Oil migration in chocolate and almond product confectionery systems

Oil migration from high oil content almond confections into adjacent chocolate causes changes in product quality. The objective of this study was to quantify the oil migration from almond products to dark chocolate. Magnetic resonance imaging (MRI) was used to monitor spatial and temporal changes of liquid lipid content. A multislice spin echo pulse (MSSE) sequence was used to acquire images with a 7.8-ms echo time and a 1000-ms repetition time using a 1.03T Aspect AI MRI spectrometer. Samples were prepared as a 2-layer model system of chocolate and almond confection. Six different almond products and 1 type of dark chocolate were used. Samples were stored at 20, 25, and 30°C for a time frame of several months. Rate and extent of migration were quantified by a kinetic expression based on the linear dependence of oil uptake by chocolate and the square root of the time. Samples showed distinctly different rate and extent of oil migration, as evidenced by quantitative differences in the kinetic rate constants and equilibrium uptake for the different sample types. This work will be helpful to design formulations for almond and almond-based products in confections. PRACTICAL APPLICATION: This work will be helpful to design formulations for almond use in confections.     

Development of free-flowing peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles via atomization with carbon dioxide

The main objective of this study was to overcome the issues related to the volatility and strong smell that limit the efficient utilization of essential oils as “natural” antimicrobials in the food industry. Peppermint essential oil-loaded hollow solid lipid micro- and nanoparticles were successfully formed using a novel “green” method based on atomization of CO₂-expanded lipid mixture. The highest essential oil loading efficiency (47.5%) was achieved at 50% initial essential oil concentration at 200 bar expansion pressure and 50 μm nozzle diameter, whereas there was no significant difference between the loading efficiencies (35%–39%) at 5%, 7%, 10%, and 20% initial essential oil concentrations (p > 0.05). Particles generated at all initial essential oil concentrations were spherical but increasing the initial essential oil concentration to 20% and 50% generated a less smooth particle surface. After 4 weeks of storage, 61.2%, 42.5%, 0.2%, and 2.0% of the loaded essential oil was released from the particles formed at 5%, 10%, 20%, and 50% initial essential oil concentrations, respectively. This innovative simple and clean process is able to form spherical hollow micro- and nanoparticles loaded with essential oil that can be used as food grade antimicrobials. These novel hollow solid lipid micro- and nanoparticles are alternatives to the solid lipid nanoparticles, and overcome the issues associated with the solid lipid nanoparticles. The dry free-flowing products make the handling and storage more convenient, and the simple and clean process makes the scaling up more feasible.     

Time–temperature study of the kinetics of migration of DPBD from plastics into chocolate,chocolate spread and margarine

Migration of low molecular weight substances into foodstuffs is a subject of increasing interest and an important aspect of food packaging because of the possible hazardous effects on human health.The migration of a model substance (diphenylbutadiene) from low-density polyethylene (LDPE) was studied in foodstuffs with high fat contents: chocolate, chocolate spread and margarines (containing 61% and 80% fat).A simplifying mathematical model based on Fick’s diffusion equation for mass transport processes from plastics was used to derive effective diffusion coefficients which take also kinetic effects in the foods into account and to determine partition coefficients between plastic and food. With this model migration levels obtainable under other storage conditions can be predicted. The effective diffusion coefficients for both margarines stored at 5 °C (3.0–4.2 × 10⁻¹⁰ cm² s⁻¹) and at 25 °C (3.7–5.1 × 10⁻⁹ cm²  s⁻¹) were similar to each other, lower than for chocolate spread stored at 5 °C (9.1 × 10⁻¹⁰ cm² s⁻¹) and higher than the diffusion coefficient for chocolate stored at 25 °C (2.9 × 10⁻¹⁰ cm² s⁻¹). Good agreement was found between the experimental and the estimated data, allowing validation of this model for predicting diffusion processes in foodstuffs with high fat contents.     

