Mycobiota of cocoa: from farm to chocolate

The present work was carried out to study the mycobiota of cocoa beans from farm to chocolate. Four hundred and ninety-four samples were analyzed at various stages of cocoa processing: (i) primary stage at the farm (fermentation, drying, and storage), (ii) secondary stage at processing (testa, nibs, liquor, butter, cake and powder) and (iii) the final chocolate product (dark, milk, white and powdered) collected from retail outlets. Direct plating or dilution plating on Dichloran 18% Glycerol agar were used for cocoa beans and processed product analyses, respectively. Fungi were isolated and identified using different keys of identification. The largest numbers and diversity of fungi were observed in the samples collected at the farm, especially during drying and storage. The species with the highest occurrence among samples were: Absidia corymbifera, Aspergillus sp. nov., A. flavus, Penicillium paneum and yeasts. A total of 1132 potentially toxigenic fungi were isolated from the following species or species groups: A. flavus, Aspergillus parasiticus, Aspergillus nomius, Aspergillus niger group, Aspergillus carbonarius and Aspergillus ochraceus group. The highest percentage of toxigenic fungi was found at the drying and storage stages. The industrial processing reduced the fungal contamination in all fractions and no fungi were found in the final chocolate products. The knowledge of which fungi are dominant at each processing stage of cocoa provides important data about their ecology. This understanding leads to a reduction in fungal spoilage and mycotoxin production in this product.     

Determination of aflatoxins in by-products of industrial processing of cocoa beans

This study has examined the occurrence of aflatoxins in 168 samples of different fractions obtained during the processing of cocoa in manufacturing plants (shell, nibs, mass, butter, cake and powder) using an optimised methodology for cocoa by-products. The method validation was based on selectivity, linearity, limit of detection and recovery. The method was shown to be adequate for use in quantifying the contamination of cocoa by aflatoxins B(1), B(2), G(1) and G(2). Furthermore, the method was easier to use than other methods available in the literature. For aflatoxin extraction from cocoa samples, a methanol-water solution was used, and then immunoaffinity columns were employed for clean-up before the determination by high-performance liquid chromatography. A survey demonstrated a widespread occurrence of aflatoxins in cocoa by-products, although in general the levels of aflatoxins present in the fractions from industrial processing of cocoa were low. A maximum aflatoxin contamination of 13.3 ng g(-1) was found in a nib sample. The lowest contamination levels were found in cocoa butter. Continued monitoring of aflatoxins in cocoa by-products is nevertheless necessary because these toxins have a high toxicity to humans and cocoa is widely consumed by children through cocoa-containing products, like candies.     

Determination of aflatoxins in by-products of industrial processing of cocoa beans

This study has examined the occurrence of aflatoxins in 168 samples of different fractions obtained during the processing of cocoa in manufacturing plants (shell, nibs, mass, butter, cake and powder) using an optimised methodology for cocoa by-products. The method validation was based on selectivity, linearity, limit of detection and recovery. The method was shown to be adequate for use in quantifying the contamination of cocoa by aflatoxins B₁, B₂, G₁ and G₂. Furthermore, the method was easier to use than other methods available in the literature. For aflatoxin extraction from cocoa samples, a methanol–water solution was used, and then immunoaffinity columns were employed for clean-up before the determination by high-performance liquid chromatography. A survey demonstrated a widespread occurrence of aflatoxins in cocoa by-products, although in general the levels of aflatoxins present in the fractions from industrial processing of cocoa were low. A maximum aflatoxin contamination of 13.3?ng?g^?1 was found in a nib sample. The lowest contamination levels were found in cocoa butter. Continued monitoring of aflatoxins in cocoa by-products is nevertheless necessary because these toxins have a high toxicity to humans and cocoa is widely consumed by children through cocoa-containing products, like candies.     

