The application of Borneo tallow in dark chocolate shell

Dark chocolate shells, formulated using cocoa butter (CB shell), and fat blends containing 15% Borneo tallow (IP) in cocoa butter (CBIP shell), were filled with truffles formulated using white chocolate (W truffle), milk chocolate (M truffle) and dark chocolate (D truffle). Anhydrous milk fat (AMF) content of the W truffles, M truffle and D truffle were 26·3%, 13·7% and 9·2%, respectively. Degree of tempering was determined using a tempermeter. The chocolates were kept at ambient temperature (25·5±0·5°C) for 3 months. Physical changes of chocolate shells and centres were monitored using DSC and a texture analyser. Results showed that the CBIP shell had to be tempered at 32·5%, ie 1°C higher than the normal CB shell. Physical measurements indicated the occurrence of fat migration. The presence of IP reduced the effect and increased the bloom resistance of the chocolate. © 1998 SCI.     

An improved method for the measurement of added vegetable fats in chocolate

A method for identifying refined vegetable fats added to chocolate (cocoa butter equivalents, CBEs) was combined with established quantitative methods for determining the level of vegetable fat added to cocoa butter with the aim of providing improved precision. The identification of fats was based on the analysis of sterol and triterpene alcohol degradation products formed during the processing of the fat. The procedure was able to successfully discriminate between 95% of pairs of fats from a set (33) of CBE-type vegetable fats. Subsequent analysis of 80 mixtures of four CBEs with chocolate successfully identified, on cross-validation, 94% of the samples. Combining the qualitative procedure with established quantitative methodology, based on the analysis of triacylglycerols, improved the method precision from ± 2.1% to ± 0.3% (5% addition of CBE at 95% confidence). Identifying the fat analytically permits the use of quantitative methods for determining the level of added fat in chocolate that have improved precision in comparison with the measurement of an unidentified fat. This may obviate the need to use factory inspection as a means to identify the ingredients of a product and monitor compliance with proposed legislation.     

Review of cocoa butter and alternative fats for use in chocolate—Part A. Compositional data

This work reviews the literature on the compositional data of vegetable fats used or proposed as alternatives to cocoa butter in chocolate and confectionery products. Cocoa butter is the only continuous phase in chocolate, thus responsible for the dispersion of all other constituents and for the physical behaviour of chocolate. Unique to cocoa butter is its brittleness at room temperature and its quick and complete melting at body temperature. There were, and are, strong efforts to replace cocoa butter in part for chocolate production for technological and economic reasons. Such cocoa butter alternatives are the so-called cocoa butter equivalents (CBEs), cocoa butter substitutes (CBSs) and cocoa butter replacers (CBRs). These are mostly mixtures of various vegetable fats (often modified) and can consist of palm and palm kernel oil, illipé fat, shea butter, sal fat and kokum butter. In addition, a large variety of other vegetable oils can be used. Their composition according to triglycerides, fatty acids, sterols and other unsaponifiable components is discussed in this report.     

Influence of local convective heat flux on solidification,contraction and wall detachment behavior of molded chocolate during air cooling

The cooling process is an important step during chocolate production. It influences final product quality characteristics such as gloss, texture and melting behavior. Furthermore, it is a high energy consuming operation and its optimization leads to an increase in energy efficiency of the chocolate production. Dark chocolate was cooled in a pilot-scale cooling tunnel with cooling air temperatures of T_air = 2, 12 and 18 °C and air mean velocities of v_in = 1.5, 3.5, and 6.0 m s⁻¹. Convective heat transfer coefficients at the top and the bottom of the mold were received from model calculations applying a CFD model. Crystallization and detachment behavior from the mold walls were newly analyzed by measuring the damping characteristics of ultrasound waves transferring the filled molds during cooling. In addition, for this-like treated well-tempered dark chocolate, the crystallization and detachment behavior were analyzed in further detail. The convective heat transfer from the bottom of the mold increases in flow direction due to the existence of a typical mold geometry-dependent recirculating zone of the cooling air below the chocolate mold and also dependent on the local air velocity. It was shown that depending on intensity and homogeneity of the heat transfer in the air-cooling phase, the structure density of the chocolate can be increased which has a positive impact on resulting product quality characteristics. Moreover, the detachment of the chocolate from the mold wall was demonstrated to have an optimum for typical chocolate plate formats with 125 g weight at an apparent heat flux of 550 W/m², for which the time until detachment reaches a minimum.     

