Fat bloom in chocolate and compound coatings

Flow properties of single origin chocolates: Effect of product formulation and particle size

The objective of this research was to evaluate changes in flow behavior of chocolate during chocolate grinding using a stone grinder as affected by chocolate formulation. Three different types of chocolates were evaluated. Two chocolates without milk added (70% chocolate) and two chocolates with milk added and with different amounts of cocoa nibs (30% chocolate and 14% chocolate) were tested. For the 70% chocolates, nibs of two different origins were used; therefore, a total of four samples were evaluated. Chocolates were processed in a stone grinder, and samples were taken as a function of grinding time. For each timepoint, the flow behavior of the samples was measured using a rotational rheometer and fitted to the Casson model. Particle size was measured using a laser scattering instrument. Results showed that yield stress increased linearly while the Casson plastic viscosity decreased exponentially with grinding time (smaller particles). Particle size distribution of the chocolates showed a prominent bimodal distribution for short grinding times (∼9 h) with small (∼15 µm) and large (∼100 µm) particles; with longer grinding time, the population of larger particles decreased. Yield stress values were higher for the 70% chocolate, but they were not very different between the two milk chocolates tested. The Casson plastic viscosity was greatest for the 70% chocolate, followed by the 30% chocolate. The 14% chocolate had the lowest Casson plastic viscosity. Changes of Casson plastic viscosity with particle size were more evident for the dark chocolates compared to the milk ones. These results are helpful to small chocolate producers who need better understanding of how the formulation and grinding of chocolate affect its flow behavior, which will ultimately affect chocolate handling during production.

Chemical Composition of Fat Bloom on Chocolate Products Determined by Combining NMR and HPLC-MS

To reduce unwanted fat bloom in the manufacturing and storage of chocolates, detailed knowledge of the chemical composition and molecular mobility of the oils and fats contained is required. Although the formation of fat bloom on chocolate products has been studied for many decades with regard to its prevention and reduction, questions on the molecular level still remain to be answered. Chocolate products with nut-based fillings are especially prone to undesirable fat bloom. The chemical composition of fat bloom is thought to be dominated by the triacylglycerides of the chocolate matrix, which migrate to the chocolate's surface and recrystallize there. Migration of oils from the fillings into the chocolate as driving force for fat bloom formation is an additional factor in the discussion. In this work, the migration was studied and confirmed by MRI, while the chemical composition of the fat bloom was measured by NMR spectroscopy and HPLC-MS, revealing the most important triacylglycerides in the fat bloom. The combination of HPLC-MS with NMR spectroscopy at 800 MHz allows for detailed chemical structure determination. A rapid routine was developed combining the two modalities, which was then applied to investigate the aging, the impact of chocolate composition, and the influence of hazelnut fillings processing parameters, such as the degree of roasting and grinding of the nuts or the mixing time, on fat bloom formation.

Effect of alternative sweetener and carbohydrate polymer mixtures on the physical properties, melting and crystallization behaviour of dark compound chocolate

This study aims to evaluate the effect of sucrose replacer mixtures (erythritol, mannitol, or tagatose in combination with inulin or polydextrose) on the crystal morphology, particle size distribution, rheology, melting properties, and fat polymorphism of dark compound chocolate. The result showed that the replacer mixture's hygroscopicity, particle size, and sugar crystal shape might significantly impact dark compound chocolate's rheological and textural properties but had no substantial impact on the melting properties and fat crystallization. Mannitol-containing samples exhibited the highest rheological value, likely related to their high moisture content, small particle size, and elongated crystal shape. Due to the similar specific surface area and comparable D90 value, the sample containing erythritol-polydextrose mixture resulted in a similar (P ≥ 0.05) Casson yield value (46.184 ± 2.45 Pa) compared to the sample containing sucrose (38.348 ± 1.68 Pa). It could be a potential sucrose replacer in the dark compound chocolate.