Characterization of fucoxanthin-loaded microspheres composed of cetyl palmitate-based solid lipid core and fish gelatin–gum arabic coacervate shell

Fucoxanthin-loaded microspheres, composed of a cetyl palmitate (CP)–canola oil (CO) mixed solid lipid core and a fish gelatin–gum arabic complex coacervate shell cross-linked by tannic acid, were developed and characterized for efficient oral delivery of fucoxanthin. Two types of solid lipid-core microspheres (CP:CO = 30:70 and 50:50) in both wet and freeze-dried forms were investigated in their morphology, size, moisture content, and fucoxanthin encapsulation efficiency, in comparison with oil–core microspheres (CP:CO = 0:100). The melting and solidification of the cores were also analyzed by DSC. Compared to the oil–core microspheres, the solid lipid-core microspheres, especially of CP:CO = 50:50, exhibited greatly enhanced sustained fucoxanthin release performance under a simulated gastrointestinal condition and much stronger fucoxanthin-stabilizing capability when stored in the dark atmosphere of 0% or 51% relative humidity at 40 °C, although the encapsulation efficiency was lowered from 85.34% to 74.81% with the increase of the CP fraction from 0% to 50%.     

Ethylcellulose solvent substitution method of preparing heat resistant chocolate

In the present study a structuring technique was developed to produce chocolate which resists deformation at temperatures above 40 °C. It was hypothesized that by adding ethylcellulose (EC) solubilized in ethanol (EtOH) to chocolate and evaporating the EtOH an organogel could be formed in situ with the fat phase of the chocolate. Heat resistant chocolate (HRC) was produced by mixing a 20% EC in EtOH solution with molten chocolate. The EtOH was evaporated and the resulting chocolate was incubated at 40 °C for 2 h and tested for hardness. The effect of various EC viscosities (4, 10, 20, 22, and 45 cP) and concentrations ranging from 1.0 to 2.2% on different types of chocolates was studied. Milk chocolate containing 1.9% EC had a hardness of 26.0 N whereas the control chocolate was too soft to be tested. Further experiments revealed that white and dark chocolates had hardnesses of 29.5 and 10.5 N, respectively. The hardness of the chocolate was dependent on the chocolate formulation and concentration of EC, and independent of EC viscosity. It was observed that the addition and evaporation of EtOH from the compound milk chocolate samples led to an increase in the lightness of the chocolate surface if the EtOH was evaporated at temperatures of 40 °C or higher. Addition of EC to chocolate represents a new strategy for the manufacture of HRC. Future work should focus on determining the mechanism by which heat resistance is achieved in these chocolates.     

Composition and stability of olive oil following partial crystallization

Extra virgin olive oils were separated into two fractions, one being liquid at 4 °C and one solid. Each of the oils and their associated fractions underwent analysis for fatty acid composition, analysis of the total antioxidant activity and stability towards oxidation when heated at 150 °C. The solid fraction contained greater amounts of saturated fatty acids, although analysis of the fatty acids on position 2, obtained via a pancreatic lipase treatment, showed similar total levels of unsaturated fatty acids for all fractions. Analysis of the antioxidant components showed that there was a higher proportion associated with the liquid fractions. This trend, in combination with the results of the heating trials of the oils and associated fractions, indicated that the liquid fraction was not more susceptible to oxidation. Hence it is possible to fractionate olive oil to give fractions with onset of melting differing by some 10 °C without compromising stability towards oxidation.     

Effect of cocoa butter structure on oil migration

Oil migration from a high oil content filling into adjacent chocolate causes changes in product quality. The objective of this study was to quantify the oil migration from a cream filling system into cocoa butter, which provided a model for the behavior of chocolate-enrobed confectionery products with a soft, creamy center. Magnetic resonance imaging (MRI) was used to monitor spatial and temporal changes of liquid lipid content. A multislice spin echo pulse sequence was used to acquire images with a 7.8 ms echo time and a 200 ms repetition time using a 1.03 T Aspect Imaging MRI spectrometer. Samples were prepared as a 2-layer model system of cocoa butter and model cream filling. Three methods were used to prepare the cocoa butter: static, seeded, and sheared. Samples were stored at 25 °C for a time frame of 56 d. The rate of oil migration was quantified by a kinetic expression based on the linear dependence of oil uptake by cocoa butter and the square root of the time. Samples showed distinctly different rates of oil migration, as evidenced by quantitative differences in the kinetic rate constant. Practical Application: This work will be helpful to elucidate the influence of crystallization process and structural properties such as crystal nanostructure and crystal habit on the migration of oil through a crystalline fat matrix.     