类可可脂原料油中低熔点甘油三酯的组成、含量调控与综合利用

为了实现类可可脂在巧克力中更为高效的应用,降低其对产品品质的影响,综述了类可可脂原料油中低熔点甘油三酯的组成与熔化性质,概括了不同种类甘油三酯对巧克力霜变行为的作用特征;进一步讨论了控制低熔点甘油三酯含量的技术方法,包括基因工程和分提;最后,总结了经分提获得的低熔点成分的再利用。类可可脂原料油中低熔点甘油三酯可能对巧克力的制造(尤其是调温)和质量控制(如软化、起霜等)产生不利影响。通过分提选择性降低低熔点甘油三酯含量是制备高品质类可可脂的优选路径。     

Structural characteristics of cocoa particles and their effect on the viscosity of reduced fat chocolate

Aimed at the manufacture of reduced fat chocolates, a novel method of trapped fat reduction was assessed: Manipulation of the cocoa ingredient. Cocoa mass was replaced with cocoa powder (11 g/100 g or <1 g/100 g fat) and added ‘free’ cocoa butter. A cocoa solids approach to design reduced fat chocolates with satisfactory flow properties is attractive to industry since it circumvents introduction of ingredients not commonly used in chocolate manufacture. Results showed that the cocoa mass chocolate had a higher viscosity than cocoa powder chocolates of the same total fat content due to the presence of trapped fat globules as identified by confocal laser scanning microscopy. The chocolate prepared with standard defatted cocoa powder containing 11 g/100 g fat had a lower viscosity than the chocolate containing highly defatted cocoa powder (<1 g/100 g) due to particle shape and fat diffusion into the particles as revealed by microscopy analyses. Based on the evidence presented, it can be concluded that standard defatted cocoa powder, as widely used by the industry, is indeed the best compromise in terms of free fat, particle size and morphology attempting to formulate fat reduced chocolate of acceptable molten state viscosity.     

EFFECTS OF CONCHING TIME AND INGREDIENTS ON PREFERENCE OF MILK CHOCOLATE

The objective of this study is to determine how the conching time and the quantity of sucrose, lecithin, cocoa butter and whole milk powder affect consumer preference for milk chocolate. Untrained panelists performed a sensory study consisting of acceptability, preference and attribute intensity. Longer conching time produced significantly smoother chocolate with smaller particle size. The longest conche times had the smallest particle size and were the most mouthcoating. There was no change in flavor with conching. The longer conche times were preferred. Panelists preferred higher sucrose levels, and increasing sucrose decreased bitterness and increased chocolate flavor. Increasing lecithin increased smoothness, but less lecithin was preferred, possibly due to off-flavors at high levels of lecithin. Increasing cocoa butter yielded softer chocolate but did not affect bitterness. Panelists preferred 10% over higher levels of cocoa butter. More milk powder produced smoother chocolate with more caramel flavor and was preferred.

PRACTICAL APPLICATIONS

The perceived quality of milk chocolate is affected by conching time, sucrose, lecithin, cocoa butter and whole milk powder. Texture was affected the most by conching, milk powder, lecithin and cocoa butter. Flavor was affected the most by milk powder and sugar. The only variable that did not affect acceptability and preference of milk chocolate was time for underconched samples. While this study did not determine the optimum conditions for milk chocolate, the most preferred and/or acceptable samples were conched for at least 12 h, had 35 to 50% sucrose, 0–0.5% lecithin, 5–10% cocoa butter and 13–30% milk powder.     

