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Bloom Formation on Poorly-Tempered Chocolate and Effects of Seed Addition
Abstract
Bloom on chocolate with different levels of cocoa butter seed addition was investigated. When insufficient cocoa butter seed
crystals were added to give proper temper, the chocolate developed bloom as dark brown spheres in lighter color areas, similar
to that seen in bloom on untempered chocolate. These dark colored spheres overlapped and the lighter color areas disappeared
with increasing seed amount added. The relationship between seed amount and lighter color area (bloom), as quantified by image
analysis, showed that over 270ppm seeds (fat basis) were needed to accomplish good tempering. The cocoa butter crystallization
behavior with various amounts of seed was observed by light microscopy. Too few seeds caused sparse β crystallization and
massive β′ crystallization, which explains the appearance of poorly tempered chocolate bloom. As seed amount increased, β
crystallization of cocoa butter took less time to reach the upper level of solid fat content and the size became smaller.
In addition, DSC analysis was carried out to study crystallization and melting behavior of cocoa butter with different seed
amounts. Higher levels of added seeds resulted in greater amounts of β crystal formation and the crystallization temperature
increased, which meant crystallization occurred earlier. These results showed that the mechanism of bloom formation on poorly
tempered chocolate (insufficient seeds) is due to sufficient time and space for phase (particles and fat) separation as the
stable polymorphs grow.
... Seeding with chocolate involves blending two chocolate masses at varying temperatures, with the cooler chocolate serving as the nucleating agent (Jewett, 2017). Meanwhile, CBCP offers precise control over CB crystal stability and quantity compared to chocolate-based seeding (Debaste et al., 2008;Descamps & Kegelaers, 2007;Kinta & Hartel, 2010). On the other hand, CB crystal suspension (CBCS), produced via high-shear crystallizers, furnishes a stable seed crystal polymorph at a specific concentration within liquid CB, delivering accuracy and superior seed crystal distribution compared to other seeding agents (Padar et al., 2008;Windhab, 2017). ...
... On the other hand, CB crystal suspension (CBCS), produced via high-shear crystallizers, furnishes a stable seed crystal polymorph at a specific concentration within liquid CB, delivering accuracy and superior seed crystal distribution compared to other seeding agents (Padar et al., 2008;Windhab, 2017). The continuous process of industrial applications of CBCS and batch seeding with CBCP has demonstrated equivalence in product quality when compared to chocolate pre-crystallized through the multistep industrial conventional process (Kinta & Hartel, 2010;Svanberg et al., 2013;Winkelmeyer et al., 2016). ...
... A mass of 120 g was prepared for subsequent pre-crystallization, and non-tempered (NT) samples were prepared as a standard comparison prior analysis and molding. CBCP Mycryo™ (Barry Callebaut, Lebbeke-Wieze, Belgium) was used as seeding material and weighed to the value of 0.12 mg, which is equal to 0.28% of total fat in chocolate for every pre-crystallization requiring seeding, the amount above the previously recommended to achieve a well-tempered chocolate with CBCP (Kinta & Hartel, 2010). An analytical balance (Antylia Scientific, Vernon Hills, USA) with 0.01 mg sensitivity was used to weigh the molten chocolate and CBCP. ...
Seeding (SD) is a chocolate pre-crystallization technique (PT) that serves as a more efficient alternative to conventional tempering (CT), yielding equivalent characteristics within the category of well-tempered chocolate. However, variability in macroscopic quality attributes may persist. This study aims to discern variations among well-tempered chocolates obtained through various configurations of PTs: CT, SD, and a combination of both (CS), focusing on changes during pre-crystallization, solidification, and subsequent storage at 20 °C. The increased yield stress (> 1.2 Pa) of pre-crystallized chocolate in comparison to non-tempered chocolate, melting peak alignment with the βV cocoa butter (CB) polymorph (29–34 °C) after 6-h storage and fat-bloom resistance up to 9 months, affirm the successful integration of different PTs within the well-tempered chocolate category. However, distinct melt⟶2L⟶3L lamellar packing transition mechanisms for each PT were identified in the first hour of solidification through synchrotron-assisted time-resolved X-ray scattering. Varied polymorphic transition and microstructural growth kinetics were also observed over 28 days of storage, as indicated by melting profiles. CS chocolate exhibited limited transition, remaining stable as βV. In contrast, CT and SD underwent rapid microstructural growth with an indication of a small fraction of CB polymorph transitioning to the undesirable βVI CB polymorph (> 34 °C), linked to fat bloom development. Surface topography observation through accelerated shelf-life test at 26 °C over 9 months marked the link with CB crystal microstructural growth, with fat bloom occurring faster on SD chocolate, then CT chocolate, and finally the CS chocolate. These findings highlight the potential to tailor crystallization kinetics by adapting PT to achieve improved product qualities, such as extended fat-bloom resistance or accelerated solidification while remaining within the well-tempered category.
... (w/w) cocoa-butter crystals in their most stable and desired form with pre-cooled chocolate (32-34°C) which results in having a great number of small and welldefined crystal nuclei. Pre-crystallization with seeding has the potential to retard fat bloom (Kinta & Hartel, 2010;Lindecrantz, 2014;Svanberg, Ahrne, Loren, & Windhab, 2013) and fat migration in chocolate. Also it could work out the disadvantages including; inadequate tempering, heterogeneous nucleation during cooling, incomplete crystallization and crystalline instability (Ribeiro et al., 2015). ...
... The seeding technology confers several advantages including improvement in shelf life (Svanberg et al., 2011), faster crystallization (Kinta & Hartel, 2010), lower energy consumption due to one stage of heat treatment and therefore less equipment and specialized personnel needs, (Lindecrantz, 2014) all resulting in cost reduction of the process. Furthermore, seeding has the ability to improve thermodynamic stability (Hachiya, Koyano, & Sato, 1989;Ribeiro, Basso, dos Santos, et al., 2013) and melting profile (Lindecrantz, 2014;Ribeiro, Basso, dos Santos, et al., 2013) as well as other quality properties associated with chocolate such as glossy surface and good molding properties (Lindecrantz, 2014). ...
... The obtained results showed that the mechanism of bloom development in poorly tempered chocolate is due to formation of insufficient seeds. Higher amounts of added seed crystals lead to greater level of β crystal formation (Kinta & Hartel, 2010). Hachiya et al. (1989) examined the effects of seeding of fat crystals on the crystallization kinetics of cocoa butter and dark chocolate. ...
Pre-crystallization is an important step in the production of chocolate, which is defined as tempering of cocoa butter through primary and secondary nucleation. The goal of tempering is to obtain a sufficient amount of βV polymorph of the right size. The pre-crystallization process has a great impact on the quality and production cost of final product. Development of chocolate technology requires the use of the most appropriate techniques and ingredients without negatively affecting the quality characteristics. Applications of novel technologies within the confectionery industry have allowed production of chocolate in sufficient quantities to meet the public needs. In order to provide and investigate the potential and usage of novel technologies, the present review focused on different pre-crystallization methods and factors affecting the processing conditions. Seeding and ultrasound-assisted pre-crystallization can be used as alternatives to conventional tempering process. However, in both methods, optimization of experimental conditions is required.
... The use of seeding technique in chocolate production has the following potential benefits: (1) increasing shelf-life [10], (2) better moulding ability [11], (3) improvement of thermodynamic stability [12,13] and melting profile [11,13], (4) fat blooming reduction [14,15], (5) re-crystallization with lower energy consumption [11], (6) reduced fat migration [14], (7) transformation of unstable polymorphic forms to stable forms [15], (8) higher crystallization [15] and (9) relative cost reduction with the requirement of fewer equipment and specialized staff [11]. ...
... The use of seeding technique in chocolate production has the following potential benefits: (1) increasing shelf-life [10], (2) better moulding ability [11], (3) improvement of thermodynamic stability [12,13] and melting profile [11,13], (4) fat blooming reduction [14,15], (5) re-crystallization with lower energy consumption [11], (6) reduced fat migration [14], (7) transformation of unstable polymorphic forms to stable forms [15], (8) higher crystallization [15] and (9) relative cost reduction with the requirement of fewer equipment and specialized staff [11]. ...
... The use of seeding technique in chocolate production has the following potential benefits: (1) increasing shelf-life [10], (2) better moulding ability [11], (3) improvement of thermodynamic stability [12,13] and melting profile [11,13], (4) fat blooming reduction [14,15], (5) re-crystallization with lower energy consumption [11], (6) reduced fat migration [14], (7) transformation of unstable polymorphic forms to stable forms [15], (8) higher crystallization [15] and (9) relative cost reduction with the requirement of fewer equipment and specialized staff [11]. ...
In this study, sugar-free dark chocolate was produced from isomalt and maltitol by β V seeding technique as an alternative to conventional tempering process. The effect of β V seed concentrations on the particle size distribution, textural, rheological and melting properties of the end products was studied, and the results were compared with those of conventional sugar-free dark chocolates. For this aim, conched dark chocolates were melted and crystallized with β V seeds added at different concentrations (0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 %, m/m). Conventional tempering process was performed by using temper machine (47–27–32 °C). Brightness, chroma, whiteness index and tetramethyl pyrazine content (as marker compounds of dark chocolate volatile compound) were not influenced by seeding technique compared to conventional tempering method. The water activity of the dark chocolate samples was substantially affected by β V seed level according to used bulk sweetener. However, all the values were determined below 0.4 which is critical limit for chocolate. Regarding overall acceptability, sugar-free dark chocolates tempered by β v seeds had very close scores compared with conventional one, implying that sugar-free chocolates can be produced by β v crystals with desired quality characteristics similar to conventional samples. Results of this study showed that it is possible to produce sucrose-free dark chocolates by using β V seeds with desired quality similar to chocolate produced by using conventional tempering.