Influence of cocoa butter refining on the quality of milk chocolate

A refining step is often crucial for the removal of undesired components in fats and oils. More flexible refining technologies are required due to a global decline in cocoa butter quality and to meet industry’s demand for cocoa butters with improved properties. The aim was to investigate the impact of the cocoa butter refining process on milk chocolate quality. Therefore a crude cocoa butter was subjected to a steam refining at different temperatures and this with or without a silica pretreatment. The major effect of the silica pretreatment was the complete removal of phosphorus (thus phospholipids), iron and alkaline components. During the steam refining step mainly Free Fatty Acids (FFA) were removed at increased temperatures (T ? 200 °C). The refining of the cocoa butter influenced the rheological properties of the chocolate. An increased packed column temperature, coinciding with the removal of FFA, resulted in a lower yield stress and a higher viscosity. Reduction of FFA positively influenced the crystallization kinetics and the formation of the crystal network, resulting in differences on a macroscopic scale.     

Effect of enzymatic interesterification on physicochemical properties of mahua oil and kokum fat blend

Speciality fats were prepared by utilising non-traditional fats, such as mahua and kokum, made by enzymatic interesterification (IE). The fats were blended in a 1:1 ratio and subjected to IE for different times of 0.5–24 h, using 1,3-specific lipase, Lipozyme TL IM. DSC cooling and melting thermograms showed a new peak at higher temperature region on IE. The enthalpy of the newly formed peak increased with increase in the time of IE. There was a significant change in the solids fat content with time of IE and this is attributed to the decrease in monounsaturated and disaturated (SUS) types of triglycerides (TGs) and increase in trisaturated TGs. The melting profile of the blend subjected to IE for 1 h resembled that of commercial milk fat and the one interesterified for 6 h showed a wider melting range, similar to that of hydrogenated fats used for culinary and bakery purposes.     

Investigating the effect of starting mode on food fat gel layer formation on cold surfaces

In a previous study, Huang et al. (2012) employed a spinning disc apparatus to study deposition of fats on cooled stainless steel surfaces using model solutions of tripalmitin in non-crystallising paraffin. The apparatus was modified to give more accurate estimation of the test surface temperature, allowing the surface temperature and shear stress to be manipulated independently. The effect of different starting modes, simulating various situations which arise in pipelines, was studied. When fouling is induced by a step change in the test surface temperature, the presence of a subcooled surface promotes the rapid formation, initially, of a gel layer, followed by a period of linear fouling, and eventually falling rate fouling behaviour. When fouling is driven by a change in concentration the initial gel formation step is absent. The linear fouling regime was relatively insensitive to temperature, shear stress and starting mode for the conditions studied here. In the falling rate regime, the rate was determined by the deposit/solution interface temperature, following normal growth kinetics. At low tripalmitin concentrations, of 2.5 wt.%, sigmoidal growth behaviour was observed, which is attributed to the wall shear stress being initially high enough to disrupt the gel. As time proceeded, the gel increased in strength and was able to grow as before.     

乌桕类可可脂及其巧克力结晶性质的研究(II)

为探索乌桕类可可脂(CTCBE)巧克力调温工艺操作困难的原因与机理,采用差示扫描量热法(DSC)、X-射线衍射(XRD)对添加天然生物乳化剂(香菇粉)的CTCBE巧克力(LC)和空白CTCBE巧克力(CC)在调温过程中结晶行为进行研究分析。并采用粘度法、升温破乳法对两种巧克力浆料在调温过程中的流散性及乳化稳定性进行对比研究。DSC和XRD结果均表明添加香菇粉明显促使CTCBE巧克力形成高熔点稳定晶型,LC比CC酱料的粘度降低近20%,乳化稳定性提高100倍以上,有效地改善了CTCBE巧克力调温工艺操作条件,提高产品产量及质量(具有良好热稳定性、抑制霜花效果及抗氧化性)。     

