Rheological, textural and calorimetric modifications of dark chocolate during process

Correlation of rheology and oral tribology with sensory perception of commercial hazelnut and cocoa-based spreads

This study examined the effects of spread formulation and the structural/lubricant properties of six different commercial hazelnut and cocoa spreads on sensory perception. Rheology, tribology, and quantitative descriptive analysis (QDA) was assessed by also evaluating the correlation coefficients between the quality descriptor and the rheological and textural parameters. The viscosity was evaluated at different temperatures to better simulate conditions before and after ingestion. Tribological analysis was executed at 37°C to mimic the human oral cavity. The effect of saliva presence and the number of runs on tribological behaviors was investigated. Moreover, textural, calorimetric, and particle size distribution measurements were performed to reinforce the correlation between structural/thermal parameters (e.g., firmness, stickiness, sugar melting point) and sensory aspects. "Visual viscosity," defined as a sensory attribute evaluated prior to consumption, negatively correlated with apparent viscosity measured at 20°C and 10 s-1, whereas "body," defined during oral processing and related to creaminess, positively correlated with apparent viscosity measured at 37°C and 50 s-1. These attributes were mainly influenced by particulate microstructure and solid volume fraction within the formulation. Textural stickiness positively correlated with sensory "adhesiveness" and was related to fat composition and milk powder addition, while "sweetness" was related to sucrose content and sugar melting enthalpy. Tribological data provided meaningful information related to particle-derived attributes, as well as after-coating perception (fattiness/oiliness), thus better predicting food evolution during oral consumption.

Combining fracture mechanics and rheology to investigate the impact of micro-aeration on chocolate oral processing

This study presents a rigorous mechanical characterisation investigation on milk chocolate with varying porosities, at different temperatures and strain rate levels. Uniaxial compression tests at temperatures varying from 20 °C to 30 °C were performed to measure the bulk properties of chocolate as a function of porosity and temperature. Fracture experiments were also conducted to compute the fracture energy at temperature levels between 20 °C and 30 °C for all tested samples. Additionally, rheological experiments are conducted to compute the viscosity of the different chocolates at 37 °C. This combined experimental analysis of solid mechanics, fracture mechanics, and rheology aims to define the impact of temperature and chocolate's phase change from solid to liquid on its mechanical properties. Moreover, the impact of micro-aeration on the relationship between material properties and temperature is discussed. The results demonstrate a significant impact of both temperature and micro-aeration on the chocolate's material properties; fracture stresses decrease with micro-aeration due to the presence of micro-pores creating weak links in the chocolate matrix, the critical strain energy release rate decreases with micro-aeration at temperatures up to 25 °C and increases at temperatures above 30 °C. Finally, the viscosity at 37 °C increases with increasing porosity due to the obstruction of the flow by micro-pores acting as "solid" particles. The results highlight how the impact of micro-aeration on the material properties of chocolate alters as the testing temperature rises and the material changes phase. The relationships between the micro-aeration and material properties and the dependence of temperature on the different mechanical properties are used to explain the difference in textural attributes as obtained from temporal dominance sensation tests. This study seeks to contribute valuable insights into the field of chocolate technology, emphasizing the need for a combined engineering approach to understand the structural breakdown of chocolate during oral processing as mechanisms such as chewing, melting, mixing and shearing occur.

Exploring the effects of structure and melting on sweetness in additively manufactured chocolate

In view of the health concerns associated with high sugar intake, this study investigates methods to enhance sweetness perception in chocolate without increasing its sugar content. Using additive manufacturing, chocolate structures were created from masses with varying sugar and fat compositions, where hazelnut oil served as a partial cocoa butter replacement. The study found that while variations in sugar content minimally affected the physical properties of the chocolate masses, hazelnut oil significantly modified melting behavior and consumption time. Chocolate masses with higher hazelnut oil content but similar sugar content exhibited a 24% increase in sweetness perception, likely due to accelerated tastant (i.e., sucrose) release into saliva. Multiphase structures, designated as layered, cube-in-cube, and sandwich structures, exhibited less sensory differences compared to the homogeneous control. Nonetheless, structures with hazelnut oil-rich outer layers resulted in an 11% increase in sweetness perception, even without sugar gradients. This suggests that tastant release plays a more critical role than structural complexity in modifying sweetness perception. This research highlights the efficacy of simpler multiphase structures, such as sandwich designs, which offer sensory enhancements comparable to those of more complex designs but with reduced manufacturing effort, thus providing viable options for industrial-scale production.

