Enzymatically modified tea seed oil as cocoa butter replacer in dark chocolate

Cocoa butter replacer (CBR) was prepared by enzymatic interesterification of hydrogenated and solid fraction (SF) of tea seed oil at weight percent ratio of 30:70, using sn‐1,3 specific lipase from Thermomyces lanuginosus. Dark chocolate samples were then prepared with the prepared CBR as a replacement for 5%, 10%, 15% and 20% of cocoa butter (CB) and the effect of the replacement on hardness (as a key quality factor in chocolate) of the chocolate samples was investigated. Results showed that chocolate samples containing 5% and 10% of interesterified sample (EIS), had the closer texture to that of CB chocolate than other samples. The solid fat content (SFC) profiles also revealed that blending 10% of EIS with CB in chocolate formulation dose not affect the sharp melting point of CB. Based on the results taken from bloom formation, polymorphic structure and sensory evaluation, adding up to 10% of EIS in chocolate formulation reduces the bloom development without adverse affecting the desirable β crystal formation and sensory qualities in the chocolate samples.     

The application of Borneo tallow in dark chocolate shell

Dark chocolate shells, formulated using cocoa butter (CB shell), and fat blends containing 15% Borneo tallow (IP) in cocoa butter (CBIP shell), were filled with truffles formulated using white chocolate (W truffle), milk chocolate (M truffle) and dark chocolate (D truffle). Anhydrous milk fat (AMF) content of the W truffles, M truffle and D truffle were 26·3%, 13·7% and 9·2%, respectively. Degree of tempering was determined using a tempermeter. The chocolates were kept at ambient temperature (25·5±0·5°C) for 3 months. Physical changes of chocolate shells and centres were monitored using DSC and a texture analyser. Results showed that the CBIP shell had to be tempered at 32·5%, ie 1°C higher than the normal CB shell. Physical measurements indicated the occurrence of fat migration. The presence of IP reduced the effect and increased the bloom resistance of the chocolate. © 1998 SCI.     

Influence of lactic acid ester on chocolate quality

Influence of concentration of emulsifier Lactem P 22 (lactic acid ester of monodiglyceride) as blooming inhibitor on the quality and fat bloom stability of laboratory made samples of chocolate was investigated. This ingredient was added during the pre-crystallization process of chocolate mass. The pre-crystallization was performed in the laboratory crystallizer modified Brabender pharinograph, where the rheological characteristics of the pre-crystallized fluid chocolate mass were measured. The experiments were performed according to the factorial plan 3² (two factors on three levels). Statistical results processing was performed according to the Response Surface Methodology. Physics characteristics of chocolate—hardness and lightness—were obtained by instrumental methods. The results has shown that Lactem P 22 improve fat bloom stability of chocolate samples but decrease sensory quality of chocolate. Better sensory quality of chocolate was achieved with combination of the crystallization promoter—Dynasan 118. The best sensory quality of chocolate has been obtained with 0.5% Dynasan 118 and 1 and 2% Lactem P 22. Samples of chocolate which was pre-crystallized on 23°C and with 3% Lactem P 22, showed the highest fat bloom stability.     

Lipid migration in two-phase chocolate systems investigated by NMR and DSC

The migration of lipids in two-phase chocolate systems (i.e. lauric acid+chocolate and peanut butter+chocolate) was analyzed by magnetic resonance and differential scanning calorimetry. Kinetics of fat migration was evaluated and the diffusion coefficient of lauric acid in chocolate was found to be dependent on migration time. This may be due to the capillary nature of fat migration in chocolate. Fat bloom characteristics were determined and related to the thermal history of samples and the presence of fat in the chocolate layer. Both lauric acid and peanut butter increased the liquid-to-solid ratio of chocolate and helped prevent fat bloom.     

Surface structure and composition of fresh and bloomed chocolate analysed using X-ray photoelectron spectroscopy, cryo-scanning electron microscopy and environmental scanning electron microscopy

Bloom on chocolate is an unsightly surface condition resulting in a white, powdery appearance that consumers interpret as a sign of poor quality. Bloom results from incorrect processing or storage. Two innovative methods have been developed, and used in conjunction, to investigate the morphology and composition of bloomed chocolate.Environmental scanning electron microscopy (ESEM) was used to image the morphology of the surface of fresh and bloomed chocolate and to observe the changes in morphology, in real time, during heating and cooling. The nodular morphology of sugar bloom was easily distinguished from the blade like crystals of fat bloom. Surface details for the fat blades indicated an extrusion mechanism during their formation on the chocolate surface.“Cold stage” X-Ray Photoelectron Spectroscopy (XPS) was used to analyse the surface composition of fresh and bloomed samples. The carbon species present in the bloom on poorly tempered chocolate were a combination of CH₂, C-OH, OC-OH and O-C-O groups indicating a mixture of sugar and fat bloom. Conversely the species present on bloomed, well tempered chocolate comprised only CH₂, C-OH, OC-OH indicating the bloom was comprised of fat (from cocoa butter) and no sugar.     