Solid Fat Content,Pre-Crystallization Conditions,and Sensory Quality of Chocolate with Addition of Cocoa Butter Analogues

The objective of this study was to determine how the addition of two cocoa butter equivalents and cocoa butter improver affect the physical and sensory properties of chocolate. The laboratory-made chocolate samples were tempered at three different pre-crystallization temperatures (25, 27, and 29°C), using different concentrations (3, 5, and 7%) of two commercial cocoa butter equivalents as well as commercial cocoa butter improver of the chocolate. The nucleation time of the chocolate mass primarly depended on pre-crystallization temperature while the value of maximum torque of chocolate mass were influenced by both, pre-crystallization temperature and concentration of fats. Sensory evaluation revealed that cocoa butter equivalents were acceptable in chocolate formulation without producing a negative impact on the sensory quality, while usage of improver required adjustment of raw formulations or process parameters. The results of the instrumentally measured hardness revealed that addition of cocoa butter improver significantly (p > 0.05) increased hardness of chocolate samples.     

端羟基聚丁二烯聚氨酯相变微胶囊的制备及其性能

为解决调温纤维纺丝过程中微胶囊易堵网的问题,利用端羟基聚丁二烯和六亚甲基二异氰酸酯的界面聚合反应制备以复配石蜡为芯材、聚氨酯为壁材的可形变相变微胶囊,借助激光粒度仪、扫描电子显微镜、傅里叶红外光谱仪、热分析仪等测试手段,研究了聚氨酯相变微胶囊的粒度及其分布、微观形貌、分子结构和芯材包覆率,并 考察了其热稳定性、循环稳定性以及抗渗透性。结果表明：微胶囊的粒径分布集中在1 ～15 μm,平均粒径为8 μm,分散良好无黏连,表面圆整致密,具有较好的形变能力;差热分析显示包覆率为46.45%,相变潜热为121.13 J/g;微胶囊耐热温度为182 ℃,相比纯石蜡提高了29 ℃,经30 次冷热循环仍保持良好稳定性,且有较高的抗渗透性。     

Monitoring Tempered Dark Chocolate Using Ultrasonic Spectrometry

Ultrasonic spectrometry was used to distinguish between properly tempered and untempered commercial dark chocolate. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to characterize the polymorphic state of tempered and untempered chocolate, results that were correlated to those of ultrasonic spectrometry. Four different kinds of dark chocolate samples with different amounts of sugar (7.5–50 %), fat (30–50 %), and cocoa mass (70–90 %) were subjected to two different tempering protocols. The tempering was achieved using cocoa butter seeds under static cooling from 50 to 14 °C. The ultrasonic generator and analyzer SIA-7 (V.N. Instruments) was used to monitor the crystallization process. The instrument generated a chirp signal with a bandwidth of 0.5 to 3 MHz and was set to work in a four-pathway configuration with two transducers and a center frequency of 2.25 MHz. Spectrometric analysis was carried out with chocolate samples containing 2, 4, and 6 % solid fat content (SFC). The SFC was obtained from DSC measurements. Ultrasonic signals for attenuation, reflection, and velocity were compared between tempered and untempered chocolates. It was shown that seed-tempered chocolate with 30 % sugar and 47.5 % fat attenuated 2.5 MHz of ultrasonic waves by 0.8, 1.7, and 2.0 dB/cm at 2, 4, and 6 % SFC, respectively. On the other hand, untempered chocolate attenuated the ultrasound signal by 3.5, 3.6, and 4.3 dB/cm. Furthermore, it was found that ultrasound reflection signals were stronger and ultrasonic velocity was higher in chocolates with high sugar content.     

The effect of various substances on the blooming of chocolate

Summary. The effects of many edible substances and pure chemicals on chocolate have been studied in relation to the prevention of chocolate blooming. Bile acids, cholesterol, other sterols and choline promoted the blooming of chocolate. Tripalmitin, added in good dispersion, made chocolate very resistant to fat bloom and chocolate had a high gloss. Hydrogenated fats made very difficult temperable chocolate and it had a waxy taste. Only Delft 37 and some Edelfette improved the resistance of chocolate, but they made it waxy. Butylated hydroxyanisole (BHA) has undesirable effects.
Anhydrous glucose added at the rate of 15-20% of the weight of chocolate increased the resistance. Other sugars were either inert or diminished the resistance. Glycerol had a strikingly unfavourable effect on both quality and resistance. Amino acids did not exhibit any special influence on chocolate. Chemical additives and biological treatment also influenced the blooming of milk chocolate. Unusually long bloom crystals were produced on the surface of milk chocolate on special occasions.     

