磷脂在巧克力调温工艺中的作用

探索磷脂对CTCBE及CB两种巧克力调温工艺及抗霜性的影响。通过粘度法、耐促霜组合实验方法测定两种巧克力中添加磷脂后在调温点的粘度变化规律、变稠时间及延缓起霜花作用。以及DSC和XRD方法从动力学、热力学、晶体学角度进行对比分析研究。结果表明添加磷脂对CTCBE及CB两种巧克力均有一定降粘减稠效果,但延缓结晶作用不明显;延缓CTCBE巧克力起霜花作用不明显,对CB巧克力有轻微延缓起霜花作用。两种组合方法的研究结果具有一致性。     

乌桕类可可脂及其巧克力结晶性质的研究(Ⅱ)

为探索乌桕类可可脂(CTCBE)巧克力调温工艺操作困难的原因与机理，采用差示扫描量热法(DSC)、X-射线衍射(XRD)对添加天然生物乳化剂(香菇粉)的CTCBE巧克力(LC)和空白CTCBE巧克力(CC)在调温过程中结晶行为进行研究分析。并采用粘度法、升温破乳法对两种巧克力浆料在调温过程中的流散性及乳化稳定性进行对比研究。DSC和XRD结果均表明添加香菇粉明显促使CTCBE巧克力形成高熔点稳定晶型，LC比CC酱料的粘度降低近20％，乳化稳定性提高100倍以上，有效地改善了CTCBE巧克力调温工艺操作条件，提高产品产量及质量(具有良好热稳定性、抑制霜花效果及抗氧化性)。     

乌桕类可可脂及其巧克力结晶性质的研究(II)

为探索乌桕类可可脂(CTCBE)巧克力调温工艺操作困难的原因与机理,采用差示扫描量热法(DSC)、X-射线衍射(XRD)对添加天然生物乳化剂(香菇粉)的CTCBE巧克力(LC)和空白CTCBE巧克力(CC)在调温过程中结晶行为进行研究分析。并采用粘度法、升温破乳法对两种巧克力浆料在调温过程中的流散性及乳化稳定性进行对比研究。DSC和XRD结果均表明添加香菇粉明显促使CTCBE巧克力形成高熔点稳定晶型,LC比CC酱料的粘度降低近20%,乳化稳定性提高100倍以上,有效地改善了CTCBE巧克力调温工艺操作条件,提高产品产量及质量(具有良好热稳定性、抑制霜花效果及抗氧化性)。     

乌桕类可可脂晶型衍变与胀罐的关系

研究不同冷却结晶条件下CTCBE和CB的晶型衍变与胀罐的关系。采用差示扫描量热仪(DSC)、X-射线衍射仪(XRD)对不同结晶条件下两种可可脂样品进行热分析及晶相分析研究。结果表明未经调温CTCBE缓冷时中心样存在十分严重晶型衍变(粉状物,DSC测试显示双熔点峰),引起晶体结构的改变,导致胀罐发生;而急冷时晶型衍变程度低,不导致胀罐。同样条件下CB晶型衍变程度极低(DSC测试显示单熔点峰),不发生胀罐。经调温处理CTCBE急冷和缓冷对XRD晶相衍射数据基本无影响;而未经调温处理CTCBE在急冷和缓冷时两者晶相衍射数据存在一定差异。调温与未经调温CB在缓冷或急冷时的X-射线衍射数据均具有一致性。     

聚甘油脂肪酸酯对可可脂结晶特性的影响

可可脂(CB)是巧克力及巧克力制品的主要成分,其热力学及结晶特性决定了产品的品质、加工特性和货架期。以聚甘油单硬脂酸酯31S、61S和聚甘油蓖麻醇酯(PGPR)为研究对象,利用差示扫描量热(DSC)和X射线衍射技术,研究乳化剂种类、添加量、变温条件对可可脂结晶特性的影响。研究发现:调温温度下,31S和61S具有促进可可脂结晶从Ⅳ型向Ⅴ型转变的效果;而PGPR在添加量大于0.1%的情况下,则表现出对Ⅳ型向Ⅴ型转变的抑制效果;在变温条件下,31S和61S具有促进可可脂热力学亚稳定态晶型的形成和晶型转换的效果,特别是促进了可可脂Ⅱ型晶型的形成,而PGPR无显著影响。     

乌桕类可可脂同质多晶型及其衍变规律研究

用XRD和DSC对鸟桕类可可脂(CTCBE)同质多晶型进行了研究，发现CTCBE有6种同质多晶型，而且有与天然可可脂(CB)类似的衍变路径和规律，但CTCBE与CB相比，晶型Ⅴ-→Ⅵ衍变速率快，这是CTCBE巧克力比CB巧克力更易起霜花的原因。     