月桂酸类代可可脂巧克力脂霜组成及形态学研究

通过气相色谱分析和显微镜观察对起霜前后月桂酸类代可可脂巧克力的脂肪酸组成以及形态学特征进行了研究。结果表明,与新鲜巧克力相比,脂霜中C12∶0、C18∶0、C18∶1含量明显增加,而C14∶0含量相对减少;原子力显微镜结果显示,新鲜巧克力表面相对平滑,起霜后平滑表面破坏,形成明显凹凸面;扫描电镜观察发现新鲜巧克力表面结晶网络结构疏松,起霜巧克力表面油脂晶体形成致密网络结构;偏光显微镜显示脂霜中晶体颗粒明显大于新鲜巧克力晶体颗粒,发生了向更稳定晶体的转变。     

Application of kokum (Garcinia indica) fat as cocoa butter improver in chocolate

Although cocoa butter (CB) is an ideal fat for use in chocolate, it softens with heat and is not suitable for use in warm climates. CB extenders or improvers, preferably from stearic acid‐rich fats, are good candidates to increase the heat‐resistance property of CB and chocolate. In the present investigation, one such fat, kokum, is used as an improver to increase the hardness of chocolate. Kokum fat is added in various proportions replacing CB in dark and milk chocolate formulations and its effects on rheology, hardness and triglyceride composition were studied. The results revealed that up to 5% kokum fat addition by weight of the product did not significantly affect the plastic viscosity or yield stress of milk or dark chocolate. Hardness of both dark and milk chocolate increased with increase in addition of kokum fat. The solids fat content at and above 30 °C increased with increase in level of kokum fat with CB, especially at and above 15%. These physical properties are due to increase in 2‐oleodistearin triglycerides with addition of kokum fat with CB. The results revealed that kokum fat could be used up to 5% by wt of the product to increase the heat‐resistance property of chocolate so that it can be used in warm climates. Copyright © 2004 Society of Chemical Industry     

Fat Bloom and Chocolate Structure Studied by Mercury Porosimetry

The structure of dark chocolate samples was analyzed by mercury porosimetry in order to determine whether the formation of fat bloom was related to the presence of pores. The influence of cocoa butter concentration and tempering conditions on porosity were determined by using samples containing 29.5 or 31.9% fat, which were under, well or over-tempered. All Mercury porosimetry analysis confirmed the presence of a porous structure in all chocolates. Empty spaces represented about 1% of the whole volume of a well-tempered chocolate containing 31.9% cocoa butter but made up about 4% of the over-tempered chocolate. A well-tempered chocolate with only 29.5% cocoa butter showed the presence of about 2% empty spaces. From these observations and gas permeability a possible model for the microscopic structure was developed.     

延黄牛脂制备高纯度1,3-甘油二酯工艺

目的:提高延黄牛脂的附加值。方法:采用固定化脂肪酶Lipozyme RM IM为催化剂,牛油脂肪酸乙酯(乙醇解法自制)和甘油为原料制备1,3-甘油二酯,运用氢谱考察脂肪酶添加量、底物摩尔比、反应时间以及反应温度对粗反应混合物中1,3-甘油二酯含量的影响,并阐明醇解酯交换前后牛油与甘油二酯产物的脂肪酸组成变化。结果:1,3-甘油二酯合成最佳条件为脂肪酶Lipozyme RM IM质量分数为1%,底物摩尔比(n_{脂肪酸乙酯}∶n_甘油)2∶1,反应时间6 h,反应温度50℃。此条件下的1,3-甘油二酯生成率为72.5%,甘油酯得率为77%;纯化后纯度提高至90.79%。与原油(延黄牛脂)相比,甘油二酯产物中亚油酸和油酸含量分别升高了13.65%,6.47%,饱和度降低了7.17%。结论:延黄牛脂制备1,3-甘油二酯不仅能改变甘油酯结构,还可以改变牛脂的脂肪酸组成,降低其饱和度。     

巧克力“白霜”的解决方案

<正>巧克力风味独特、口感好,颇受人们的喜爱。随着巧克力制品消费量的增加,其质量问题也越来越受到各方的关注。其中巧克力起白霜是巧克力产业的世界性难题。白霜花是指加工、贮存、销售过程中,巧克力表面均一发白(酷似秋霜)或起凹凸不平的花斑点,甚至全部变成灰白色而失去光泽。外观使顾客误以为发霉而令人难以接受。严重时,内部组织呈干砂粒状,失去坚脆、断而有声、入口即化,凉爽润滑、细腻而不糊口等特征, 食似嚼蜡,失去商品价值。     