Preservation of Cocoa Antioxidant Activity, Total Polyphenols, Flavan-3-ols, and Procyanidin Content in Foods Prepared with Cocoa Powder

ABSTRACT:  Little is known about the effects of common cooking processes on cocoa flavanols. Antioxidant activity, total polyphenols (TP), flavanol monomers, and procyanidin oligomers were determined in chocolate frosting, a hot cocoa drink, chocolate cookies, and chocolate cake made with natural cocoa powder. Recoveries of antioxidant activity, TP, flavanol monomers, and procyanidins ranged from 86% to over 100% in the chocolate frosting, hot cocoa drink, and chocolate cookies. Losses were greatest in the chocolate cake with recoveries ranging from 5% for epicatechin to 54% for antioxidant activity. The causes of losses in baked chocolate cakes were investigated by exchanging baking soda with baking powder or combinations of the 2 leavening agents. Use of baking soda as a leavening agent was associated with increased pH and darkening color of cakes. Losses of antioxidant activity, TP, flavanol monomers, and procyanidins were associated with an increased extractable pH of the baked cakes. Chocolate cakes made with baking powder for leavening resulted in an average extractable pH of 6.2 with essentially complete retention of antioxidant activity and flavanol content, but with reduced cake heights and lighter cake color. Commercially available chocolate cake mixes had final pHs above 8.3 and contained no detectable monomeric flavanols after baking. These results suggest that baking soda causes an increase in pH and subsequent destruction of flavanol compounds and antioxidant activity. Use of an appropriate leavening agent to moderate the final cake pH to approximately 7.25 or less results in both good leavening and preservation of cocoa flavanols and procyanidins.     

可可脂的结晶特性对巧克力质量的影响

<正> 巧克力的物理性质很大程度上取决于制造过程中所用的可可脂质量,特别是可可脂融化、结晶和固化的方法。以下将对可可脂在巧克力制造过程中的物理与化学特性,以及各种可可脂如何充分地改变巧克力的风味、易碎程度及口感进行讨论。 可可脂的结晶性 晶形的形成 由于可可脂具有复杂的结晶性,可通过多种不同的变性而结晶成多晶型脂肪,正是这些     

The effect of cocoa fermentation and weak organic acids on growth and ochratoxin A production by Aspergillus species

The acidic characteristics of cocoa beans have influence on flavor development in chocolate. Cocoa cotyledons are not naturally acidic, the acidity comes from organic acids produced by the fermentative microorganisms which grow during the processing of cocoa. Different concentrations of these metabolites can be produced according to the fermentation practices adopted in the farms, which could affect the growth and ochratoxin A production by fungi. This work presents two independent experiments carried out to investigate the effect of some fermentation practices on ochratoxin A production by Aspergillus carbonarius in cocoa, and the effect of weak organic acids such as acetic, lactic and citric at different pH values on growth and ochratoxin A production by A. carbonarius and Aspergillus niger in culture media. A statistical difference (ρ<0.05) in the ochratoxin A level in the cured cocoa beans was observed in some fermentation practices adopted. The laboratorial studies demonstrate the influence of organic acids on fungal growth and ochratoxin A production, with differences according to the media pH and the organic acid present. Acetic acid was the most inhibitory acid against A. carbonarius and A. niger. From the point of view of food safety, considering the amount of ochratoxin A produced, fermentation practices should be conducted towards the enhancement of acetic acid, although lactic and citric acids also have an important role in lowering the pH to improve the toxicity of acetic acid.     

Review of cocoa butter and alternative fats for use in chocolate—Part A. Compositional data

This work reviews the literature on the compositional data of vegetable fats used or proposed as alternatives to cocoa butter in chocolate and confectionery products. Cocoa butter is the only continuous phase in chocolate, thus responsible for the dispersion of all other constituents and for the physical behaviour of chocolate. Unique to cocoa butter is its brittleness at room temperature and its quick and complete melting at body temperature. There were, and are, strong efforts to replace cocoa butter in part for chocolate production for technological and economic reasons. Such cocoa butter alternatives are the so-called cocoa butter equivalents (CBEs), cocoa butter substitutes (CBSs) and cocoa butter replacers (CBRs). These are mostly mixtures of various vegetable fats (often modified) and can consist of palm and palm kernel oil, illipé fat, shea butter, sal fat and kokum butter. In addition, a large variety of other vegetable oils can be used. Their composition according to triglycerides, fatty acids, sterols and other unsaponifiable components is discussed in this report.     