Characterization of white chocolate enriched with co-encapsulated Lactobacillus acidophilus (La-5) and rose hip shell fruit extract: Characterization, probiotic viability during storage, and in vitro gastrointestinal digestion

This research focused on the production of a new kind of probiotic chocolate containing co-encapsulated Lactobacillus acidophilus (La-5) bacteria and rose hip shell fruit extract. Several properties of chocolate samples, including rheological, textural, thermal properties, particle size distribution, color indices, total phenolic and anthocyanin magnitude, antioxidant potential, and Raman spectroscopy were performed. The prepared white chocolates were assessed for the survival of the probiotic cell and the stability of anthocyanins and phenolic components in different storage times (until 90 days) and different storage temperatures (at 4 and 25°C). Observations imply that both temperature and duration of storage had an impact on the extent of survival of probiotics as well as stability of total phenolic content (TPC) and anthocyanin content (p < .05). During in vitro gastrointestinal circumstances, the extent of survival of L. acidophilus, in two chocolate matrixes, was assessed. At the end of gastric and intestinal condition, the log of viable cells was 7 and 6, respectively. The magnitude of the bioaccessibility of anthocyanin and phenolic components was 81% and 78%, respectively. Sensory evaluation affirmed that there was no remarkable variation between samples in terms of overall acceptance.

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.

Formation and application of edible oleogels prepared by dispersing soy fiber particles in oil phase

Oleogels containing less saturated and trans-fats were considered as an ideal option to replace the solid fats in foods. In this research, oleogel was fabricated by dispersing soy fiber particles (SFP) in soy oil, and further it was used in bread preparation. Effect of the particle size, particle content and the second fluid content on the formation of oleogels were evaluated, based on the appearance and rheological properties. Results showed that the suspension of SFP in soy oil (24%, w/w) could be transformed into gel-like state, upon the addition of the second fluid. The SFP based networks were dominated by the capillary force which was originated from the second fluid. The rheological properties and yield stress of the oleogels could be modulated by particle size and particle content of SFP in oil phase, as well as the second fluid content in the system. When the oleogels were applicated in bread preparation, a layered structure could be formed in the bread, indicating the possibility of replacing the solid fats in bakery products by our oleogels. Our results offered a feasibility approach for oil structuring with natural raw materials, and developed a new approach to replace the solid fats in foods.

Aroma-active volatiles and rheological characteristics of the plastic mass during conching of dark chocolate

Chocolate conching is a highly complex, thermomechanical process that transforms the aroma and flow properties of a dry starting material. Different conched plastic masses of dark chocolate were characterized. Rheological characterization of plastic masses was performed for the first time using a closed cavity rheometer (CCR¹). In free cocoa butter derived from the plastic masses, acetic acid, benzaldehyde, (R,S)-(±)-linalool, 2,3,5,6-tetramethylpyrazine, and 2-phenylethanol were quantified by stable isotope dilution analysis (SIDA²) and gas chromatography-mass spectrometry. During the conching process, the amount of free cocoa butter increased possibly due to de-agglomeration. The complex viscosity of the plastic mass decreased as a function of conching time. Regarding aroma refinement, the concentrations of all five aroma-active volatiles decreased with increasing conching duration, albeit to varying degrees. The level of acetic acid showed the most pronounced decrease of about 60%, whereas linalool exhibited the lowest decrease in concentration, up to 26%. Overall, a lower polarity or boiling point of the aroma-active volatiles was linked to a stronger decrease in concentration during conching. These data illustrate the influence of conching on texture and the respective aroma changes, which deepens understanding of the conching effect on the sensory quality of dark chocolate.