Application of kokum (Garcinia indica) fat as cocoa butter improver in chocolate

Although cocoa butter (CB) is an ideal fat for use in chocolate, it softens with heat and is not suitable for use in warm climates. CB extenders or improvers, preferably from stearic acid‐rich fats, are good candidates to increase the heat‐resistance property of CB and chocolate. In the present investigation, one such fat, kokum, is used as an improver to increase the hardness of chocolate. Kokum fat is added in various proportions replacing CB in dark and milk chocolate formulations and its effects on rheology, hardness and triglyceride composition were studied. The results revealed that up to 5% kokum fat addition by weight of the product did not significantly affect the plastic viscosity or yield stress of milk or dark chocolate. Hardness of both dark and milk chocolate increased with increase in addition of kokum fat. The solids fat content at and above 30 °C increased with increase in level of kokum fat with CB, especially at and above 15%. These physical properties are due to increase in 2‐oleodistearin triglycerides with addition of kokum fat with CB. The results revealed that kokum fat could be used up to 5% by wt of the product to increase the heat‐resistance property of chocolate so that it can be used in warm climates. Copyright © 2004 Society of Chemical Industry     

The influence of formulation and cooling rate on the rheological properties of chocolate

Rheological properties of chocolate play a relevant role either in process design or texture definition. Nevertheless, only flow properties of molten product or mechanical properties of samples cooled at fixed temperature (usually 20 °C) are measured, whilst testing conditions close to the industrial applications (temperature close to 30 °C) are less common to be used. In this work, chocolate samples (cooled at 1 and 5 °C min⁻¹) were characterised at 30 °C by using small-amplitude oscillations and low-stress creep tests, aiming at establishing how material properties are related to the chocolate microstructure. The effects of either 3 anhydrous milk fats (AMF), having different melting points, or sugar particle size were evaluated. It was found that addition of AMFs, owing to their solid content, can yield an increase in consistency; however, this effect is less relevant when coarse sugar is used, because of the broader particle size distribution, and it depends on the thermal history because of the different fat crystallisation time. Finally, creep tests resulted to be very sensitive in detecting changes in chocolate rheological properties.     

Rapid Determination of Total and Solid Fat Contents in Chocolate Products by Pulsed Nuclear Magnetic Resonance

A rapid pulsed NMR method of fat analysis in chocolate without prior solvent extraction was developed. Total fat content of 43 chocolate products was determined at 60°C using sucrose-oil mixtures as standards. Solid fat content (SFC) was calculated from the liquid oil content at different temperatures. Total fat content agreed to 0.90% standard error of prediction as compared with the Soxhlet method. SFC as determined by NMR correlated well with the dilatometry (r = 0.98) and the DSC (r = 0.96) results. This technique is suitable for quality control of chocolate and other lowmoisture, high-fat products.     

熔纺双组分调温聚丙烯纤维

 以正构烷烃和聚合物相变材料为芯层,聚丙烯为纤维的皮层,采用双组份熔融复合熔融纺丝法制备储热调温纤维。采用扫描电子显微镜(SEM)、差示扫描量热仪(DSC)和单纤维电子强力仪等观察了纤维的形貌,研究纤维的热力学性能和物理机械性能。结果表明：纤维的结构致密,具有明显的皮芯分界,相变材料质量分数为28%时,纤维的热焓值可达到36~40J/g,对纤维进行2.75倍的牵伸后处理,断裂强度和伸长率分别为2.3cN/dtex和29%,可满足纺织服装的应用要求。     