Polymorphic phase transitions in triglycerides and their mixtures studied by SAXS/WAXS techniques: In bulk and in emulsions

Triacylglycerols (TAGs) exhibit a monotropic polymorphism, forming three main polymorphic forms upon crystallization: α, β' and β. The distinct physicochemical properties of these polymorphs, such as melting temperature, subcell lattice structure, mass density, etc., significantly impact the appearance, texture, and long-term stability of a wide range products in the food and cosmetics industries. Additionally, TAGs are also of special interest in the field of controlled drug delivery and sustained release in pharmaceuticals, being a key material in the preparation of solid lipid nanoparticles. The present article outlines our current understanding of TAG phase behavior in both bulk and emulsified systems. While our primary focus are investigations involving monoacid TAGs and their mixtures, we also include illustrative examples with natural TAG oils, highlighting the knowledge transfer from simple to intricate systems. Special attention is given to recent discoveries via X-ray scattering techniques. The main factors influencing TAG polymorphism are discussed, revealing that a higher occurrence of structural defects in the TAG structure always accelerates the rate of the α → β polymorphic transformation. Diverse approaches can be employed based on the specific system: incorporating foreign molecules or solid particles into bulk TAGs, reducing drop size in dispersed systems, or using surfactants that remain fluid during TAG particle crystallization, ensuring the necessary molecular mobility for the polymorphic transformation. Furthermore, we showcase the role of TAG polymorphism on a recently discovered phenomenon: the creation of nanoparticles as small as 20 nm from initial coarse emulsions without any mechanical energy input. This analysis underscores how the broader understanding of the TAG polymorphism can be effectively applied to comprehend and control previously unexplored processes of notable practical importance.

Physical Properties and Fat Bloom Stability of Compound Chocolates Made with Ternary Fat Blends of Cocoa Butter, 1,3-Dioleoyl-2-stearoyl-triacylglycerol-Fat, and Lauric-Based Cocoa Butter Substitute

Compound chocolates made of lauric-acid-based cocoa butter substitute (CBS) and cocoa butter (CB) often exhibit serious fat blooms caused by phase separation and polymorphic transformation of CB and CBS triacylglycerols. Herein, we found that the fat bloom of CBS-based chocolates could be completely inhibited by adding fat containing 1,3-dioleoyl-2-stearoyl-triacylglycerol (OSO) to CBS/CB blends. Unlike the CBS/CB chocolates that presented fat blooms within 3 wk under isothermal storage at 15, 20, and 25°C and 15 wk under thermal thawing storage at 15-25°C , no fat blooms appeared in the CBS/CB/OSO compound chocolates under any storage condition up to 6 months. The following key factors are involved in the addition of the OSO fats: the (1) concentration ratio of CB/OSO should be 1/1 such that CB/OSO can form molecular compound crystals and (2) total amount of CB+OSO in the CBS/CB/OSO blends should reach 20%. The solid fat content, hardness, and crystallisation rate of the CBS/CB/OSO blend-based chocolate compound were confirmed to be suitable for chocolate production.

Development of a nutritionally balanced, melt-in-the-mouth chocolate for patients with epidermolysis bullosa

Epidermolysis bullosa (EB) is a group of inherited blistering disorders that primarily affect the skin and mucous membranes of the digestive tract, which can lead to poor nutritional status. Dietary supplements and nutritional support methods, such as nasogastric tubes and gastrostomy, have been employed to improve the nutritional status of patients with EB; however, few foods are suitable for enjoyable eating with family and friends. Here, we introduce a nutritionally balanced, melt-in-the-mouth chocolate called andew, which was specifically designed for patients with EB. The andew chocolate is nutritionally superior and melts more easily than traditional chocolates, thus it is suitable for patients with EB, who are prone to oral erosions. Patients responded more favorably to the taste and texture of andew than to those of other dietary supplements. Not only does andew provide nutritional benefits, but it also promotes enjoyable eating with family members and friends, which could positively impact patients' mental health.