Evaluation of the effect of processing on cocoa polyphenols: antiradical activity,anthocyanins and procyanidins profiling from raw beans to chocolate

The content and composition of anthocyanins and procyanidins in fermented cocoa beans (from different geographic origins: Ecuador, Cameroon, Ivory Coast, Ghana and Nigeria), roasted nibs, cocoa mass and chocolate were determined, beside the determination of the total antiradical capacity. Concerning geographic origin, cocoa beans and processed products from Ecuador showed the highest levels of anthocyanins, followed by Nigeria and Cameroon. Generally, as cocoa beans were further processed, the levels of anthocyanins and flavan‐3‐ols decreased. The largest observed losses of phenolics occurred during roasting. A progressive decreasing trend in polyphenol concentration was observed in the other processed samples as well. Despite the original content of polyphenols in raw cocoa beans, technological processes imply a significant impact on cocoa quality, confirming the need of specific optimisation to obtain high value chocolate.     

Technofunctional barrier layers for preventing fat bloom in triple-shot pralines

The storage stability of dark chocolate with nougat fillings is mainly limited by the formation of fat bloom, which arises because of the migration of nut oil from the filling to the outside of the chocolate shell where it leads to the formation of visible cocoa butter crystals. The triple-shot technique, which allows the simultaneous deposition of three viscous fluids, was applied for the laboratory-scale manufacture of pralines with a technofunctional barrier layer to prevent blooming. Base component of the barrier layer was palm kernel oil, pure or in combination with milk fat; micro-milled sugar or skim milk powder served as disperse phase. As compared to control experiments, the formation of fat bloom was significantly reduced for selected barrier layers because of the reduced transfer of nut oil to the outside of the praline shells. These results indicate that triple-shot depositing is a promising technique for the manufacture of filled chocolate with enhanced physical shelf life.     

巧克力香精新典范——可可脂浓缩物

<正> 钟情于巧克力的消费者们所关注的是巧克力的风味和产品所富含的奶油口感。在市场倡导天然健康食品的今天,为达到上述两个质量重点而又能减少产品的脂肪含量,原料供应商便开发出一种称为可可脂浓缩物的配料产品、在提供浓郁芳香口味的同时,能降低生产成本及加工方面所受的限制,也减少了产品的脂肪含量,为巧克力产品生产商及消费者带来了佳音。 风味质感来源 浓郁的巧克力香味基本上取决于可可豆中香味物质正确的平衡比例,这是因为某些香味特征只来自可可固体物,部分则来自可可豆的脂肪中,而来自可可固体物的香味又比来自可可脂肪的最     

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。     

Analysis and occurrence of deoxynivalenol (DON) in cocoa

The primary objective of this study was to establish a current situation assessment of the possible occurrence of deoxynivalenol in cocoa and cocoa products. Since there was no analytic method for determining DON in cocoa and cocoa products, a special method was developed. The applicability and consistency of the method was confirmed by performing recovery assays on various cocoa products. A special post-column derivatisation procedure was used to increase selectivity and raise sensitivity by a factor of 80. The method’s limit of detection (LOD) was thereby reduced to 7 μg/kg; the limit of quantification (LOQ) was 14 μg/kg. The method was used to test 230 samples for possible DON content, ranging from cocoa beans to cocoa bean shells, nibs, cocoa liquor and cocoa powders through to finished cocoa-based products. In the case of cocoa beans and cocoa bean shells, DON content close to the detection limit was only determined in isolated cases. No DON content was detected in nibs, cocoa liquor, cocoa powders and finished cocoa-based products. Analogous to ochratoxin A and aflatoxins, the results show DON is more likely to be found in cocoa bean shells. Separation of shells during cocoa processing can reduce potential DON contents. Since no DON was determined in the fractions relevant for chocolate production, these assays show it does not represent a considerable issue for the cocoa and chocolate industry.     

