Fat bloom development and structure-appearance relationships during storage of under-tempered dark chocolates

Dark chocolate: An overview of its biological activity, processing, and fortification approaches

Dark chocolate gets popularity for several decades due to its enormous health benefits. It contains several health-promoting factors (bioactive components - polyphenols, flavonoids, procyanidins, theobromines, etc, and vitamins and minerals) that positively modulate the immune system of human beings. It confers safeguards against cardiovascular diseases, certain types of cancers, and other brain-related disorders like Alzheimer's disease, Parkinson's disease, etc. Dark chocolate is considered a functional food due to its anti-diabetic, anti-inflammatory, and anti-microbial properties. It also has a well-established role in weight management and the alteration of a lipid profile to a healthy direction. But during the processing of dark chocolate, several nutrients are lost (polyphenol, flavonoids, flavan 3 ol, ascorbic acid, and thiamine). So, fortification would be an effective method of enhancing the overall nutrient content and also making the dark chocolate self-sufficient. Thus, the focus of this review study is to gather all the experimental studies done on dark chocolate fortification. Several ingredients were used for the fortification, such as fruits (mulberry, chokeberries, and elderberries), spices (cinnamon), phytosterols, peanut oil, probiotics (mainly Lactobacillus, bacillus spices), prebiotics (inulin, xanthan gum, and maltodextrin), flavonoids, flavan-3-ols, etc. Those fortifications were done to raise the total antioxidant content as well as essential fatty acid content simultaneously reducing total calorie content. Sometimes, the fortification was done to improve physical properties like viscosity, rheological propertiesand also improve overall consumer acceptance by modifying its bitter taste.

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Dark chocolate gets popularity for several decades due to its enormous health benefits.

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Dark chocolate is considered a functional food due to its health benefits.

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During the processing of dark chocolate, several nutrients are lost.

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Fortification would be an effective method of enhancing the overall nutrient content.

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This review study is to gather all the experimental studies done on dark chocolate fortification.

Effect of tempered procedures on the crystallization behavior of different positions of cocoa butter products

The effects of tempered procedures (well and under-tempered) on the crystalline behaves of cocoa butter were elaborated through detecting crystalline structure and compositions of crystals located at different positions of cocoa butter products in this study. The under-tempered products couldn't form crystalline structures as uniform as the well-tempered ones, whose internal contained more low saturated triacylglycerol and structurally unstable crystals. The low saturated triacylglycerol further created the diverse microstructure and thermal properties between center and outer part of cocoa butter products. During storage, the concentration differences drive migration of low saturated triacylglycerol from center to outer part of the product. Although this reduces the differences in triacylglycerol composition, it results in the polymorphism conversion between β'-IV and β-VI form and the fat bloom formation. This work indicates that the monitor for crystalline properties of different positions in cocoa butter products helps the chocolate industry to control formation of fat bloom.

The Evaluation of Dark Chocolate-Elicited Emotions and Their Relation with Physico Chemical Attributes of Chocolate

The aim of this study was to evaluate the effect of different origin (Venezuela, Ghana, Peru) dark chocolates on emotions induced for consumers, and to analyse the relationships among overall acceptability (OA), emotions, and physicochemical attributes of the chocolate (fatty acids (FAs) and volatile compounds (VC)). Chocolate-elicited emotions were measured with FaceReader 8 software, scaling 10 emotion patterns (neutral, happy, sad, angry, surprised, scared, disgusted, contempt, valence, arousal). The OA was carried out by using a 10-point hedonic scale, ranging from 1 (extremely dislike) to 10 (extremely like). The obtained results showed that, among all chocolate-elicited emotions, the intensity of “happy” was the highest. In most cases, the influence of the different origin chocolate on the emotions induced for consumers was significant (except on emotions “neutral”, “scared”, and “disgusted”). Significant differences between the tested chocolates OA were not found. The origin of chocolate had a significant effect on most of the identified VC and the content of the main FAs (methyl palmitate, methyl stearate, cis,trans-9- oleic acid methyl ester, and methyl linoleate). Significant correlations between chocolate-elicited emotions and separate FAs and VC were found. Finally, this study showed that the origin of dark chocolate significantly influenced most of chocolate-elicited emotions and physicochemical attributes of chocolate, while separate FAs or VC can be used as chocolate quality indicators related to the chocolate OA, as well as chocolate-elicited emotions.

Fibre-based oleogels: effect of the structure of insoluble fibre on its physical properties

Solid fat is a "staple" in the modern diet in the form of products such as butter, margarine, and shortening. Due to its potentially detrimental effects on health, numerous dietary guidelines recommend its restriction. This opens up opportunities to develop fat replacers via edible oil structuring. In this study, we report the development of a unique, non-thermal method to create oleogels which contain only natural food fibres and liquid vegetable oil. Moreover, they do not oil off on compression. The objective was to understand how the structure of insoluble fibre influenced the physical properties of oleogels, specifically physical robustness and apparent melting point. The fibres studied were citrus fibre of different particle sizes, and nata de coco fibre known for its thinner dimension and finer three-dimensional structure. The melting characteristics of oleogels were studied by differential scanning calorimetry and visual observation. The physical robustness of oleogels was characterised by the spreadability method using a texture analyser. The presence of fibre was found to disrupt fat crystallisation, leading to proportionately more crystal species that were less stable. However, the true melting point of fat was not significantly altered. Despite greater disruption, oleogels made with longer and/or more extensive fibres were mainly firmer and capable of keeping the oil in the solid oleogel form, even under elevated temperatures. Our novel approach for manufacturing oleogels opens up a range of opportunities for their application in various products and systems.

