Chocolate Shell Research Articles

Effect of adding of sabah snake grass (clinacanthus nutans) on the antioxidant and sensory properties of chocolate

This research was carried out to identify the effect of drying methods on the antioxidant activity of Sabah snake grass leaves as well as the addition of Sabah snake grass powder on the antioxidant and sensory properties of chocolate. Antioxidant properties of chocolate samples were determined through total phenolic content and DPPH radical scavenging activity tests. The best formulation of chocolate filled with Sabah snake grass was determined based on sensory and antioxidant test. Nutrient content of chocolate was determined through AOAC methods whereas water activity and hardness of chocolate shell were determined using water activity meter and Texture Analyzer. Changes of chocolate during storage was reviewed through the aspect of moisture content, water activity, hardness, melting point, microorganism count and sensory score. Results showed that chocolate F2, chocolate filled with 100g of Sabah snake grass powder was the best formulation with satisfaction by panels and higher antioxidant activity. This sample contain 7.25% moisture, 2.19% ash, 30.61% fat, 5.41% protein, 1.94% crude fibre and 52.61% carbohydrate. The storage sample showed significantly difference (p<0.05) in moisture content, water activity, hardness and melting property after kept for eight weeks but still safe to be consumed.

The impact of shell formation duration during manual tempering process on the hardness and melting point of couverture praline chocolate

Praline chocolate usually contains soft fillings such as water-based filling from fruits. The interaction between water in chocolate filling and fat in praline shell formulation is interesting to be studied. Water in the water-based filling may migrate to the chocolate shell and thus influence chocolate quality. The aim of the study was to physically investigate the impact of duration of shell formation during manual tempering process on the characteristics of couverture praline chocolate filled with blueberry filling. The variables used in this study was shell formation duration (10, 15, 20 minutes), and duration of crystal maturation (day 0, 4, 8, 12). Chocolate shell was formulated with sucrose and 34% of fat content. The result showed that the longer the shell formation, the higher the chocolate hardness and particle size. While, chocolate lightness ranged between 25.47 to 27.57.

Alcohol in praline fillings influences the water migration within the surrounding chocolate shell

Migration of water and/or ethanol from praline fillings into the surrounding chocolate, during storage can cause severe quality defects in such products. Therefore, knowledge about migration behaviour is crucial to produce high quality, shelf-stable, confectioneries. We measured contents of water and ethanol in several chocolate, layers differing in their distance to such fillings during storage for 8 weeks at 18 or 26, °C. Fillings were formulated to possess different water activities between 0.65 and 0.75, as well as ethanol contents between 0% and 16%. As could be expected, the higher, storage temperature increases the rate of migration of water as well as ethanol, However, the presence of ethanol in the filling was much more important for the water, migration. It tremendously increased the water contents in the chocolate but also led to, non-linear kinetics of the migration rate during storage. The migration of water could be, successfully modelled using the diffusion model with some adaptations to be able to, describe the special influence of ethanol on water migration and chocolate properties. • Presence of ethanol in the filling has a huge influence on water migration within chocolate. • Swelling and dissolving processes in the chocolate matrix resulted in a non-linear migration behaviour of the water. • Migration kinetics can be described by the diffusion model with special adaptations on changing material properties.

Regenerative efficacy of tert-butyl hydroquinone (TBHQ) on dehydrogenated ascorbic acid and its corresponding application to liqueur chocolate

In this study, a polyethylene (PE) film contained tert-butyl hydroquinone (TBHQ) was immersed into an aqueous solution containing dehydrogenated ascorbic acid (DHA) as a separable system for verifying the regenerative effect between the two antioxidants with different solubilities. It was confirmed that DHA was regenerated to either ascorbic acid (AA) with the presence of TBHQ; and the regeneration rate of AA was significantly increased compared with the control without using the TBHQ-contained PE film. The extent of regeneration from DHA to AA was influenced by the following factors, including surface area of PE film, content of TBHQ, reaction time, and temperature. The regenerative mechanism of DHA to AA by TBHQ was proposed accordingly in which DHA was regenerated to AA by TBHQ, and the TBHQ was reacted to 2-tert-butyl-1,4-benzoquinone (TQ) as one of the oxidation products. A further application of the two antioxidants to liqueur chocolate was adopted. Results showed that the TBHQ added into chocolate shell significantly improved the antioxidant capacity of AA when added into the liquor filling. Therefore, such an established antioxidant combination would expect to extend the shelf-life of liqueur chocolate.