Exploring the hedonic and incentive properties in preferences for bitter foods via self-reports,facial expressions and instrumental behaviours

Preferences for and consumption of bitter foods such as vegetables and fruit are important in addressing the epidemic of obesity as healthy dietary patterns contribute to its prevention. However, few studies have been undertaken to understand the preference for bitter-tasting foods. A generally accepted but not proven explanation is that these acquired preferences involve changes in affective and motivational processes in order to overcome the innate rejection of bitter tastes. To examine this issue we compared the hedonic and incentive responses to bitter substances among bitter likers and dislikers. In addition, the effects of hunger, stress and weight concern on bitter preferences were also explored. Fifty-nine healthy adults (age = 24.8 ± 6.3; body mass index = 22.0 ± 2.8) were divided into bitter likers and bitter dislikers according to their food preferences. Both groups sampled the unreinforced flavours of coffee, beer, chocolate and grapefruit under four motivational states induced by static pictures (neutral, food, stressor and obesity) at the time of testing. The results showed that the bitter solutions elicited less aversive responses (higher hedonic ratings and less intense disgust reactions) and fewer avoidance behaviours (slower response time and lower amount of water for rinsing) in bitter likers after viewing neutral images. On the other hand, likers exhibited a further reduction in disgust to coffee after viewing stressor pictures, and also drank more water after tasting chocolate following the obesity pictures, compared with the dislikers. The expression of disgust increased in bitter likers, as well as the amount of water used to rinse the mouth, after tasting chocolate following pictures showing obesity compared with pictures showing food. These results show, for the first time, not only the implication of affective and incentive components in reversal of the predisposition to reject bitterness but also the motivational modulation of the expression of rejection of bitter tastes in humans.     

Determination of 5-hydroxymethyl-2-furfural and 2-furfural in oils as indicators of heat pre-treatment

This study describes a method for the determination of 5-hydroxymethyl-2-furfural (HMF) and 2-furfural (F) in oils. The method entails liquid–liquid extraction and reversed-phase liquid chromatography. Spiked hazelnut oil was used to test the accuracy and reliability of the method. Furan compounds were extracted from oil using 70% methanol. Mean recoveries were 97 ± 2% and 99 ± 1% for HMF and F, respectively. To investigate the presence of HMF and F in oils, seven oily nuts and seeds were roasted at 180 °C for 30 min. Different oils were found to contain HMF and F ranging from 0.8 to 13.8 and 1.4 to 8.7 mg/kg, respectively. Increasing solvent polarity also increased the rate of HMF transferred to the oil. Spectral analyses of the 70% methanol extracts indicated that absorbance at 285 nm may be used to monitor the accumulation of furan compounds in oil phase during the roasting process of nuts.     

In vitro study of anti-oxidative effects of β-carotene and α-lipoic acid for nanocapsulated lipids

In this study we attempted to assess the efficacy of the in vitro activities of β-carotene and α-lipoic acid in conjugation with an encapsulated lipid. Nanoemulsion was prepared and freeze-dried to get nanocapsules. Highest encapsulation efficiency 84.32 ± 1.08% was achieved for α-lipoic acid nanocapsules, whereas for β-carotene nanocapsules it was 79.63 ± 1.41%. Morphology study showed that the dried capsules had an irregular, rough surface. Both anti-oxidants were equally effective in releasing core materials. Complete release of the total lipid occurred within 210 min from both β-carotene and α-lipoic acid bearing nanocapsules. Stability study revealed that β-carotene nanocapsules showed decrease in oil content from 79.63 g lipid to 72.8 g lipid for every 100 g lipid encapsulated, in 3 months, whereas α-lipoic acid nanocapsules retained oil much better, the oil retention being from 84.32 g lipid to 78.08 g lipid per 100 g lipid encapsulated. DPPH radical scavenging activity of β-carotene and α-lipoic acid ranged from 62.75% and 44.13% to 32.94% and 36.95% (after 90 days) respectively. Reducing activity of β-carotene was higher (absorbance 0.492 to 0.291 at 90 days) compared to α-lipoic acid (absorbance 0.243 to 0.109 after 90 days). Again β-carotene and α-lipoic acid metal-chelation activity ranged from 47.65% and 48.59% to 32.315% and 39.29% after 90 days.     