巧克力； 调温； 结晶特性； 香菇； 茶叶；

前期研究表明香菇和茶叶有很好的抗霜效果，为进一步研究香菇和茶叶在调温巧克力中对乌柏类可可脂结晶行为的影响，分别用XRD和DSC对乌柏类可可脂的香菇巧克力（LC）、茶叶巧克力（TC）和对照样巧克力（CC）在调温过程中的结晶行为进行了测试，结果表明降温和回温二队阶段结晶行为差异显著,而且，LC和TC在浇模时所形成晶相熔点分别为29．62℃和27．84℃，明显比对照组CC熔点（21．93℃）高，说明香菇和茶叶在浇模时有助于形成对照组更多的稳定晶相，进一步证明其抗霜效果与动力学结果一致。     

乌桕类可可脂抗氧化方法的研究

乌桕是我国特有油料树种，从中提取的类可可脂(简称CTCBE)因其独特的性能，可替代天然可可脂(简称CB)制作巧克力。但CB氧化稳定性高，而CTCBE易氧化酸败变质。通过Ranci-mat法及Schaal法对CTCBE抗氧化方法研究得出，抗氧化剂BHA、TBHQ、茶多酚、BHA与柠檬酸或EDTA二钠螯合剂混合使用对CTCBE均具有一定的抗氧化作用，能延长诱导期，抑制过氧化值升高，尤以BHA的功效最好。试验结果还表明，采用金属螯合剂与抗氧化剂配伍，能增强抗氧化剂的作用效果。     

乌桕类可可脂及可可脂氧化稳定特性之形态学研究

乌桕类可可脂(简称CTCBE)可替代天然可可脂用于制作巧克力，口感好，但容易被氧化。氧化稳定特性之形态学研究中扫描电镜(SEM)结果表明：CTCBE形态结构特征为排列中存在许多细微的孔洞，增大了CTCBE与O2作用比表面积，且有利于O2向CTCBE的界面扩散，进入CTCBE内部进行氧化。而天然可可脂(CB)的组织排列结构致密，可以产生一种天然物理屏障阻止O2渗入CB固体内部。这是CTCBE氧化稳定性差。而CB氧化稳定性极其高的一个重要原因。     

蛋白质抗巧克力霜花机理研究(Ⅰ)

选用具有一定意义的植物蛋白（茶叶、大豆）、动物蛋白（明胶、酪蛋白）、食用菌蛋白（香菇），在同等条件下与空白进行平行对比实验。将上述几种蛋白质分别以不同添加量加于类可可脂巧克力酱料中，用ＮＤＪ－７９型粘度计测其粘度物变化大小；将添加了各种蛋白质的巧克力经２０℃循环３０℃促霜实验后，比较各种蛋白南的抑霜能力，结果表明：各种蛋白质与巧克力酱料间交互作用都很显著，而不同蛋白质与酱料间交互作用及抗霜效果却明     

乌桕类可可脂及其巧克力结晶性质的研究(Ⅰ)

研究乌桕类可可脂结晶及其巧克力结晶性质的关系,揭示乌桕类可可脂巧克力加工性能差的原因。采用分光光度法、差示扫描量热法、粘度法研究乌桕类可可脂和天然可可脂及其巧克力的结晶、固化过程,探讨添加茶叶粉生物乳化剂对改善乌桕类可可脂巧克力加工性能的影响。研究表明乌桕类可可脂结晶固化速率比天然可可脂快,而乌桕类可可脂巧克力结晶速率较天然可可脂巧克力快得多。添加5%～8%茶叶粉不仅改善乌桕类可可脂巧克力加工性能,而且能提高巧克力的热稳定性和抗霜花能力。     

Rapid instrumental methods and chemometrics for the determination of pre‐crystallization in chocolate

Three rapid instrumental methods for the determination of the pre‐crystallization stage in six types of chocolate were studied. The methods were near‐infrared (NIR) spectroscopy, fluorescence spectroscopy and tri stimulus colour measurements. The chocolates were tempered into five categories: two levels of under‐tempered, two levels of over‐tempered and one level of well‐tempered chocolate. A temper meter was used as the reference method. NIR and fluorescence data were orthogonalized before modelling in order to remove the chocolate type characteristics. NIR spectroscopy was capable of discriminating between the five tempering groups when the principal component analysis (PCA) model was used on all chocolate types. A partial least squares discriminant analysis on the NIR spectra with the three main tempering groups (over‐, well‐, and under‐tempered) as the dependent variable showed perfect separation of the groups. Using fluorescence spectroscopy it was possible to separate the chocolates into the three main tempering groups in a PCA model, while the colour measurements did not reflect the degree of pre‐crystallization.     