Effects of Feeding Protected Tallow on Composition of Milk and Milk Fat

Official methods were used to analyze composite samples of milk collected during the first 15 wk of lactation from 21 Holstein cows fed a milled ration containing 0 (basal), 15% (medium), or 30% (high) protected-tallow supplement (seven cows per treatment). Protein fractions and amino acid composition of the total proteins were determined from samples of individual milking. Melting characteristics of pooled samples were determined by nuclear magnetic resonance. Milk yield was similar for the three treatments, but percent fat and fat yield were higher for cows fed protected tallow. Percentages and yields of protein and solids-not-fat were decreased on the protected tallow treatments, especially for high tallow. The decrease in protein was in the casein fraction. Amino acid composition of the total proteins was similar for the three treatments. Feeding protected tallow caused decreases in all fatty acids except 4:0, 16:1, 18:0, and 18:1 which increased. Nuclear magnetic resonance indicated that butter from the basal group would be harder than that from cows fed protected tallow.     

TEXTURAL CHANGES IN CHOCOLATE CHARACTERIZED BY INSTRUMENTAL AND SENSORY TECHNIQUES

Cocoa butter has a distinct texture due to unique interactions of polymorphic lipid structures. Part of chocolate's appeal is smooth mouthfeel; as fat or sugar bloom forms, textural change is perceived. Correlation of instrumental and sensory texture analysis has not been conducted in stored chocolate. The objective of this study was to analyze texture and color of dark and milk chocolate stored under conditions leading to fat and/or sugar bloom by instrumental and sensory measurements. Milk and dark chocolate was stored 5 weeks at various temperatures and relative humidity (RH), followed by instrumental and sensory texture analysis. All attributes, except springiness, were significantly affected by treatments. According to partial least squares linear regression, instrumental hardness, cohesiveness, chewiness and gumminess modeled sensory hardness. The 30.0C incubator experienced temperature fluctuations, resulting in severe fat bloom. Temperature fluctuations during storage had more influence on texture perception than storage at high temperatures or high RH.

PRACTICAL APPLICATIONS

This research serves as an initial study on textural aspects of chocolate quality upon storage that is the first report to correlate instrumental textural analysis of chocolate to sensory evaluation. Storage temperature and humidity of chocolate greatly impacts consumer texture perception, which is valuable information to small chocolate handlers and manufacturers who have noted to us that many of the larger companies may have this information – but it is not widely available. It also sets the stage for more detailed studies on texture and flavor of chocolate during storage. Although many storage studies on chocolate exist, those that intertwine studies of quality from both an instrumental and a sensory standpoint are lacking.     

The effect of various substances on the blooming of chocolate

Summary. The effects of many edible substances and pure chemicals on chocolate have been studied in relation to the prevention of chocolate blooming. Bile acids, cholesterol, other sterols and choline promoted the blooming of chocolate. Tripalmitin, added in good dispersion, made chocolate very resistant to fat bloom and chocolate had a high gloss. Hydrogenated fats made very difficult temperable chocolate and it had a waxy taste. Only Delft 37 and some Edelfette improved the resistance of chocolate, but they made it waxy. Butylated hydroxyanisole (BHA) has undesirable effects.
Anhydrous glucose added at the rate of 15-20% of the weight of chocolate increased the resistance. Other sugars were either inert or diminished the resistance. Glycerol had a strikingly unfavourable effect on both quality and resistance. Amino acids did not exhibit any special influence on chocolate. Chemical additives and biological treatment also influenced the blooming of milk chocolate. Unusually long bloom crystals were produced on the surface of milk chocolate on special occasions.     

Influence of high-melting milk fat fraction on quality and fat bloom stability of chocolate

The aim of this paper was to define the optimal concentration of a high-melting milk fat fraction with a suitable precrystallization temperature time regime in order to obtain chocolate which would have satisfactory sensory characteristics and an increased fat bloom stability. The precrystallization was performed in a laboratory crystallizer, that is in a modified Brabender pharinograph, which measures the rheological characteristics of the precrystallized fluid chocolate mass with a milk fat fraction. The experiments were performed according to the factorial plan 3² (two factors on three levels). Hardness as well as solid fat content of chocolate was measured by instrumental methods. The optimal sensory quality of chocolate was achieved by adding 1–3% of the milk fat fraction and under the 25 °C precrystallization temperature. These samples of chocolate showed the highest fat bloom stability.     