DIFFERENTIAL SCANNING CALORIMETRIC ANALYSIS FOR DETERMINATION OF SOME ANIMAL FATS AS ADULTERANTS IN PALM OLEIN

A study was conducted to assess the use of differential scanning calorimetry (DSC) for monitoring the presence of common animal fats such as genuine lard (GLD), chicken fat (CF) and beef tallow (BT) as adulterants in palm olein. Pure palm olein samples spiked separately with GLD, CF and BT in various levels (1 to 20%) were analyzed using DSC to obtain the cooling profiles. High performance liquid chromatographic (HPLC) analyses were also performed to obtain compositional changes in triacylglycerols (TAG) of these samples. Qualitative differences in the cooling-thermograms of adulterated samples are proposed as a basis for identification of adulteration peaks and differentiating the unadulterated sample of palm olein from those adulterated with the above mentioned animal fats. As the adulteration increased from 3 to 20%, the peaks corresponding to GLD and CF were found to appear in the low-temperature region below -42.75C whereas that corresponding to BT adulteration appeared in the high-temperature region above 8.5C. Despite their close proximity in position, GLD and CF adulteration peaks were shown to be distinguishable by making use of the subtractive procedures facilitated by the DSC computer software.     

The use of cooling and heating thermograms for monitoring of tallow, lard and chicken fat adulterations in canola oil

The use of cooling and heating thermograms from differential scanning calorimetry (DSC) for monitoring the presence of genuine lard (GLD), beef tallow (BT), chicken fat (CF) as adulterants in canola oil has been investigated. Mixing of animal fats especially lard and tallow in any form in food products is a cause of concern for certain religions. Canola oil samples spiked separately with BT, GLD and CF in levels ranging from 1 to 20% (w/w) were analysed by DSC to obtain their cooling and heating profiles. The heating measurements showed that detection of GLD and BT adulterations could be possible based on characteristic differences of GLD and BT adulteration peaks appearing in the higher temperature region of heating thermograms while cooling measurements showed that BT adulteration could be determined by a distinct exothermic peak appearing in the higher temperature region of the cooling thermograms. The determination of GLD by cooling measurements could not be possible since the changes due to GLD and CF adulterations were very similar.     

Investigation of changes in formulation and processing parameters on the physical properties of cocoa butter emulsions

The aim of this work was to understand the physical characteristics of cocoa butter water in oil emulsions made using a process typically used for margarine production (a scraped surface heat exchanger and pin stirrer). Processing parameters were manipulated, and the effect of aqueous phase volume, polyglycerol polyricinoleate (PGPR) concentration, and the addition of a hydrocolloid to the aqueous phase were investigated. This process allowed small droplets to be formed (3–5 μm). Tempering could also be mimicked, with the temperature of the units affecting the polymorphic form of cocoa butter produced. Sintered crystalline shells were observed at the oil/water droplet interface, acting as Pickering particles. This work highlights the potential for the use of cocoa butter emulsions to give fat reduction in chocolate, using a one step process to achieve emulsification and to mimic tempering.     

Use of Palm Mid-Fraction in White Chocolate Formulation

Samples of two types of palm mid-fraction (PMF I, a commercial sample and PMF II, from a laboratory-scale acetone fractionation of PMF I) and a Malaysian deodorised cocoa butter sample were used as the main components in the fat phase for white chocolate formulation. The monounsaturatedtriacylglycerol contents of these fats were 853, 899 and 903 g kg⁻¹, respectively.All the fats had free fatty acid contents of less than 10 g kg⁻¹ and melting points in the range of 34·0–34·5°C. The solid fat content profiles for the three fats were very steep. Differential scanning calorimeter analyses showed that all the fats had two melting peaks, T1 and T2. Results of the study showed that the tempering time to produce a well-tempered chocolate using PMF I was longer than that using PMF II, whereas, the time to produce a well-tempered cocoa butter chocolate increased with increase in the tempering temperature. Chocolates made with PMF I and II were well tempered between 17 and 19°C and with cocoa butter at 23°C. Thermal analyses, carried out on the chocolate showed that PMF I and II produced three melting peaks, T1, T2′ and T2 whereas most of the cocoa butter chocolates exhibited only one melting peak, T2. Storage studies showed that most of the chocolates had good bloom resistance for up to 12 weeks storage.