Physical, functional and sensory properties of bitter chocolates with incorporation of high nutritional value flours

Due to the growing demand for healthy food products, the industry is seeking to incorporate inputs with high nutritional potential to traditional products. The objective of this research was to evaluate the effect of incorporating Lepidium meyenii, Chenopodium pallidicaule, Amaranthus caudatus, Sesamum indicum and Salvia hispanica flours on the physical, chemical, rheological, textural and thermal characteristics, and the degree of sensory acceptance of dark chocolate bars (65% cocoa). To this end, chocolate bars were made with the incorporation of five flours in four doses (1, 2, 3 and 4%), obtaining 20 different formulations compared with a control treatment (without flour addition). It was found that as flour incorporation levels increased, viscosity, antioxidants and particle size of the chocolates increased, but hardness and pH decreased. The addition of the flours also affected the acceptability and microstructure of the chocolate bars. The incorporation of up to 4% of the flours studied improved the degree of acceptance of the chocolates. Consequently, the incorporation of grain flours with high nutritional value can enhance the characteristics of dark chocolates, becoming a technological alternative for the chocolate industry.

Formulating and studying compound chocolate with adding dried grape pomace as a bulking agent

The use of dried grape pomace (DGP) as a bulking agent for partly substitution of sugar, milk powder and whey powder in compound chocolate (CC) was investigated. D-optimal mixture design was used to determine the effect of composition on the particle size, flow behaviour (Casson yield value and plastic viscosity), as well as total phenolic and resveratrol contents before and after in vitro digestion. The various models (linear, quadratic and cubic) which were identified as significant (P < 0.05) were used in this study. As a result, DGP was found suitable to be used in CC as a bulking agent to partially substitute sucrose, milk powder and whey powder to increase functional properties and decrease the cost of the CC. For CC with the most acceptable rheological properties and a satisfactory level of TPC and resveratrol, optimum usage levels of DGP were identified as 7.1% to 10.0%. Further studies will require to modify flow behaviours by optimizing the particle size of pomace.

Chocolate flow behavior: Composition and process effects

Chocolate is a non-Newtonian substance, and such substance has different viscosities at different shear rates. Rheological evaluations have become indispensable instruments for characterizing final chocolate, forecasting product efficiency and consumer acceptance. During production, the different steps depend on a well-defined viscosity and yield stress. Furthermore, the characteristics of the final chocolate (the surface and mouth-feel) are directly related to the chocolate's viscous behavior. There is a demand for better understanding the variables affecting chocolates flow behavior. Current research realized great insight into the chocolate flow behavior in different processes such as refining, conching, and tempering. Also, the influence of formulation and particle characteristics on flow behavior of the intermediate product and the final product were discussed. Each stage of the production process: mixing, refining, conching and tempering involves modifications of macroscopic characteristics of the chocolate ingredients thus affecting the rheological attributes of the final product. Particle size distribution and ingredient composition play substantial roles in shaping its flow behavior and sensory perception. The rheological properties of chocolate provide substantial information for food scientists to improve and optimize their products and manufacturing processes. Nowadays, a thorough understanding of chocolate flow behavior is a necessity for food scientists and industry.

Influence of Two Different Coating Application Methods on the Maintenance of the Nutritional Quality of Fresh-Cut Melon during Storage

This study aimed at evaluating the effects of two coating application methods, spraying and dipping, on the quality of fresh-cut melons. An alginate-based coating containing both ascorbic and citric acid was applied at two concentrations (5% and 10%) with both methods on fresh-cut melon. The nutritional quality of the products was investigated during 11 days of storage at 10 °C. The suitability and adaptability of the applied coatings on the fruit were evaluated based on rheological and microstructural properties. Moisture, carotenoids, total polyphenols and ascorbic acid content were analyzed on melon samples during storage. Results showed that the coating solution applied by the dipping method and at the highest concentration (10%), allowed to better maintain some quality characteristics of fresh-cut melon, thanks also to the better coating homogeneity and higher thickness observed through microstructural analysis.