... In the this technique (seeding), the most stable crystals of cocoa butter (βv) is used in conched chocolate at 32-34ºC which results in a large number of small welldefined crystal nuclei. Pre-crystallization with seeding may ensure some advantages such as, faster crystallization, lower energy consumption, less equipment and specialized personnel needs and also cost reduction (Kinta and Hartel, 2010). This technique is beneficial for food industry manufacturers, because it can increase efficiency of productivity in terms of fastening process and decreasing costs. ...
... This technique is beneficial for food industry manufacturers, because it can increase efficiency of productivity in terms of fastening process and decreasing costs. In addition pre-crystallization have considerable effects on chocolate quality, such as, fat blooming reduction (Zeng et al., 2002), shelf life improvement (Riberio et al., 2013) and thermodynamic stability and melting profile (Kinta and Hartel, 2010). ...
... Bloom on chocolate with different levels of cocoa butter seed addition was investigated by Kinta and Hartel (2010). The results indicated that when inadequate cocoa butter seed crystals were added to give proper temper, the chocolate developed bloom as dark brown spheres in lighter color areas, similar to that seen in bloom on untempered chocolate. ...
In the present study, synbiotic milk chocolate including Lactobacillus acidophilus and inulin was prepared using βv seeds as an alternative to conventional tempering method. For this aim, different concentrations of βv seeds (0.5-1.5%) were used in the chocolate production. The effect of βv seed concentration on water activity, moisture content, hardness value, color and rheological properties of the chocolate was examined and compared with those of the sample produced by conventional tempering method. Water activity and moisture content values of the samples were found to be very close to each other. Hardness value was significantly affected by βv seed concentration. Yield stress and plastic viscosity values decreased with increasing seed concentration. All of the quality parameters highlighted that βv seed can be used as a pre-crystallization technique without negatively affecting quality characteristics, providing economic gain and fast production when compared with classical one.
... When blooming occurs, the surface whiteness of the non-fat particles increases, but the particle size distribution exhibits a limited white color change effect. Kinta and Hartel [35] investigated the relationship between insufficient tempering and the yield of cocoa beans produced by chocolate during blooming formation. The results indicated that increasing the number of cocoa beans formed more β crystals, and the crystallization temperature increased. ...
... significantly reduce the bloom rate in chocolate Processing treatment It is possible to keep chocolate products from blooming by adding maltitol and tagatose sweeteners [31] Processing treatment White chocolate products with stevia and sucralose sweeteners can prevent lower fat blooms if the stevia sweetener content is equal to or greater than the sucralose sweetener content [32] Processing treatment Re-tempering chocolate products can increase fat bloom resistance [34] Processing treatment Without tempering chocolate products, blooming can occur on the 25th day of storage [44] Processing treatment Insufficient tempering time and space for phase separation (particles and fat) resulted in the formation of blooms in chocolate [35] Chocolate storage conditions When chocolate is stored at 20-32 °C, it can bloom [36] Chocolate storage conditions Blooming was observed on the first day of storage at 35 °C. However, after seven days, the sensory quality of chocolate had deteriorated [37] Chocolate storage conditions 12 °C is the optimal temperature for storing chocolate products during their storage period [38] ...
One of the indications of chocolate product degradation is blooming. It is distinguished by the loss of surface shine, which is replaced by a white coating. These effects are caused by insufficient processing, inappropriate chocolate content, and incompatible storage conditions. It can alter these characteristics to enhance chocolate's resistance to blooming and its texture, flavor, and appearance. Several factors must be considered when creating blooming-resistant chocolate, such as chocolate particle size, fat content, processing techniques, and storage conditions. This concise review will discuss fat blooming in chocolate, from its formation to its contributing factors and methods for resolving it.
... The key processes of fat bloom formation are polymorphic transformations from metastable to more stable forms of confectionery fats, and the growth of large crystals in accordance with these polymorphic transformations. The many studies on the causes and mechanisms of fat bloom formation have focused on improper thermal treatment during production and storage (Jin & Hartel, 2015;Kinta & Hartel, 2010;Kinta & Hatta, 2005;Lonchampt & Hartel, 2006;Walter & Cornillon, 2001;Zhao, Young, & James, 2018), oil migration (Khan and Rousseau, 2006;Smith, Cain, & Talbot, 2007;Dahlenborg, Millqvist-Fureby, & Bergenståhl, 2015;Hondoh, Yamasaki, Ikutake, & Ueno, 2016;Wang & Maleky, 2018), defects in chocolate (Rousseau & Smith, 2008), effects of CB alternatives CBE and CBS (Bahari & Akoh, 2018;Biswas, Cheow, Tan, & Siow, 2017;Jin, Jin, Wang, & Akoh, 2019), effects of emulsifiers (Buscato et al., 2018), and non-fat particulate network (Zhao, Bingol, & James, 2018). Based on the research on fat-bloom mechanisms, various retardation techniques have also been reported (Buscato et al., 2018;Son et al., 2018). ...
... Monitoring methods of fat bloom have also been developed: scanning probe techniques (Rousseau, 2006;Khan & Rousseau, 2006;Sonwai & Rousseau, 2008, optical microscopy and image analyses (Nopens et al., 2008;Kinta & Hartel, 2010;Zhao, Young et al., 2018), whiteness index (Jin & Hartel, 2015;Kalnin, 2012), scanning electron microscopy (SEM) (Dahlenborg, Millqvist-Fureby, Bergenståhl, & Kalnin, 2011;Kinta & Hatta, 2005;Rousseau & Smith, 2008;Son et al., 2018;Zhao, Bingol et al., 2018;Zhao, Young et al., 2018), confocal Raman microscopy (Dahlenborg, Millqvist-Fureby, Brandner, & Bergenstahl, 2012), profilometry (Dahlenborg et al., 2011;Rousseau, Sonwai, & Khan, 2010), X-ray photoelectron spectroscopy (James & Smith, 2009) and X-ray scattering and diffraction Reinke et al., 2015;Zhao, Li, and James, 2018). These methods are grouped into ex-situ (e.g., SEM) and in-situ (e.g., optical microscopy and profilometry). ...
This paper reports the experimental study for the quantitative analysis of fat bloom formation of chocolate using 3D-laser scanning confocal microscopy (3D-LSCM). We focused on observation of very early stages of fat bloom formation (pre-bloom), which do not exhibit any whitish haze patterns that can be identified by the naked eye or whiteness index instruments. The final stage of the pre-bloom→bloom formation was confirmed using cryo-SEM measurements. The following results were obtained. (1) The initial occurrence of pre-bloom was monitored as concave and convex patterns whose depth and height were of the order of 0.2 μm. (2) The evolution of fat bloom was quantitatively measured as increases in depth, surface, and volume of concave/convex patterns in a separate manner. (3) The total volumes of the convex patterns were larger than those of the concave patterns, indicating that the cocoa butter (CB) molecules forming the convex patterns were supplied not only from the surface but also from the interior of the chocolate.
... In addition, the liquid fat in the solid chocolate may be siphoned to the surface through cracks or crevices, where it further promotes fat bloom formation on the surface [88]. Fat bloom in under-tempered chocolate typically develops shortly after cooling, whereas untempered chocolate requires several days to develop bloom [97]. In both cases, the surface changes dramatically. ...
... In both cases, the surface changes dramatically. The fat bloom appears as lighter colored areas or "coronas" surrounding dark colored spheres [17,97]. Kinta and Hartel [97] attribute this to phase separation between CB and solid sugar and cocoa particles. ...
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.
... Furthermore, it could also be a consequence of weaker interactions (van der Waal forces) between the crystals in over-tempered chocolate as described by Afoakwa et al. (2009). Both under-tempered samples, Seed-UT and Conv-UT, showed the weakest fat crystal structure, and thus, lower structure density which also coincides with previous structure characterizations of chocolate with low temper-degree (Afoakwa et al., 2009; Kinta and Hartel, 2010; Talbot, 2009). The results from the traction tests presented inFig. ...
... The Seed-WT samples showed the best resistance against fat bloom and measureable levels of color standard S3 (heavy bloomed) were first observed in these samples after 13 weeks of storage. These results are also consistent with previous findings of fat bloom in optimal versus sub-optimal processed chocolate (Afoakwa et al., 2008; Kinta and Hartel, 2010; Loisel et al., 1997). However, comparing the effect of conventional versus b VI -seeding pre-crystallization process, the latter showed a significantly better resistance against fat bloom for both under-and well-tempered samples. ...
... Analysis of microstructure was determined according to Campos et al. [27] and Kinta and Hartel [28] using a polarized light microscope (PLM). The butter sample was placed on a thin glass preparation, and then observed under PLM at room temperature. ...
