Effects of milk powders in milk chocolate

The physical characteristics of milk powders used in chocolate can have significant impact on the processing conditions needed to make that chocolate and the physical and organoleptic properties of the finished product. Four milk powders with different particle characteristics (size, shape, density) and "free" milk fat levels (easily extracted with organic solvent) were evaluated for their effect on the processing conditions and characteristics of chocolates in which they were used. Many aspects of chocolate manufacture and storage (tempering conditions, melt rheology, hardness, bloom stability) were dependent on the level of free milk fat in the milk powder. However, particle characteristics of the milk powder also influenced the physical and sensory properties of the final products.     

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.     

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。     

巧克力专用乳粉

研究了不同乳粉的颗粒大小和结构、游离脂肪含量对巧克力浆料粘度的关系。滚筒乳粉与喷雾乳粉之对比，滚筒干燥的全乳粉具有下列优点；游离脂肪含量高，可减少可脂的用量，赋与巧克力以更好的风味；可降低巧克力浆料的粘度。乳粉中羟甲基糠醛含量可增进巧克力风味、口感，提高喷雾乳粉中游离脂肪含量改进的工艺。     

Development and application of confocal scanning laser microscopy methods for studying the distribution of fat and protein in selected dairy products.

Confocal scanning laser microscopy (CSLM) methods were developed to identify fat and protein in cheeses milk chocolate and milk powders. Various fluorescent probes were assessed for their ability to label fat or protein in selected food products in situ. Dual labelling of fat and protein was made possible by using mixtures of probes. Selected probes and probe mixtures were then used to study (a) structure development of Mozzarella cheese during manufacture and ripening, and (b)) the distribution of fat and protein in milk chocolate made with milk powders containing varying levels of free fat. Microstructural changes in the protein and fat phases of Mozzarella cheese were observed at each major step in processing. Aggregation of renneted micelles occurred during curd formation; this was followed by amalgamation of the para-casein into linear fibres during plasticization. Following storage, the protein phase of the Mozzarella became more continuous; entrapping and isolating fat globules. Chocolate made with a high free-fat spray-dried powder blend showed a homogeneous fat distribution, similar to that of chocolate made with roller-dried milk. Chocolate made with whole milk powder containing 10 g free fat/100 fat showed a non-homogeneous fat distribution with some fat occluded within milk protein particles. These differences in fat distribution were related to Casson yield value and Casson viscosity of the chocolates.     

Impact of pre-crystallization process on structure and product properties in dark chocolate

Dark chocolate microstructures with different structure densities, i.e., close-packing of the fat crystal lattice, and homogeneity i.e., evenness and connectivity of the fat crystal network, were created by β_VI-seeding or conventional pre-crystallization with various degrees of temper and were evaluated with respect to storage stability. The structure characterization was conducted by measuring the strength of the cocoa butter crystal network with traction tests combined with DSC melting curves. Subsequent storage stability was evaluated with DigiEye technique for fat bloom development and gravimetrical techniques for fat/moisture migration. The two pre-crystallization processes generated significantly different structures and storage stability. Well-tempered β_VI-seeding resulted in a dense and homogenous chocolate structure directly after solidification, which was optimal in order to retard fat bloom and fat migration. However, a too high structure density generated heterogeneous structures with reduced ability to withstand fat bloom. A lower structure density exhibited optimal resistance against moisture migration.     

Extrinsic Attributes That Influence Parents’ Purchase of Chocolate Milk for Their Children

The consumption of milk is essential for children's heath; and flavored milk, especially chocolate milk, is often purchased to increase children's milk consumption. However, the sugar content of chocolate milk has raised health concerns. As such, it is important to understand chocolate milk extrinsic attributes that influence parents’ purchase decisions when they are purchasing chocolate milk for their children. The objective of this study was to determine the key extrinsic attributes for parents when they purchase chocolate milk for their children. An online survey with a conjoint analysis design, emotions questions, and Kano questionnaire that focused on chocolate milk was conducted targeting parents. Three hundred and twelve parents participated in the survey. Parents reported positive emotions including good, good natured, happy, loving, and satisfied when purchasing chocolate milk for their kids. Three segments of parents were identified with subtle but distinct differences in their key preferences for chocolate milk attributes for their children. Type of sweetener was the primary driver of choice for purchasing chocolate milk for children followed by fat content. Among sweetener types, natural noncaloric/nonnutritive sweeteners or sucrose were preferred over artificial sweeteners, and reduced fat was preferred over full fat or skim milk. Kano results revealed that reduced fat and sugar with an all natural label and added vitamins, minerals, and protein were attractive to the majority of parents when purchasing chocolate milk for their kids.     