Sugar-Free Milk Chocolate as a Carrier of Omega-3 Polyunsaturated Fatty Acids and Probiotics: A Potential Functional Food for the Diabetic Population

Chocolate is an adequate matrix to deliver bioactive ingredients. However, it contains high sugar levels, one of the leading causes of chronic degenerative diseases. This work aimed to evaluate the effects of milk chocolate reformulation with alternative sugar sweeteners (Sw; isomalt + stevia), probiotics (Prob), and ω-3 polyunsaturated fatty acids (PUFAs) on its physicochemical properties and consumers' acceptability. Lactobacillus plantarum 299v (L. p299v) and Lactobacillus acidophilus La3 (DSMZ 17742) were added as Prob strains, and fish oil (FO) was added as the source of ω-3 PUFAs. Prob addition resulted in chocolates with >2 × 107 colony forming unit (CFU) per serving size (12 g). Except for Prob, aw values of all treatments were <0.46. Sw and Sw + Prob presented the nearest values to the control in hardness, whereas Sw without FO increased fracturability. FO, Sw + FO, and Sw + Prob + FO contained 107.4 ± 12.84, 142.9 ± 17.9, and 133.78 ± 8.76 mg of ω-3 PUFAs per chocolate, respectively. Prob + FO increased the resistance of chocolate to shear stress, while Sw + FO showed a similar flow behavior to the control. The consumers' acceptability of Sw + Prob chocolate was adequate, while Sw + Prob + FO had higher acceptability than Prob + FO. Health benefits of reformulated milk chocolates requires further assessment by in vitro, in vivo and clinical studies.

Enrichment of dark chocolate with vitamin D3 (free or liposome) and assessment quality parameters

Liposomes are suitable carrier for bioactive components. Ethanol injection method was chosen for preparation liposomes included vitamin D₃ for addition into dark chocolate [5 µg/serving (10 g)]. Assessment the quality of prepared liposomes were performed by measurement particle size distribution, zeta potential, loading efficiency and FTIR. Loading efficiency was 62.58 ± 1.2%. It could be concluded the chosen method for liposome preparation was suitable. In vitro release of vitamin D₃ from liposome structure showed the release follow Korsmeyer-Peppas model. Fortified chocolate properties included Differential Scanning Calorimeter (DSC), color indexes, casson viscosity and sensory properties were evaluated. According to the results, there was no significant changes in all tested properties in fortified chocolate than control sample. Vitamin D₃ retention during storage time (0, 15, 30, 45, 60 and 70 days) were evaluated and results revealed there was better retention of vitamin D₃ in fortified samples with liposomes than free vitamin D₃. Observation showed addition both forms of vitamin D₃ (free or liposome) had no significant impact on color indexes, rheological properties, DSC parameters as well as sensory characteristics.

Physico-chemical and sensory acceptability of no added sugar chocolate spreads fortified with multiple micronutrients

Vitamin D and magnesium-calcium carbonate nanoparticles were used to fortify a newly developed healthy chocolate spread formulated with inulin and maltitol as sugar replacers and alternative to palm oil to reduce the concentration of saturated fatty acid. These samples were compared with well-known commercially available chocolate spreads in terms of rheology, polyphenols content and in vitro digestion, sensory attributes and willingness to buy. The fortified chocolate spreads showed comparable if not better acceptability than the current products on the market and over 80% of the participants were inclined to buy and 66% prepared to spend 10 to 15% more money on the product enriched with the three micronutrients. The results also demonstrate that the incorporation of nanoparticles could affect the rheological and physio-chemical properties of the formulations and an appropriate ratio between the fat phase and particles seems an important factor to consider.

Agarose Stearate-Carbomer940 as Stabilizer and Rheology Modifier for Surfactant-Free Cosmetic Formulations

Some commonly used surfactants in cosmetic products raise concerns due to their skin-irritating effects and environmental contamination. Multifunctional, high-performance polymers are good alternatives to overcome these problems. In this study, agarose stearate (AS) with emulsifying, thickening, and gel properties was synthesized. Surfactant-free cosmetic formulations were successfully prepared from AS and carbomer₉₄₀ (CBM₉₄₀) mixed systems. The correlation of rheological parameter with skin feeling was determined to study the usability of the mixed systems in cosmetics. Based on rheological analysis, the surfactant-free cosmetic cream (SFC) stabilized by AS-carbomer₉₄₀ showed shear-thinning behavior and strongly synergistic action. The SFC exhibited a gel-like behavior and had rheological properties similar to commercial cosmetic creams. Scanning electron microscope images proved that the AS-CBM₉₄₀ network played an important role in SFC’s stability. Oil content could reinforce the elastic characteristics of the AS-CBM₉₄₀ matrix. The SFCs showed a good appearance and sensation during and after rubbing into skin. The knowledge gained from this study may be useful for designing surfactant-free cosmetic cream with rheological properties that can be tailored for particular commercial cosmetic applications. They may also be useful for producing medicine products with highly viscous or gel-like textures, such as some ointments and wound dressings.

