CHOCOLATE SCIENCE AND TECHNOLOGY This second edition provides information on recent advances in the science and technology of chocolate manufacture and the entire international cocoa industry. It provides detailed reviews of a wide range of topics, including cocoa production, cocoa and chocolate manufacturing operations, sensory perception of chocolate quality, flavour release and perception, sugar replacement and alternative sweetening solutions in chocolate production, industrial manufacture of sugar-free chocolates and the nutrition and health benefits of cocoa and chocolate consumption. The topics cover modern cocoa cultivation and production practices with special attention to cocoa bean composition, genotypic variations in the bean, post-harvest pretreatments, fermentation and drying processes and the biochemical basis of these operations. The scientific principles behind industrial chocolate manufacture are outlined, with detailed explanations of the various stages of chocolate manufacturing, including mixing, refining, conching and tempering. Other topics covered include the chemistry of flavour formation and development during cocoa processing and chocolate manufacture; volatile flavour compounds and their characteristics and identification; sensory descriptions and character; and flavour release and perception in chocolate. The nutritional and health benefits of cocoa and chocolate consumption and the application of HACCP and other food safety management systems such as ISO 22000 in the chocolate processing industry are also addressed. Additionally, detailed research on the influence of different raw …
Flavor formation and character in cocoa and chocolate: a critical review
Chocolate characters not only originate in flavor precursors present in cocoa beans, but are generated during post-harvest treatments and transformed into desirable odor notes in the manufacturing processes. Complex biochemical modifications of bean constituents are further altered by thermal reactions in roasting and conching and in alkalization. However, the extent to which the inherent bean constituents from the cocoa genotype, environmental factors, post-harvest treatment, and processing technologies influence chocolate flavor formation and relationships with final flavor quality, has not been clear. With increasing speciality niche products in chocolate confectionery, greater understanding of factors contributing to the variations in flavor character would have significant commercial implications.
Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Angela Ryan
Factors influencing rheological and textural qualities in chocolate–a review
Chocolate, a complex emulsion, is a luxury food that during consumption evokes a range of stimuli that activate pleasure centres of the human brain. Central to chocolate quality is an appropriate melting behaviour so that products are solid at ambient temperature and on ingestion melt to undergo dissolution in oral saliva, with a final assessment of texture after phase inversion. Particle size distribution and ingredient composition play important roles in shaping its rheological behaviour and sensory perception but are poorly understood. With opportunities for improvements in quality possible through improved and more transparent supply chain management, plant breeding strategies and new product development, associated with fair trade and development of niche premium quality products, there is a need for greater understanding of variables.
Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler
Factors influencing quality variation in cocoa (Theobroma cacao) bean flavour profile—A review
This review examined the factors that influence flavour volatiles of cocoa beans and the volume of work that needs to be done on these factors and their impact on the flavour volatiles of commercial cocoa beans. Cocoa bean flavour is one of the most important quality attributes as flavour is central to acceptability of cocoa beans and cocoa products such as chocolate. The complex composition of cocoa bean flavour depends on bean genotype, postharvest treatments such as pulp pre-conditioning, fermentation and drying, industrial processes such as roasting as well as the type of soil and age of cocoa tree. The bean genotype determines the chemical composition of the bean, specifically the contents of bean storage proteins, polysaccharides, and polyphenols. This determines the quantities and type of precursors formed during fermentation and drying processes leading to flavour formation, hence, influencing both …
John Edem Kongor, Michael Hinneh, Davy Van de Walle, Emmanuel Ohene Afoakwa, Pascal Boeckx, Koen Dewettinck
Effects of particle size distribution and composition on rheological properties of dark chocolate
Control of chocolate viscosity is vital to its quality and production cost, and directly influenced by solids particle size distribution (PSD) and composition. Effects of PSD and composition on rheological properties of molten dark chocolate were investigated by varying PSD [D90 (90% finer than this size) of 18, 25, 35 and 50 μm], fat 25, 30 and 35% and lecithin (0.3 and 0.5%) using a shear rate-controlled rheometer. PSD, fat and lecithin content significantly affected all rheological parameters, with significant interaction among factors. Increasing particles size gave significant reductions in Casson plastic viscosity, Casson yield value, yield stress, apparent viscosity and thixotropy, with greatest effect with 25% fat and 0.3% lecithin, which reduced with increasing fat and lecithin contents. Statistical analysis revealed that fat exerts the greatest effect on the variability in all the rheological properties followed by PSD …
Chemical composition and physical quality characteristics of Ghanaian cocoa beans as affected by pulp pre-conditioning and fermentation
Investigations were conducted to evaluate the effects of pod storage (as a means of pulp preconditioning) and fermentation on the chemical composition and physical characteristics of Ghanaian cocoa beans. A 4× 2 full factorial design with factors as pod storage (0, 7, 14, 21 days) and cocoa treatment (fermented and unfermented) were conducted. Samples were analyzed for their chemical composition (moisture, crude fat, crude protein, ash and carbohydrate content) and mineral content using standard analytical methods. The physical qualities of the beans were analyzed for their proportions of cocoa nibs, shells and germ. Fermentation and increasing pod storage resulted in significant (P< 0.05) decreases in ash (3.48–2.92%), protein (21.63–17.62%) and fat (55.21–50.40%) content of the beans while carbohydrate content increased from 15.47% to 24.93% with both treatments. As well, increasing pod storage ...