Pre-Crystallization of Nougat by Seeding with Cocoa Butter Crystals Enhances the Bloom Stability of Nougat Pralines.

Fat bloom is an outstanding quality defect especially in filled chocolate, which usually comprises oils of different origins and with different physical properties. Dark chocolate pralines filled with nougat contain a significant amount of hazelnut oil in their center and have been reported as being notably susceptible to oil migration. The current study was designed to test the assumption that a targeted crystallization of nougat with cocoa butter seed crystals is an appropriate technological tool to reduce filling oil transfer to the outside of the praline and, hence, to counteract chocolate shell weakening and the development of fat bloom. For this purpose, the hardness of nougat/chocolate layer models and the thermal properties of chocolate on top of nougat were analyzed during storage at 23 °C for up to 84 days. Pronounced differences between layer models with seeded nougat and with control nougat that was traditionally tempered were observed. The facts that chocolate hardness increased rather than decreased during storage, that the cocoa butter melting peak was shifted towards a lower temperature, and that the hazelnut oil content in the chocolate was reduced can be taken as explicit indicators for the contribution of seeded nougat to the fat bloom stability of filled chocolate.

Formulation, development and characterization of a novel functional fruit snack based on fig (Ficus carica L.) coated with sugar-free chocolate

The aim of the present investigation was to explore the possibility of developing a fruit snack formulation based on dried fig powder and chocolate-coated. Dried Fig (Ficus carica L.) powder with a maximum particle size of 354 μm and the lowest compaction force was formulated as the core. Persian gum was prepared at the concentrations of 1.5, 2 and 2.5% and xanthan gum was prepared at the levels of 0.25, 0.39 and 0.54% as the middle layer to the coating of the core. Regarding rheological assessments, sugar-free chocolate containing 29.3% isomalt was selected for the coating of the outer chocolate shell in the entitled snack. Textural analysis showed that coating of the core with hydrocolloids decreased hardness and adhesiveness of the samples (p < 0.05). It was also observed that increasing the xanthan gum and Persian gum concentration led to the reduction of adhesiveness in the snacks (p < 0.05). Coating of cores with hydrocolloids resulted in lower thickness of the chocolate outer shell, as well (p < 0.05). Results of the sensory evaluation tests demonstrated that, the samples with hydrocolloid coating were the most preferred ones by the panelists.

Comparison of isothermal and cycling temperature storage of filled dark chocolate products for accelerated shelf life prediction

Beside a loss in texture, the main quality aspect of filled chocolate products during storage is the development of fat bloom. For these products isothermal or cycling temperature storage tests are used for accelerated shelf life prediction. However, the applicability of these tests compared to real storage conditions is complicated and shelf life estimation is vague. Com;1;paring storage tests of different authors is difficult because products and analysis methods vary. Additionally most of the storage tests are performed to identify the reasons for fat bloom and therefore the storage conditions are not separately investigated. However, all studies agree that temperature has a major impact due to its influence on migration and crystallization. While migration is accelerated at higher temperatures, crystallization shows an optimum at lower temperatures. Therefore, migration and crystal state have to be evaluated during storage, as well as fat bloom formation. In this study, cold stamped dark chocolate shells with nougat filling were chosen to compare isothermal and cycling temperature storage conditions. Cycling temperature storage at adequate levels includes optimum for fat bloom formation, but takes crystallization and migration influence in unequal account. In contrast, isothermal storage at optimum temperature leads to faster fat bloom formation.Practical applications: A precise shelf life prediction helps to reduce food waste. Shelf life estimation is relevant to almost all chocolate manufacturers. Increasing quality standards accompanied by shortened development time demand accelerated tests for shelf life prediction. Conventional storage tests are too expensive and time‐consuming, especially for small and medium‐sized enterprises, which often sell premium filled chocolate products. Additionally a short time to market is needed to be capable of competing. In the present study different accelerated storage tests were compared. The results can be used to choose the relevant test for new developed products and optimization of existing products and processes.In filled pralines storage is a complex interaction of migration and crystallization, which is highly depending on temperature and temperature fluctuation

Relationship between chocolate microstructure, oil migration, and fat bloom in filled chocolates

