Molten Chocolate Research Articles

Importance of emulsifiers in chocolate industry: Effect on structure, machinability, and quality of intermediate and final products

AbstractMany parameters are effective in obtaining optimum rheological and sensory properties in chocolate. Lecithin, ammonium phosphatides (AMP), and less commonly glycerol monopalmitate (GMP) are typically used as emulsifiers to achieve the desired viscosity in chocolate. In addition to these emulsifiers, polyglycerol polyricinoleate (PGPR) is used as a complement to regulate the yield value in chocolate. In this review, the properties of these additives, their interactions with each other, and the mechanism of their structural improvement functions in chocolate production are discussed. Depending on the type and amount of emulsifier, adjustments can be made to the flow behavior of molten chocolate, textural, melting character, tempering and tempering index, color and other properties of the chocolate. In addition to the use of emulsifiers, other parameters such as particle size distribution, moisture and fat content should also be taken into account, which can affect all these quality parameters. In this regard, the correct selection of the type of emulsifiers used in chocolate production and their combined usage rates will ensure that the demands of producers and consumers are met.

Accurate Evaluation of the Flow Properties of Molten Chocolate: Circumventing Artefacts

Accurate Evaluation of the Flow Properties of Molten Chocolate: Circumventing Artefacts

Fluidisation of yield stress fluids under vibration

<h2>Abstract</h2> Motivated by the industrial processing of chocolate, we study experimentally the fluidisation of a sessile drop of yield-stress fluid on a pre-existing layer of the same fluid under vertical sinusoidal oscillations. We compare the behaviours of molten chocolate and Carbopol which are both shear-thinning with a similar yield stress but exhibit very different elastic properties. We find that these materials spread when the forcing acceleration exceeds the same threshold which is determined by the initial deposition process. However, the height reduction due to spreading is typically at least three times greater in chocolate than in Carbopol under similar forcing. Moreover, the two materials exhibit very different spreading behaviours: whereas chocolate exhibits slow long-term spreading, the Carbopol drop rapidly relaxes its stress by spreading to a new equilibrium shape with an enlarged footprint. This spreading is insensitive to the history of the forcing. In addition, the Carbopol drop performs large-amplitude oscillations with the forcing frequency, both above and below the threshold. We investigate these viscoelastic oscillations and provide evidence of complex nonlinear viscoelastic behaviour in the vicinity of the spreading threshold. In fact, for forcing accelerations greater than the spreading threshold, our drop automatically adjusts its shape to remain at the yield stress. We discuss how our vibrated-drop experiment offers a new and powerful approach to probing the yield transition in elastoviscoplastic fluids.

Sugar-sugar interactions in oil suspensions containing surfactants and effects on macroscopic phenomena

Surfactants are used in confectionery production to control the viscosity and yield value of molten chocolate. To develop a deeper understanding of the structure–function relationship of surfactants in food-related particle suspensions, the apparent viscosity, yield value, sedimentation, and particle interactions of 10 wt% confectioner’s sugar-in-canola oil suspensions were investigated in the presence of up to 1 wt% commercial soy lecithin, polyglycerol polyricinoleate (PGPR), citric acid esters of monoacylglycerols (CITREM) or ammonium phosphatides (AMP). Atomic force microscopy (AFM) was used to measure attractive forces at the nano-Newton scale between a sugar substrate and a sugar crystal-functionalized AFM cantilever in an oil environment. For all but PGPR, addition of surfactant reduced the adhesion force between sugar surfaces up to a critical concentration above which the force increased, implying the presence of additional interactions. This critical concentration was assumed to be when monolayer coverage of the sugar surfaces by surfactant occurred (0.05 wt% for lecithin, 0.10 wt% for CITREM and AMP). No critical concentration was found for PGPR, with its greatest effect for each analysis occurring at the highest concentrations tested (0.60 and 1.00 wt%). The significance of these interactions on macroscopic phenomena such as apparent viscosity and sedimentation was also assessed. Like with the AFM data, there was an optimal concentration of added surfactant above which viscosity increased. Sedimentation rate greatly decreased with addition of PGPR while being only slightly affected by addition of lecithin, CITREM and AMP. An argument regarding their efficacy was made based on the relative sizes of the polar headgroup and nonpolar tail groups of the molecules, which contributed to how they adsorbed to the sugar surface. Overall, these results suggested that surfactant properties such as molecular weight and head group properties played an important role in modifying the interactions between sugar crystals in an oil-continuous environment.