Occurrence of ochratoxin A in cocoa beans: Effect of shelling

The aim of this study was to investigate the influence of the shelling process on the presence of ochratoxin A (OTA) in cocoa samples. Twenty-two cocoa samples were analysed for the determination of OTA before (cocoa bean) and after undergoing manual shelling process (cocoa nib). In order to determine OTA contamination in cocoa samples, a validated high-performance liquid chromatography (HPLC) method with fluorescence detection was used for the quantitative analysis of ochratoxin A (OTA). In both types of samples, OTA was extracted with methanol-3% sodium hydrogen carbonate solution and then purified using immunoaffinity columns prior to HPLC analysis. Due to the fact that different recovery values were obtained for OTA from both types of samples, a revalidation of the method in the case of cocoa nibs was needed. Revalidation was based on the following criteria: Selectivity, limits of detection and quantification (0.03 and 0.1 µg kg^-1, respectively), precision (within-day and between-day variability) and recovery 84.2% (RSD = 7.1%), and uncertainty (30%). Fourteen of the twenty-two cocoa bean samples (64%) suffered a loss of OTA of more than 95% due to shelling, six samples suffered a loss of OTA in the range 65-95%, and only one sample presented a reduction of less than 50%. The principal conclusion derived from this study is that OTA contamination in cocoa beans is concentrated in the shell; therefore, improvements of the industrial shelling process could prevent OTA occurrence in cocoa final products.     

Solid Fat Content,Pre-Crystallization Conditions,and Sensory Quality of Chocolate with Addition of Cocoa Butter Analogues

The objective of this study was to determine how the addition of two cocoa butter equivalents and cocoa butter improver affect the physical and sensory properties of chocolate. The laboratory-made chocolate samples were tempered at three different pre-crystallization temperatures (25, 27, and 29°C), using different concentrations (3, 5, and 7%) of two commercial cocoa butter equivalents as well as commercial cocoa butter improver of the chocolate. The nucleation time of the chocolate mass primarly depended on pre-crystallization temperature while the value of maximum torque of chocolate mass were influenced by both, pre-crystallization temperature and concentration of fats. Sensory evaluation revealed that cocoa butter equivalents were acceptable in chocolate formulation without producing a negative impact on the sensory quality, while usage of improver required adjustment of raw formulations or process parameters. The results of the instrumentally measured hardness revealed that addition of cocoa butter improver significantly (p > 0.05) increased hardness of chocolate samples.     

Inhibitory Effect of Chocolate Components Toward Lard Detection in Chocolate Using Real Time PCR

An identification method of lard in chocolates using real-time polymerase chain reaction was developed to address Halal authentication. However, polymerase chain reaction detection of lard in chocolate has been in vain. In order to investigate the inhibitory effect exerted by each of the chocolate components, four basic chocolate components, sugar, milk powder, cocoa butter, and cocoa powder, were adulterated with lard and examined using porcine-specific real-time polymerase chain reaction assay. The results discovered cocoa powder, as the only component that prevents DNA extraction of lard in chocolate. No substantial polymerase chain reaction inhibition was detected, and thus confirms the cocoa powder’s inhibition on DNA extraction of lard from lard-adulterated chocolate. This finding will expedite new research to develop a method to dissociate the lard from the lard-cocoa powder complex, which will have high potential to be applied as a pre-treatment of the chocolate prior to the DNA extraction and polymerase chain reaction.     

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.     

彩色花生巧克力豆加工工艺技术及设备

本文介绍了制作花生巧克力所需设备以及设备的基本工作原理、构造和使用方法;探讨了彩色巧克力豆制作过程的工艺条件和配方。采用巧克力花生豆成套设备,以花生为芯料,可可粉、可可脂、糖粉、卵磷脂、色素和抛光剂按一定的比例,可制作出来色泽光亮、营养丰富、风味独特的花生巧克力豆。