Accelerated Fat Bloom in Chocolate Model Systems: Replacement of Cocoa Powder with Sugar Particles and the Effects of Lecithin

To investigate the effects of particulates on fat bloom in chocolate, model systems were formulated with 50% nonfat particles and 50% cocoa butter on a mass basis, where cocoa powder was gradually replaced by sugar particles (sucrose, maltitol, corn syrup solids [CSS], and polydextrose [PD]). Bloom extents were investigated in three ways: the change in whiteness index (ΔWI), white area percentage, and visual bloom level. All three bloom evaluation methods showed similar trends, although the methods were more sensitive under different conditions. Bloom extents in sucrose model systems were the highest compared to the other three sugar types, whether crystalline or amorphous. Increasing sucrose crystal levels significantly promoted bloom, whether with or without 0.5% lecithin. Adding 0.5% lecithin significantly reduced bloom extents in all model systems except for the system with CSS. The effects of sugars and lecithin might be due to the difference in the interactions between sugar particles, cocoa powder, and lecithin in the chocolate matrix, as supported by the contact angle and tensiometry results.     

CLA-Rich Chocolate Bar and Chocolate Paste Production and Characterization

Conjugated linoleic acid (CLA) is an 18‐carbon fatty acid with multiple health benefits, including anti‐obesity and anti‐carcinogenic properties. CLA‐rich soy oil (CLARSO) can be produced through a heterogeneous catalysis process, and this oil was previously used to produce CLA‐rich margarines and shortenings. The objectives of this study were to produce CLA‐rich chocolate bars and pastes by replacing a portion of the fat with CLARSO and compare the rheological, textural, and thermal properties of these pastes/bars to controls made with either soy oil or traditional fats. CLARSO was used to prepare bars/pastes. Rheology, firmness, and thermal behavior of the pastes and fracturability, hardness, and thermal behavior of the bars were determined. The CLARSO chocolate pastes/bars contained no additional saturated fat relative to soy oil controls but the pastes had more solid‐like rheology and were firmer and the bars had a higher fracture force relative to soy oil controls. Relative to non‐soy controls, CLARSO pastes had similar rheology and CLARSO bars had similar fracturability, despite containing less saturated fat. The fat crystals of all samples were in the same polymorphic form. Therefore, it was successfully demonstrated that CLARSO has the ability to produce chocolate pastes/bars with similar physical properties as traditional products containing more saturated fat.     

Amido-Amine-Based Cationic Gemini Surfactants: Thermal and Interfacial Properties and Interactions with Cationic Polyacrylamide

Experimental studies were conducted to investigate thermal and interfacial properties of two in‐house synthesized amido‐amine‐based cationic gemini surfactants namely: dodecanoic acid [3‐({4‐[(3‐dodecanoylamino‐propyl)‐dimethyl‐amino]‐butyl}‐dimethyl‐amino)‐propyl]‐amide dibromide ( 12‐4‐12 ) and dodecanoic acid [3‐({6‐[(3‐dodecanoylamino‐propyl)‐dimethyl‐amino]‐hexyl}‐dimethyl‐amino)‐propyl]‐amide dibromide ( 12‐6‐12 ). Thermogravimetric analysis showed the excellent thermal stability of surfactants and no structural degradation was observed at temperatures up to 250 °C. The long‐term thermal stability of the surfactants was investigated with the aid of spectroscopic techniques such as nuclear magnetic resonance (NMR (¹H and ¹³C) and Fourier transform infrared (FTIR) spectroscopy. Both surfactants were found to be thermally stable, and no changes in structure were observed after aging for 10 days at 90 °C. The interfacial tension of the surfactants was measured at three different temperatures (30, 60, and 80 °C), and the results showed a decrease in interfacial tension with increasing temperature and increasing spacer length of the surfactants. Rheological measurements were used to assess the interactions between the cationic gemini surfactant and cationic polyacrylamide. The addition of cationic surfactant reduced the viscosity and storage modulus of the polymer at low shear rate and frequency due to surfactant–polymer interactions and charge screening. The investigated surfactant–polymer system has great potential in high‐temperature carbonate reservoirs, where conventional anionic surfactants are not recommended due to high adsorption.     