Jurnal Transformatif ANALISIS PENENTUAN LUAS PRODUKSI PADA PERUSAHAAN ROTI BANGKIT JAYA DI KOTA KUPANG

The purpose of this study is to analyze the determination of production volumeto maximize profits. This research is a quantitative research. Data analysis techniques are Forecasting and Linear Programming (Simplex Method). The result of analysis concluded thatthe production volume using Linear Programming simplex method obtained in 2019 should produce as many as 405,792,000 molten chocolate bread per year and by 2020 should produce as many as 4,107,480 molten chocolate bread per year for earning maximum profit. Meanwhile, the Forecasting result is to produce 4 types of bread as many as 6,308,240 breads in 2019 and 6,365,560 breads in 2020. In terms of profit optimization then calculation using Linear Programming is better however considering the marketing aspect where consumers require a variety of bread flavors then calculation using forecasting method is more recommended.

Fluidisation of yield stress fluids under vibration

Motivated by the industrial processing of chocolate, we study experimentally the fluidisation of a sessile drop of yield-stress fluid on a pre-existing layer of the same fluid under vertical sinusoidal oscillations. We compare the behaviours of molten chocolate and Carbopol which are both shear-thinning with a similar yield stress but exhibit very different elastic properties. We find that these materials spread when the forcing acceleration exceeds the same threshold which is determined by the initial deposition process. However, the height reduction due to spreading is typically at least three times greater in chocolate than in Carbopol under similar forcing. Moreover, the two materials exhibit very different spreading behaviours: whereas chocolate exhibits slow long-term spreading, the Carbopol drop rapidly relaxes its stress by spreading to a new equilibrium shape with an enlarged footprint. This spreading is insensitive to the history of the forcing. In addition, the Carbopol drop performs large-amplitude oscillations with the forcing frequency, both above and below the threshold. We investigate these viscoelastic oscillations and provide evidence of complex nonlinear viscoelastic behaviour in the vicinity of the spreading threshold. In fact, for forcing accelerations greater than the spreading threshold, our drop automatically adjusts its shape to remain at the yield stress. We discuss how our vibrated-drop experiment offers a new and powerful approach to probing the yield transition in elastoviscoplastic fluids.

The science behind molten chocolate cake

The science behind molten chocolate cake

Interpreting rheological behaviour of sugar-fat mixtures as a function of solids phase volume

Abstract Many confectionary items and food components are based on complex suspensions of hydrophilic sugar particles in a hydrophobic fat phase. We hypothesise that the rheology of these suspensions is defined by either the Maron-Pierce-Quemada (MPQ) model, which theoretically predicts the viscosity of hard spheres, or by the percolation model describing a network of attractive particles (gel). The rheology of two sugar-fat mixtures, sugar-shortening based biscuit-creams and chocolate, are characterised as a function of phase volume, particle size distribution (PSD) and emulsifier concentration. It is found that their rheological behaviour shows the formation of a network gel structure at sufficient concentration of sugar particles. We find that, upon addition of sufficient emulsifier, the suspension viscosity follows the MPQ hard sphere model, which only depends on phase volume and particle size distribution. Combining the use of the theoretical model and emulsifiers, we are able to decouple the effects of phase volume and particle size distribution from that of particle interactions. The results provide a theoretical basis for identifying levers to control the rheological behaviour of molten chocolate, biscuit-creams, and other sugar-fat based systems, which is relevant to food processing and sensory perception during consumption.

Frictional behaviour of molten chocolate as a function of fat content.

Soft tribology is used to probe the lubrication behaviour of molten chocolate between soft contacts, analogous to in-mouth interactions between the tongue and palate. Molten chocolate is a concentrated suspension of solid particles (sugar, cocoa and milk solids) in cocoa butter. We hypothesise that the complex frictional behaviour of molten chocolate depends on its particulate nature and thus solid volume fraction (sugar & cocoa solids/fat content). In this work, we assess the properties of molten chocolate as a function of fat content by diluting milk chocolate containing 26, 27 and 29% fat with cocoa butter. The tribological behaviour of molten chocolate deviates notably from the typical Stribeck curve of Newtonian fluids. Additional transitions are observed in mixed and elastohydrodynamic lubrication which are respectively attributed to the effect of shear-thinning rheology (i.e. breakdown of aggregates) and the selective entrainment or exclusion of particles depending on interfacial gap height. These transitions are more pronounced in chocolate of high solid fraction, and correlate with the influence of particle aggregation on rheology. In addition, we assess oral lubrication by preparing model chocolate boluses with aqueous buffer, which produces a ternary system of oil droplets and insoluble cocoa solids dispersed within a continuous aqueous phase. The frictional behaviour of chocolate boluses is determined by the viscosity ratio between cocoa butter and aqueous phase, in agreement with previous findings for oil-in-water emulsions. We provide a conceptual model to interpret how fat content influences the oral lubrication and mouthfeel of chocolate during consumption.