Butter is generally made from milk fat, which contains high levels of saturated fatty acids, thus providing health risks. Therefore, alternatives are needed, namely recombined butter by substituting other healthier saturated fats, namely fat rich in monoacylglycerols (MAG) and diacylglycerols (DAG) from glycerolysis of coconut stearin which is rich in medium chain fatty acids, which are then called MAG-DAG fat (MDF). This research aimed to determine the effect of MDF substitution in recombined butter, which produced the best physicochemical and sensorial properties. The substitution of MDF was carried out at concentrations 0%, 5%, 10%, 15%, and 20%. Substitution of MDF had a significant effect on physicochemical properties and sensory acceptability. Recombined butter with substitution of MDF-5% produced good physicochemical properties and was liked by the panelists. Recombined butter of MDF-5% contained MAG, DAG, and triacylglycerol (TAG) of 0.48%, 8.71%, and 90.81%, respectively, and it had a higher medium chain fatty acids (MCFAs) content, namely 10.72% compared to the MDF-0% (control) which was only 7.45%. The hardness, adhesiveness, and cohesiveness of recombined butter of MDF-5% were about 1247.44 N, −671.28 N, and 0,09 N, respectively. The crystal microstructure was in the form of small spherulites in large quantities, and polymorphism showed a mixture of β’- and β-crystals. Substitution of MDF-5% did not change the new functional groups, but increased the intensity of the hydroxyl groups. Substitution of MDF in recombined butter was suitable to produce butter with good characteristics and potentially healthier.
... The higher the saturated fatty acids in the composition of processed Pendawa chocolate, the higher the hardness value obtained [21]. Conversely, the higher the unsaturated fat, the faster the chocolate product will soften [22,23]. Other ingredients in making chocolate bars also affect it, such as the type of oil used, lecithin, cream milk powder, chocolate powder, chocolate paste, baking soda, and sugar [24]. ...
Chocolate bars are a food that is in demand by almost all age groups, both men and women. Aside from being a healthy snack, chocolate products are included in the refreshing plant, which can stimulate the central nervous system. It creates a happy dopamine effect for those who consume it. The demand for chocolate bar products has increased every year. As one of the world’s largest cocoa-producing and supplying countries, Indonesia must evaluate the quality of its cocoa beans. This research uses fermented cocoa beans, which are then processed into cocoa butter cocoa paste, which is used to manufacture pendawa chocolate bars. Other ingredients include mustard oil, coconut oil, cocoa butter, cocoa paste, powdered sugar, powdered milk, baking soda, vanilla, and lecithin, which are added to the chocolate bar formulation. Color, total dissolved solids, hardness, and melting time of chocolate bars were analyzed. The formulation of ingredients with palm oil was better for improving the quality of the chocolate bars produced based on the level of hardness, total dissolved solids, and melting time. The best treatment in this research was the F5 formulation, namely the addition of coconut oil in making Pendawa chocolate bars with a melting time of close to 24 hours at room temperature.
... The microstructure of the crystal was observed by a polarized light microscope, according to Kinta and Hartel [28] and Basso et al.. [29] The sample was heated at 60-80°C and then cooled to 25-30°C. The sample was spread on a glass slide at 25-30°C and viewed at three different points. ...
Iron fortification in the form of ferrous sulfate is associated with several disadvantages, particularly related to the unpleasant after-taste. In this context, ferrous sulfate must be encapsulated by forming solid lipid nanoparticles (SLNs), which can be applied to fat-based foods such as chocolate bar. Therefore, this study aimed to provide chocolate bar fortified by SLN-ferrous sulfate with good physicochemical characteristics and sensory acceptability. The process was carried out by providing fats rich in monoacylglycerol (MAG) and diacylglycerol (DAG) from coconut stearin as a lipid matrix and emulsifier, fabricating SLN-ferrous sulfate, and fortifying SLN-ferrous sulfate in the chocolate bar at 0% (control), 2.5%, 5%, and 7.5%. The results showed that the fortification significantly affected texture, color, iron content, and sensory acceptability. The addition of SLN-ferrous sulfate of 2.5% produced chocolate bar with good physicochemical properties, which were preferred by the panelists. The chocolate bar contained iron reaching 79.23 mg/kg, a small spherulitic crystal microstructure, dominated by stable β-crystals, and no fat bloom was formed. Furthermore, SLN-ferrous sulfate based on fats rich in MAG and DAG from coconut stearin was compatible with good characteristics.
... Thermal analysis such as melting profile from differential scanning calorimetry (DSC) or spectroscopic analysis such as X-ray diffraction (XRD) techniques are often utilized to deduct tempering degree by qualifying and quantifying the CB polymorph from a solid pre-crystallized chocolate (Afoakwa et al. 2009;Bolliger et al. 1998;Bolliger et al. 1999;Dhonsi and Stapley 2006;Le Révérend et al. 2009;Le Révérend et al. 2010;Loisel et al. 1997;Svanberg et al. 2013). Determination of the macroscopic quality of solid chocolate could be performed by observing the contraction before demolding ), hardness using a texture analyzer (Afoakwa et al. 2008a), or fat bloom development (Afoakwa et al. 2008a;Bolliger et al. 1998;Kinta and Hartel 2010;Svanberg et al. 2013;Svenstrup et al. 2005). These techniques are useful to monitor exclusively certain aspect among the extensive crystallization phases in chocolate that includes primary crystallization, polymorphism, microstructural, or macroscopic development. ...
The typical quality attributes of chocolate, such as its glossy appearance, hard and brittle texture, sharp melting, and fat bloom resistance, are determined by the process conditions under which solidification occurs. It is therefore reasonable to test the success of this process from their solid form through thermal, textural, and/or optical analysis. However, the solidification process of chocolate consists of a dynamic pre-crystallization step and a subsequent static crystallization step that relies on the crystallization of cocoa butter in its matrix. Each of these crystallization steps has a different mechanism and target. Additionally, the flow parameters such as apparent viscosity and yield stress during each crystallization step change and may affect the subsequent process steps. This work evaluates the possibility of performing rheological tests to follow changes in the flow behavior of dark chocolate during and immediately following pre-crystallization, as well as during solidification. Different tempering protocols, consisting of distinct time and temperature profiles, were performed by manually stirring and scraping the molten chocolate from a glass beaker in temperature-controlled water baths. Selected protocols were mimicked in the rheometer equipped with sandblasted parallel plates by performing a rotational test with temperature ramps to monitor changes in flow behavior. Key experimental settings including gap size, shear rate, pre-conditioning temperature, and residential time are discussed in this paper. Thermal and shear effects attributed to the evolution of apparent viscosity can be monitored within different phases of pre-crystallization. The flow curves of tempered chocolates from corresponding manual and rheometer tempering protocols, as well as the melting profiles upon their solidification, were comparable, reproducible, and indicating well-tempered chocolate characteristics. Furthermore, it was possible to follow up static crystallization in the rheometer after tempering. Thus, rheometrical techniques are proven to be a useful tool to monitor flow behavior changes in different phases of the solidification step in chocolate manufacturing and may provide important rheological data of molten, pre-crystallized, and solid chocolate.
... (w/w) of the desired polymorphs of cocoa butter are uniformly mixed into chocolate at 32-35°C. This method has the advantages of preventing fat migration and fat blooming (Kinta & Hartel, 2010); and solve the shortcomings such as incomplete crystallisation, heterogeneous nucleation and inadequate tempering (Ribiero et al., 2015). "Sono-crystallisation" using ultra sound at 20 Khz is an energy and time saving technique that could provide similar results as tempering, when applied under optimal conditions. ...
The use of 3D printing (3DP) for food applications is gaining attention both as a research topic, and for industrial applications. Chocolate is one of the most common food commodities used for 3DP, owing to its melt extrusion capability and popularity in the high‐end food industry. However, chocolate remains a difficult substrate to work with, due to its complex composition as well as rheological properties. The quality of cocoa beans and the processing conditions of chocolate manufacture influence the quality of 3DP. This review briefly covers areas such as processing of chocolate, types of 3D printing of chocolate, rheology of chocolate inks, textural attributes and sensory evaluation of the 3D chocolate products.
... The microstructure of chocolate bars was observed using a Polarized Light Microscope (PLM). [28] The chocolate bar was melted at a temperature of 60°C and cooled to 30°C. The chocolate was spread on a glass slide set on a temperature control unit that was kept at 30°C under circulating refrigeration. ...
The chocolate bar is a processed cocoa product that is rich in polyphenols, but polyphenols decrease during processing. Gallic acid encapsulated in the form of solid lipid nanoparticles (SLN) can be a solution for the fortification of phenolic compounds in chocolate bars. This study aimed to obtain the right concentration of SLN-gallic acid in the manufacture of chocolate bars. SLN was made by the double emulsion method and added fat rich in Monoacylglycerol (MAG) and Diacylglycerol (DAG) from coconut stearin as an emulsifier as well as a solid lipid matrix. The concentrations of SLN-gallic acid used for fortification were 0%, 2.5%, 5%, and 7.5%. The results showed that the addition of SLN-gallic acid affected the characteristics of physicochemical, sensorial, and antioxidant activity of chocolate bars. The higher the concentration of the addition of gallic acid SLN increased the total phenolic and antioxidant activity. However, the characteristics of color, texture, and organoleptic properties were decreased. The microstructure of the chocolate bar did not show a significant difference, namely the spherulite needlelike crystal. The best treatment was obtained by adding 5% of SLN-gallic acid on chocolate bars with an IC50 of 174.24 ± 2.48 and was favored by the panelists. The best treatment resulted in crystal morphology in the form of spherulite, small and spread out, and the polymorphism pattern was dominated by beta crystals. Thus, SLN-gallic acid was suitable for the fortification of up to 5% into chocolate bars.