Oxidative stability and physicochemical changes of dark chocolates with essential oils addition

This research aimed to evaluate the oxidative stability and rheological properties of dark chocolates with the addition of essential oils (EO) of Cymbopogon citratus, Pimpinella anisum, and Mintostachys mollis. For this purpose, before the inclusion in chocolates, the EO were chemically characterized to identify the most important volatile compounds. We added essential oils of P. anisum, C. citratus and M. mollis to dark chocolates (cocoa 70%) at doses of 10, 12 and 14 μL per 500 g, separately. These chocolates were evaluated for oxidative activity, hardness, microstructure, rheological and melting properties and antioxidant capacity. It was found that C. citratus EO (10 μL/500 g of chocolate) improve the oxidative stability of the chocolates at 90 days of storage at 25 °C (230 meq O₂/kg), while higher concentrations promote lipid oxidation. The incorporation of essential oils improves the antioxidant capacity, likewise, it changes the rheological, thermal, and microstructural properties. Therefore, essential oils can improve the physicochemical characteristics of dark chocolates allowing greater stability in oxidative fat and thus increase the shelf life.

Physicochemical and antioxidative properties of ultrasound-assisted extraction of mahua (Madhuca longifolia) seed oil in comparison with conventional Soxhlet and mechanical extractions

Ultrasound-assisted solvent extraction (UAE) was applied to extract underutilized Madhuca longifolia seed oil. The effect of extraction time, temperature, solvent type, solvent/sample ratio, and amplitude on the oil yield and recovery were investigated. Approximately 56.97% of oil yield and 99.54% of oil recovery were attained using mild conditions of 35 min, 35 °C, 40% amplitude, isopropanol to acetone (1:1), and solvent to sample (20 mL/g). UAE oil yield and recovery were comparable with Soxhlet extraction (SXE) whilst mechanical pressing (ME) yielded < 50% of UAE recovery. UAE does not affect the fatty acids composition (46% C18:1; 22% C16:0; 21% C18:0, 10% C18:2), and triacylglycerol profile (23% POO, 17% POS, 16% SOO, and 14% POP). Interestingly, UAE extracted oil conferred remarkably (P < 0.05) higher antioxidant capacity (IC₅₀ of DPPH 106.60 mg/mL and ABTS 39.80 mg/mL) than SXE (IC₅₀ of DPPH 810.40 mg/mL and ABTS 757.43 mg/mL) or ME (IC₅₀ of DPPH 622.38 mg/mL and ABTS 392.87 mg/mL).

Thermodynamics predicts a stable microdroplet phase in polymer-gel mixtures undergoing elastic phase separation

We study the thermodynamics of binary mixtures with the volume fraction of the minority component less than the amount required to form a flat interface and show that the surface tension dominated equilibrium phase of the mixture forms a single macroscopic droplet. Elastic interactions in gel-polymer mixtures stabilize a phase with multiple droplets. Using a mean-field free energy we compute the droplet size as a function of the interfacial tension, Flory parameter, and elastic moduli of the gel. Our results illustrate the role of elastic interactions in dictating the phase behavior of biopolymers undergoing liquid-liquid phase separation.

Rice bran wax effects on cocoa butter crystallisation and tempering

The effects of up to 5 wt% rice bran wax (RBX) on the crystallisation, tempering and storage stability of cocoa butter (CB) and a model dark chocolate were assessed. Presence of RBX significantly accelerated tempering and the formation of the desirable form V polymorph in CB. The form V to VI transition in both CB and chocolate was slowed in the presence of RBX during temperature-cycling, with addition of 1 wt% wax effectively reducing the extent of bloom formation in model chocolate following two weeks of temperature-cycling from 25 to 29 °C. Overall, this study has shown that RBX may be considered a viable seed material to accelerate tempering of CB and retard fat bloom in chocolate.

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.

Texture, color, and sensory changes occurring in chocolate bars with filling during storage

The impact of storage temperature (6, 12, 20, 30℃) and period (2, 6, 10, 18, 26 weeks) on the texture, color, and sensory characteristics of dark and milk-filled chocolate bars was studied. Temperatures of 6 and 12℃ were the most suitable for bar storage; these samples were evaluated not to be significantly deteriorated by the storage period. The condition of samples stored at 20℃ started to deteriorate after 10 weeks in storage; the decline was observed mainly in meltdown rate and off-flavors, resulting in low overall acceptability. This effect was more evident in dark chocolate bars. Keeping the bars at 24℃ for 24h immediately after production (retemperation) improved the bar resistance to fat bloom, even if the decrease in the sensory quality was observed at the beginning of the storage period.