Effect of micro-aeration on the mechanical behaviour of chocolates and implications for oral processing

Aeration in foods has been widely utilised in the food industry to develop novel foods with enhanced sensorial characteristics. Specifically, aeration at the micron-sized scale has a significant impact on the microstructure where micro-bubbles interact with the other microstructural features in chocolates. This study aims to determine the effect of micro-aeration on the mechanical properties of chocolate products, which are directly correlated with textural attributes such as hardness and crumbliness. Uniaxial compression tests were performed to determine the mechanical properties such as Poisson's ratio, Young's modulus and macroscopic yield strength together with fracture tests to estimate the fracture toughness. In vivo mastication tests were also conducted to investigate the link between the fracture properties and fragmentation during the first two chewing cycles. The uniaxial stress-strain data were used to calibrate a viscoplastic constitutive law. The results showed that micro-aeration significantly affects mechanical properties such as Young's modulus, yield and fracture stresses, as well as fracture toughness. In addition, it enhances the brittle nature of the chocolate, as evidenced by lower fracture stress but also lower fracture toughness leading to higher fragmentation, in agreement with observations in the in vivo mastication tests. As evidenced by the XRT images and the stress-strain measurements micro-aeration hinders the re-arrangement of the microscopic features inside the chocolate during the material's deformation. The work provides a new insight of the role of bubbles on the bulk behaviour of complex multiphase materials, such as chocolates, and defines the mechanical properties which are important input parameters for the development of oral processing simulations.

Providing new formulation for white compound chocolate based on mixture of soy flour, sesame paste, and emulsifier: An optimization study using response surface methodology

This study was aimed at evaluating the suitability of sesame paste as an ingredient in white compound chocolate using response surface methodology. A D-optimal combined mixture-process design with three mixture components, sesame paste (15%-30% w/w), soy flour (0%-15% w/w), and milk powder (0%-15% w/w) under variable amount of emulsifier was used to optimize textural (hardness, cohesiveness, and adhesive force) and thermal (T onset and T m) properties of white compound chocolate containing sesame paste. The results showed that the linear effect of all the mixture components was significant (p < .05) on the responses. Applying a desirability function method, the optimum proportion of mixture components, and emulsifier level were as follows: sesame paste 15.5% w/w, milk powder 7.5% w/w, soy four 7% w/w, and emulsifier 0% w/w, respectively. At optimum point, hardness, cohesiveness, adhesive force, T onset, and T m were 367.07 (N), 0.63, 8.46 (N), 28.1 (°C), and 33.7 (°C), respectively. The predicted values were confirmed through validation experiment.

Rheological, bioactive properties and sensory preferences of dark chocolates with partial incorporation of Sacha Inchi (Plukenetia volubilis L.) oil

We studied the effect of substituting partially, cocoa butter (CB) with Sacha Inchi (Plukenetia volubilis L.) oil (SIO) on rheology, bioactive properties, and sensory preferences in potentially functional chocolate. For this 70% dark chocolates were prepared and the CB was substituted with 1.5%, 3%, and 4.5% of SIO. Hardness and viscosity of the SIO-chocolates were significantly reduced compared to the control (5451 ± 658 g; 17.01 ± 0.94 Pa s, respectively). Total phenolic content remained constant while the antioxidant capacity increased up to IC₅₀ of 2.48 ± 0.10 as the content of SIO increased. The Casson yield stress and Casson plastic viscosity decreased as the amount of SIO increased. Chocolates with 4.5% SIO had a similar color, better glossiness, preferable snap attributes, and were more accepted (7.50 ± 0.08) compared to the control (p < 0.05), measured with a hedonic scale. Then, SIO can improve the bioactive properties of dark chocolates obtaining a potentially functional food with acceptable physicochemical characteristics. SIO can be considered as a new cocoa butter equivalent.