... Once the chocolate mass is conched, the next step is tempering; this is another critical step in chocolate's physicochemical characteristics since this step aims to obtain a solidified chocolate bar. Therefore, it is needed to ensure proper cocoa butter crystals such as β V [82]. These β V crystals can be obtained through temperature and depend on the fat phase's nature in the chocolate [70]. ...
Consumer demand for healthier foods with improved taste and convenience has urged the food industry to develop functional foods added with bioactive ingredients that can supplement basic nutrition (food supplement) or exert a pharmacological effect (nutraceuticals). Chocolate could be used as an ideal carrier to deliver bioactive ingredients, mainly due to its high acceptability by consumers. However, a drawback of using chocolate as functional food is its high sugar content, which impedes its commercialization with the diabetic population. Therefore, there is need to develop sugar-free chocolate formulations added with bioactive ingredients. Nevertheless, sugar replacement and bioactive ingredients addition is a major technological challenge that affects texture, rheology, and sensory properties of chocolate. This review is designed as a practical guide for researchers and food industries to develop the next generation of functional chocolates. Different functional chocolate formulations, including sugar-free, are reviewed as potential carriers for the delivery of bioactive compounds. The physicochemical properties and sensory acceptability of the functional chocolates presented are also highlighted. Finally, future perspectives, such as the use of nanotechnology to improve the bioaccessibility and bioavailability of active ingredients, as well as the need for clinical trials to validate the pharmacological effect of functional chocolates, are also discussed.
... The presence of cocoa butter makes the chocolate a temperature sensitive material. In addition, by doing a proper tempering, a more stable β crystal (Form V) can be obtained and this produces chocolate with a better quality such as a glossy appearance, a snap and a desirable texture (Afoakwa et al., 2007;Afoakwa et al., 2008;Afoakwa et al., 2009;Beckett, 1995;Chen and Mackley, 2006;Chocolate Alchemy, 2008;Cidell and Alberts, 2006;Kinta and Hartel, 2010;Talbot, 1994). Chocolate has a complex structure and its character significantly varies even with a small variation in temperature. ...
The 3D printing technology has been applied to directly to construct physical model from 3D modelling without any aid of mold. Several industries such as automobile, aerospace including and recently food industry has utilize this technology to manufacture a complicated and intricate part required in the industry. It is foreseeable that 3D food printing (3DP) are possible to produce complex food model with unique internal pattern. A 3D food printing technique is composed of an extrusion-based printing, selective laser sintering and inkjet (liquid binding) printing. The food materials such as sugar, gelatin-based chocolate, and are used to create designed shape based on layer-by-layer method. This paper presents a review of 3D food printing techniques. This review is to categorize, printability, productivity, properties of printable material and mechanism of 3D food printing techniques, as well as to propose the future direction of this novel technology.
... Depending on the research approach, monitoring of fat bloom formation can be accomplished by varying specific conditions of chocolate formulation, storage or processing parameters, so as to accelerate or delay this defect formation and development. In regard to tempering, it is known that the final chocolate structure of a sub-tempered or an over-tempered chocolate mass changes spontaneously, favoring the formation of the bloom (Kinta & Hartel, 2010;Graef et al., 2005). In other hand, a well-tempered chocolate presents structure characteristics suitable to resist for several months to the fat bloom formation, if stored under constant temperature, below 20°C. ...
Today, food not only needs to satisfy hunger and provide the necessary nutrients for the body, but also to prevent the occurrence of diseases that are related to nutrition and improve the physical and mental health of consumers. Functional foods can improve the general condition of the body, reduce the risk of some diseases and furthermore be used to treat some diseases. Given the growing popularity of functional foods and frequent consumption of confectionery products, especially chocolate, the goal of this chapter was to create innovative, functional chocolate - chocolate with soy milk. Chocolate with soy milk is composed of 8-10% soy proteins, which have a positive impact on human health. Soy milk contains more protein and less fat than cow’s milk. It is characterized by the absence of cholesterol and lactose, has a low content of saturated fatty acids, while the content of polyunsaturated fatty acids is significantly higher than in cow’s milk. This chocolate is not only interesting because of its health effects, but also because of its textural properties. The greatest impact on the thermoreological, thermal and textural properties of chocolate have the composition of the ingredients, fat content, selection of emulsifiers, solid particle size distribution and particle packing method. In milk chocolate the ratio of milk fat and cocoa butter determines the quality of chocolate and today everything about it is well known, while the ratio of soy milk - cocoa butter has not been completely defined. For this chapter, chocolate was produced in an unconventional way, i.e., in a ball mill applying variable refining time (30, 60 and 90 minutes) and pre-crystallization temperature of chocolate mass (26, 28 and 30°C). The chocolate was produced with 20% of soy milk powder. The quality of chocolate was monitored by investigating nutritive composition, polyphenol content, hardness of chocolate, solid triglyceride content (SFC), thermal characteristics, rheological parameters (Casson yield flow (Pa), Casson viscosity (Pas), the thixotropic loop area, elastic modulus and creep curves) as well as sensory properties. Results showed that chocolate with soy milk had a higher nutritional value and better antioxidant properties than chocolate with powdered milk. The proteins of the soy milk, which are capable of forming a gel if the protein concentration is greater than 8%, lead to the viscoelastic behavior of the chocolate mass. Rheology of the chocolate mass with soy milk depends solely on the soy proteins, while thermal and sensory properties and content of solid triglycerides depends on the fatty phase, i.e., soybean oil. In order to maintain optimal sensory quality, hardness as well as melting resistance of chocolate, it is necessary for the chocolate with soy milk to be refined longer in a ball mill, however also to use lower temperatures for pre-crystallization.
... Bloom is the result from bad tempering, improper preparation temperature, storage conditions, incorrect cooling methods, and/or fats crystallization, which are incompatible with cocoa butter. (Hartel, 1999;Kinta & Hartel, 2010;Lonchampt & Hartel, 2006). In this sense, changing the triglyceride ratios in chocolate products may also influence organoleptic properties such as mouth feel and taste. ...
The effects of replacing cocoa butter with different percentages and proportions of a mango kernel fat/palm olein (MKF/POL) blend, are reported. Samples were prepared by melting together mango kernel fat, palm olein, cocoa butter and cocoa mass and powdered sugar combinated. The samples were milled, conched, tempered, and molded to obtain three sets of seven samples as follows: one control omitting mango kernel fat and palm olein, and six samples with cocoa butter replacement of 15 and 22.5% and MKF/POL ratios of 2.3, 4.0, and 9.0. Casson viscosity, Casson yield stress, fat bloom and sensory acceptability were all measured. In fact, all samples had achieved a low Casson viscosity (ηCA) and Casson yield stress (τ_oCA), which indicates molding and enrobing as appropriate uses. In addition, some significant differences (p ≤ 0.05) were found among samples. Fat bloom was accelerated in the samples relative to control, but high MKF proportions tended to retard appearance of fat bloom. No differences were observed in organoleptic properties between samples and control.
... (w/w) cocoa-butter crystals in their most stable form with pre-cooled chocolate (32-34 °C) which results in a large number of small well-defined crystal nuclei [11]. Pre-crystallization with seeding may ensure some advantages as fat blooming reduction, decrease in cocoa butter migration [12,13], improvement in shelf life [14], thermodynamic stability and melting profile, conversion of unstable polymorphic forms in crystals to stable forms [15], faster crystallization, lower energy consumption, better molding property, less equipment and specialized personnel needs and also cost reduction [16]. There are limited studies related using the seeding for pre-crystallization. ...
In the present study, it was aimed to produce sucrose-free milk chocolate including isomalt or maltitol by βV seeding technique as an alternative to conventional tempering process which was performed by using temper machine (47–27–32 °C). For this aim, conched milk chocolates were melted and crystallized with βV seeds added at different concentrations (0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 g/100 g chocolate). The influence of βV seed concentrations on the textural, rheological and melting properties of the end products was investigated, and the results were compared with those of conventional sucrose-free milk chocolates. Hardness value of isomalt including samples decreased at βV seeds concentrations of 0.7, 0.8, 0.9 g/100 g chocolate. For the maltitol containing samples it increased significantly at 0.9 g/100 g chocolate compared to traditional chocolate. However, generally, hardness value of the samples varies in a narrow range by seeding technique. Milk chocolate samples containing maltitol were found to have higher hardness values than isomalt containing chocolate samples (p < 0.05). Melting characteristics of the samples were not affected by βV seed concentrations. According to casson model, seeding at 1 g/100 g chocolate for maltitol samples and 0.9 g/100 g chocolate for isomalt samples significantly increased yield stress compared to control samples. However, by seeding technique yield stress only varied between 2.48 and 5.91 Pa. Therefore, the findings of this study showed that it is possible to produce sucrose-free chocolates by tempering with βV seeds with desired quality similar to sucrose-free milk chocolate produced by using conventional tempering.