Effects of Particle Size,Applied Pressure and Pressing Time on the Yield of Oil Expressed from Almond Seed

An investigation of the effects of particle size, applied pressure and pressing time on the yield of oil expressed from almond seeds was undertaken. The oil was expressed mechanically using a mini laboratory oil press. The fixed processing parameters were: moisture content of 17% wet basis, heating temperature of 65 – 70°C and heating time of 15 min. The pressing pressures used were 60.6 kPa, 101.3 kPa and 116.6 kPa. Pressing times used were 2, 4, 8 and 12 min, and particle size of Φ < 0.5 mm (fine sample) and Φ > 0.5 mm (coarse sample) were used. The result shows that oil yield increased with increase in applied pressure and pressing time, however result obtained from fine and coarse sample sizes are similar. Pressing time and applied pressure had significant (p < 0.05) difference on oil yield; particle size had no significant (p > 0.05) difference on oil yield. Regression and correlation analysis gave a reasonable experimental prediction between oil yield and applied pressure with correlation coefficient r = 0.952 and also with pressing time with r = 0.7342. Higher oil yields were obtained from samples with fine particles size (Φ < 0.5 mm) and coarse particles size (Φ > 0.5 mm) samples pressed at 116.6 kPa pressure for 12 min. Maximum oil yields of 48.44% and 48.40% were obtained from coarse and fine samples respectively. The results obtained can be used in the design of a suitable process and machine for the expression of oil from almond seed.     

Image analysis of changes in surface color of chocolate

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.     

An investigation on the appropriateness of chocolate to match tea and coffee

The aim of this study was to provide some recommendations for selecting a befitting tea and coffee to match chocolate with different cocoa contents. Three coffee samples (chocolate flavored, vanilla flavored and unflavored coffee), four tea samples (black tea, green tea, vanilla flavored tea and citrus flavored tea) and three chocolates (30%, 70%, and 99% cocoa) were hedonically rated by eighty regular chocolate consumers. The beverages were then paired with each chocolate, and the consumers were asked to indicate the hedonic liking of the resulting pairings, and to indicate whether the chocolate or beverage flavor dominated the pairing flavor. This study showed that liking of chocolate and coffee pairings and chocolate and tea pairings significantly varied (p < 0.001) across samples. Consumers preferred pairings with 30% cocoa and 70% cocoa chocolate to pairings with 99% cocoa chocolate. Overall, coffee is significantly (p < 0.001) preferred to tea as a chocolate partner.Chocolate and beverage pairing liking was biased by the liking of the beverage tasted alone, the liking of chocolate tasted alone, beverage type, chocolate type and the level of flavor match between chocolate and tea or coffee in a given pairing. When chocolate and beverage flavor balanced out in a given pairing, chocolate and coffee/tea pairings were significantly preferred by the consumers. A significant decrease in acceptance was observed when beverage or chocolate flavor dominated the flavor of the pairing, much more so when the chocolate flavor dominated the pairing flavor. However consumers don't enjoy any preferred chocolate with any preferred tea or coffee because some flavors match better than do others. Indeed, consumers formulate their hedonic responses taking into consideration what flavors go well together more than they rely exclusively on their hedonic judgments of the chocolates, the teas, and the coffees tasted alone.     

Effect of active and modified atmosphere packaging on quality retention of dark chocolate with hazelnuts