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.     

Spatial mapping of solid and liquid lipid in confectionery products using a 1D centric SPRITE MRI technique

Oil migration is responsible for the poor keeping qualities of composite confectionery products. Quality defects arising from oil migration include softening of the coating, hardening of the filling, deterioration in sensory quality and a greater tendency toward fat bloom formation. For this reason, oil migration has been extensively studied, and yet a clear understanding of the oil migration mechanisms still remains a challenge.Traditional MRI techniques are unable to acquire images from the solid lipid in chocolate. In this paper we employ a newly developed one-dimensional, centric-scan MRI technique to acquire images from the short lived signal components from the solid lipid, as well as the longer timescale components of the liquid lipid in a chocolate sample. We present one-dimensional images of a dynamic hazelnut oil absorption experiment, and one-dimensional solid and liquid distribution maps in a 5 mm thick chocolate sample in which oil migration occurs.     

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.     

Oil Migration in a Chocolate Confectionery System Evaluated by Magnetic Resonance Imaging

ABSTRACT: Oil migration is a common problem in composite chocolate confectionery products resulting in softening of chocolate and hardening of the filling. Spatial and temporal changes in the liquid oil content of a 2-layer peanut butter and chocolate model system were evaluated using a magnetic resonance imaging (MRI) technique. The experimental factors were chocolate particle size, milk fat content, emulsifier concentration, degree of temper, and storage temperature. The responses were migration rate and overall change in signal intensity (amount of migration). Based on analysis of variance (ANOVA), particle size, milk fat content, and storage temperature were significant factors for oil migration rates. Milk fat content and temperature were significant factors for overall change in signal intensity.     

On the porous mesostructure of milk chocolate viewed with atomic force microscopy

The surface structure of commercial milk chocolate is examined using atomic force microscopy. It is shown that its surface topography is complex, comprising a finely mottled, yet irregular texture with most structural elements measuring <3 μm in size. It is also demonstrated that a large number of microscopic pores exists at the surface. The morphology of these pores is highly variable, with observed cavities generally being conical in nature with irregularly shaped openings. Typical pore depths range from 1 to 3 μm and are randomly distributed on the surface of milk chocolate, without any defining features in their vicinity to suggest their existence. In the past, it has been postulated that such pores are opening to channels; these being responsible for liquefied cocoa butter transport and subsequent promotion of fat bloom formation. To shed light on any such relationship, milk chocolate is subjected to multiple (6, 12 and 24) temperature cycles (each from 25 to 27 °C and 25 °C over 2 h). Results show that following many cycles, there is crystal growth around some pores, but that the pores themselves are not appreciably altered. This suggests that, under these experimental conditions, they are not directly involved in bloom mediation or liquefied fat transport in milk chocolate.     

Effect of nut oil migration on polymorphic transformation in a model system

Fat migration in confectionery products can lead to significant deterioration in quality. This occurs not only through loss in texture contrast between chocolate and filling but also through the appearance of fat bloom on the surface of the chocolate. This latter aspect is often, although not exclusively, linked to the transformation of the cocoa butter β_V phase into β_VI. In this study, the influence of hazelnut oil on the polymorphic transformation of cocoa butter has been determined, showing that even small additions (1%) of nut oil can have a significant impact on the rate of transformation. Additionally, use of a model system has shown that polymorphic transformation in cocoa butter is linked to the degree of migration of nut oil from a filling. Portions of the cocoa butter close to the filling experience both greater degrees of migration and faster transformation.     