... Bloom formation on chocolates, stored at 24 ± 1 C and 29 ± 1 C, was captured and examined every two weeks for a total of 3 months using a stereomicroscope (Nikon, SMZ1500, Tokyo, Japan) fitted with a digital Nikon camera (Nikon, Digital Sight DS-2Mv, Tokyo, Japan), according to previously described method (Kinta & Hartel, 2010). ...
This study examined the physical properties of enzymatically produced palm oil-based cocoa butter substitute (CBS) in dark chocolate. Melting profile, particle size distribution (PSD), rheological, textural behaviors, bloom formation and polymorphism were analysed using differential scanning calorimetry (DSC), master-sizer/polarized light microscopy (PLM), rheometer, stereomicroscope and x-ray diffraction (XRD), respectively. Dark chocolates were produced with cocoa butter (CB, without CBS), 5 g CBS (formulation-1) and 20 g CBS/100 g blend (formulation-2). Both chocolates with addition of CBS showed maximum melting temperature similar to CB-chocolate. However, the peak area and melting enthalpy for formulation-2 were significantly (P<0.05) different from CB-chocolate. Significant differences (P < 0.05) in PSD, flow behavior, hardness and sensory characteristics were observed for formulation-2 whilst no significant difference (P ≥ 0.05) was observed for formulation-1. Stereomicroscope images of all the chocolate samples did not show bloom at 24 °C for up to 8 weeks. Conversely, at 29 ± 1 °C, bloom formation was only observed for CB-chocolate and formulation-1 after two weeks of storage. Noticeable changes in XRD peaks were observed for bloomed chocolate. Overall, chocolate with formulation-1 was similar to CB-chocolate in terms of physical and sensory properties. However, chocolate with formulation-2 exhibited significantly lower sensory profiles particularly taste acceptance and hardness compared to CB-chocolate.
... The impacts of seed addition on cocoa butter crystallization were investigated by Kinta and Hartel [52]. Their findings indicated that over 270 ppm seeds (fat basis) were required to achieve good tempering. ...
Oil migration is a common problem in chocolate confectionery products leading to quality defects, particularly fat bloom. Several factors such as contact area, ratio of the two fat phases, type of the fat, solid fat content, presence of non-fat solid particles, particle size, viscosity, structure, concentration gradient of triacylglycerols (TAGs), and storage temperature have all effect on migration rate. Mechanism of oil migration has still not been clearly understood, but possible mechanisms have been suggested and studied in the literature. Diffusion mechanism was demonstrated and modeled in many studies. Although there are so many methods to monitor and quantify migration, magnetic resonance imaging (MRI) is among the most promising techniques as being non-destructive. This review covers the literature related to basics of migration, mechanisms, and monitoring and modeling migration in chocolate through MRI and also includes a brief description about chocolate, chocolate processing, and fundamental concepts in MRI.
... (w/w) cocoa-butter crystals in their most stable form with pre-cooled chocolate (32-34 °C) which results in a large number of small well-defined crystal nuclei [11]. Pre-crystallization with seeding may ensure some advantages as fat blooming reduction, decrease in cocoa butter migration [12,13], improvement in shelf life [14], thermodynamic stability and melting profile, conversion of unstable polymorphic forms in crystals to stable forms [15], faster crystallization, lower energy consumption, better molding property, less equipment and specialized personnel needs and also cost reduction [16]. There are limited studies related using the seeding for pre-crystallization. ...
... Ziegleder and Schwingshandl [32] asserted that the migration fat bloom in chocolate diminishes from 23°C onward. Temperature cycling is often applied as accelerated shelf life test on fat bloom development [33][34][35][36]. However, the applied high temperature probably induces fat melting and structural changes due to abuse rather than normal ageing [37]. ...
The presented study investigates the functionality of hard and soft StOSt‐rich fats in plain and hazelnut‐based filled dark chocolates. Blends of cocoa butter (CB) with different StOSt‐rich fats, namely Vietnamese mango fat (VMF), Indian mango fat (IMF), its stearin (IMFst) and olein fraction (IMFol) were selected for application in these chocolate products based on their phase and crystallisation behaviour. It was shown that a fat phase formulation with CB/VMF 70/30 and CB/IMFst 70/30 increased the heat resistance of dark chocolate and maintained similar chocolate quality attributes (colour, hardness, melting and flow properties) compared to the CB reference. Furthermore, these fat blends increased the fat bloom stability following oil migration, as shown by visual assessment by a trained panel, cryo‐SEM imaging and oil migration monitoring by HPLC‐ELSD. In addition, the fat blend CB/IMFol 90/10, suitable for chocolate applications under non‐tropical conditions, was shown to retard oil migration fat bloom as well. Distinct mechanisms for the observed phenomena were proposed. Furthermore, the different steps of fat bloom development, starting from the appearance of oil blisters to the presence of crystals (∼30 μm) on the chocolate surface were captured using cryo‐SEM.
Practical applications: (i) heat resistant chocolate with increased fat bloom stability was developed; (ii) fat boom development in filled chocolates can be delayed tuning the TAG composition and (iii) a cost‐effective source of mango fat was provided with several technical applications for the tropics.
By tuning the TAG composition, several compatible fat blends of cocoa butter (CB) and mango fats (MF) are obtained. In comparison to the CB reference chocolate, the fat phase formulation with hard StOSt‐rich fats (CB/VMF 70/30 and CB/IMFst 70/30) increases the heat resistance of dark chocolate likely without inducing a waxy mouthfeel. Furthermore, both hard and soft StOSt‐rich fats increase the stability towards oil migration fat bloom, as observed by cryo‐SEM imaging. Explanations are proposed based on TAG composition.
... As cocoa butter is the major fat component in chocolate, it is the crystalline structure that greatly influences product's final physical properties, such as snap, gloss, melting properties and stability. If chocolate is not processed under well-controlled crystallisation conditions, cocoa butter would crystallise in the unstable polymorphic form, resulting in a dull, soft, low melting point, susceptible to blooming chocolate (Kinta & Hartel, 2010;Beckett, 2011;Garti & Widlak, 2012;Fernandes et al., 2013). It is thus important to ensure that cocoa butter develops the correct structure during crystallisation. ...
The effects of different shearing conditions on the crystallisation of cocoa butter (CB) with the addition of other confectionery ingredients (sugar and lecithin) were investigated. Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and polarised light microscopy (PLM) were conducted to measure the thermal, polymorphic and microstructural properties, of these mixtures, respectively. Both shearing conditions and ingredients have a pronounced impact on the thermal and polymorphic behaviour of CB, and its microstructure. In the absence of shear, the addition of lecithin delayed the polymorphic transformation in CB and results in slightly bigger crystal clusters. When both sugar and lecithin are added to nonsheared CB, they retard the formation of stable polymorphism. Moreover, sugar particles tended to agglomerate in the absence of lecithin under static conditions. With the application of shear, a more homogenous microstructure of the samples was observed. Shear significantly increases the crystallisation rate, polymorph transformation and the formation of a higher number of smaller crystals at both the presence and absence of lecithin.
... The seeds were easily mixed in the samples, which resulted in a homogenous microstructure, with small proportions of liquid fat trapped within the fat crystal network. A more heterogeneous microstructure was observed in the non-seeded samples which coincide with previous reports, where the microstructure of poorly tempered chocolate has been investigated with various microscopy techniques [18][19][20]. The non-seeded samples containing cocoa particles formed small rod-shaped crystals (Figure 1(c)) which differed significantly from the homogenous microstructure formed in corresponding seeded samples where no such crystal morphology was detected. ...
The kinetics of cocoa butter crystallisation during solidification and resulting compactness of structure during storage for different chocolate model systems were investigated with respect to solid particle addition (sugar and cocoa particles) and pre-crystallization process (seeded/non-seeded). Confocal laser scanning microscopy (CLSM) was used to monitor microstructural evolution during solidification and image analysis were applied in order to quantify the kinetics. In order to quantify the compactness of structure during storage the migration rate of small-molecules was measured at different length scales. On the meso-scale, FRAP (Fluorescence Recovery After Photobleaching) was utilized to quantify local migration rate solely in the fat phase, whilst HPLC (High Performance Liquid Chromatography) measurements were performed to assess the global migration of same molecules on a macro scale. Both techniques were used in combination with microstructure characterization using CLSM and supported by differential scanning calorimeter melting curves for estimating cocoa butter polymorphism. During solidification, seeded samples tended to form multiple nucleation sites, inducing rapid growth of a crystal network. The non-seeded samples showed an altering structure, with some domains developing large spherical crystals while in other domains a more heterogeneous microstructure resulted. For the non-seeded samples, the impact of solid particles on the crystallization kinetics was also most pronounced. Both FRAP and HPLC analysis proved to generate relevant information of the effect of pre-crystallization and solid particles on compactness of structure during storage. FRAP-measurements gave detailed information of the hetero- or homogeneity in microstructure within the cocoa butter whilst the HPLC clearly showed the impact of solid particles. The combination of the two techniques revealed that a compact and homogeneous structure obtained through fast crystallization during solidification is required in order to retard global migration in confectionery systems. (c) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of 11th International Congress on Engineering and Food (ICEF 11) Executive Committee.
... VI polymorphic transition, thermodynamically favored in CB, is a primary mechanism in the formation of bloom, acting as a precursor for various structural changes that characterize this damaging phenomenon. Therefore, actions that are able to inhibit this specific change in CB are conceived as bloom formation suppressants [7,35,36]. Figure 3 shows the diffractograms obtained for the five hardfats after 180 days of storage at 25°C and Table 4 presents the identified short spacings. For the FHPO and FHCO hardfats peaks at 4.2 and 3.8 Å were observed, characteristic of the b 0 polymorph, associated with the high content of palmitic acid found in these compounds. ...