Impact of Limonene on the Physical Properties of Reduced Fat Chocolate

The addition of limonene, a low molecular weight hydrophobic compound, to chocolate was reported to decrease the hardness and the viscosity of chocolate, facilitating the production and improving the eating quality of reduced fat chocolate. The objective of this study is to understand the functionality of limonene in decreasing the viscosity and the hardness of chocolate, a fat (cocoa butter)-based particulate suspension. This study shows that chocolate hardness was decreased because limonene mixes with cocoa butter, affects its crystallization pattern and decreases its solid fat content. After checking that limonene does not significantly affect the continuous phase volume fraction, we show that limonene decreases chocolate viscosity by decreasing the viscosity of the continuous phase, cocoa butter. The addition of low quantities of limonene in cocoa butter leads to a great decrease in the liquid fat viscosity. The dependence of the viscosity on the ratio of cocoa butter to limonene analyzed using Kay’s equation seems to indicate that limonene mixes with and within the cocoa butter triglycerides, diluting the fat and leading to a decrease in the overall fat viscosity.     

大豆磷脂的提取与分析

以新鲜的油脚为原料，经丙酮脱油，正已烷萃取，并以维生素Ｃ为抗氧化剂，制得粉状大豆磷脂。产品的各项指标不仅符合食品添加剂的标准，而且其色泽也有所改善．     

Structure and Physical Properties of Organogels Developed by Sitosterol and Lecithin with Sunflower Oil

High linoleic acid sunflower oil (HLSO) with various sitosterol (Sit) to lecithin (Lec) mass ratios (i.e., 0:100–100:0) were used to develop organogels at two storage temperatures (T_s: 5 and 25 °C). The results showed that, at 25 °C, the hardness value of organogels obtained from HLSO with both Sit and Lec was higher than that of organogels developed from HLSO with only Sit or Lec. Microscopy revealed that the shapes of the crystals in the organogels varied significantly with the composition of the structurant and the T_s. At both T_s used, the Sit:Lec (80:20) system had a lower degree of supersaturation compared with the (100:0) system. X‐ray diffraction (XRD) revealed that Sit:Lec mass ratio of 70:30, 80:20 and 100:0 had similar short spacings, and the presence of Lec might be adverse to the formation of Sit crystal in oil. Small‐angel X‐ray scattering (SAXS) showed that the layer thickness of Sit/Lec/HLSO organogel was larger than that of Sit/HLSO organogel. It was found that the presence of Lec induced the change of self‐assembly structure of Sit in HLSO and caused the changes of physical properties of organogels obtained.     

Measurement and Control of the Gloss of Chocolate

Taste and melting behavior are important quality criteria for chocolate. Beyond these, the gloss, snap, and texture are relevant. Different process parameters influence the gloss as well as other criteria such as shell life and fat bloom resistance. In this work, a method to measure the gloss of chocolate is introduced and adapted to small chocolate articles. With this, the gloss could be measured reproducibly. Different process parameters are varied and the gloss of the chocolate is determined. Various methods to improve the gloss are suggested and evaluated.     

PVC/NE复合材料的结构流变学及力学性能

采用熔融共混法制备了聚氯乙烯/霞石复合材料(PVC/NE),并测试了其形态、结构流变学和力学性能。结果表明,NE用量存在最佳值,用量过多对复合材料介观结构的贡献不大;NE均匀分散在PVC基体中,且用量约为50phr时,复合材料的冲击强度和表面硬度最佳。     

Physical Chemical Properties of Shea/Cocoa Butter Blends and their Potential for Chocolate Manufacture

Cocoa butter (CB) is the preferred fat for chocolates and confections. However, for technological and economic reasons, there have been strong efforts for partially replacing it. As shea butter (SB) has become an important natural source of symmetrical stearic-rich triacylglycerols (TAG), the aim of this work was to study physical chemical behavior of blends of CB and SB and the dynamic mechanical and polymorphic behaviors of chocolates prepared with these systems as added fat. The compatibility of SB and CB blends was studied using the isosolid diagram. Data showed that softening occurred due to both dilution effects and a slight eutectic formation. Chocolates formulated with a fat phase consisting in CB, or SB, or blends with 10, 20, or 30 wt.% SB in CB showed different polymorphic behaviors during storage. The polymorphic transition from β₂ to β₁ occurred to a greater extent with increasing content of SB in formulation. Dynamic mechanical analysis (DMA) results agree with X-ray findings. E′ modulus significantly increased during storage most likely due to formation of β₁ form. As shown by Grazing incidence wide-angle X-ray scattering (GIWAXS) studies, crystals preferred growing on the chocolate surface than on bulk chocolate. However, even after a year at 18°C, chocolates had good appearance indicating that SB was a good CB extender.     