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 packaging information on consumer liking of chocolate milk

Chocolate milk varies widely in flavor, color, and viscosity, and liking is influenced by these properties. Additionally, package labels (declared fat content) and brand are some of the extrinsic factors that may influence consumer perception. The objective of this study was to evaluate the effects of packaging labels and brand name on consumer liking and purchase intent of chocolate milk. A consumer acceptance test, conjoint analysis survey, and Kano analysis were conducted. One hundred eight consumers evaluated 7 chocolate milks with and without brand or package information in a 2-d crossover design. A conjoint analysis survey and Kano analysis were conducted after the consumer acceptance test. Results were evaluated by 2-way ANOVA and multivariate analyses. Declared fat content and brand influenced overall liking and purchase intent for chocolate milks to differing degrees. A subsequent conjoint analysis (n = 250) revealed that fat content was a driver of choice for purchasing chocolate milk followed by sugar content and brand. Brand name was less important for purchase intent of chocolate milk than fat or sugar content. Among fat content of chocolate milk, 2 and 1% fat level were most appealing to consumers, and reduced sugar and regular sugar were equally important for purchase intent. Kano analysis confirmed that fat content (whole milk, 1, or 2% fat chocolate milk) was an attractive attribute for consumer satisfaction, more so than brand. Organic labeling did not affect the purchase decision of chocolate milk; however, Kano results revealed that having an organic label on a package positively influenced consumer satisfaction. Findings from this study can help chocolate milk producers as well as food marketers better target their product labels with attributes that drive consumer choice of chocolate milk.     

Ability of crystal promoters to delay fat bloom development in heat‐resistant compound chocolate with or without the presence of crystal inhibitor

Three additives that acted as crystal promoters (CP1, CP2 and CP3), at varying concentrations, were studied to determine their effect on fat bloom inhibition in heat‐resistant compound chocolates. CP1 was composed of mono‐ and diglycerides and polyglycerol esters from high‐oleic sunflower oil. CP2 consisted of mono‐ and diglycerides, lecithin and citric acid esters from blended canola oil and palm stearin. CP3 was composed of triglycerides from fully hydrogenated canola oil. Based on instrumental and sensory evaluations, all crystal promoters significantly (P ≤ 0.05) delayed fat bloom formation. Although compound chocolate with 0.25% CP1 showed more rapid bloom development than those with CP2 and CP3, addition of the crystal inhibitor sorbitan tristearate (STS) to the sample at 0.5% concentration further delayed (P ≤ 0.05) fat bloom development. The considerable delay in fat bloom formation suggests that the addition of carefully selected crystal modifier additives can improve the quality of heat‐resistant compound chocolates.     

Interactions of milk fat and milk fat fractions with confectionery fats

The objectives of this study were to provide a better understanding of the effects of triacylglycerol (TAG) and non-TAG components (minor lipids) of milk fat on phase and crystallization behavior of binary mixtures of palm kernel oil (PKO) and the physical properties of corresponding compound coatings. Binary mixtures of a fractionated PKO with the different milk fats were examined for melting profiles, crystallization kinetics, and crystalline microstructures, and polymorphic changes during storage. Compound coatings were made with equivalent binary fat mixtures and measured for hardness and bloom formation. Milk fat and milk fat fractions affected crystallization rates of fractionated PKO, depending on the melting point of the fat. High-melting components resulted in more rapid crystallization, whereas the original milk fat and low-melting components inhibited crystallization. The crystal structure (e.g., number, size, shape) of the PKO crystals was influenced significantly by the addition of milk fat fractions and was influenced by the presence or absence of the minor lipids in milk fat. Milk fat and milk fat fractions had a softening effect on fractionated PKO, which was apparent in the binary mixtures as well as the compound coatings. In general, as the solid fat content (at 25 degrees C) of the binary mixtures increased, the hardness of the respective coatings increased. This also was related to an increased rate of bloom formation during storage.     

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.     

巧克力风味牛奶的研制与开发

近年来市场上出现的巧克力牛奶一般都是用巧克力加牛奶直接配制而成的,由于巧克力热量高,易导致肥胖、高血脂等疾病,因此在市场上的销售受到了一定的限制。本课题通过选用巧克力香精替代巧克力,以鲜牛奶为主要原料,选用L9(33)正交表,通过正交实验筛选最佳配方。试验结果表明鲜牛奶85.0%,复合稳定剂0.16%,巧克力香精0.07%,食用色素0.106%,AK糖0.02%,可可粉0.4%,白砂糖2.0%。产品经分析检测符合国家质量卫生标准,口感细腻,巧克力风味浓郁,奶香突出,色泽诱人,是一种非常有发展前途的新型风味牛奶。     

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.