The present study investigated the effect of active and modified packaging as well as packaging material oxygen permeability on quality retention of dark chocolate with hazelnuts. Dark chocolate was packaged in: a) polyethylene terephthalate//low density polyethylene (PET//LDPE), and b) polyethylene terephthalate coated with SiOx//low density polyethylene (PET-SiOx//LDPE). Samples were packaged either under, vacuum or N₂ or with an oxygen absorber and stored in the dark at 20 °C for a period of 12 months. “Commercial” control samples for comparison purposes consisted of chocolate packaged in aluminum foil in air while “model” control samples used for sensory evaluation consisted of chocolate packaged in glass jars and stored at ? 18 °C. Quality parameters monitored were: peroxide value, hexanal content, color, fatty acid composition and volatile compounds. Of the sensory attributes color, texture, odor and taste were evaluated. PV ranged between 0.80 for fresh dark chocolate with hazelnuts and 6.51 meq O₂/kg chocolate fat for commercially packaged samples after 12 months of storage. Respective values for hexanal were 0.53 and 7.56 mg/kg. % Saturated fatty acids (SFA) increased with a parallel decrease in monounsaturated fatty acids (MFA) and polyunsaturated fatty acids (PUFA) after 12 months of storage mainly in least protected samples (commercial package). Likewise, after 12 months of storage an increase in concentration of aldehydes, ketones, alcohols and alkanes (p < 0.05) with a parallel decrease in pyrazines where observed especially in case of least protected products after 6 and 12 months of storage. In general after 12 months of storage chocolate showed whitening of the surface resulting to an increase in L* and a* values (p < 0.05) and a decrease in b* value. Dark chocolate with hazelnuts retained acceptable quality for ca. 8 months in commercial packages. For samples packaged in PET//LDPE irrespective of storage atmosphere the shelf life was 8 to 9 months and for samples packaged in PET-SiOx//LDPE irrespective of storage atmosphere the shelf life was 11 months. Finally for samples packaged with an oxygen absorber irrespective of packaging material the shelf life was at least 12 months.Industrial relevanceChocolate packaged with an oxygen absorber in a barrier packaging material will maintain its aroma, taste and nutritional quality substantially longer than other packaging methods.     

Migration of α-tocopherol from LDPE films to corn oil and its effect on the oxidative stability

The migration of α-tocopherol (α-T) from low density polyethylene (LDPE) films, added with 20 (film A) and 40 mg g^?1 (film B) to corn oil for 12 weeks at 5, 20 and 30 °C was determined. A LDPE film added with no α-T was used as control (film C). Diffusion coefficient (D) values for the film A system were 1.4 × 10^?11, 7.1 × 10^?11 and 30.3 × 10^?11 cm² s^?1 at 5, 20 and 30 °C, respectively. Meanwhile, D values for the film B system were 1.3 × 10^?11, 9.6 × 10^?11 and 51.1 × 10^?11 cm² s^?1 at the same temperatures. The activation energy (E_a) for the diffusion of α-T was 126.5 (film A) and 105.9 kJ mol^?1 (film B). The effect of the migration of α-T on the oxidative stability of corn oil was evaluated by monitoring hexanal content by solid phase micro-extraction (SPME) and gas chromatography. The hexanal content in the oil showed that both films added with α-T resulted suitable to maintain the oxidative stability of the oil for about 16 weeks at 30 °C, compared to 12 weeks for the oil in contact with the film C.     

Temperature of served water can modulate sensory perception and acceptance of food

Cross-cultural differences exist in the typical temperature of water served with meals. North American people typically drink iced water/beverages while eating, whereas European or Asian people show a preference for room temperature water or hot water/tea, respectively. It has been reported that food perception and acceptance are influenced by oral temperature, as well as by serving temperature of food. Based on the fact that the iced or hot water served with meals can alter the oral temperature, the present study aimed to determine whether the temperature of served water can affect the sensory perception and acceptance of food subsequently consumed. Following a mouth rinse with water served at 4, 20, and 50 °C for 5 s, two different types of food, dark chocolate and cheddar cheese, were evaluated in terms of sensory intensity and overall liking. For the dark chocolate, the intensity ratings for sweetness, chocolate flavor, and creaminess were significantly lower when following water at 4 °C than when following water at either 20 or 50 °C. However, the modulatory effect of water temperature on sensory perception was not obtained with cheddar cheese. In addition, the temperature of served water altered the acceptance for the foods subsequently presented. Specifically, the overall liking for the dark chocolate was significantly lower when following water at 4 °C than when following water at either 20 or 50 °C. In conclusion, the present study demonstrates new empirical evidence that the consumption of iced water can decrease perceived intensities of sweetness, chocolate flavor, and creaminess for subsequently consumed chocolate. Our findings may provide one of plausible answers to the question of why North American people, who are more used to drinking iced water, show a strong preference for more highly sweetened foods.     