Fat bloom is one of the main quality problems in the chocolate industry. A bloomed chocolate product is characterized by the loss of its initial gloss and the formation of a gray‐whitish haze, which makes the product unappealing from a consumer point of view. In the industry, most of the fat bloom related problems arise in filled chocolate products, like pralines and chocolate‐coated biscuits. In these products, oil migration is considered the main cause of fat bloom development. It leads to the dissolution of solid cocoa butter crystals in the chocolate shell which may recrystallize with the formation of undesired crystals. These give rise, upon growth, to visual fat bloom. When looking at the available literature, most of the studies elucidate the possible mechanisms of oil migration and the subsequent fat bloom formation using model systems. These model systems are sometimes too distant from the real industrial applications and the important role of the microstructure of the products are often neglected, although it plays a crucial role in migration‐induced fat bloom development. The main objective of this review is to describe the relationships between chocolate microstructure, oil migration, and fat bloom.Practical applications: This review can be used as a base for the development of microstructural strategies to retard oil migration and fat bloom development in filled chocolates. An important strategy to retard oil migration and migration‐induced fat bloom is the creation of more dense structures. By creating denser structures, the overall mobility is reduced leading to a decrease in the rate and extent of oil migration. Also, more dense structures hinder recrystallization and Ostwald ripening, thereby delaying the migration‐induced fat bloom development. As fillings are less standardized and not bound by legislation, modification of the filling composition and microstructure offers more opportunities in delaying fat bloom.The main objective of the review is to describe the relationships between chocolate microstructure, oil migration, and fat bloom, as illustrated in this scheme. The numbers indicate the four parts that are discussed in this review.

Changes in chocolate crystallization are influenced by type and amount of introduced filling lipids

Filled chocolates are particularly susceptible to quality loss due to oil migration. Since the fillings are often softer than the chocolate coatings, the filling lipids can function as an activator for diffusion processes with the formation of fat bloom as a consequence. Filling lipids can merge with chocolate during production or storage. However, in most studies concerning crystallization or migration cocoa butter and hazelnut oil were analyzed, investigations on chocolate are rare. To cover a broad variety of fillings, dark chocolate was blended with hazelnut oil, butterfat, and coconut oil and crystallization was analyzed. All investigated lipids reduced the solid fat content to the same extend. However, crystallization behavior of the blended samples differed. Hazelnut oil accelerated crystallization rate and did not affect crystallization time, while butterfat reduced crystallization rate and time. The effect of coconut oil addition was in between those of hazelnut oil and butterfat. Nucleation and crystal growth rate, which affect the crystallization speed, have been shown to be affected by the type of filling lipid. Additionally, there is evidence that crystal transformation during crystallization is also affected by filling lipids.Practical applications: Based on the results of this study, manufacturers of filled chocolate products may adapt their processing parameters such as temperature and retention time in the cooling tunnel accordingly. The analytical methods may be used to control the production of confectionery and to determine filling fat concentrations in the chocolate shells of freshly produced pralines. As different filling lipids in small contents cause similar softening of chocolate shells, the solid fat content (SFC) of chocolate is an appropriate method to control filling lipid migration into chocolate.Isothermal crystallization of non‐tempered samples shown as solid fat content (SFC) versus time indicate that hazelnut oil has a less retarding effect on crystallization than butterfat and the effect of coconut oil is in between, but closer to hazelnut oil.

Effect of particle size in chocolate shell on oil migration and fat bloom development

The effects of chocolate shell particle size were investigated by means of its influence on rate of oil migration and fat bloom development. The particle size of the non-fat particles in the chocolate, i.e. sugar and cocoa particles was varied between 15, 22 and 40μm. A novel set of analytical techniques was used and by combining migration results with surface topology results clear differences could be observed between the samples. At 23°C storage the samples with a particle size of 15μm showed higher rate of oil migration and further, the earliest development of fat bloom at the surface. This could be observed both macroscopically and microscopically. Thus, it appears as a larger specific surface area of the non-fat particles facilitates migration of filling oil, possibly due to a more heterogeneous and coarser crystal network with higher permeability. Molecular diffusion cannot explain the level of oil migration observed and, thus, convective flow is assumed to be an important contribution in addition to the molecular diffusion.

A new species of Crepipatella (Gastropoda: Calyptraeidae) from northern Chile

Crepipatella occulta n. sp. is described from the intertidal zone in northern Chile. This species is morphologically cryptic with two other Crepipatella species from Chile, Crepipatella dilatata (Lamarck, 1822) and Crepipatella peruviana (Lamarck, 1822) (a senior synonym of C. fecunda), with respect to adult shell morphology and anatomy. However, Crepipatella occulta is clearly distinguishable from both of them on the basis of embryonic development. It can be distinguished from Crepipatella peruviana, a planktotroph, and Crepipatella dilatata, a direct developer with uncleaved nurse eggs, because it has direct devel-opment with developing nurse embryos that are consumed before the juveniles hatch. Genetic data from DNA sequences also support the distinct status of this species, and show that the South African species C. capensis (Quoy Gaimard, 1832–33) is more closely related to C. dilatata and C. peruviana than is C. occulta. In addition Crepipatella occulta displays diagnostic alleles in 14 allozyme loci when compared with the other two co-occuring Chilean species in northern Chile. Morphologically, Crepipatella occulta n. sp. does not attain the large size often observed in C. peruviana, and it typically has a shiny dark chest-nut or chocolate shell interior.