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.

Novel processing techniques and spinach juice: Quality and safety improvements

In this study, the combined effect of ultrasound (US) and pulsed electric field (PEF) techniques was analyzed for the quality improvement and microbial safety of spinach juice. The spinach juice was treated with US at frequency of 40 kHz, radiating power of 200 W below 30 ± 2 °C temperature for 21 min in ultrasonic bath cleaner, and PEF treatment (pulse frequency: 1 kHz, flow rate: 60 mL/min, temperature: 30 ± 2 °C, time: 335 µs, electric field strength 9 kV/cm) was done. In results, the combined (US-PEF) treatment attained the highest value of minerals and total free amino acids as compared to US or PEF treatment alone. US-PEF treatment significantly reduced the total plate count (3.83 to 1.97 log CFU/mL), E. coli/Coliform (1.90 to 0.75 log CFU/mL) and yeast and mold (4.23 to 2.22 log CFU/mL). Fourier-transform infrared spectroscopy (FT-IR) spectra showed that all nonthermal treatments led to a higher concentration of carbonyl compounds rather generate new carbonyl compounds. US-PEF treatment significantly reduced the particle size. The rheology of spinach juice was drastically changed by all nonthermal techniques, indicating non-Newtonian modal accompanied by a decrease of consistency index (K), apparent viscosity (η), and increase of flow behavior (n). Overall, the improved quality of spinach juice shows the suitability of both technologies for industrial applications despite the variations in rheological properties. PRACTICAL APPLICATION: Nowadays, nonthermal technologies like US and PEF are being used to enhance the nutritional quality and stability of different fruits and vegetable juices. The current research shows that US-PEF application can enhance the free amino acids and mineral contents while significantly decrease microbial activities and particle size. The rheology of spinach juice can be dramatically changed, through the reduction of consistency index (K), apparent viscosity (η) and elevation of flow behavior (n). The results of this research proposed that US-PEF treatment can be a more suitable nonthermal application to enhance the quality of spinach juice at an industrial scale.

Strategies for synchronizing chocolate conching batch process data using dynamic time warping

In batch processing, process control is typically carried out comparing trajectories of process variables with those in an in-control set of batches that yielded products within specifications. However, one strong assumption of these schemes is that all batches have equal duration and are synchronized, which is often not satisfied in practice. To overcome that, dynamic time warping (DTW) methods may be used to synchronize stages and align the duration of batches. In this paper, three DTW methods are compared using supervised classification through the k-nearest neighbor technique to determine the in-control set in a milk chocolate conching process. Four variables were monitored over time and a set of 62 batches with durations between 495 and 1170 min was considered; 53% of the batches were known to be conforming based on lab test results and experts' evaluations. All three DTW methods were able to promote the alignment and synchronization of batches; however, the KMT method (Kassidas et al. in AIChE J 44(4):864-875, 1998) outperformed the others, presenting 93.7% accuracy, 97.2% sensitivity, and 90.3% specificity in batch classification as conforming and non-conforming. The drive current of the main motor was the most consistent variable from batch to batch, being deemed the most important to promote alignment and synchronization of the chocolate conching dataset.

Properties of dark chocolate enriched with free and encapsulated chlorogenic acids extracted from green coffee

