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.     

Comparision of acidic and basic volatile compounds of cocoa butters from roasted and unroasted cocoa beans

A total of nine acidic and 83 basic compounds was identified in the roasted and unroasted cocoa butter samples. Forty seven of the compounds identified are being reported for the first time in cocoa. The higher concentration of short chain fatty acids in the unroasted cocoa butter is responsible for its acidic aroma characteristics. The roasted cocoa butter generally contained greater numbers and higher concentrations of compounds whose formations would be favored by thermal processing. These compounds included pyrazines, thiazoles, oxazoles and pyridines. The aromas of many of these compounds are characteristic of the aroma differences between the two cocoa butters and contribute to the cocoa aroma of roasted cocoa butter.     

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.     

Synthesis of cocoa butter equivalent by lipase-catalyzed interesterification in supercritical carbon dioxide

With supercritical carbon dixoide as a reaction medium, the syntheses of cocoa butter equivalent by interesterification with various lipases were investigated. The study showed that among those five lipases tested, lipase IM-20 from Mucor miehei was the most effective and specific in synthesizing this cocoa butter equivalent product by interesterification. The yields of cocoa butter equivalent are affected by pressure, substrate oil composition, solubility and co-solvent. The best reaction conditions were: reaction pressure at 1500 psi, triglyceride with high content of POP (P, palmitate; O, oleate) and POO, reaction medium with 5.0% water, and reaction temperature at 50°C. The major component of cocoa butter, POS (S, stearate), can be increased by 6.0% by adding a small amount of carbon dioxide. The yield and melting point of the purified cocoa butter equivalent are 53.0% and 34.3°C, respectively.     

Physical Properties of Chocolate with Addition of Cocoa Butter Equivalent of Moderate Hardness

In this study, the fat phase of chocolate samples which contained cocoa butter from Ghana and cocoa butter equivalent (CBE) of moderate hardness was analyzed. Physical properties and shelf life of chocolate depend on the fat phase behavior as well as the amount and composition of added CBE. The laboratory-made chocolate samples were tempered at three different pre-crystallization temperatures (25, 27 and 29 °C), with three different concentrations of CBE, amounting to 3, 5 and 7 %, calculated on chocolate. The color and other physical attributes of chocolate samples were investigated by the following analytical methods: thermoreographic measurement, solid fat content (SFC) of chocolate, Blooming test (thermo-cycle test 32/20 °C) and color measurement. It was found that using CBE of moderate hardness did not change the melting properties of chocolate in relation to the investigated cocoa butter from Ghana (of moderate hardness). It was found that all three applied temperatures of pre-crystallization are optimum for the chocolate mass with the addition of the investigated CBE under the given measurement conditions. At all these temperatures, the chocolate had excellent fat bloom resistance.     

Influence of Soft Cocoa Butter Equivalents on Color and Other Physical Attributes of Chocolate

The physical characteristics and color of chocolate depend on the physical properties and crystallization behavior of the fat phase. In this study, the fat phase of chocolate samples contains cocoa butter from Ghana and soft cocoa butter equivalent (CBE). The laboratory-made chocolate samples were tempered at three different precrystallization temperatures (25, 27 and 29 °C), using three different concentrations of CBE (3, 5 and 7%), calculated as percentage of the chocolate. Physical characteristics of chocolate, namely thermoreographic parameters and solid fat content (SFC), were measured. The color of the chocolate was determined instrumentally, before and after thermo-cycle testing at 32/20 °C. It was found that CBE changed the melting properties of chocolate produced with cocoa butter from Ghana, which is of moderate hardness. It was determined that the optimum precrystallization temperature for chocolate mass with addition of CBE in the given conditions of measurement was 27 °C, the temperature that resulted in the best fat bloom resistance.     

Zur Spezifität des Kakaoaromas

Specificity of Cocoa Aroma Aroma precursors in crude cocoa from Ghana were separated into substance classes and their significance in aroma formation was examined. Coaction of a peptide, which was isolated and characterized for the first time, is especially necessary for the specific reaction which occurs via a side path of Maillard-reaction. Furthermore, aroma formation in other varieties of cocoa was studied on the basis of precursors. From chemical viewpoint the 310 aroma components known so far were classified and compared with other food aromas in order to obtain information on the specific components.     