Emmanuel Ohene Afoakwa, Jennifer Quao, Jemmy Takrama, Agnes Simpson Budu, Firibu Kwesi Saalia
Matrix effects on flavour volatiles release in dark chocolates varying in particle size distribution and fat content using GC–mass spectrometry and GC–olfactometry
Influences of matrix particle size distribution (PSD) (18, 25, 35 and 50μm) and fat content (25%, 30% and 35%) on flavour release of dark chocolate volatiles were quantified by static headspace gas chromatography using GC–MS. Sixty-eight (68) flavour compounds were identified, comprising alcohols, aldehydes, esters, ketones, furans, pyrans, pyrazines, pyridines, pyroles, phenols, pyrones and thiozoles. From GC–olfactometry, 2-methylpropanal, 2-methylbutanal and 3-methylbutanal had chocolate notes. With cocoa/roasted/nutty notes were trimethyl-, tetramethyl-, 2,3-dimethyl-, 2,5-dimethyl-, 3(or 2),5-dimethyl-2(or 3)-ethyl- and 3,5(or 6)-diethyl-2-methylpyrazine and furfuralpyrrole. Compounds with fruity/floral notes included 3,7-dimethyl-1,6-octadien-3-ol and 5-ethenyltetrahydro-R,R,5-trimethyl-cis-2-furanmethanol. Caramel-like, sweet and honey notes were conferred by 2-phenylethanol, phenylacetaldehyde …
Particle size distribution and compositional effects on textural properties and appearance of dark chocolates
Particle size distribution (PSD) and composition in dark chocolate were varied and their effects on textural properties of molten and tempered chocolates determined using a TA.HD Plus Texture Analyzer. Surface colour was evaluated in terms of CIELAB parameters L*, C* and h° using a HunterLab Miniscan Colorimeter. Compositional parameters for particle size distribution were [D90 (>90% finer) of 18μm, 25μm, 35μm and 50μm], fat (25%, 30% and 35%) and lecithin (0.3% and 0.5%) contents. Results showed that PSD, fat and lecithin content significantly (P⩽0.05) influenced the textural parameters with significant interactions among factors. Particle size was inversely correlated with firmness (1235–173g), consistency (50,410–7029gs), cohesiveness (1594–262g), index of viscosity (5737–1099gs) and hardness (7062–5546g) with chocolates containing 25% fat and 0.3% lecithin. With higher fat and lecithin …
Emmanuel Ohene Afoakwa, Alistair Paterson, Mark Fowler, Joselio Vieira
Industrial manufacture of sugar-free chocolates–Applicability of alternative sweeteners and carbohydrate polymers as raw materials in product development
Chocolate is dense suspension of solid particles comprising 60–70% sugar and non-fat cocoa solids. Until recently, it was rarely produced as a sugar-free product due to the multi-functional properties of sweetness, bulkiness and textural characteristics that sugar offers to products. Today's consumers are concerned about the high sugar levels, calories and cariogenicity effects in confectionery products, hence increasing popularity of ‘light’ and ‘sugar-free’ products. Development of sugar-free chocolates is most challenging since all sugar needs to be replaced. In-depth understanding of the applicability of alternative sweeteners and carbohydrate polymers as ingredients in sugar-free chocolate manufacture would therefore have significant industrial applications.
Roger Philip Aidoo, Frédéric Depypere, Emmanuel Ohene Afoakwa, Koen Dewettinck
Chemical composition and quality changes occurring in Dioscorea dumetorum pax tubers after harvest
Studies were conducted on the chemical composition, as well as the biochemical and textural changes, occurring during storage of two cultivars of Dioscorea dumetorum yam tubers. The tubers were harvested and stored under tropical ambient (28°C) and cold room conditions (4°C) for 24, 48 and 72 h. The samples were evaluated for moisture, starch, sugars, fibres and textural properties. Chemical analysis showed no significant differences between the means obtained for moisture, ash, protein, fibre, fat, carbohydrate, calcium, phosphorus, iron, vitamin A and vitamin C contents of the cultivars (white and yellow) studied. During storage, moisture contents decreased by approximately 6–10% after 72 h of harvest due to dehydration. Starch levels declined from 70.5–66.5 g/100 g, while sugars and fibre contents increased slightly in the samples. Textural properties (peak force and curve areas) also increased … Total citations Cited by 194
Emmanuel Ohene Afoakwa, Samuel Sefa-Dedeh