Hardfats, or fully hydrogenated oils, consist of materials with homogeneous composition, composed of high melting point triacylglycerol. Hardfats are regarded as relatively new materials, and remain unexplored in lipid technology, notwithstanding being low‐cost industrial products. They can behave as modulators of the crystallization process, acting as preferential nuclei for ordering the crystal lattice and inducing specific polymorphic habits, with great potential for use in crystallization processes. This work evaluated the influence of the addition of different hardfats on the crystallization patterns of cocoa butter (CB). Fully hydrogenated oils with significantly different chemical composition, obtained from palm kernel oil (FHPKO), palm oil (FHPO), cottonseed oil (FHCO), soybean oil (FHSO), and crambe oil (FHCrO), were considered. Blends of CB/hardfats, at concentrations of 1%, 3%, and 5% (by weight) were produced and the crystallization isotherms, thermal behavior, and polymorphism determined. Hardfats FHPO, FHCO, FHSO, and FHCrO proved to be effective additives to modulate the crystallization characteristics of CB, in respect to crystallization kinetics and thermal behavior. Only the hardfat from crambe oil, FHCrO, presented stabilizing effect on the polymorphism of CB, delaying the transition V → VI.
Practical applications: The use of hardfats as crystallization additives in products containing CB, for technological adjustment of CB formulations in order to harmonize events like solidification kinetics, thermal behavior, and polymorphism. Hardfats may act as potential modulators of CB crystallization, with the purpose to obtain higher quality products at significantly reduced cost in industrial processing.
... At the interface between praline shell and filling, the occurrence of migration and diffusion and its contribution to quality decay such as fat bloom formation or chocolate softening has to be considered [2]. When a particular compound of one of the participating phases exhibit an enhanced mobility, as it is the case in aqueous fillings which contain ethanol, mass transport is accelerated [3,4]. ...
Commercial praline shells made from dark chocolate were filled with a mixture of invert sugar syrup, wine distillate and sucrose, which was adjusted to a viscosity of approximately 4 Pa·s by addition of pregelatinized starch. The pralines which also contained malt extract were subjected to storage at 20 and 24 °C. The liquefaction rate induced by enzymes of the malt extract depended on ethanol (0–15% w/w) and moisture content (approximately 30%) of the filling, and on storage temperature. The decay of apparent viscosity immediately after adding malt extract was delayed when ethanol was present in the filling, implying that viscosity stability after mixing and during subsequent processing is improved. Softening of the praline shells and fat bloom formation also depended on the ethanol concentration of the filling. A cross-comparison with praline shells which were filled with pure invert sugar syrup implies that the enzymes of the malt extract do not exhibit a negative influence on praline shell firmness. Electron micrographs give evidence that ethanol in contact with chocolate causes structural damage which results in a partial solubilization of praline shells.
Handbook of Industrial Crystallization - edited by Allan S. Myerson June 2019
To investigate the effects of phospholipids (PLs) in chocolate, model systems were designed by adding 0.3%, 0.5%, and 0.8% (w/w) phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS) to the control system (0.0% PL). Bloom behaviors were quantified by changes in whiteness index (ΔWI), white area percentage (WA%) and surface morphology over 28-day accelerated storage. Bloom was significantly retarded in all PL systems (p < 0.0001), especially showing almost no visual bloom in PE and PS systems during 28-day storage: ΔWI was reduced to below 1.5 (16.97 for the control) and WA% was reduced to below 10% (99.47% for the control). This reduction in bloom was further confirmed by low surface roughness and porosity. Particle interactions (quantified by Casson viscosity and sedimentation volume) were significantly reduced (p < 0.0001) and amount of crystallization (quantified by differential scanning calorimetry and oscillatory rheology) were significantly increased in all PL systems (p < 0.05). These results suggest that PLs can improve the microstructural stability of the nonfat particle phase and the crystalline fat phase, thereby reducing fat migration and preventing bloom formation.
The most useful properties of food, i.e. the ones that are detected through look, touch and taste, are a manifestation of the food’s structure. Studies about how this structure develops or can be manipulated during food production and processing are a vital part of research in food science. This book provides the status of research on food structure and how it develops through the interplay between processing routes and formulation elements. It covers food structure development across a range of food settings and consider how this alters in order to design food with specific functionalities and performance. Food structure has to be considered across a range of length scales and the book includes a section focusing on analytical and theoretical approaches that can be taken to analyse/characterise food structure from the nano- to the macro-scale. The book concludes by outlining the main challenges arising within the field and the opportunities that these create in terms of establishing or growing future research activities.
Edited and written by world class contributors, this book brings the literature up-to-date by detailing how the technology and applications have moved on over the past 10 years. It serves as a reference for researchers in food science and chemistry, food processing and food texture and structure.
In this work, we studied the influence of fatty acid chain length and crystallization temperature on the crystallization behavior during the storage of binary blends modified by chemical interesterification. The blends were produced with soybean oil and fully hydrogenated oils from palm kernel, palm, soybean, microalgae, and crambe, evaluated separately, at a ratio of 50:50 (% w/w). The blends were crystallized by two crystalline stabilization methods. In method I, the samples were maintained at 25 °C for 24 h before the analyses. In method II, the samples were maintained at 5 °C for 24 h, followed by crystalline stabilization at 25 °C for 24 h before the analyses. The interesterification reaction caused considerable changes in the TAGs profile with increasing asymmetric TAGs. These TAGs changes promoted an increase in the crystallization induction time, a decrease in the maximum solids content, and changes in crystals morphology. The increase in the FAs chain length promoted the increased nucleation rate that influenced morphology crystals. Method II promoted a reduction in the medium diameter of crystals and the appearance of the β phase with storage time. For crystallization carried out at higher temperatures (method I), we observed that β’ was favored. Unusual polymorphic transitions were observed with storage time in samples with higher tristearin content. We identified clear correlations between the predominance of β’ phase in the interesterified blends and TAGs of S2U and SU2-type. In addition, the blends with a more diverse range of fatty acids concerning chain size also showed the β’ polymorph. β polymorph, on the other hand, was associated with symmetric TAGs, S3 and U3, and CN-54 type TAG. In this study, we used the Rietveld method to quantify the polymorphs and amorphous content in the blends before and after the randomization reaction. This approach allowed a deeper understanding of the crystalline behavior in the blends, which would be difficult to achieve by performing only a visual analysis of the X-ray diffractograms.
The sucrose-free dark chocolate development is receiving attention due to increasing market demand for foods with reduced sugar. This study aimed to determine the physical and sensory properties, and the storage stability of sucrose-free dark compound chocolate by replacing the sucrose with inulin, Fructo-oligosaccharides (FOS), trehalose, or maltodextrin (M10 and M30) on a volume basis along with stevioside as a sweetening agent. Melting and crystallization properties, particle size, moisture content, rheological behaviour, hardness, bloom formation and sensory evaluation were examined using differential scanning calorimetry, particle size analyser, rheometer, and texture analysis, respectively. Sucrose substitution had no significant impact on the melting and crystallization behaviour in a compound chocolate model system. However, all sucrose-free dark compound chocolate displayed lower Casson viscosity, yield value and hardness than sucrose-containing dark compound chocolate, which may because the weaker particle-particle interaction in sucrose-free dark compound chocolate. Sucrose-free dark compound chocolate had lower sweetness (P < 0.05) and stronger bitterness (P < 0.05) compared to the sucrose compound chocolate. Trehalose was the most suitable sucrose replacer in dark compound chocolate because it resulted in similar rheological and sensory properties as the sucrose-containing dark compound chocolate and greater resistance to bloom formation after 12 weeks of storage.
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.
Control of crystallization of lipids is important in many food products, including margarine, chocolate, butter, and shortening. In these products, the aim is to produce the appropriate number and size distribution of crystals in the correct polymorphic form since the crystalline phase plays a large role in such food properties as appearance, texture, spreadability, and flavor release. Thus, understanding the processes that control crystallization is critical to controlling quality in these products. Controlling crystallization requires an understanding of the driving force that leads to crystallization, the process of forming the crystalline phase (nucleation) and then subsequent crystal growth and polymorphic transformation to obtain the final crystalline phase volume in equilibrium with the remaining liquid fat. Owing to the complex composition of most natural fats, our understanding of these processes remains incomplete.
Spray cooling or spray chilling is a technique for obtaining solid lipid microparticles (SLMs) within the diameter range in micrometers using low temperatures and no organic solvents. It is a low-cost technique and is easy to scale-up. The production of SLMs into β-form represents a technological challenge due to the fast crystallization given by the spray cooling system, which generally results in SLMs crystallized into the metastable polymorphic form α. This study focuses on the production and characterization of SLMs by spray cooling using hard fat soybean oil (HS) added of D-limonene or canola oil, aiming to their application as β-seed crystals into lipid systems. The β-seed crystals could turn into an alternative lipid material to be used in fat-based products that present the preferential β' crystallization, like palm oil, increasing its compatibility with cocoa butter (CB) and allowing for the development of substitutes. The obtained SLMs showed spherical geometry and no agglomeration during storage at 25 °C for up to 30 days, verified by scanning electron microscopy (SEM). The mean diameters (D50) were between 150 and 200 μm and the β' and β-form, determined by X-ray diffraction (XRD), appeared immediately after the crystallization process by spray cooling using HS added of 5% D-limonene (the HS control sample presented only the α-form). The SLMs of this study demonstrated their potential use as β-seed crystals into lipid systems.