Isolation and thermal characterization of high-melting seed crystals formed during cocoa butter solidification

Seed crystals which formed during early stages of cocoa butter solidification have been isolated and determined to have extremely high melting points. The melting points of the seed crystals generally exceeded 60°C, in contrast to cocoa butter, which melts between 30–35°C. In addition, the melting point of the seed crystals decreased as a function of crystal growth time. Evidence suggests that the high-melting seed crystal is not an additional polymorphic form of cocoa butter, but rather a distinct crystalline entity. Consequently, a unique compositional make-up is suspected as being responsible for the elevated melting point. A technique to separate seed crystals from the molten cocoa butter mass has been developed. The procedure has been shown not to alter the thermal and compositional properties of the isolated seed crystals.     

Über die Bildung des Kakaoaromas aus seinen Vorstufen

Formation of Cocoa Aroma from Its Precursors Isolation and chemical composition of a highly purified mixture of aroma-precursors from raw cocoa were extensively studied and the alterations due to heating at roasting temperatures were followed quantitatively. Cocoa aroma is formed in the course of a Maillard reaction between amino acids and reducing sugars. Participation of oligopeptides in the alterations that are specific for the process of roasting could be detected for the first time. From the high-boiling components present in the reaction product, a fraction having the typical cocoa flavour could be isolated and resolved by gas chromatography. The consequences of these observations on the technology of roasting of cocoa are discussed.     

Confectionery Fat from Phulwara (Madhuca butyracea) Butter

Phulwara butter behaved like a plastic fat without showing any supercooling property, which is mainly due t o presence of trisaturated triacylglycerols. The olein obtained after removal of about 10% harder stearin fraction showed considerable improvement in supercooling property. However, the olein had lower solids content at ambient temperatures, which make it unsuitable for use in chocolate and confectionery. On the other hand, the middle stearin fraction obtained by two-stage fractionation had sufficient solids content at these temperatures. The middle fraction, when mixed with cocoa butter, depressed the overall melting range of the latter by lowering the solids content at 32.5°C, the effect being more pronounced as the level of the fraction in the mixture increased. At 15% concentration with cocoa butter, the fraction had cooling curve similar to that of cocoa butter. The fraction was found t o have slightly better tolerance towards milk fat compared to that of cocoa butter. The results revealed that the fraction when incorporated into chocolate along with cocoa butter, imparted more cooling sensation in the mouth compared to those prepared with cocoa butter alone. The fraction was found to be suitable to replace part of cocoa butter in chocolate and other confectionery products, where cooling sensation is desirable and finds application in cold climates and also in the preparation of ice-cream coatings.     

Dynamic crystallization of cocoa butter. II. Morphological,thermal, and chemical characteristics during crystal growth

After an induction period, crystallization of cocoa butter under dynamic conditions at 26.5°C occurs in two stages, primary and secondary. The primary stage involves nucleation, crystal growth, aggregation, and sintering. Crystals formed during the primary stage were slightly or non-birefringent, and had long, irregular-shaped filaments. The secondary stage was initiated by the formation of spherulites. Total crystallization time may depend upon the crystal growth rate in the primary stage and the time that coca butters take to form the spherulitic crystals in the secondary stage. After the spherulitic crystals formed, the crystal growth rates were rapid. Cocoa butters crystallized into two fractions during the primary and secondary stages. The low-melting fractions had onset melting temperatures similar to those of polymorphs IV and V of cocoa butter. The high-melting fractions, which were observed at the latter stages of crystallization, had differential scanning calorimetry endotherms with peak maxima at approximately 34–36°C (Form VI). The concentrations of 1,3-stearoyl-2-oleoylglycerol (SOS) in the crystals during growth were higher than those in the original cocoa butter. As crystallization progressed, crystals increased in their proportions of SOS in the triacylglycerol fraction. Concentrations of the C₁₈ free fatty acids were lower during early crystallization as compared to the original cocoa butter.     

Production of cocoa butter-like fat from interesterification of vegetable oils

Cocoa butter-like fat was prepared from completely hydrogenated cottonseed and olive oils by enzymatic interesterification. The optimum reaction time to produce the major-component of cocoa butter, 1(3)-palmitoyl-3(1)-stearoyl-2-monoolein (POS), was 4 hr. The cocoa butter-like fat was isolated from the reaction mixture by two filtration steps. The yield of cocoa butter-like fat was 19%, based on the weight of the original oils. Chromatographic analysis of the product by reversephase high-performance liquid chromatography (HPLC) has shown it contains triglyceride components similar to those of cocoa butter, but that it has slightly more diglycerides. The melting point of this product, as measured by a differential scanning calorimeter, is 39°C, which compares well to the 36°C melting point of natural cocoa butter. Presented in part at the AOCS meeting in Cincinnati, Ohio, in 1989.     

