巧克力非活性乳酸菌饮料的研制

研究了以脱脂奶粉、可可粉为主要原料,生产巧克力非活性乳酸菌饮料的生产工艺,通过试验确定了工艺参数。     

Composition and Structure of Fat Bloom in Untempered Chocolate

It is generally accepted that visual fat bloom is caused by the separation of cocoa butter toward the surface. However, this is not always true for all types of bloom. One type of fat bloom, which can occur due to lack of tempering, has still not been completely elucidated. We performed a compositional and structural study of this type of fat bloom in plain chocolate. More specifically, we performed (1) an investigation of its crystallographic properties, (2) investigation of fat content, (3) analysis of the composition of triacylglycerol (TAG), (4) stereomicroscopic observations, and (5) observation and elemental analysis using a scanning electron microscope with an energy‐dispersive X‐ray spectrometer (SEM‐EDS). In the bloomed chocolate, the fat content in the light brown phase was lower than that in the black phase. Concerning fat composition, the content of sn‐1,3‐saturated acyl, sn‐2‐oleoyl glycerols (Sat‐O‐Sat type TAGs) in the light brown phase was lower. The lower fat content is thought to result in its lighter color. The results of our composition analysis and morphological observations suggest that the mechanism of the bloom generation due to nontempering involves not the separation of fat toward the surface but the crystallization of fat which leads to withdrawal of fat from the vicinity of the growing crystal, leading to differences in fat content.     

巧克力起霜研究进展

巧克力起霜导致产品品质下降,成为困扰糖果工业的一个世界性难题。基料油种类不同,起霜的机理显著不同。从基料油性质出发,详细阐述基料油组成、加工条件以及储存条件对巧克力起霜的影响。在此基础上,对各类巧克力起霜的机理进行总结,为解决起霜问题提供理论支持。参考国内外文献报道,对巧克力起霜的研究方法进行总结,并详细阐述具有延缓起霜作用的措施,为巧克力生产提供参考。     

HACCP在劲跳巧克力生产中的应用

本文按照HACCP体系的监控要求对劲跳巧克力生产过程进行危害分析和品质控制,确立了四个关键控制点:原辅料验收、化油、精磨、过滤和两个特殊过程,即水分控制过程和细度控制过程,并建立了相应的监控程序和纠偏措施,提高了劲跳巧克力的生产效率。     

Tempering of Chocolate in a Scraped Surface Heat Exchanger

Crystallization of dark chocolate during different tempering processes has been studied in-situ in a lab-scale Scraped Surface Heat Exchanger. The linear relationship between torque and viscosity made possible the control of chocolate crystallization during tempering by following torque variations vs. time and converting them to equivalent viscosity values. These variations of equivalent viscosity of chocolate observed during tempering were correlated with temper-meter measurements which had been related to the content of cocoa butter seeding crystals. A temperature cycle (50-26.1-30.5-33.3°C) enabled preparation of a well-tempered chocolate stable for ≥30 min at that temperature. It was characterized by a seed crystals content of about 1.15 ± 0.1% of cocoa butter, crystallization temperature of 23.9 ± 0.2°C in the temper-meter and an equivalent viscosity of 3.0 ± 0.4 Pa.s.     

巧克力中砷含量的石墨炉原子吸收测定

研究了用石墨炉原子吸收法测定巧克力中砷的含量,采用氧化镁添加-干式灰化法消解样品,有效地抑制了砷的挥发；添加硝酸镍大大提高了石墨炉工作程序中的灰化温度,消除了样品基体中磷的干扰。此方法亦适合于其它高含磷样品的砷的测定。     

Quantitative X-Ray Diffraction Determination of α-Lactose Monohydrate and β-Lactose in Chocolate

ABSTRACT:  Lactose is a constituent of milk chocolate. During processing and cooling, lactose may precipitate as α-lactose monohydrate and β-lactose. The presence of α-lactose monohydrate has a deleterious effect on the quality of milk chocolate. A quantitative X-ray diffraction method for determination of α-lactose monohydrate and β-lactose in chocolate is described. The α-lactose monohydrate signal at 19.9°2θ with Cu-Kα X-rays is a cubic function of concentration. The β-lactose signal at 20.9°2θ is a linear function of concentration. α-Lactose monohydrate is detectible at about 0.1 weight% and can be quantified at >0.5 weight%. β-Lactose is detectible at about 1 weight% and can be quantified at >3 weight%. About 10 min is required to prepare and run a sample.
Practical Application: The crystalline form of lactose affects the quality of chocolate. A rapid method for quantifying crystalline forms of lactose in chocolate is described. The method can be used for quality control and for improving chocolate quality.     

