Impact of Storage on Dark Chocolate: Texture and Polymorphic Changes

Impact of composition and aeration on the migration of TAGs in sandwich type confectionery products

A sandwich type confectionery product is made with a soft filling and a chocolate coating. The fats used for these two parts are generally different to provide specific organoleptic sensations. Thus, their compositions, in terms of the triacylglycerols (TAGs) profile, are different. Depending on the ambient temperature conditions, the chemical potential gradient at the interface for TAGs, and the microstructures in the bulk of two parts, the migration of TAGs is influenced. We have studied the impact of different filling recipes on the migration of specific TAGs from the filling to the coating and vice versa with a newly developed tool, referred to as lipstick method. Also, the influence of the micro-aeration of the filling on the transfer process is evaluated. Furthermore, Fick's law of diffusion-based model is developed. The migration of TAGs as predicted by the model is compared to the experimental measurements, and limitations of the model are discussed. This approach can be used to tune the recipes of coating and filling to enhance the shelf-life stability of such products while delivering on specific liking attributes of taste.

The Influence of a Chocolate Coating on the State Diagrams and Thermal Behaviour of Freeze-Dried Strawberries

Chocolate-coated fruit is becoming more and more popular as a tasty snack. The subjects of the research were freeze-dried strawberries and dark and milk chocolate-coated freeze-dried strawberries. The DSC curves, sorption isotherms, and glass transition temperature were determined. The state diagrams of the freeze-dried strawberries and dark and milk chocolate-coated freeze-dried strawberries were investigated. The modulated differential scanning calorimetry (MDSC) technique was used to determine the glass transition temperature. The DSC diagrams of the studied samples showed differences in shape and course. The sorption isotherms of the freeze-dried strawberries and dark and milk chocolate-coated strawberries belonged to type II according to BET classification. A coating of milk or dark chocolate resulted in a significant reduction in the hygroscopic behaviour of the freeze-dried strawberries and could be considered a promising way to improve the shelf life of the product and improve the nutritional value for commercial production purposes.

Microencapsulation of Phenolic Extracts from Cocoa Shells to Enrich Chocolate Bars

Cocoa bean shells were subjected to green extraction technologies, based on the absence of toxic organic solvents, to recover polyphenols; the extract was then encapsulated using a spray dryer and maltodextrin as coating agent. The best conditions observed in the spray drying tests (core-to-coating ratio 1:5; inlet temperature 150 °C; flow rate 6 ml min^-1) were applied to produce the microcapsules used to enrich the same cocoa mass as the shells and processed for the preparation of the chocolate bars. Sensory analysis showed no significant differences between enriched chocolate bar and the unenriched reference one, except for the appearance. Both samples were then subjected to accelerated storage tests, at the end of which the polyphenols in the control chocolate bar (0.85 g 100 g^-1) were reduced by about 50% (0.42 g 100 g^-1), while in the enriched chocolate (1.17 g 100 g^-1) by only 22% (0.97 g 100 g^-1). The proposed process significantly enriched the chocolate bars with phenolic antioxidants recovered from cocoa waste without increasing the sensations of bitterness and astringency.

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.

Investigation of the rheological, thermal, sensory properties, and particle size distribution of sesame paste white compound chocolate as influenced by the soy flour and emulsifier levels

The impacts of replacing various levels of skim milk powder with soy flour (0%, 7%, and 14.5% w/w), as well as the quantity of emulsifier (mono-glyceride, 0 and 1.5% w/w) on particle size distribution, rheological, textural, thermal, and sensory properties of sesame paste white compound chocolate were studied. Enhancing the percentage of soy flour along with concurrent decrease of milk powder, increased particle size distribution parameters, as D90 increased from 9.33 to 16.6 (μm). The outcomes indicated that different contents of soy flour affected the hardness along with having greater impact on the samples containing emulsifier. Adding mono-glyceride to chocolate resulted in an excessive reduction in the hardness and also in particle size distribution parameters. Values of Casson plastic viscosity ranged from 2.46 to 5.8 (Pa.s), the Casson yield values and apparent viscosity varied between 9.95 and 111.72 (Pa), and 6.3 and 12.1(Pa.s), respectively. Moreover, analyzing the data demonstrated that soy flour had notable impact on the sensory properties of the samples. Also, soy flour and emulsifier could be manipulated for achieving the desirable rheological properties of sesame paste white compound chocolate.

Enriching novel dark chocolate withBacillus coagulansas a way to provide beneficial nutrients

The aim of the present study was to develop a novel type of probiotic chocolate with the additiveBacillus coagulansbacteria and determine the concentration of polyphenols and their bioaccessibility.

Molecular and nanoscale compositional contrast of soft matter in liquid: interplay between elastic and dissipative interactions

We demonstrate that the phase contrast observed with an amplitude modulation atomic force microscope depends on two factors, the generation of higher harmonics components and the energy dissipated on the sample surface. Those factors are ultimately related to the chemical composition and structure of the surface. Our findings are general, but they specifically describe the results obtained while imaging soft materials in liquid. Molecular resolution experiments performed on a protein membrane surface in liquid confirm the theory.

Changes in dark chocolate volatiles during storage

Chocolate storage is critical to the quality of the final product. Inadequate storage, especially with temperature fluctuations, may lead to a change in crystal structure, which may eventually cause fat bloom. Bloom is the main cause of quality loss in the chocolate industry. The impact of various storage conditions on the flavor quality of dark chocolate was determined. Dark chocolate was stored in different conditions leading to either fat or sugar bloom and analyzed at 0, 4, and 8 weeks of storage. Changes in chocolate flavor were determined by volatile analysis and descriptive sensory evaluation. Results were analyzed by analysis of variance (ANOVA), cluster analysis, principal component analysis (PCA), and linear partial least-squares regression analysis (PLS). Volatile concentration and loss were significantly affected by storage conditions. Chocolates stored at high temperature were the most visually and texturally compromised, but volatile concentrations were affected the least, whereas samples stored at ambient, frozen, and high relative humidity conditions had significant volatile loss during storage. It was determined that high-temperature storage caused a change in crystal state due to the polymorphic shift to form VI, leading to an increase in sample hardness. Decreased solid fat content (SFC) during high-temperature storage increased instrumentally determined volatile retention, although no difference was detected in chocolate flavor during sensory analysis, possibly due to instrumental and sensory sampling techniques. When all instrumental and sensory data had been taken into account, the storage condition that had the least impact on texture, surface roughness, grain size, lipid polymorphism, fat bloom formation, volatile concentrations, and sensory attributes was storage at constant temperature and 75% relative humidity.