Dynamic crystallization of cocoa butter. I. characterization of simple lipids in rapid- and slow-nucleating cocoa butters and their seed crystals

Six cocoa butters with different crystallization induction times and their seed crystals were analyzed for simple lipid composition. The rapid-nucleating cocoa butter samples had higher concentrations of 1-palmitoyl-2-oleoyl-3-stearoylglycerol and 1,3-stearoyl-2-oleoylglycerol (SOS), and lower concentrations of the diunsaturated triacylglycerols, 1-palmitoyl-2,3-oleoylglycerol and 1-stearoyl-2,3-oleoylglycerol, as well as higher stearic acid concentrations within their diacylglycerol fractions when compared to the slow-nucleating samples. At the early stages of crystallization, under agitation conditions at 26.5°C, cocoa butters solidified into two fractions, high-melting and low-melting. The low-melting fractions were composed of polymorphs IV and V of cocoa butter, as indicated by the onset melting temperatures of the endotherms from differential scanning calorimetry. The high-melting fractions, which had wide melting ranges, had peak maxima of 38.5–52.2°C. Seed crystals isolated at the early stage of crystallization were characterized by high concentrations of complex lipids, saturated triacylglycerols, saturated fatty acid-rich diacylglycerols, and monoacylglycerols. The rapid-nucleating seed crystals had higher concentrations of SOS when compared to their respective cocoa butters. The slow-nucleating seed crystals did not exhibit this characteristic.     

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.     

Heat-resistant cocoa butter extenders from mahua (Madhuca latifolia) and kokum (Garcinia indica) fats

Cocoa butter extenders with heat-resistant properties were prepared using mahua and kokum fats. The stearin fraction [Fraction (Fr.) 1, 77–80% yield] obtained by solvent fractionation of 50:50 blends of these fats showed a steep melting profile with a higher solid fat content (SFC) at 32.5°C than cocoa butter, even after mixing with it at 25 or 50% levels. The solidification characteristics showed that the Fr. 1 had a supercooling property similar to cocoa butter, but showed higher temperature rise with less crystallization time on the cooling curve, which is advantageous for chocolate molding. Fr. 1 was compatible with cocoa butter at all proportions, as revealed by cooling curves and isothermal solid diagrams. The stearin fraction obtained by dry fractionation of mahua/kokum blend (Fr. 2, 77% yield), though, had similar solidification characteristics and showed lower SFC compared to that of Fr. 1. Fr. 1 and Fr. 2 have high levels of 2-oleo-distearin triacylglycerols (46–51%), which are responsible for better stand-up property at high temperatures compared to cocoa butter. The suitability of the blends of mahua/kokum fats and mahua stearin/kokum fats as cocoa butter extenders was also evaluated. The isothermal solid diagrams showed complete miscibility of the two fats fractions. The results showed that a series of cocoa butter extenders with varying melting characteristics could be prepared by fractionating and by physical blending of mahua and kokum fats in selected proportions.     

A new industrial process for extracting cocoa butter and xanthines with supercritical carbon dioxide

This research explores the feasibility of extracting cocoa butter and xanthines (theobromine and caffeine) from cocoa beans with supercritical CO₂. It is difficult to carry out the extraction with CO₂ alone in the temperature range 40–90°C at pressures between 80 to 300 bar. However, the addition of a polar cosolvent, such as ethanol, greatly enhances solubilities, especially that of cocoa butter. Based on experimental investigations and theoretical inference, the design of a potential industrial process for extracting cocoa butter and xanthines is proposed, in which ethanol is used as cosolvent, and distillation is used to separate and regenerate ethanol. The pressure required is much less than that for CO₂ alone as specified in the patent literature.     