Light-Oxidized Flavor Development and Vitamin A Degradation in Chocolate Milk

Samples of several chocolate milk formulations were exposed to light to determine if the components masked and/or prevented light-oxidized flavors or prevented photodegradation of vitamin A. Chocolate flavor added either before or after light exposure masked light-oxidized flavor (p<0.05). Neither carrageenan nor chocolate color prevented development of light-oxidized flavor. Vitamin A degradation was reduced by the addition of carrageenan alone or in combination with chocolate dairy powder (chocolate flavor and color), chocolate color or chocolate flavor (p<0.05).     

近红外光谱快速测定巧克力中掺假淀粉

巧克力作为一种休闲食品,以其细腻的口感和独特的口味而广泛受到消费者的青睐。然而,近几年来关于巧克力掺假的报道不断涌入人们的视野。其中,以廉价淀粉掺假巧克力的手段最为常见。本文研究利用近红外光谱快速检测巧克力中掺假红薯淀粉和马铃薯淀粉的方法,采用主成分回归(principal component regression,PCR)和偏最小二乘法(partial least squares regression,PLS)建立校正模型,并对比了光谱区间、光谱预处理方式以及主因子数对模型的影响。结果显示,采用PLS建模,光谱采用一阶导数处理(7pts),光谱区间选择在7000~4200 cm-1,主因子数为8时,模型预测效果最佳。结果表明,模型的预测误差均方根RMSEP=1.7%,实际值与预测值相关系数RP2=0.9426。该模型对不同掺假比例样品的加样回收率为94.2%~105.6%,日内RSD为4.7%~8.9%,日间RSD为5.1%~11.3%。结果表明,近红外光谱技术可用于快速检测巧克力中掺假淀粉。     

巧克力样品中反式脂肪酸含量的测定

采用气相色谱内标法,对20个巧克力样品中的反式脂肪酸含量进行测定分析。试验结果表明,以代可可脂为主要原料的巧克力样品中,反式脂肪酸含量范围在未检出至4．96％之间。以可可脂为主要原料的巧克力样品中,反式脂肪酸含量范围在未检出至0．844％之间。所测定的巧克力样品中反式脂肪酸以反十八碳一烯酸为主。     

Thin Film Rheology and Tribology of Chocolate

We investigated relations between food texture and thin film properties rather than bulk properties. Such thin film rheological or‘tribological’effects may characterize physical behavior and physical perceptions of food products. Experiments were done on three chocolate samples. The Surface Forces Apparatus (SFA) proved to be effective for studying the very complex chocolate system. Very complex thin film behavior was found to be quite different for the three samples. Fat constitution and average particle size were important in determining the type of friction forces generated between shearing/sliding surfaces separated by thin films of chocolate. Such studies can help characterize specific physical qualities of chocolate.     

巧克力食品中可可脂及其代用品的鉴别研究

巧克力食品中的常用油脂主要包括天然可可脂、类可可脂、代可可脂和乳脂,采用高温气相色谱法对这四种油脂的甘油三酯组成进行分离。结果表明,天然可可脂与类可可脂的甘油三酯组成较相似,但与代可可脂完全不同,乳脂的甘油三脂组成非常复杂,以其特殊的峰型区别于其它各脂。通过甘油三酯组成的谱图特征可快速、直观地鉴别出这四种油脂。实际应用可区分市售可可脂巧克力和代可可脂巧克力。     

Sensory Characteristics of Milk Chocolate with Lactose from Spray-Dried Milk Powder

Dry whole-milk powders with 0-70% nominal lactose prepared by spray-drying alone (containing amorphous lactose) or combined with post-drying crystallization (containing crystalline lactose) were incorporated into milk chocolate to give 0-50% substitution of lactose for sucrose. No significant differences occurred in sweet, bitter, and thickness of melt (P > 0.10) based on milk powder preparation method or lactose concentration. As lactose increased, hardness and onset of melt increased regardless of milk powder preparation method; but, chocolates containing crystalline lactose were softer than those containing amorphous lactose. Higher chocolate, milk and caramel flavors were perceived in milk chocolates containing crystalline lactose. Graininess of milk chocolate increased at the highest level of added lactose.     