Rheology,Crystallization Kinetics and Mechanical Properties of HDPE/Vinyl-POSS Nanocomposites

Polyhedral oligomeric silsesquioxane (POSS) is usually prepared from the hydrolytic condensation of organotrialkoxysilanes. The rheology, non-isothermal crystallization kinetics and mechanical properties of high density polyethylene (HDPE)/vinyl-containing POSS (V-POSS) nanocomposites were investigated. The results show that the molten HDPE/V-POSS belong to pseudoplastic fluid. The V-POSS can accelerate the nucleation of HDPE at starting stage of crystallization. However, it will decrease the crystallization ability of HDPE in the subsequent crystallization process. The modified Avrami analysis by Jeziorny can well explain the crystallization behaviour of HDPE/V-POSS. The yield strength and tensile modulus of nanocomposites both increase when V-POSS content is 6%.     

Physical Properties of Chocolate with Addition of Cocoa Butter Equivalent of Moderate Hardness

In this study, the fat phase of chocolate samples which contained cocoa butter from Ghana and cocoa butter equivalent (CBE) of moderate hardness was analyzed. Physical properties and shelf life of chocolate depend on the fat phase behavior as well as the amount and composition of added CBE. The laboratory-made chocolate samples were tempered at three different pre-crystallization temperatures (25, 27 and 29 °C), with three different concentrations of CBE, amounting to 3, 5 and 7 %, calculated on chocolate. The color and other physical attributes of chocolate samples were investigated by the following analytical methods: thermoreographic measurement, solid fat content (SFC) of chocolate, Blooming test (thermo-cycle test 32/20 °C) and color measurement. It was found that using CBE of moderate hardness did not change the melting properties of chocolate in relation to the investigated cocoa butter from Ghana (of moderate hardness). It was found that all three applied temperatures of pre-crystallization are optimum for the chocolate mass with the addition of the investigated CBE under the given measurement conditions. At all these temperatures, the chocolate had excellent fat bloom resistance.     

Influence of Individual Phospholipids on the Physical Properties of Oil-Based Suspensions

The impact of soybean lecithin and three individual phospholipids at different concentration (C_PL) on rheology and sedimentation behavior of sugar/soybean oil suspensions (? = 0.31) was studied and compared with attraction and retraction forces between sugar surfaces in soybean oil as measured by atomic force microscopy (AFM). In general, a surfactant‐induced reduction of yield stress, apparent viscosity and sediment volume of the suspensions coincides with a decrease of adhesive interactions between sugar particles in soybean oil. Although the general influence of individual phospholipids and soybean lecithin is comparable, it is concluded from investigations at low C_PL that individual phospholipids exhibit a less pronounced impact on the analyzed parameters. Furthermore, at low C_PL, binary mixtures of the phospholipids are more efficient than individual phospholipids as regards the reduction of yield stress and sediment volume. While the same tendency was detectable for AFM results, these differences were not statistically verified. Slight differences were also evident when comparing individual phospholipids and their influence on rheology and sedimentation which are, however, not in line with the results of AFM. A general understanding of these interrelations between surfactant composition and possible synergistic or antagonistic effects in mixtures of individual phospholipids contributes to optimizing lecithin composition with respect to functionality.     

Accelerated Fat Bloom in Chocolate Model Systems: Solid Fat Content and Temperature Fluctuation Frequency

Chocolate model systems were designed with high‐melting fat (cocoa butter stearin, CB‐S) mixed with low‐melting fats (sunflower oil, canola oil, cottonseed oil, peanut oil) to give 45, 55, and 65 % solid fat content (SFC). Defatted cocoa powder provided a 50 % particulate level in the model chocolates. The effects of SFC, low‐melting fat type and storage temperature fluctuation frequency on bloom whiteness were investigated. Both SFC and storage condition had significant influences on bloom whiteness (p < 0.0001), although the type of low‐melting fat did not (p = 0.1223). Increasing the SFC significantly reduced bloom formation, as did more rapid temperature fluctuations.     

改性木纤维/PVC复合材料界面及性能的研究

比较了硅烷偶联剂处理、氢氧化钠溶液浸泡与硅烷偶联剂双重处理,接枝改性等3种木纤维表面处理方法对木纤维/PVC复合材料界面及性能的影响,通过扫描电镜照片发现接枝改性木纤维在PVC基体中分散更均匀,与PVC界面相容性好.接枝改性木纤维/PVC复合材料的拉伸强度、冲击强度、断裂伸长率等力学性能有明显提高.最后分析了木纤维接枝改性处理时引发剂用量对复合材料力学性能的影响.     