MR imaging and diffusion studies of soaked rice

The effects of lipid on magnetic resonance (MR) images and diffusion data in soaked rice were investigated using MR imaging and pulsed field gradient (PFG)-NMR spectroscopy, as well as water diffusion within rice. Lipid contributed to proton density-weighted MR image and found to be diffused by diffusion-ordered spectroscopy (DOSY). During diffusion experiments, two components for the self-diffusion coefficient (D_s1 and D_s2) of water and one component for lipid (D_s3) were observed in soaking rice. It suggests that D_s2 of water self-diffusion corresponds to water diffusion within starch granules of rice, resulting in a restricted diffusion. Based on the restricted diffusion, the average size (a) of the starch granules was estimated to be 4.6 μm. The permeability of water (P) of starch granule was increased from 1.77 × 10^?5 m/s to 2.49 × 10^?5 m/s as the soaking time increased from 3 to 6. This study demonstrates that lipids play a role in MR images contrast and diffusion data, and that physicochemical properties of the starch granule can be characterized in soaked seeds by PFG-NMR.     

Visualisation of Liquid Triacylglycerol Migration in Chocolate by Magnetic Resonance Imaging

This study has demonstrated that magnetic resonance imaging can be used to visualise the migration of liquid triacylglycerols in composite chocolate confectionery. Migration was observed between a layer of hazelnut oil filling (oil+icing sugar) and a layer of dark chocolate used as a model of composite chocolate confectionery products. In addition, low-resolution nuclear magnetic resonance measurements of the solid fat content (%) were also made. Substantial differences were observed between the migration profiles at 19 and 28°C, and in the distribution of liquid triacylglycerols across the chocolate layer after migration. It is suggested that the mechanism of migration involves both diffusion of the liquid triacylglycerols and capillary attraction of the hazelnut oil into the chocolate matrix. © 1997 SCI.     

Encapsulation,protection, and release of polyunsaturated lipids using biopolymer-based hydrogel particles

Delivery systems are needed to encapsulate polyunsaturated lipids, protect them within food products, and ensure their bioavailability within the gastrointestinal tract. Hydrogel particles assembled from food-grade biopolymers are particularly suitable for this purpose. In this study, hydrogel microspheres were fabricated by electrostatic complexation of low methoxy pectin and caseinate by decreasing the solution pH from 7 to 4.5. After hydrogel particle formation, the caseinate was enzymatically cross-linked using transglutaminase to improve the stability of the biopolymer matrix. The effect of hydrogel particle encapsulation on the physical location, chemical stability, and lipase digestibility of emulsified polyunsaturated lipids (fish oil) was investigated. The cross-linked hydrogel particles formed using this process were relatively small (D₄₃ = 4.6 μm), negatively charged (ζ = − 37 mV), and evenly distributed within the system. Confocal microscopy confirmed that the fish oil droplets were trapped within casein-rich hydrogel microspheres. Encapsulation of the fish oil droplets improved their stability to lipid oxidation compared to conventional emulsions, which was attributed to a high local concentration of antioxidant protein around the emulsified lipids. The rate and extent of digestion of the encapsulated lipid droplets within a simulated small intestine were similar to those of non-encapsulated ones. These results suggest that casein-rich hydrogel microspheres may protect polyunsaturated lipids in foods and beverages, but release them after ingestion.     

Influence of lecithin–PGPR blends on the rheological properties of chocolate

Lecithin and polyglycerol polyricinoleate (PGPR) are common emulsifiers used in the manufacture of chocolate products. The effects of systematically varied blends of lecithin and PGPR added in a concentration up to 14 g/kg on the flow properties of melted dark and milk chocolate were determined by means of rotational rheometry. The results show that, independent of the total amount of the emulsifier, the yield stress of both dark and milk chocolate mass is most efficiently reduced by applying mixtures of approximately 30% lecithin and 70% PGPR. As regards total emulsifier concentrations between 4 and 6 g/kg, lowest viscosity values were found for lecithin–PGPR blends of 50:50 and 75:25 for dark chocolate and milk chocolate, respectively. The obtained results indicate that it is possible to tailor yield stress and viscosity of melted chocolate to specific requirements by the appropriate adjustment of both blending ratio and quantity of the emulsifiers.