Abstract To increase the functionality of dark chocolate, chlorogenic acids extracted from green coffee were added in free or encapsulated forms at different concentration (10, 20, 30, 40 and 50 mg/5 kg of free chlorogenic acids and equal quantity of encapsulated form). The extraction of chlorogenic acids was carried out by maceration of ground green coffee beans in distilled water (30 min at 80 °C), then, cooling, filtration and adsorption by active carbon were done. The final step was filtration and desorption from active carbon and rotary drying (at 60 °C and 120 rpm). Encapsulation of chlorogenic acids was done by coacervation of pectin and gelatin. For quality assessment, several analysis on chocolate samples were performed included color index and melting behavior by Differential Scanning Calorimeter. Flow behavior of the chocolate samples melted at 40 °C was determined using stress or strain controlled rheometer. The microstructure of the chocolate samples was analyzed by Scanning Electron Microscope technique at 500-1000x magnification. Particle size distribution and sensory evaluation was also performed. Results showed addition of free and encapsulated forms of chlorogenic acids decreased Tonset, Tpeak and ΔH of dark chocolate. Casson viscosity increased in the case of addition chlorogenic acids. Color indexes of chocolate samples were influenced by addition of chlorogenic acids. Particle size distribution decreased with addition of free form and increased when encapsulated form was added. Sensory characteristics were also influenced by chocolate formulation and samples included encapsulated chlorogenic acids exhibit better sensory properties than samples enriched with free form.

Chocolate Quality Assessment Based on Chemical Fingerprinting Using Near Infra-red and Machine Learning Modeling

Chocolates are the most common confectionery and most popular dessert and snack across the globe. The quality of chocolate plays a major role in sensory evaluation. In this study, a rapid and non-destructive method was developed to predict the quality of chocolate based on physicochemical data, and sensory properties, using the five basic tastes. Data for physicochemical analysis (pH, Brix, viscosity, and color), and sensory properties (basic taste intensities) of chocolate were recorded. These data and results obtained from near-infrared spectroscopy were used to develop two machine learning models to predict the physicochemical parameters (Model 1) and sensory descriptors (Model 2) of chocolate. The results show that the models developed had high accuracy, with R = 0.99 for Model 1 and R = 0.93 for Model 2. The thus-developed models can be used as an alternative to consumer panels to determine the sensory properties of chocolate more accurately with lower cost using the chemical parameters.

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.

Rheological behaviour of chocolate at different temperatures

The rheological behaviour of the chocolate at different temperatures was studied using a concentric cylinder viscometer with precision small samples adapter, temperature sensor and standard spindle. BIO chocolate (100% organic cocoa) has been used for the whole types of experiments. At the first, the range of temperature has been chosen 36 °C, 38 °C, 40 °C, 42 °C, and 44 °C. The shear deformation rate was established from the 0.1 s-1 up to 68 s-1. Rheological behaviour was non-Newtonian (plastic) with inconsiderable yield stress in all temperatures. The chocolate unambiguously demonstrated plastic behaviour and flow curves were fitted by the power law model (Herschel-Bulkley model), Bingham model, and Casson model with taking into account the coefficient of determination R2. The obtained results of rheological behaviour of chocolate can be best described as Casson fluid. Exactly coefficients of models can be used for modelling of flow velocity, volume flow, friction factor, Reynolds number, two dimensional and three dimensional velocity profiles and much more for flow in the real technical elements e.g. pipes, trough, tubes. Finally, temperature dependence of apparent viscosity of chocolate was also continuously measured in the range from 35 °C up to 62 °C. The apparent viscosity decreased in the temperature range. This decrease was fitted using power law equation. The knowledge of the plastic flow behaviour of chocolate is very important, because it is not quite common flow behaviour of foodstuffs.

Formulation of dark chocolate as a carrier to deliver eicosapentaenoic and docosahexaenoic acids: Effects on product quality

In this study, dark chocolate enriched with EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) was developed using various forms and origins. Quality characteristics such as physical, thermo-gravimetric, rheological, textural and sensory properties of chocolates were investigated. The highest EPA/DHA stability was determined in samples prepared by free-flowing powder and microencapsulated forms of omega-3 fatty acids (FA). The L^∗ and C^∗ values varied from 32.16-33.37 and 7.45-8.09, respectively for the all samples. Hardness values ranged between 6422 and 8367 N and the use of EPA/DHA in the triglyceride form caused softer chocolate whereas control sample was the hardest sample. Melting and rheological properties were not significantly affected by the studied EPA/DHA sources (P < 0.05). Microencapsulated EPA/DHA added chocolate was the most preferred source whereas sample with algae oil showed the lowest acceptability. According to the results, dark chocolate can be used for delivering omega-3 FA by considering their origin and physical form.