Of all confections, chocolate arguably has the longest history, having been already cultivated thousands of years ago in the reign of the Olmec. After Spanish explorers brought cocoa beans back to Europe, its usage slowly expanded. Used initially to create a drink, chocolate gradually developed into the smooth, creamy product we know today as a result of a series of technological advances. The history of chocolate cultivation and development has been the subject of numerous treatises (see, for example, Coe and Coe 2007).
Cocoa butter has responsibility for dispersion medium to create a stable chocolate bar. Due to the economic reason, cocoa butter is partially or wholly substituted by edible oils e.g palm oil and coconut oil. The objective of the research was to observe the effect of oil substitution in the chocolate bar towards its melting point and texture. The research were divided in three steps which were preliminary research started with fat content analysis in cocoa powder, melting point analysis of substituted oils anc cocoa butter, and iodine number analysis in vegetable fats (cocoa butter, coconut oil, and palm oil), chocolate bar production with substitution 0%, 20%, 40%, 60%, 80%, and 100%wt of cocoa butter with each of substituted oils, and analysis process to determine the chocolate bar melting point with DSC and chocolate bar hardness with texture analyser. The increasement of substituted oils during substitution in chocolate bar would reduce the melting point of chocolate bar from 33.5°C to 31.6°C in palm oil substitution with cocoa butter and 33.5°C to 30.75°C in coconut oil substitution. The hardness of chocolate with palm oil were around 88.5 to 139 g on the 1st cycle and 22.75 to 132 g on the 2nd cycle. The hardness of chocolate with coconut oil were around 74.75 to 152.5 g on the 1st cycle and 53.25 to 132 g on the 2nd cycle. Maximum amount of fats substitution to produce a stable texture chocolate bar is 60% wt.
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 and did not achieve final equilibrium after 60 min of cooling, indicating incomplete crystallization.
A bloom appears on chocolate when the unfavorable properties of cocoa butter are manifested. The bloom can be classified as sugar bloom or fat bloom. When chocolate is produced under the appropriate conditions, both sugar and fat are present in fine texture and are dispersed uniformly at the macroscopic level. It allows the cocoa butter to melt smoothly and pleasurably in the mouth, releasing the taste and aroma of the solid particles dispersed in it. Bloom is a condition in which the fine texture of sugar and fat crystals is lost for some reason and the chocolate becomes non-uniform. Sugar bloom is caused by changes in the morphology of the sugar crystals and is mediated by water. Fat bloom is caused by fat melting due to high temperatures and/or dissolution of fat in oil. Chocolate fat bloom is a major problem in the confectionery industry. This chapter provides the classification of chocolate fat bloom according to bloom morphology. Organizing the morphological states can help to understand the developing mechanism, which gives a complicated flow chart showing the dependence on the type of chocolate item and its storage conditions.
The mixture of milk fat and cocoa butter provides challenges for controlling lipid interactions to give consistent product quality. From phase behavior to crystallization kinetics, understanding the interactions between milk fat and cocoa butter is critical for controlling the quality characteristics and shelf life of milk chocolate. The addition of milk fat to chocolate creates a complex mixture of TAGs whose crystallization behavior is quite complex. There are several notable changes in chocolate due to the effects of milk fat addition. The softening effect from adding milk fat to cocoa butter is easily explained through phase behavior. Milk fat also has an inhibitory effect on cocoa butter crystallization, which means that chocolate containing milk fat must be tempered at different conditions. Specifically, milk chocolate is tempered at slightly lower temperatures than dark chocolate to offset the inhibitory effects and allow more rapid cocoa butter crystallization. The milk fat is known as a bloom inhibitor, most likely through its effect on slowing the polymorphic transformation of cocoa butter to the most stable polymorph, β-VI.
The crystallization process of cocoa butter in chocolate is crucial to achieving the correct crystal form. Besides processing, the crystallization behavior of cocoa butter in chocolate is also affected by particulate solids, foreign fats (e.g. milk fat), and emulsifiers, which offer additional nucleation sites and/or steric hindrance to crystal nucleation and growth. This chapter discusses the effect of non-cocoa ingredients in chocolate, i.e. sugar, milk powder, and emulsifiers, on the crystallization of cocoa butter. The non-cocoa ingredients in chocolate, i.e. sugar, lecithin, and milk powder, influence the crystallization of cocoa butter. Of the three ingredients, the effect of milk fat is the best documented. Although the exact mechanisms remain unknown, milk fat has been found to retard cocoa butter crystallization, delay transformation into higher melting polymorphic forms, and exhibit anti-bloom effects. Microscopy studies have shown that sugar particles do not reduce the induction time for static cocoa butter crystallization except in the presence of an emulsifier, while rheological investigations have reported the opposite effect of plain sugar enhancing crystallization.
Heat transfer in foods is commonplace in the home and restaurant, but is also the basis for a very large industry. Foods are complex non-Newtonian soft solids or structured liquids whose thermal behavior is difficult to model; engineering understanding is needed to develop processes that are safe and products that are attractive to the consumer. The increasing incidence of obesity in the developed world, and of food shortage elsewhere, demands that the industry adopts processes that give nutritious products in environmentally acceptable ways. Heat transfer is often limited by the low thermal conductivity of foods and increasing heating and cooling rates is critical in maximizing product quality. This paper briefly reviews the heat transfer problems found in food processing, with particular reference to the modeling of heating to ensure safety, problems found in the fouling and cleaning and process plant, and how heating and cooling are used to generate food microstructure. Research challenges for the future are outlined.
Heat transfer in foods is a commonplace operation in the home and restaurant, but is also the basis for a very large industry. Foods are complex non-Newtonian soft solids or structured liquids whose thermal behaviour is difficult to model; but engineering understanding is needed to develop processes that are safe and products that are attractive to the consumer. The increasing incidence of obesity in the developed world, and of food shortage elsewhere, demands that the industry adopts processes that give nutritious products in environmentally acceptable ways. This paper reviews the heat transfer problems that are found in food processing, with particular reference to the modelling of heating operations to ensure safety, problems that are found in the fouling and cleaning and process plant, and how heating and cooling are used to generate structure. Research challenges for the future are outlined.
It is somewhat surprising that chocolate chips baked in cookies do not exhibit bloom despite what seems to be sufficient heat to melt and break temper of the chocolate. We hypothesize that fat migration from the cookie dough into the molten chocolate chip during baking disrupts cocoa butter crystallization upon cooling and is responsible for this bloom inhibition. To test this hypothesis, both chocolate chip cookies and a sand–fat model system were baked with different types and levels of fat in the matrix. Bloom was evaluated 10 days after baking by image analysis of stereomicroscope images to quantify white areas on the flat bottom surface of oriented chips in sample cookies. All fats used in the dough, except cocoa butter, were shown to inhibit bloom when fat levels were sufficiently high. For palm oil and olive oil, a minimum degree of fat migration of about 16% was required to inhibit bloom. Below this critical level, bloom was observed on chocolate chips. A sand model system was also studied with palm oil. Since a higher level of fat migration was required to inhibit bloom for the sand model system than for cookies, other ingredients in the cookie dough must also play a role in bloom inhibition.
The microstructure of chocolate model systems was investigated at the meso (~10μm), micro (~50μm), and macro (0.1–1mm) scales simultaneously, to examine effect of pre-crystallization process and/or solid particle addition on the formation of a dense structure. The structure density was quantified by measuring the diffusion rate of small molecules at different length scales. At the meso scale, fluorescence recovery after photobleaching (FRAP) was utilized to quantify local diffusion rate solely in the fat phase, whereas high-performance liquid chromatography (HPLC) measurements were made to assess the global diffusion of the same molecules at the macro scale. Both techniques were used in combination with microstructure characterization using confocal laser scanning microscopy (micro scale) and supported by differential scanning calorimeter melting curves for estimating cocoa butter polymorphism. Both FRAP and HPLC analysis generated relevant information on the effect of pre-crystallization and solid particle addition on the structure density. FRAP measurements gave detailed information on microstructure heterogeneity or homogeneity in the cocoa butter, whereas HPLC clearly revealed the impact of solid particles on the structure density. Combining the two techniques revealed that a compact and homogeneous structure obtained through optimized pre-crystallization is required at all times, i.e., immediately after cooling and throughout the product's shelf life, to retard global diffusion in confectionery systems.
Crystals often play an important role in food product quality and shelf life. Controlling crystallization to obtain the desired crystal content, size distribution, shape, and polymorph is key to manufacturing products with desired functionality and shelf life. Technical developments in the field have improved the tools with which we study and characterize crystals in foods. These developments also help our understanding of the physico-chemical phenomena that govern crystallization and improve our ability to control it during processing and storage. In this review, some of the more important recent developments in measuring and controlling crystallization are discussed.
