for a wide range of cocoa butters shows that a straight line relationship between the C₅₀ and C₅₄ contents exists. This relationship has been used as the basis for a quantitative method determining the amount and type of cocoa butter equivalent added to chocolate. The application of the method to both plain and milk chocolate is described. The method is also used to determine the amount of milk fat in chocolate.     

Prediction of migration fat bloom on chocolate

The objective of this study was to investigate whether it is possible to predict migration fat bloom based on measurements shortly after production. At different storage times shortly after production (0, 1, 4 h), the chocolate batches, varying in tempering method, tempering degree and amount of added butter oil, were evaluated by DSC, pNMR and texture analysis. Discriminant analysis and principal component analysis were combined to investigate the potential towards prediction. The batches were classified into groups depending on the time when white spots appeared (<8 wk, 8–13 wk, >13 wk). A good separation (100% correct classifications, 100% using cross‐validation) was obtained using the afore‐mentioned analyses and storage times. It was also shown that it is possible to exclude DSC analyses or analyses at 0 h storage time without compromising the classification performances too drastically. The study further elucidated that the tempering method has no significant effect on visual fat bloom development. Furthermore, undertempered chocolates bloomed quicker than well‐tempered ones, while fat bloom was delayed on overtempered chocolates. Addition of 6% butter oil promoted fat bloom development, while no significant difference was detected between chocolate with no added butter oil and chocolate with 3% butter oil added.     

Determination of the glyceride structure of fats; analysis of 14 animal and vegetable fats

The glyceride compositions of seven animals and seven vegetable fats have been determined by GLC analysis of the oxidized esterified glycerides as described in an earlier paper in this series. The compositions determined are compared with those calculated from lipase hydrolysis data according to the method of VanderWal. Good agreement was found between the calculated and determined compositions for the majority of the 14 fats. The exceptions were human fat and the more satu-rated vegetable fats, palm oil and cocoa butter, where some discrepancies occurred. Issued as NRC No. 8052. National Research Council of Canada Postdoctorate Fellow.