Online Tempercurve Analysis of Praline Products with the Objective of Cooling Process Optimization

AbstractParameter evaluation for cooling tunnel equipment as used for solidification of chocolate masses was realized by evaluation of online temperature curves (real‐time tempercurves). A praline system (dark chocolate shell, hazelnut filling) was cooled by variation of cooling temperature (12, 7, −10C) and air flow rate (1, 3, 6 m/s). By evaluation of real‐time tempercurves with respect to main crystallization events in different product layers and final fat bloom resistance a critical crystallization temperature of T = 18C was determined. In parallel, the significant potential of time reduction by cooling temperature decrease and air flow increase has been worked out by exemplification. Evaluation is based and discussed on cocoa butter crystallization within literature. Furthermore, this rather simple technique is capable of monitoring several details of local cooling situations in the black box cooling tunnel, such as relative cooling capacity, consistency of cooling temperature and effect of production shutdowns.Practical ApplicationsThe real‐time tempercurve technique is adaptable to a wide range of industrial molds and cooling equipment in the chocolate industry. It is so far developed for molded products only. For coated products, an alternative construction of surface analysis by infrared technique is conceivable. On the other hand, the operating experience with cooling tunnels of manufacturers is less detailed in comparison to other process units because it is a closed system (black box). With this approach, the producer is capable of monitoring the performance and continuance of his cooling equipment (air cooler) and is able to set up appropriate process parameters (temperature, air speed) for new or optimize them for existing products.

Study of the porous structure of white chocolate by confocal Raman microscopy

AbstractConfocal Raman microscopy has been shown to be a useful technique for investigation of white chocolate surfaces. The appearance of protrusions and pores, and the distribution of fat, sucrose, and milk powder at and below the surface of white chocolate pralines were investigated using confocal Raman microscopy. Raman horizontal and depth scans showed that the protrusions and pores continue at least 10 µm into the chocolate shell and that some protrusions and channels mainly consist of fat, while some consisted of a fat layer, leaving a hollow space underneath. Further, the pores and their continuing channels consisted of nothing but air. These findings indicate that the protrusions might be connected to channels where we suggest a pressure driven convective flow of liquid fat from within the chocolate matrix that, depending on temperature, moves up to the surface or goes back into the matrix, leaving an empty pore with a shell of fat at the surface, which in some cases collapse and leaves a hollow pore and channel. Therefore, these findings support that the protrusions could be connected to oil migration in chocolate and, thus, further to fat bloom development.Practical applications: Confocal Raman microscopy can be used to investigate the local distribution of different components in white chocolate. This technique offers the possibility to acquire the local distribution of different components within the sample, with a resolution down to the optical diffraction limit. Further, the analysis can be performed at ambient conditions, without requiring any special sample preparation or marker molecules. The results obtained by using this technique suggest that specific surface imperfections on chocolate could be part of a network of pore structures at and beneath the chocolate surface, which could be related to oil migration and thus, to fat bloom formation.

Modelling the rapid cooling and casting of chocolate to predict phase behaviour

In recent years, rapid cooling processes have been developed to manufacture complex, three-dimensional shapes for confectionery products (e.g. chocolate Easter eggs). These processes are similar to injection moulding and casting processes used in the metallurgic and polymer industries. Although these manufacturing routes are commonly used, they are still poorly understood and thus not optimised. In traditional chocolate processing, cocoa butter is cooled at a low rate (<2 °C/min) to obtain the desired polymorph (form V), and higher cooling rates lead to undesired products. It is thus a paradox that rapid cooling processes which generate very high cooling rates (>100 °C/min) are used to manufacture acceptable products. To obtain an understanding of the occurring phenomena, a mathematical model of the phase change of cocoa butter and heat transfer has been developed, solved using the finite element method and validated against X-Ray diffraction data. During this rapid cooling step, only a small fraction of the cocoa fats is solidified. This fraction increases the viscosity and the yield stress of the material locally. This allows maintaining the shape prescribed during the rapid cooling throughout the rest of the process. Numerical experiments over a range of processing conditions indicated that the Planck solution of the Stefan problem could be used to design processes. The numerical simulation shows that the rest of the material does not crystallise during the rapid cooling step but when subsequently passing through cooling tunnels. If a filling is injected at high temperature into the egg shells, local melting of the chocolate shells will occur. It was calculated using the model that for polycarbonate moulds a deposition at temperatures above 36 °C would compromise the structure of the chocolate shell. The model predicted that metal moulds of higher thermal conductivity would allow better cooling efficiency and raise the critical filling deposition temperature up to 45 °C.