Thermal properties and volatile compounds profile of commercial dark-chocolates from different genotypes of cocoa beans (Theobroma cacao L.) from Latin America

There is a growing interest in the identification of chemometric markers that allow the distinction and authentication of dark-chocolates according to their cocoa geographical origin and/or genotype. However, samples derived from Latin American cocoa, including specimens from North and South America, have not been studied in this context. An exploration of the melting behavior, fat composition, bioactive content, and volatile profile of commercial darkchocolates was conducted to identify possible patterns related to the genotype and/or origin of cocoa from Latin America. The melting properties were evaluated by DSC and related to fat content and fatty acids profile. Total polyphenol, anthocyanin, methylxanthine, and catechin content were analyzed. Finally, the volatile compounds were extracted and identified by HS-SPME/GC-MS and were analyzed through Principal Component Analysis (PCA) and the Hierarchical Cluster Analysis Heatmap (HCA Heatmap). The fatty acids profile showed a relationship with the melting properties of dark chocolate. The samples exhibited two glass-transition temperatures (T_g) at ≈19 °C and ≈25.5 °C, possibly related to traces of unstable polymorphic forms of monounsaturated triacylglycerides. The analysis of bioactive compounds demonstrated great variability among samples independent of the cocoa origin, genotype, and content. The PCA and HCA Heatmaps allowed discriminating against the chocolates in relation to the cocoa origin and genotype. Compounds like tetramethylpyrazine, trimethylpyrazine, benzaldehyde, and furfural could be considered as dark-chocolate aroma markers derived from Latin American cocoas (North American region). The 2-phenylethyl alcohol, 2-methylpropanoic acid, 2,3-butanediol, 2-nonanone, and limonene for derived from South America. And the 2-phenylethyl acetate, 3-methyl-butanal, and cinnamaldehyde could allow to distinguishing between regional genotypes.

Alternative Tempering of Sugar-Free Dark Chocolates by βv Seeding: Sensorial, Micro-Structural and Some Physical Properties and Volatile Profile

In this study, sugar-free dark chocolate was produced from isomalt and maltitol by βV seeding technique as an alternative to conventional tempering process. The effect of βV 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 βV 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 βV 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 βv seeds had very close scores compared with conventional one, implying that sugar-free chocolates can be produced by βv 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 βV seeds with desired quality similar to chocolate produced by using conventional tempering.

The effect of jujube powder incorporation on the chemical, rheological, and sensory properties of toffee

One of the major problems caused by the consumption of toffee is its high sugar content. So, great efforts have been made to replace sugar in toffee with bioactive ingredients. To the best of our knowledge, there is no research relevant to the application of jujube powder as sugar replacer in toffee. In this study, the sugar content of the toffee was replaced with the jujube powder in six different levels 0%, 20%, 40%, 60%, 80%, and 100%, and the physico-chemical, rheological, and sensory properties of the toffee were evaluated. The results showed that the fat, raw energy, pH, color (L*, a*, b*), sucrose, and firmness of the toffee samples decreased by increasing the percentage of jujube powder in the formulas but their moisture, water activity, ash, protein, glucose, and fructose increased. The rheological results revealed that storage modulus (G') was greater than loss modulus (G″), which represents the elastic behavior (solid-like) of the samples. Also storage modulus (G') of the control sample (jujube powder instead of 0% sugar) was greater than that the other samples. On the other hand, the firmness of the samples was decreased by increasing the percent of jujube powder. According to the chemical and rheological results, samples III and IV (jujube powder instead of 40% and 60% sugar, respectively) were selected as optimum samples. Then the sensory properties were compared to that of control. No significant difference observed in chewiness, taste, flavor, sweetness, color, after-taste, and overall acceptance between the control and the two other samples.

Dark chocolate with a high oleic peanut oil microcapsule content

BACKGROUND

In accordance with the market demand for healthier indulgent food products, the present study aimed to determine the viability of the industrial production of dark chocolate with microcapsules of high oleic peanut oil content. Microcapsules of high oleic peanut oil were added to a control formulation using variations of mixing time.