Blooming or the migration of fat to the surface of chocolate results in color changes and development of non-uniform color patterns. These phenomena were assessed during storage of milk chocolate tablets (cycling temp. between 16 and 28 °C for 52 days) by a computer vision system and image analysis. Eight features were extracted from images (L*, a* and b* values, whiteness index, chroma, hue, % bloom and energy of Fourier). Major changes occurred after day 36 of storage, coincidental with visual perception. Initially, white specks emerged on the brown background but were superseded by the development of a whitish color extending over most of the surface. L*, whiteness index, a* and chroma correlated well with values taken with a commercial colorimeter (R2>0.70). Changes in image texture (energy of Fourier) followed a similar trend as color changes. The sequential forward selection strategy allowed correct classification of 97.8% of samples into four classes with only five features. The computer vision system has the capability to quantify overall changes as well as particular features over the whole chocolate surface thus enabling customization and standardization for quality assessment.
Although bloom in chocolates and compound coatings has been studied for many decades, the specific mechanisms of fat bloom still remain largely unknown. Furthermore, it is generally considered that the mechanisms for fat bloom formation in chocolate are different than those for compound coatings.
After a brief review of chocolates and compound coatings, we summarize past studies on fat bloom formation in both products. A comparison of the effects of various parameters on bloom formation, either as accelerators or inhibitors, provides insight into the similarities and differences in these phenomena.
Based on this analysis, a global view of the mechanisms of bloom formation in both chocolates and compound coatings is suggested.
It is generally accepted that visual fat bloom is caused by the separation of cocoa butter toward the surface. However, this is not always true for all types of bloom. One type of fat bloom, which can occur due to lack of tempering, has still not been completely elucidated. We performed a compositional and structural study of this type of fat bloom in plain chocolate. More specifically, we performed (1) an investigation of its crystallographic properties, (2) investigation of fat content, (3) analysis of the composition of triacylglycerol (TAG), (4) stereomicroscopic observations, and (5) observation and elemental analysis using a scanning electron microscope with an energy-dispersive X-ray spectrometer (SEM-EDS). In the bloomed chocolate, the fat content in the light brown phase was lower than that in the black phase. Concerning fat composition, the content of sn-1,3-saturated acyl, sn-2-oleoyl glycerols (Sat-O-Sat type TAGs) in the light brown phase was lower. The lower fat content is thought to result in its lighter color. The results of our composition analysis and morphological observations suggest that the mechanism of the bloom generation due to nontempering involves not the separation of fat toward the surface but the crystallization of fat which leads to withdrawal of fat from the vicinity of the growing crystal, leading to differences in fat content.
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.
Demolding property just after solidification, we examined the polymorphism of cocoa butter in seed-solidified dark chocolate and fat-bloom stability through two thermocycle tests between 38 and 20°C (38/20) and between 32 and 20°C (32/20). The seed crystals employed are Form VI of cocoa butter,β
1 of SOS (1,3-distearoyl-2-oleoyl-glycerol), pseudo-β’ andβ
2 of BOB (1,3-dibehenoyl-2-oleoylglycerol) and β of SSS (1,2,3-tristearoylglycerol). The influence of the seed concentration was also examined. The seeding of cocoa butter (Form VI) and SOSβ
1 caused the crystallization of Form V of cocoa butter and exhibited better demolding. As to the fat-bloom stability, the two, seed crystals were effective through the 32/20 cycle test, but the fat-bloom occurred through the 38/20 test. The seeding ofβ
2 of BOB caused better demolding, crystallization of Form V of cocoa butter, and the most preferable fat-bloom stability; particularly, the seeding of 5 wt% concentration ofβ
2 of BOB completely prevented the fat-bloom after the 38/20 test, although the seeding of all of the other materials and conditions caused the fat-bloom by this thermo-cycle test. The seeding of pseudo-β’ of BOB did not prevent the fat-bloom, although the demolding property was improved. In the case of the seed of β of SSS, both the demolding and fat-bloom stability were not improved. We concluded that the seeding ofβ
2 of BOB revealed the most desirable, influences on the demolding and the fat-bloom stability of dark chocolate. This conclusion suggests the usage ofβ
2 of BOB as the most preferable seed material in the solidification of dark chocolate, since the crystallization rate was also enhanced by this material as described in Paper I.
A complete isothermal phase-transition scheme of cocoa butter under static conditions is presented, based on time-resolved
X-ray powder diffraction experiments. In contrast to what is known from literature, not only β V, but also β VI can be obtained
directly through transformation from β′. Another remarkable result is that β′ exists as a phase range rather than as two separate
phases. Within this β′ phase range no isothermal phase transitions have been observed. More detailed information concerning
the observed cocoa butter polymorphs was obtained by determination of melting ranges, using time-resolved X-ray powder diffraction.
Also standard X-ray powder diffraction patterns of the γ, the α, and the two β phases and parts of the β′ phase range have
been recorded. The observed phase behavior of cocoa butter has been explained based on the concept of individual crystallite
phase behavior of cocoa butter
A type of fat bloom, which had not previously been fully characterized, was investigated to identify the state of its existence
and its formation mechanism. Samples of bloom on solid chocolate resulting from the partial liquefaction of fat during temperature
variations were analyzed to determine the crystal characteristics, fat contents, and triacylglycerol (TAG) compositions. Also,
observation and elemental analyses were performed by scanning electron microscope with an energy-dispersive X-ray spectrometer,
color analyses of minute regions were made by using PARISS®, and Fourier-transform infrared (FT-IR) analyses were performed. The dark- and light-brown areas did not show any differences
in fat content or TAG compositions that could lead to the observed color differences. Although differences in component distributions
were noted in micrometer-sized regions, no relation to the colors was confirmed. The bloom samples in this study and bloom
developed without a tempering process resembled each other in the tone of color at their discolored regions, but the states
they adopted differed from one another. It is suggested that the color in this type of bloom was affected by the roughness
and/or porosity of the microstructure and could also be a result of the coarsened fat crystal network and of the liquid fat
migration.
This chapter discusses the topic of chocolate. The purposes of on farm processing of cocoa are manifold. Processing usually consists of fermentation and drying. The fermentation is 2–8 days long depending on bean type, custom, and other factors. Cocoa is fermented in various ways throughout the world depending on the scale of the operation and tradition. The most important result of fermentation is the autolytic process, which occurs within the seed and generates the flavor precursors. Degradation of storage proteins occurred during fermentation-like incubations. The total extractable protein increases slightly from day 0 to day 1. Chocolate manufacturers measure a number of cocoa bean physical properties to judge the overall quality of an incoming lot. It is reasonably well known that peptides and amino acids, sugars, and perhaps polyphenols are important precursors of chocolate flavors, which on roasting produce the characteristic chocolate flavor. All products prepared from milk will have flavors arising from several factors. There are also cocoa substitutes available that are whey based. Cocoa mass, cocoa butter, milk solids, and sugar are the essential components of cocoa and milk chocolate products. Milk fat is well documented as an important component in milk chocolate. Sucrose is a major raw material in chocolate. Chocolate manufacturing is very dependent on sucrose (sugar). In fact, chocolate and confectionery may have become less cost competitive in the marketplace against other foods such as jams and jellies, bakery products, and carbonated sodas, which benefit from sweetener flexibility.
Largely by x-ray diffraction six crystalline states, I–VI, in order of increasing melting point, have been identified for
cocoa butter. Of these states II, IV, V and VI are pure and identifiable with previously (or presently) identified polymorphs
of 2-oleoylpalmitoyl stearin (POS), namelyα-2,β′-2,β-3 (“V”) andβ-3 (“VI”); V and VI representing distinct but very closely related crystalline structures. State I is a definite but fleeting
and not readily characterized subα state and may be a phase mixture, as state III may be also.
Melting points, heats of fusion and dilatometric data are reported for all states to the extent that their stability permits.
The normal state of cocoa butter in chocolate is apparently V, certainlyβ-3. While it is true that “bloom” has not been observed for pure V nor observed to exist in the absence of VI, it is premature
to say that VI is specifically the phase of chocolate “bloom”.
Phase behavior and extended phase scheme of static cocoa butter investigated with real-time X-ray powder diffraction Fig. 10 Peak temperatures for DSC curves in cocoa butter crystallized with different seed addition levels (top cooling at 0.25 °C/min; bottom heating at 5 °C/min
- Van K Malssen
- A Langevelde
- R Peschar
- Schenk
van Malssen K, van Langevelde A, Peschar R, Schenk H (1999) Phase behavior and extended phase scheme of static cocoa butter investigated with real-time X-ray powder diffraction. J Am Oil Chem Soc 76:669–676 Fig. 10 Peak temperatures for DSC curves in cocoa butter crystallized with different seed addition levels (top cooling at 0.25 °C/min; bottom heating at 5 °C/min) J Am Oil Chem Soc (2010) 87:19–27 27 123
Diagnosing chocolate bloom
- Seguine E
Fat bloom in chocolate
- McCarthy MJ
Crystallization properties of cocoa butter Crystallization processes in fats and lipid systems
- K Sato
- T Koyano
Phase transitions in chocolate and coatings
- R W Hartel
- RW Hartel
10 Peak temperatures for DSC curves in cocoa butter crystallized with different seed addition levels (top cooling at 0.25 °C/min
- Fig
Fig. 10 Peak temperatures for DSC curves in cocoa butter crystallized with different seed addition levels (top cooling at 0.25 °C/min;
bottom heating at 5 °C/min)