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.     

低场核磁共振在线检测巧克力的熔化过程

构建了低场核磁共振(LF-NMR)在线控温分析系统,对不同品种巧克力的熔化过程进行了表征,研究了可可脂和粗脂肪含量对巧克力熔化温度的影响。通过对样品的程序升温,持续测定了巧克力的横向弛豫时间(T₂),对四个不同品牌巧克力的熔化过程进行了评价。结果表明,巧克力熔化过程中T₂值随温度增大,巧克力中液体脂肪的运动性增强,且熔化温度随可可脂和粗脂肪含量的增加而升高。本文首次利用LF-NMR在线控温分析系统实时在线检测了巧克力熔化过程,并直观准确地测定了巧克力的熔化温度,为改善巧克力的加工工艺和配方提供了理论指导。     

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.     

GC-0-MS法鉴定黑巧克力中关键香气物质

采用同时蒸馏萃取法（SDE）和吹扫捕集法（P＆T）对醇浓黑巧克力中挥发性物质进行提取。利用气相色谱,嗅闻-质谱联用的方法对其中的挥发性性物质定性分析,共鉴定出52种物质,包括醛类、烯醛类、吡嗪类、醇类、酯类、酮类、呋喃类、酸类等物质,其中吡嗪类物质的种类最多,其次为醛类物质。通过香气提取物稀释分析（AEDA）和动态顶空稀释分析（DHDA）,确定关键的香气物质（10g3FD〉4／FD值〉125）共有10种,分别为醛4种（2-甲基丙醛、3-甲基丁醛、2-甲基丁醛、苯乙醛）,吡嗪4种（乙基吡嗪、2,3-二甲基吡嗪、三甲基吡嗪、四甲基吡嗪）,酯1种（苯甲酸异戊酯）,吡咯1种（2-乙酰基．1-吡咯啉）。其中巧克力香气特征主要表现为黑巧克力香、爆米花味、烤香、水果香、咖啡香、坚果香等。     

GC-O-MS法鉴定黑巧克力中关键香气物质

采用同时蒸馏萃取法(SDE)和吹扫捕集法(P&T)对醇浓黑巧克力中挥发性物质进行提取。利用气相色谱-嗅闻-质谱联用的方法对其中的挥发性性物质定性分析,共鉴定出52种物质,包括醛类、烯醛类、吡嗪类、醇类、酯类、酮类、呋喃类、酸类等物质,其中吡嗪类物质的种类最多,其次为醛类物质。通过香气提取物稀释分析(AEDA)和动态顶空稀释分析(DHDA),确定关键的香气物质(log3FD≥4/FD值≥125)共有10种,分别为醛4种(2-甲基丙醛、3-甲基丁醛、2-甲基丁醛、苯乙醛),吡嗪4种(乙基吡嗪、2,3-二甲基吡嗪、三甲基吡嗪、四甲基吡嗪),酯1种(苯甲酸异戊酯),吡咯1种(2-乙酰基-1-吡咯啉)。其中巧克力香气特征主要表现为黑巧克力香、爆米花味、烤香、水果香、咖啡香、坚果香等。     

Oil Migration in Chocolate–Peanut Butter Paste Confectionery as a Function of Chocolate Formulation

ABSTRACT:  Migration of oil from high oil content filling to the chocolate coating can result in undesirable quality changes in filled chocolate confectionery products. The objective of this study was to monitor and model peanut oil migration in a 2-layer chocolate–peanut butter paste model confectionery. Spatial and temporal oil content changes were evaluated using magnetic resonance imaging. Five formulations of chocolate, which varied in chocolate particle size, milk fat content, and emulsifier level, were assessed at 2 temperatures, 20 and 30 °C. The spatial and temporal experimental data were modeled using a Fickian-based diffusion model, fitting for the diffusion coefficient, D , over a time frame of 17 d. Values of the diffusion coefficient ranged from 1.82 to 3.23 × 10⁻¹¹ m²/s for the chocolate formulations stored at 30 °C. No significant mass transfer took place in the 20 °C samples over the experimental time frame. This study describes the dynamic nature of the interface between the chocolate and peanut butter paste layers, quantifies the mass transfer from the peanut butter paste to the chocolate, and reinforces the importance of temperature control.