RESULTS

The chocolates presented a rheology characterized by a pseudoplastic behavior adjusted to the Casson model (r > 0.98) and calorimetric behavior indicating melting onset (21 °C), peak melting (32 °C) and melting end (41 °C); caramelization peak (183 °C); and carbonization peak (237 °C), being considered thermal stable. The mixing time and the amount of microcapsules added to the control chocolate did not significantly influence the flow limit (11.09 ± 1.73 Pa) or the physical characteristics of the chocolate: pH (6.74 ± 0.14), maximum particle size (0.019 ± 0.001 mm), water activity (0.358 ± 0.023) and brittleness (18.61 ± 3.74 N). However, the addition of microcapsules with a high oleic peanut oil content significantly increased the chocolate whiteness index, thixotropy and Casson's plastic viscosity, although it did not have a significant influence on the mixing time.

CONCLUSION

The products obtained have a desirable quality and physical properties, being suitable for industrial production. © 2018 Society of Chemical Industry.

Effects of Fat Polymorphic Transformation and Nonfat Particle Size Distribution on the Surface Changes of Untempered Model Chocolate, Based on Solid Cocoa Mass

This study aims to understand the bloom process in untempered chocolate by investigating the polymorphic transformation of cocoa butter and changes in chocolate surface. Cocoa mass with varying particle size distributions (PSD) were used to produce untempered model chocolate. Optical microscopy showed that during 25 d of storage, the chocolate surface gradually became honeycombed in appearance with dark spots surrounded by white sandy bloom areas. In conjunction with X-ray diffraction this indicates that the polymorphic transformation of form IV cocoa butter to more stable form V crystals caused the observed surface changes with the most significant changes occurring within 6 d. As bloom developed the surface whiteness increased, but the PSD of nonfat particles showed limited impact on the changes in whiteness. Moreover, scanning electron microscopy showed separated fat crystals on fat-rich dark spots and empty spaces between particles in bloom areas suggesting redistribution of fat in the chocolate matrix.

PRACTICAL APPLICATION

The results reported in this work can facilitate the understanding of fat bloom formation in untempered chocolate with respect to the changes in microstructure and surface appearances. It also contributes to show the details of IV-to-V polymorphic transformation in the fat phase as time went by.

Relationships between molecular structure and kinetic and thermodynamic controls in lipid systems. Part I: propensity for oil loss of saturated triacylglycerols

Pure saturated triacylglycerols (TAGs) in canola oil were used as model systems to analyse oil loss in structured oil both from thermodynamic and kinetic perspectives. Two important parameters which effectively and predictively measure the relative propensity of a solid network to lose/hold oil were defined: (1) the rate of oil loss, K, which is a quantified representation of the kinetics of oil loss and (2) the initial amount of oil susceptible to be lost, i.e., the propensity for oil loss (POL), which is a representation of the thermodynamics of oil binding. It was found that the POL and K values do not always trend in the same fashion, suggesting that the mechanism of oil binding is complex, depending on the structurant's crystalline form locked within the oil network. The two parameters were, however, correlated to the melting and thermal behavior of the structurants, to the polymorphic structures that are obtained during the cooling process and to the habit (shape, size and morphology) of the crystalline phase in the oil. Both POL and K had a strong correlation to the oil loss.

Dark chocolate acceptability: influence of cocoa origin and processing conditions

BACKGROUND

Chocolate properties can vary depending on cocoa origin, composition and manufacturing procedure, which affect consumer acceptability. The aim of this work was to study the effect of two cocoa origins (Ghana and Ecuador) and two processing conditions (roasting time and conching time) on dark chocolate acceptability.

RESULTS

Overall acceptability and acceptability for different attributes (colour, flavour, odour and texture) were evaluated by 95 consumers. Differences in acceptability among dark chocolates were mainly related to differences in flavour acceptability. The use of a long roasting time lowered chocolate acceptability in Ghanaian samples while it had no effect on acceptability of Ecuadorian chocolates. This response was observed for most consumers (two subgroups with different frequency consumption of dark chocolate). However, for a third group of consumers identified as distinguishers, the most acceptable dark chocolate samples were those produced with specific combinations of roasting time and conching time for each of the cocoa geographical origin considered.

CONCLUSION

To produce dark chocolates from a single origin it is important to know the target market preferences and to select the appropriate roasting and conching conditions.

Sensory evaluation of pralines containing different honey products

In this study, pralines manufactured by hand were evaluated sensorially. These pralines were obtained from dark chocolate containing 60% cocoa components, filled with Apis mellifera carnica Poll drone larvae, blossom honey and a blossom honey/pollen mixture from the protected region of Stara Planina-Eastern Serbia (a specific botanical region). The objectives of this study were investigations related to the use of sensory analysis for quality assessment of new functional products with potential benefits for human health, in particular of desserts based on dark chocolate pralines filled with different bee products characterized by a specific botanical and geographic origin, as well as of their storage properties and expected shelf life. Sensory quality (appearance, texture, odor and taste were evaluated by a group of experienced panelists immediately after the production (day 0), and then after 30, 90 and 180 days of storage under ambient conditions (temperature 18–20 °C). The results were statistically analyzed by the two-factorial analysis of variance (MANOVA) and with the LSD-test. It is possible to conclude that the storage time and composition of dark chocolate pralines containing different honey-bee products have statistically highly significant (p < 0.01) influence on the sensorially evaluated properties of pralines.