Development of a GC-FID method for the quantitative determination of polyglycerol polyricinoleate (PGPR) in foods

Polyglycerol polyricinoleate (PGPR) is a powerful lipophilic emulsifier used in low-fat spreads and chocolate. It should be used at the lowest level at which the desired technological effect is achieved, not exceeding the specified maxima according to Annexe II to Regulation (EC) No 1333/2008. A gas chromatography-flame ionisation detection (GC-FID) method was developed for quantification of PGPR. This method is based on estimating the content of ricinoleic acid using 12-hydroxyoctadecanoic acid as an internal standard, from which the PGPR concentration was deduced. The method involved saponification, methylation, a two-step solid phase extraction (SPE) separation of the fatty acid methyl esters (FAMEs), silylation, and GC-FID analysis. The limits of detection and quantification of ricinoleic acid were 2.2 and 6.7 μg/mL, respectively, at 0.1 µL injection volume. Considering the average content of ricinoleic acid in PGPR (i.e. 86.63 ± 2.0 wt%) and the amount of food product that is used in the proposed protocol (i.e. 20 mg), this resulted in a LOD and LOQ of 0.76 and 2.32 μg PGPR per mg of food product, respectively. The developed method was validated by determining PGPR recovery from a high oleic sunflower oil (HOSO) solution, from chocolate spiked with a commercially available PGPR, and from commercially available low fat spreads with a known PGPR content. The actual recovery was more than 95% for all matrices, indicating the accuracy of the developed analytical technique. Moreover, the method proved to be very reproducible, with RSD < 4% for concentrations ranging from 0.2 to 5 wt%. The results showed that our proposed GC-FID method enables the reliable and quantitative determination of the PGPR concentration in commercial food products with various fat contents.

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

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

Characterisation of Fat Crystal Polymorphism in Cocoa Butter by Time-Domain NMR and DSC Deconvolution

The polymorphic state of edible fats is an important quality parameter in fat research as well as in industrial applications. Nowadays, X-ray diffraction (XRD) is the most commonly used method to determine the polymorphic state. However, quantification of the different polymorphic forms present in a sample is not straightforward. Differential Scanning Calorimetry (DSC) is another method which provides information about fat crystallization processes: the different peaks in the DSC spectrum can be coupled to the melting/crystallisation of certain polymorphs. During the last decade, nuclear magnetic resonance (NMR) has been proposed as a method to determine, qualitatively and/or quantitatively, the polymorphic forms present in fat samples. In this work, DSC- and NMR-deconvolution methods were evaluated on their ability to determine the polymorphic state of cocoa butter, with XRD as a reference method. Cocoa butter was subjected to two different temperature profiles, which enforced cocoa butter crystallization in different polymorphic forms. It was found that XRD remains the best method to qualitatively determine the polymorphic state of the fat. Whereas the quantitative NMR and DSC deconvolution results were not fully in line with the XRD results in all cases, NMR deconvolution showed great promise both in a qualitative and quantitative way.

Heat resistant chocolate development for subtropical and tropical climates: a review

Heat resistant chocolate (HRC) which can retain the desired texture and mouthfeel in tropical and subtropical climatic conditions has become a major research area in the chocolate industry. Liking of the chocolate products keeps on changing with the geographical conditions of the world due to the availability of ingredients from local resources and consumer's taste preferences. The geographical changes also bring about the change in climatic conditions and as such no chocolates have been formulated to withstand the hot tropical or sub-tropical temperature conditions. Textural issues and various storage related problems faced due to meltability of chocolate in different countries has opened up a broad research field of sustainable HRC manufacturing. Over the years, there are broadly three different approaches (fat modification, sugar structure modification and innovative process approach) to develop the HRC and all these scientific approaches have given different scientific insights about improving the heat resistance characteristics and textural stability of chocolate. There is a lack or coordinated fundamental and applied research related to cocoa butter polymorphism, and thermal-textural issues during product development/storage. This review paper is an attempt to describe the different scientific approaches for developing HRC and how they affect the physical/sensory chocolate attributes.