Preparation and Characterization of a Lecithin Nanoemulsion as a Topical Delivery System

Purpose of this study was to establish a lecithin nanoemulsion (LNE) without any synthetic surfactant as a topical delivery vehicle and to evaluate its topical delivery potential by the following factors: particle size, morphology, viscosity, stability, skin hydration and skin penetration. Experimental results demonstrated that an increasing concentration of soybean lecithin and glycerol resulted in a smaller size LNE droplet and increasing viscosity, respectively. The droplet size of optimized LNE, with the glycerol concentration above 75% (w/w), changed from 92 (F10) to 58 nm (F14). Additionally, LNE, incorporated into o/w cream, improved the skin hydration capacity of the cream significantly with about 2.5-fold increase when the concentration of LNE reached 10%. LNE was also demonstrated to improve the penetrability of Nile red (NR) dye into the dermis layer, when an o/w cream, incorporated with NR-loaded LNE, applied on the abdominal skin of rat in vivo. Specifically, the arbitrary unit (ABU) of fluorescence in the dermis layer that had received the cream with a NR-loaded LNE was about 9.9-fold higher than the cream with a NR-loaded general emulsion (GE). These observations suggest that LNE could be used as a promising topical delivery vehicle for lipophilic compounds.     

Rheology and the resource industries

The world's resource industries, which include minerals, coal, and the sand mining of oil, are the world's largest producers of waste. Much of this waste is produced as a fine particle suspension which is pumped to a storage area generally at a low concentration where it behaves like a Newtonian fluid. Simply by removing water from the suspension and reusing and recycling water represents a step towards a more sustainable practice in this industry. As the concentration of such a suspension is increased as a result of dewatering, the materials exhibit non-Newtonian behaviour, characterised by shear thinning, a yield stress, and in some instances, by thixotropic behaviour. Such high concentration, non-ideal (dirty) suspensions in the resource industries has meant that new rheological methods and techniques were needed for both shear and compression rheology to measure and interpret the basic flow properties. Also, some older empirical techniques needed to be modified and interpreted in a more fundamental way so that the results could be used in design. The paper reviews these techniques and illustrates how the industry itself has motivated their development. Understanding and exploiting this rheology has resulted in dramatic improvement in the waste disposal strategy for some industries, but many have failed to embrace the available technology. Why? Is regulation the answer? Probably not. The paper concludes that a greater positive change in the waste management practice will occur in the future, motivated by a number of factors, including public perception and perhaps even by common sense accounting.The paper is an overview of thirty years of work with the resource industries on environmental waste minimisation. Aspects have been published in the Proceedings of Paste and Thickened Tailings Conferences held annually since 1999.¹     

聚合物/石墨烯复合材料流变学的研究进展

流动与变形是材料在生产及应用过程的普遍现象,而聚合物复合材料往往具有较为复杂的流动与变形行为。基于石墨烯的聚合物复合材料是近年来材料领域的研究热点之一,以流动与变形为研究对象的流变学对于深入探究这类复合体系的结构与性能具有重要意义。综述了针对聚合物/石墨烯复合材料的流变学的研究进展,并展望了聚合物/石墨烯复合材料流变学研究的发展方向。     

流变学在化学工程中的应用

介绍了流变学的主要内容,区分了传统与现代化学工程的的不同以及流变学在现代化学工程中的几个用例,指出流变学为现代化学工程的三大基础之一,同时也是现代化工技术人员的应有素质之一,亟待加强。     

Rheology,Sedimentation, and Filtration of TiO2 Suspensions

It is shown that with aqueous suspensions of colloidal oxide and hydroxide particles simple rheometric and sedimentation experiments allow the determination of the optimum pH for filtration and washing. This approach is more practical than zeta potential measurements, as explained by a theoretical review and illustrated by experiments with industrial TiO₂ white pigments of varying surface chemistry. Besides, the solids content of the filter cake and its dependence on pH is correctly predicted from the rheology of the suspension, thus giving an idea of the mechanism of filter cake formation. This follows from a comparison to the results of filtration experiments. There, the influences of filter vacuum as well as of pH and solids content of the pigment feed suspension on filtration capacity and washing efficiency have been studied. The experiments also illustrate an inexpensive method of how to find the optimum set of parameters for an economical drum filter operation in the plant.