ANALISIS PENENTUAN LUAS PRODUKSI PADA PERUSAHAAN ROTI BANGKIT JAYA DI KOTA KUPANG

The purpose of this study is to analyze the determination of production volume to maximize profits.This research is a quantitative research. Data analysis techniques are Forecasting and LinearProgramming (Simplex Method). The result of analysis concluded that the production volume usingLinear Programming simplex method obtained in 2019 should produce as many as 405,792,000molten chocolate bread per year and by 2020 should produce as many as 4,107,480 molten chocolatebread per year for earning maximum profit. Meanwhile, the Forecasting result is to produce 4 typesof bread as many as 6,308,240 breads in 2019 and 6,365,560 breads in 2020. In terms of profitoptimization then calculation using Linear Programming is better however considering the marketingaspect where consumers require a variety of bread flavors then calculation using forecasting method ismore recommended.&#x0D; Keywords: Forecasting, Linear Programming, Optimization, Volume Production

Measurement of molten chocolate friction under simulated tongue-palate kinematics: Effect of cocoa solids content and aeration

The perception of some food attributes is related to mechanical stimulation and friction experienced in the tongue-palate contact during mastication. This paper reports a new bench test to measure friction in the simulated tongue-palate contact. The test consists of a flat PDMS disk, representing the tongue loaded and reciprocating against a stationary lower glass surface representing the palate. The test was applied to molten chocolate samples with and without artificial saliva. Friction was measured over the first few rubbing cycles, simulating mechanical degradation of chocolate in the tongue-palate region. The effects of chocolate composition (cocoa solids content ranging between 28 ​wt% and 85 ​wt%) and structure (micro-aeration/non-aeration 0–15 ​vol%) were studied. The bench test clearly differentiates between the various chocolate samples. The coefficient of friction increases with cocoa solids percentage and decreases with increasing micro-aeration level. The presence of artificial saliva in the contact reduced the friction for all chocolate samples, however the relative ranking remained the same.

Effects of adding solid and molten chocolate on the physicochemical, antioxidant, microbiological, and sensory properties of ewe's milk cheese.

A novel dairy product, namely "chocolate cheese", was produced with two typical Sicilian food products: Pecorino cheese, processed from ewe's milk, and Modica chocolate. The cheese, manufactured with 0%, 5%, 10%, and 15% (w/w) solid or molten chocolate, was evaluated after 0, 2, 4, and 6 weeks of vacuum storage for its nutritional and health properties. The addition of chocolate reduced the pH, protein, fat, and ash; the addition of 5% or 10% molten chocolate reduced hardness (N/mm2 ). The addition of either solid or molten chocolate resulted in a slight increase (P <0.1038) in the total polyphenol content, a higher oleic acid content, and less oxidative stability. The microbiological profile showed that the total mesophilic count and the number of mesophilic coccus lactic acid bacteria (LAB) were approximately equal (about 108 CFU/g) in all cheese. The survival of the microorganisms was affected by both the chocolate added and the storage time. Chocolate cheese stored for 6 weeks had less Enterobacteriaceae than control cheese, whereas yeasts were detected at higher cell densities in the former cheese. Filamentous fungi were undetectable in some cheese. Differences were also observed in the number of mesophilic rod LAB, which increased progressively over time in all cheese, and in Enterobacteriaceae, yeasts, and filamentous fungi, which decreased during storage. Descriptive and hedonic sensory tests and principal component analysis showed that fresh cheese and cheese stored for 2 weeks, including 5% molten chocolate, were the most preferred by evaluators. Based on these results, chocolate cheese has the potential to be appreciated in the market for its nutritional, health, and sensory properties. PRACTICAL APPLICATION: Chocolate cheese, made by combining two typical Sicilian foods, Pecorino cheese and Modica chocolate, is proposed as a novel dairy product. The highest sensory acceptance was obtained with the addition of 5% molten chocolate and storage for 2 weeks. Given its improved antioxidant properties, healthier fat, and sensory properties, chocolate cheese has the potential to be appreciated in the market, especially by young consumers.