Like dissolves like: A first-principles theory for predicting liquid miscibility and mixture dielectric constant

Liquid mixtures are ubiquitous. Miscibility and dielectric constant are fundamental properties that govern the applications of liquid mixtures. However, despite their importance, miscibility is usually predicted qualitatively based on the vaguely defined polarity of the liquids, and the dielectric constant of the mixture is modeled by introducing mixing rules. Here, we develop a first-principles theory for polar liquid mixtures using a statistical field approach, without resorting to mixing rules. With this theory, we obtain simple expressions for the mixture's dielectric constant and free energy of mixing. The dielectric constant predicted by this theory agrees well with measured data for simple binary mixtures. On the basis of the derived free energy of mixing, we can construct a miscibility map in the parameter space of the dielectric constant and molar volume for each liquid. The predicted miscibility shows remarkable agreement with known data, thus providing a quantitative basis for the empirical "like-dissolves-like" rule.

Application of Complex Chitosan Hydrogels Added With Canola Oil in Partial Substitution of Cocoa Butter in Dark Chocolate

The complexation of polymeric materials can be an alternative to trapping oil in a physical network for formulating foods with reduced saturated fat content. In this research, we have evaluated the use of different polymer ratios of Sodium Alginate (ALG), Carrageenan predominance iota (CR1) and Carrageenan predominance kappa (CR2) complexed with Chitosan (CHI) at a fixed polymer concentration (2% w/v) to formulate complex hydrogels and assess their oil holding capacity. The objective was to determine the polymer ratios of CHI to anionic polysaccharides (75:25, 50:50, and 25:75), determining the oil retention capacity in different ratios, and how this can affect the stability, microstructure and rheology of to produce low saturated chocolate with trapped canola oil. The stability of the hydrogels was characterized, considering the water retention and retention of canola oil in polysaccharides complexes. The more stable system was the hydrogel CHI:CR2 in a polymer ratio of 25:75. This formulation, when added of 20% of canola oil presented an apparent viscosity of 0.631 Pa.s at 300 s−1, and its use as replacer of saturated fat allowed the production of dark chocolate with 16% reduction in fat content and 80% of added cocoa butter. Stability studies showed that polysaccharides complexes network can retain the edible oil in chocolate formulation for 60 days. It has been proven that polysaccharides complexes can be incorporated to partially replace the fatty phase in chocolates without considerable changes in relevant characteristics as consumer acceptance evaluated by sensory tests and rheological properties.

Binary Phase Behavior of 1,3-Distearoyl-2-oleoyl-sn-glycerol (SOS) and Trilaurin (LLL)

This paper reports the precise analysis of the eutectic mixing behavior of 1,3-distearoyl-2-oleoyl-sn-glycerol (SOS) and trilaurin (LLL), as a typical model case of the mixture of cocoa butter (CB) and cocoa butter substitute (CBS). SOS was mixed with LLL at several mass fractions of LLL (w_LLL); the mixtures obtained were analyzed for polymorphic phase behavior using differential scanning calorimetry (DSC) and synchrotron radiation X-ray diffractometry (SR-XRD). In melt crystallization with constant-rate cooling, SOS and LLL formed eutectics in their metastable polymorphs, allowing the occurrence of a compatible solid solution at w_LLL ≥ 0.925. With subsequent heating, the resultant crystals transformed toward more stable polymorphs, then melted in a eutectic manner. For mixtures aged at 25 °C after melt crystallization, eutectics were found in the extended w_LLL region, even at w_LLL = 0.975. These results indicate that phase separation between SOS and LLL progressed in their solid solution under stabilization. The crystal growth of the separated SOS fraction may cause fat-bloom formation in compound chocolate containing CB and CBS. To solve this problem, the development of retardation techniques against phase separation is expected.