Fat Bloom Caused by Partial De-Oiling on Chocolate Surfaces after High-Temperature Exposure

Fat bloom in chocolate is a substantial problem that affects its sensory properties, such as texture and appearance. This phenomenon is because of diffuse light reflection on a roughened surface of chocolate, caused by structural changes of fat crystals subjected to various temperature conditions. The purpose of this study is to characterize the fat bloom formed through gradual two-step cooling after exposure to temperatures (35–37 °C) slightly above the cocoa butter Form βV melting point (33.8 °C). To clarify the fat bloom formation process, the structural changes in cocoa butter and on the chocolate surface, at the dynamic thermal condition for bloom formation, was investigated using X-ray diffraction (XRD), fluorescence light microscopy, and scanning electron microscopy (SEM). The results revealed that an entirely light brown fat bloom occurred, even in the absence of the Form βVI or other polymorphic transformation. Microscopic observation showed that the light brown appearance was because of the porous structure on the chocolate surface. This porous structure was formed by liquid oil moving inside of chocolate from the surface. The formation of a coarse network and the subsequent de-oiling, because of movement of unsolidified liquid fat into the chocolate, appeared to be the main causes of bloom formation. Therefore, a coarsened fat network and oil movement besides the conventional principles of polymorphic transformation of cocoa butter should be considered.     

Production of High-Melting Symmetrical Monounsaturated Triacylglycerol-Rich Fats from Mango Kernel Fat by Acetone Fractionation

1,3‐Distearoyl‐2‐oleoyl‐glycerol, 1‐palmitoyl‐2‐oleoyl‐3‐stearoyl‐glycerol and 1‐stearoyl‐2‐oleoyl‐3‐arachidoyl‐glycerol are typical high‐melting symmetrical monounsaturated triacylglycerols (Hm‐SMT) found in cocoa butter improver (CBI). These triacylglycerols help to increase the hardness of chocolate products in tropical climates. In the present study, natural CBI products were produced from mango (Mangifera indica, Linn) kernel fat (MKF) by selective three‐stage fractionation using acetone. The second stearin (fraction I) from the first precipitate of MKF by fractionation for 180 min at 15 °C contained 86.9% of Hm‐SMT, and the third stearin (fraction II) obtained from fraction I by further fractionation for 180 min at 18 °C was enriched with 94.4% Hm‐SMT. High percentages of such triacylglycerols in these products contributed to higher slip melting points (36.5–37.7 °C) than commercial cocoa butter and cocoa butter equivalent (26.7 and 27.9 °C). Also, their differential scanning calorimetry properties and solid fat content values were superior to those in traditional confectionery fats, indicating that the tailored stearins could be used as ideal CBI. In particular, the hard fat blends consisting of 55–70% cocoa butter (CB) and 30–45% fraction II were considered as the preferred heat‐resistant chocolate ingredients. In addition, the mixture of the oleins (fraction III) was rich in diunsaturated and triunsaturated triacylglycerols and showed similar thermal properties to super palm oil, thus making it more suitable as special fat ingredients and modified fat sources.     

Evaluation of transfer of wine aroma compounds through PET bottles

Aroma compound could be lost during food storage in polymer packaging by transfers through material. The aim of this study was to develop a method that allows evaluating wine aroma compounds permeation through active PET bottles. A semiquantitative method has been adapted to the system. Results showed a regular permeation of all studied aroma compounds but a high variation between replicates. In active PET bottle containing 1% of oxygen scavenger, amount lost by permeation after 12 months storage at 20°C was about 6.13 ± 0.37 µgbottle^?1. When 50% of recycled PET was added to active PET bottle, permeation rate was increased about 15%. The study of sorption of aroma compounds in both polymer matrices did not allow to explain this difference of permeation, but the structure of recycled PET seemed to induce modifications in aroma compound diffusion through active PET which could increase transfer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41784.     

Dry Fractionation and Crystallization Kinetics of High-Oleic High-Stearic Sunflower Oil

Fractionation of fats and oils makes it possible to generate products with specific properties from natural fats that contain a variety of triacylglycerol (TAG) species. High-oleic high-stearic (HOHS) sunflower oils contain high levels of saturated fatty acids, mainly stearate, on a high-oleic background. Accordingly, HOHS oils could be a source of disaturated TAGs appropriate for cocoa butter equivalent formulations. We examined the kinetics of HOHS oil crystallization, paying special attention to the influence of crystal seeding and temperature on the process and the composition of the final fractions. This oil was fractionated at 18 °C, and seeding increased the amount of disaturated TAGs recovered in the precipitate from 23% to up to 30%. The experimental data collected were fitted using the models of Gompertz and Avrami to study how well these models fitted the data and their utility in predicting the progress of crystallization. At seeding additions above 0.25% there was a change in the crystallization mechanism that improved the process of fractionation. The effect of temperature was also studied, showing important increases in the maximum rates of crystallization when fractionations were carried out at lower temperatures. Finally, the melting profiles of the fractions enriched in saturated fatty acids were studied, showing amounts of solids intermediate between the initial oil and cocoa butter.