Enzymatically Modified Beef Tallow as a Substitute for Cocoa Butter

ABSTRACT: Dark "chocolate" samples were formulated with either cocoa butter (CB), randomized tallow (RT) made with Candida antarctica (SP 435) lipase, or a beef tallow: stearic acid structured lipid (SL) made by acidolysis using Rhizomucor miehei (IM 60) lipase. Fatty acid composition, thermal profile, solid fat content (SFC), hardness, and polymorphic structure were determined for the fats and/or "chocolate" samples. An accelerated fat bloom study was performed on the "chocolate" samples. Neither of the modified tallows had a detrimental effect on the crystallization of CB after proper tempering of the "chocolates." RT did not soften the "chocolate" and both of the modified lipids reduced bloom rates.     

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。     

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.     

Modelling tempering behaviour of dark chocolates from varying particle size distribution and fat content using response surface methodology

Central Composite Rotatable Design (CCRD) for K = 2 was used to study the combined effects of multi-stage heat exchangers for Stages 1 (14–30 °C) and 2 (12–28 °C) coolant temperatures at constant Stage 3 coolant and holding temperatures during tempering of dark chocolates using laboratory-scale mini-temperer. Quantitative data on chocolate temper index (slope) were obtained for products with varying particle size distribution (PSD) (D₉₀ of 18, 25, 35 and 50 μm) and fat (30% and 35%) content. Regression models generated using stepwise regression analyses were used to plot response surface curves, to study the tempering behaviour of products. The results showed that both Stage 1 and Stage 2 coolant temperatures had significant linear and quadratic effects on the crystallization behaviour causing wide variations in chocolate temper index during tempering of products with variable PSD and fat content. Differences in fat content exerted the greatest variability in temperature settings of the different zones for attaining well-tempered products. At 35% fat content, changes in PSD caused only slight and insignificant effect on tempering behaviour. No unique set of conditions was found to achieve good temper in dark chocolate with a specified tempering unit. Thus, different combinations of temperatures could be employed between the multi-stage heat exchangers to induce nucleation and growth of stable fat crystal polymorphs during tempering. Variations in tempering outcomes of the dark chocolates were dependent more on the fat content than PSD.

Industrial relevance

Tempering consists of shearing chocolate mass at controlled temperatures to promote cocoa butter crystallization in a stable polymorphic form. During industrial processing, multi-stage heat exchangers are used to control temperature adjustments to promote formation of appropriate stable polymorphic crystals to obtain products with good snap, colour, contraction, gloss and shelf life characteristics. The process employs varying time–temperature throughputs of the multi-stage units making it difficult to obtain standard tempering conditions for products with variable particle sizes and fat content, thus prolonging equipment standardization periods with consequential effects on processing times and product quality characteristics. Modelling the tempering behaviour of dark chocolates from varying PSD and fat content would enhance our knowledge and understanding on the optimal temperature conditions for obtaining good tempered products during industrial manufacture, with significance for reducing processing (tempering) times and assurances in quality and shelf characteristics.     

Monitoring Tempered Dark Chocolate Using Ultrasonic Spectrometry

Ultrasonic spectrometry was used to distinguish between properly tempered and untempered commercial dark chocolate. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to characterize the polymorphic state of tempered and untempered chocolate, results that were correlated to those of ultrasonic spectrometry. Four different kinds of dark chocolate samples with different amounts of sugar (7.5–50 %), fat (30–50 %), and cocoa mass (70–90 %) were subjected to two different tempering protocols. The tempering was achieved using cocoa butter seeds under static cooling from 50 to 14 °C. The ultrasonic generator and analyzer SIA-7 (V.N. Instruments) was used to monitor the crystallization process. The instrument generated a chirp signal with a bandwidth of 0.5 to 3 MHz and was set to work in a four-pathway configuration with two transducers and a center frequency of 2.25 MHz. Spectrometric analysis was carried out with chocolate samples containing 2, 4, and 6 % solid fat content (SFC). The SFC was obtained from DSC measurements. Ultrasonic signals for attenuation, reflection, and velocity were compared between tempered and untempered chocolates. It was shown that seed-tempered chocolate with 30 % sugar and 47.5 % fat attenuated 2.5 MHz of ultrasonic waves by 0.8, 1.7, and 2.0 dB/cm at 2, 4, and 6 % SFC, respectively. On the other hand, untempered chocolate attenuated the ultrasound signal by 3.5, 3.6, and 4.3 dB/cm. Furthermore, it was found that ultrasound reflection signals were stronger and ultrasonic velocity was higher in chocolates with high sugar content.