Gelation Impairs Phase Separation and Small Molecule Migration in Polymer Mixtures

Surface segregation of the low molecular weight component of a polymeric mixture is a ubiquitous phenomenon that leads to degradation of industrial formulations. We report a simultaneous phase separation and surface migration phenomena in oligomer-polymer ( O P ) and oligomer-gel ( O G ) systems following a temperature quench that induces demixing of components. We compute equilibrium and time varying migrant (oligomer) density profiles and wetting layer thickness in these systems using coarse grained molecular dynamics (CGMD) and mesoscale hydrodynamics (MH) simulations. Such multiscale methods quantitatively describe the phenomena over a wide range of length and time scales. We show that surface migration in gel-oligomer systems is significantly reduced on account of network elasticity. Furthermore, the phase separation processes are significantly slowed in gels leading to the modification of the well known Lifshitz-Slyozov-Wagner (LSW) law ℓ ( τ ) ∼ τ 1 / 3 . Our work allows for rational design of polymer/gel-oligomer mixtures with predictable surface segregation characteristics that can be compared against experiments.

Point-of-care detection, characterization, and removal of chocolate bloom using a handheld Raman spectrometer

Chocolate bloom is an off-white coating on the surface of chocolate products due to the altered distribution of the ingredients. Bloom reduces the shelf-life of chocolate and affects its visual and tactile quality, all of which are serious concerns for chocolate manufacturers and consumers. The automated, rapid, and noninvasive point-of-care detection of chocolate bloom has been an essential but challenging problem. The ability to detect and characterize chocolate bloom using portable laser spectroscopy could be used to develop in-situ quality control sensors. In this work, a handheld Raman spectrometer was used to detect chocolate bloom. Raman spectra acquired from bloomed HERSHEY’S milk chocolate, Hawaiian Host milk chocolate covered macadamia nuts, and Babayevsky Russian dark chocolate were used to characterize the type of bloom. The 1064 nm laser beam of the handheld Raman instrument was used to partially remove the fat bloom of the dark chocolate and to induce sugar bloom on the milk chocolate. The handheld Raman approach has a high potential for industrial and consumer applications for the on-site chemical analysis of chocolate bloom and as an alternative laser-based chocolate decoration.

Physicochemical characteristics of anhydrous milk fat mixed with fully hydrogenated soybean oil

There is a growing demand for fats that confer structure, control the crystallization behavior, and maintain the polymorphic stability of lipid matrices in foods. In this context, milk fat has the potential to meet this demand due to its unique physicochemical properties. However, its use is limited at temperatures above 34 °C when thermal and mechanical resistance are desired. The addition of vegetable oil hard fats to milk fat can alter its physicochemical properties and increase its technological potential. This study evaluated the chemical composition and the physical properties of lipid bases made with anhydrous milk fat (AMF) and fully hydrogenated soybean oil (FHSBO) at the proportions of 90:10; 80:20; 70:30; 60:40; and 50:50 (% w/w). The increased in FHSBO concentration resulted in blends with higher melting point, which the addition of 10% of FHSBO increase the melting point in 12 °C of the lipid base. Also, FHSBO contributed for a higher thermal resistance conferred by the coexistence of polymorphs β' and β, which remained stable for 90 days. Co-crystallization was observed for all blends due to the total compatibility of milk fat with the fully hydrogenated soybean oil. The results suggest a potential of all blends for various technological applications, makes milk fat more appropriate to confer structure, and improve the polymorph stability in foods. The blends presenting singular characteristics according to the desired thermal stability, melting point, and polymorphic habit.

Pre-crystallization process in chocolate: Mechanism, importance and novel aspects

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 β_V 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.

Comparative Study on Mixing Behavior of Binary Mixtures of Cocoa Butter/Tristearin (CB/TS) and Cocoa Butter/Coconut Oil (CB/CO)