Automated image analysis tool for migration fat bloom evaluation of chocolate coated food products

Migration fat bloom remains a major problem in the production of coated confectionary products where a layer of chocolate is added around a filling or other fat containing substrate. Fat bloom quantification is typically done by a human panel scoring samples in time using a low resolution discrete scale. In view of developing a mechanistic model for migration fat bloom, it is important to have a higher resolution. In this paper, a new, high resolution quantitative method based on image analysis is developed. The method is able to detect both the evolution of fat bloom in terms of the disappearance of gloss and the development of “whitish” portions at the chocolate surface. It was successfully applied to distinguish the difference in fat bloom development rate between samples containing different fat concentrations (0, 3 and 6g/100g) coated on fillings containing different amounts of fat (25 and 75g/100g). In the 25g/100g filling fat case, blooming occurred at a very late stage and was caused by the disappearance of gloss. In the 75g/100g filling fat case the development of a “whitish” surface was responsible for the change in acceptability. The newly developed image analysis method is a solid alternative for the panel procedure.     

Controlling fat bloom formation in chocolate – Impact of milk fat on microstructure and fat phase crystallisation

The partial replacement of cocoa butter (CB) with milk fat (MF) strongly influences micro-scale topographic evolution and fat phase crystallisation in milk chocolate. Adding MF reduces the incidence of large surface crystals and the number and diameter of amorphous, welled CB deposits (‘cones’), with a concurrent decrease in initial surface roughness (p < 0.05) and rate of surface coarsening. Presence of MF also slows the solidification of the cones into disorganised crystalline masses. Finally, MF reduces the initial solid fat content, and slows the rate of change in whiteness index, as well as the form V to VI polymorphic transition. Fat crystal growth is accelerated by repeated temperature-cycling (26–29 °C) compared to isothermal conditioning (26 °C). However, cone hardening occurs more rapidly when isothermally-stored. Irrespective of fat composition and storage conditions, fat crystal growth, welling and ultimately fat bloom begin only at specific locations on the chocolate surface, suggesting that chocolate’s microstructural heterogeneity is responsible for distinct surface fat crystallisation pathways.     

Measurement of solid fat content by ultrasonic reflectance in model systems and chocolate

A series of confectionery coating fat (CCF) and cocoa butter (CB) dispersions in corn oil were prepared and tempered to a range of temperatures (10, 12 and 15 °C and 26, 27.5 and 29 °C respectively) to produce samples with solid fat contents (SFC) between 0 and 9%. The ultrasonic velocity in the CCF samples increased with increasing SFC and decreased with temperature, however the CB samples were too attenuating to allow velocity measurements. The ultrasonic reflectance at the surface of both sets of dispersions decreased linearly with SFC but at the same level of solids was less for CB than CCF suggesting some dependence on other aspects of fat structure. The microstructures and thermal properties of the fat systems are compared in an attempt to understand these structural differences. Finally ultrasonic reflectance is shown to respond to changes in a chocolate melt during tempering.     

Effect of adding shea butter stearin and emulsifiers on the physical properties of cocoa butter

The aim of this study was to assess the feasibility of shea butter stearin (SBS) as cocoa butter equivalent (CBE). In this work, the optimal ratio of SBS and cocoa butter (CB) was evaluated by the solid fat content and deviation solid fat content. Emulsifiers added to SBS and CB blends were first screened based on β polymorph level, and mixture regression experiment was designed to obtain the optimized compound emulsifiers ratio, finally the characterization of shea butter chocolate was evaluated by sensory evaluation and texture profile analysis (TPA). The best compatibility was obtained when the mixture ratio of SBS and CB was 20:80, where ΔSFC within a range of 1.5 was shown. The appropriate compound emulsifiers were soy lecithin: polyglycerol polyricinoleate: Tween 60 = 1:1:1. Both sensory evaluation and TPA test showed SBS and CB blends could improve the taste and texture of chocolate with proper emulsifiers addition.     

几种巧克力调温过程中的结晶特性研究

本文用X-衍射法（XRD）和差示扫描量热法（DSC）对香菇巧克力（LC）,茶叶巧克力（TC）和对照样巧克力（CC）在调温工艺过程中的结晶特性进行了研究,发现3种巧克力在调温过程中的结晶行为各有其特性,这些特性在X-衍射（XRD）谱图中和热差法（DSC）熔解曲线上得到明显反映,LC和CC有相似的变化趋势,3种巧克力在浇模时所形成的晶相之熔点各不相同,LC为29.62℃,TC为21.93℃。CC为26.05℃,促霜试验表明：香菇和茶叶均有较好的延霜效果,其中香菇效果优于茶叶。