Determining casson yield value, casson viscosity and thixotropy of molten Chocolate using viscometer

Flow properties of chocolate highly determine mouthfeel and consumer acceptance. Aside from these, they are also important factors in determining the incorporation of chocolate in food products. This work investigated the possibility of using viscometer to determine the flow properties of molten chocolate. The data obtained from viscometer was fitted to Casson Model. Afterwards, Casson yield value and Casson viscosity were then derived. To observe the homogeneity of molten chocolate, thixotropy value was also determined. In this study, molten chocolate was produced using a stone melanger as an alternative processing method. Four grinding durations, namely 4, 8, 12, and 16 hours, were used to produce 4 types of dark chocolate. The results showed that viscometer was able to determine the value of Casson Model parameters, eventhough the shear rate reached was only approximately 45 s−1. Using this approach, it can be observed that the Casson Yield Value and Casson Viscosity increased as the grinding durations were increased.

Planar sucrose substrates for investigating interfaces found in molten chocolate

Abstract We present planar substrates suitable for investigating the sucrose/triglyceride fat interfaces found in molten chocolate with surface science techniques. The planar sucrose substrates are produced by spin coating sucrose onto hydrophilic, silicon oxide-capped, silicon substrates from millimolar aqueous solutions of sucrose. We present the characterisation of the sucrose film thicknesses and crystallinity using X-ray reflectivity and grazing incidence X-ray diffraction, respectively. These sucrose-coated substrates can be used in flow cells for quartz crystal microbalance with dissipation (QCM-D) and neutron/X-ray reflectivity measurements, through which triglyceride oils containing the surfactants commonly used in chocolate manufacture can be flowed. This provides a well-defined, planar, sucrose/triglyceride interface, which can be used to probe the solid/liquid interfaces that are found in molten chocolate at the molecular level.

Accurate methodology to determine slip velocity, yield stress and the constitutive relation for molten chocolate

Concentrated soft materials like molten chocolate often has the ambiguity of behaving like a solid or a liquid depending on the external constraints. Determination of the constitutive relation is often unreliable and consequently the yield stress value too. This difficulty of determining yield stress, particularly when using a standards protocol such as the IOCCC for chocolate, is a consequence of the presence of wall slip. Assessment of slip velocity using Yoshimura and Prud'homme's method most often leads to erroneous results. We propose to tackle this problem by using an easy and reliable methodology applied to a commercial chocolate in a melted state with, as equipment, a plate-plate rotational rheometer.This method allows precise determination of the yield stress value, the constitutive relation and the slip velocity versus the shear stress. Furthermore, it provides an explanation to the apparent Newtonian plateau and thickening behavior of the raw flow curve.

Correction to: Friction Measurements with Molten Chocolate

The article Friction Measurements with Molten Chocolate, written by M. Masen, P. M. E. Cann, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 26 December 2017 without open access.

Friction Measurements with Molten Chocolate

A novel test is reported which allows the measurement of the friction of molten chocolate in a model tongue–palate rubbing contact. Friction was measured over a rubbing period of 150 s for a range of commercial samples with different cocoa content (85–5% w/w). Most of the friction curves had a characteristic pattern: initially a rapid increase occurs as the high-viscosity chocolate melt is sheared in the contact region followed by friction drop as the film breaks down. The exceptions were the very high (85%) and very low (~ 5%) cocoa content samples which gave fairly constant friction traces over the test time. Differences were observed in the initial maximum and final friction coefficients depending on chocolate composition. Generally, the initial maximum friction increased with increasing cocoa content. At the end of the test, the rubbed films on the lower slide were examined by optical microscopy and infrared micro-reflection spectroscopy. In the rubbed track, the chocolate structure was severely degraded and predominately composed of lipid droplets, which was confirmed by the IR spectra. The new test provides a method to distinguish between the friction behaviour of different chocolate formulations in a rubbing low-pressure contact. It also allows us to identify changes in the degraded chocolate film that can be linked to the friction profile. Further development of the test method is required to improve simulation of the tongue–palate contact including the effect of saliva and this will be the next stage of the research.