The comparative study between the mixing behavior of two binary mixtures of cocoa butter (CB)/tristearin (TS) and cocoa butter (CB)/coconut oil (CO) was investigated by using differential scanning calorimetry (DSC). The DSC profile for CB/TS blends resulted in a monotectic temperature–concentration (T–X) phase diagram, whereas a phase diagram of eutectic type was observed for CB/CO blends at 65 wt % of CO and 35 wt % CB; this suggests that the eutectic crystal can be formed when the saturated fat (blue = CO) is smaller in size compared to monounsaturated fat (orange = CB), whereas, for similar and larger size (red = TS) to CB, phase separation under crystallization is likely to occur (as shown in the graphical abstract). In order to understand the interaction between the binary systems, the profile of the phase diagram was fitted with Bragg–Williams approximation for estimation of the nonideality mixing parameter. Moreover, the morphology of the two different systems by polarized light microscopy (PLM) also depicted the variations in phase behavior by showing a significant change in CB morphology from spherulitic, grainy to granular and needlelike after the addition of TS and CO, respectively. Our findings emphasize the fundamental understanding of the interaction of bulk fat/fat and fat/oil system.

Wetting dynamics of polydimethylsiloxane mixtures on a poly(ethylene terephthalate) fiber

HYPOTHESIS

The wetting dynamics of liquids with identical surface tensions are mostly controlled by their viscosities. We therefore hypothesized that the wetting dynamics of one- (pure liquid) and two-component (mixture) polydimethylsiloxane (PDMS) on a poly(ethylene terephthalate) (PET) fiber with similar surface tensions and viscosities should be controlled by the same underlying physical mechanisms.

EXPERIMENTS

We studied the capillary rise of PDMS liquids on a PET fiber. We compared the different contact angle relaxations and characterized the transitions between the molecular-kinetic theory (MKT) and hydrodynamic approach (HD) for the PDMS mixtures and the pure liquids as a function of their viscosities.

FINDINGS

Compared to the pure PDMS liquid with a viscosity of 20 mm²/s that presents a contact angle relaxation following a t^-1/2 scale law in agreement with HD, the PDMS mixture with a higher viscosity (27.4 mm²/s) shows a t^-1 behavior predicted by the MKT. Moreover, the transition between MKT and HD appears in a regime with higher viscosities for PDMS mixtures than for pure liquids. Surface segregation of shorter PDMS chains or precursor film may be responsible for this shift.

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.

Delaying fat bloom formation in dark chocolate by adding sorbitan monostearate or cocoa butter stearin

Two formulations of dark chocolate were developed by adding cocoa butter stearin (CBSt) or sorbitan monostearate (SMS) and compared to a standard formulation in order to investigate fat bloom formation over time. Fat bloom was monitored by Whiteness Index (WI), melting behavior and polymorphism determinations, in bars stored during 90 days at 20 °C and under oscillating temperature between 20 and 32 °C. All samples stored at 20 °C did not develop fat bloom and the required β(V) form was maintained. Under oscillating storage condition, samples with CBSt (6.0%, w/w) and SMS (0.15%, w/w) delayed the surface fat bloom formation by at least 45 and 15 days, respectively, compared to standard chocolate, observed visually and through WI increments. The β(V) to β(VI) polymorphic transition correlated well with the WI, and also with changes in DSC thermograms, confirming the higher effectiveness of specific triacylglycerol (mainly StOSt) in delaying bloom formation.

Consumers in a Sustainable Food Supply Chain (COSUS): Understanding Consumer Behavior to Encourage Food Waste Reduction

Consumers are directly and indirectly responsible for a significant fraction of food waste which, for a large part, could be avoided if they were willing to accept food that is suboptimal, i.e., food that deviates in sensory characteristics (odd shape, discoloration), or that has a best-before date which is approaching or has passed, but that is still perfectly fine to eat. The choice to accept or discard suboptimal food is taken either before or after purchase (hence, in the retail store or in the household). The aim of the European research project COSUS (Consumers in a sustainable food supply chain) was to increase consumer acceptance of suboptimal food, before and after purchase, by implementing targeted strategies that are based on consumer insights, and that are feasible for and acceptable by the food sector. To reach this aim, different methodological approaches were applied to analyze this issue, to experiment with different aspects, and to test the resulting interventions. Each of these approaches was undertaken by competent consortium partners from Denmark, Germany, Norway, Sweden and The Netherlands. The project finally provides validated strategies to promote the distribution and consumption of suboptimal foods, thereby improving resource efficiency in the food chain and contributing to a more sustainable food supply.