Triacylglycerol migration and bloom in filled chocolates: Effects of low‐temperature storage

AbstractThis study investigated the effect of storage temperature on triacylglycerol (TAG) migration, visual fat bloom and taste of industrially produced milk chocolates with a hazelnut‐based filling. The chocolates were stored for up to 10 months at 18 °C, either directly after production or with the inclusion of a variable time at –20 or 4 °C immediately after production and prior to further storage at 18 °C. TAG migration from the filling through the chocolate shell was quantified by HPLC analysis of chocolate sampled from the chocolates' surface. Both [OOO/SOS] and [LOO/SOS] were used as markers for oil migration. Compared to storage at 18 °C only, chilling or freezing of the chocolates for part of the storage time was found to reduce the amount of TAG migration. Effects on diffusion, capillary transport and TAG immobilization during the thermal treatment can be raised as possible reasons for this decrease. Furthermore, storage at –20 °C decreased oil migration during subsequent storage at 18 °C. This suggests a crystallization effect during the storage at –20 °C, leading to permanent (micro)structural changes. Although a thermal treatment at 4 °C compared to –20 °C was less effective in retarding TAG migration, storage at low positive temperatures immediately after production appears already beneficial in the prevention of visual fat bloom. Adverse effects of the thermal treatments on the chocolates' taste were not observed.

Technofunctional barrier layers for preventing fat bloom in triple-shot pralines

The storage stability of dark chocolate with nougat fillings is mainly limited by the formation of fat bloom, which arises because of the migration of nut oil from the filling to the outside of the chocolate shell where it leads to the formation of visible cocoa butter crystals. The triple-shot technique, which allows the simultaneous deposition of three viscous fluids, was applied for the laboratory-scale manufacture of pralines with a technofunctional barrier layer to prevent blooming. Base component of the barrier layer was palm kernel oil, pure or in combination with milk fat; micro-milled sugar or skim milk powder served as disperse phase. As compared to control experiments, the formation of fat bloom was significantly reduced for selected barrier layers because of the reduced transfer of nut oil to the outside of the praline shells. These results indicate that triple-shot depositing is a promising technique for the manufacture of filled chocolate with enhanced physical shelf life.

Small toys contained in chocolate eggs—good or bad surprise?

Injury from foreignbodies is awell-known cause of childhoodmorbidity and evenmortality (1,2). Sweets containing toys with small parts may present a serious choking and aspiration hazard to children under 3 years of age. In Germany and other European countries, small plastic toy components are often sold together with confectionery, e.g. contained in a chocolate shell. According to the European Community Directive concerning the safetyof toys, packaging containingedible items together with small toys which might be dangerous for children under three years of age must carry the warning ‘‘Not suitable for children under three years.’’ To assess the potential dangers of small toysmarketed with confectionery, we performed a national cross-sectional questionnaire survey, including 500 (90%) paediatric clinics, 1300 (25%) paediatricians in practice, and placed an advertisement with the questionnaire in the newsletter of the German Association of Paediatricians. The response rate of clinic and practicewas 39 and 25%, respectively.The advertisement lead to 5 returns. A total of 35 cases were reported. In all cases, the foreign body was a small toy or part of it. In 34 of the cases, the origin of the toys was a kinder surprise chocolate egg and in 1 case a magic bag. 3 (9%) of the small toys were located in the ear, 9 (26%) in the nose, 5 (14%) in the pharynx, seven (20%) in the lungs, and11 (31%) in the gastro-intestinal tract (Table1).The incorporation of toys wasmostly observedby parents.Overall 5 (14%) complications were reported: 4 children suiered from marked obstruction of the upper airways due to a small toy in the pharynx, while 1 child had a pneumonia because of intrabronchial localisation. There were no fatalities. The age of the affected children ranged from 8 months to10 years (med-

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.