Investigating the rheological, microstructural and textural properties of chocolates sweetened with palm sap-based sugar by partial replacement

Palm sugar, a natural alternative sweetener which can be made from the nectar of several species of palm tree flowers, recently gains more interest. Due to its physicochemical characteristics, utilisation of palm sugar as chocolate sweetener results in different quality attributes of chocolate. In this work, a thorough investigation about the influence of palm sugar on the rheological, microstructural and textural characteristics of chocolate was carried out through partial replacement of sucrose as chocolate sweetener. Accordingly, five sucrose–palm sugar blends with different palm sugar (PS) proportion, namely PS0, PS25, PS50, PS75, and PS100 were used as chocolate sweetener. The results showed that the Casson yield value of chocolate containing palm sugar was lower than the Casson yield value of chocolate sweetened with pure sucrose which could be attributed to the presence of agglomerates in the chocolate suspension. However, palm sugar-sweetened chocolate exhibited a higher Casson viscosity and thixotropy which could be mainly attributed to the presence of glucose and fructose and the relatively high moisture content. These factors also influenced the hardness of the chocolate to some extent. A lower melting temperature and enthalpy value of the sugar phase in chocolate were observed by DSC, whereas visualisation using SEM, polarised and normal light microscopy indicated increased agglomeration due to the presence of moisture, amorphous sugar and chemical “impurities”. Rheological behaviour of molten chocolate, hardness and polarised–normalised light microscopy were evaluated at a constant temperature of 40, 20, and 50 °C, respectively, while the melting profile was measured from 20 to 200 °C at a rate of 5 °C/min.

Improving heat stability along with quality of compound dark chocolate by adding optimized cocoa butter substitute (hydrogenated palm kernel stearin) emulsion

Conventionally manufactured chocolates demonstrate the poor melting resistance during storage and transportation in tropical regions or summer seasons. In the conventional technologies, all heat-resistant chocolates obtained have problems of quality parameters being unsuccessful as commercial products. To resolve this issue, an optimized CBS (cocoa butter substitute) emulsion (CBS: polyglycerol polyricinoleate: water: gum Arabic: invert syrup) was developed and mixed at different concentrations in the molten chocolate mass of standard recipe. Prepared formulations of chocolate mass were evaluated for their molding suitability. Prepared chocolate bars were evaluated for their color, pH, hardness, shape retention index (SRI), moisture, water activity and sensory attributes. Optimized CBS emulsion increased moisture and fat content but reduced aw of dark compound chocolate bars. Addition of CBS emulsion up to level of 60 mL/L led to decrease viscosity of molten chocolate mass and surface whiteness of chocolate bars; and improve sensory attributes. However, at level of 80 mL/L CBS emulsion maximum hardness was observed at higher temperature (36 °C and 40 °C) but fat bloom was appeared due to temperature fluctuation and scores of sensory attributes were decreased. Consequently, optimum dosage of CBS emulsion was 60 mL/L in order to produce good quality heat resistant compound dark chocolate bars.

The fluid dynamics of the chocolate fountain

We consider the fluid dynamics of the chocolate fountain. Molten chocolate is a mildly shear-thinning non-Newtonian fluid. Dividing the flow into three main domains—the pumped flow up the centre, the film flow over each dome, and the freely falling curtain flow between the domes—we generate a wide-ranging study of Newtonian and non-Newtonian fluid mechanics. The central pumped flow is a benchmark to elucidate the effects of shear-thinning. The dome flow can be modelled as a thin-film flow with the leading-order effects being a simple balance of gravity and viscosity. Finally, the curtain flow is analytically intractable but is related to the existing theory of water bells (both inviscid and viscous). In pipe flow, Newtonian fluids exhibit a parabolic velocity profile; shear-thinning makes the profile more blunted. In thin-film flow over the dome, gravitational and viscous effects balance and the dome shape is not important beyond the local slope. We find that the chocolate thins and slows down as it travels down the dome. Finally, in the curtain flow, we predict the shape of the falling sheet for an inviscid fluid, and compare this with the literature to predict the shape for a viscous fluid, having shown that viscous forces are too great to ignore. We also find that the primary effect driving the shape of the curtain (which falls inwards towards the axis of the fountain) is surface tension. We find that the three domains provide excellent introductions to non-Newtonian mechanics, the important mathematical technique of scaling, and how to manipulate existing data to make our own predictions. We also find that the topic generates interest among the public in our engagement work.