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Table 7.1 Changes of sugar content in shell-free cocoa bean during fermentation.

Days of fermentation Sucrose Berbert (3)

6 0.7 * Totals include other minor sugars not designated.

Fructose

  1. 09 0.16 0.54 0.54
  2. 1 0.12 0.40 0.39

Glucose

  1. 07 0.04 0.49 0.12
  2. 30 0.31 0.67 0.64

Total

  1. 74* 1.49* 1.20* 0.80*
  2. 05 2.04 2.23 1.73

Reineccius et al. (2) suggest that the sugars are absorbed from the pulp during fermentation. During roasting, most of the reducing sugars disappear and non-reducing sugars decrease as well (5).

Starch

Schmieder and Keeney (6) reported a mean value of 5.30% starch (4.57.0%) for 12 lots of cocoa beans (including shell) representing major geographic regions of production (Table 7.2). The mean particle size of starch was of 4.6 ^m with a range of 2.012.5 ^m, with 36% amylose. Two variables, which might affect the final starch content of cocoa beans, are fruit ripeness at harvesting and fermentation process. Starch in cocoa beans increased progressively from 4.3% to 6.8% between 4.5 months and 5.0 months, but then decreased to 6.3% at 5.5 months when pods were harvested.

Reduction of starch content does not mean it was consumed or synthesis stopped. More likely is that other constituents were accumulated at a faster rate.

Table 7.2 Starch content of cocoa beans representing regions of production. Cocoa bean source % starch in whole dry bean including shells

Ghana

7.00; 5.80

Bahia

4.78; 4.86

Samoa

4.77

Ecuador

5.51; 5.08

Venezuela

4.66; 5.63

Jamaica

4.50

Trinidad

4.77; 6.02

Source: Schmieder and Keeney (6).

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Depending upon growing conditions, synthesis of fat is especially pronounced during this period (7). Analysis of samples from a fermentation trial in Brazil revealed a gradual increase in starch content of cocoa bean throughout the fermentation. At the start, 5.5% of the bean solids was starch; after 6 days when fermentation was concluded, starch accounted for 6.5% of the solid content. The apparent increase in starch content involves the loss of soluble, non-starch solids through exudation, sweating and sugar fermentation, as shown above.

Geilinger et al. (8) found 8.4% of starch in cocoa liquor. The egg-shaped starch granules have a mean size of 4.4 ^m, ranging from 1.58 ^m, an amylose content of 30.4% and a gelatinization temperature range of 5368°C. In another lot of cocoa mass from Ghana, they found 6.4% starch in fermented beans (9). No change occurred during roasting and diverse preparations of the cocoa mass.

Data for starch analysed in various commercial products are shown in Table 7.3. When starch content was expressed as starch per unit of cocoa mass, values were quite similar. This indicates that manufacturing processes employed in making these products did not alter the amount of cocoa starch present in cocoa beans. There is no information on the digestibility of starch in roasted beans.

Table 7.3 Starch content. Product Regular cocoa

Dutched cocoa

Regular chocolate liquor

Dutched chocolate liquor

Dark, sweet chocolate

Milk chocolate (a)

Milk chocolate (b)

Source: Schmieder and Keeney (6)

Fibre

The dietary fibre (DF) fraction in a foodstuff is that part regarded as indigestible or resistant to the action of human digestive enzymes (10). Various methods have been developed and applied, and in the case of cocoa, very different data were obtained. Valiente et al. (11) found 17.8% and 16.1% DF in raw and roasted cocoa bean, respectively, using the method according to Prosky et al. (12). Approximately 20% of DF is soluble. Roasting, however, almost doubled the content of klason lignin from 4.4% in raw bean to 8.5% in roasted product due to formation of Maillard browning products, which are insoluble in the 72% sulphuric acid used for the lignin isolation (13). Bartolomé et al. (14), using the same procedure, found in defatted nib 7.8% soluble dietary fibre (SDF) and 42.2% insoluble dietary fibre (IDF), after deduction of the residual protein, which

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% starch % starch in cocoa mass (non-fat)

18.6

16.3

accounted for 14% of IDF. This represents roughly 22.5% DF in cocoa nib. Cocoa bean contains also significant amount of polyphenols (5.9%, expressed as tannic acid), but very little has been found in the fibre fractions (0.2% in SDF and 1.6% in IDF).

Geilinger et al. (9) determined the dietary fibre content using the neutral detergent method (15) and found 9.1% in fermented cocoa bean, 12.0% after roasting, and 12.115.4% in cocoa mass. This increase of apparent fibre during roasting and processing of the beans was probably due to condensation reactions between protein and polyphenols

(16). These fibre contents are, however, lower than the value reported elsewhere, in part because it does not take into account the soluble fibre fraction.

Sugars in Chocolate

The main carbohydrate present in chocolate is normally sucrose, and lactose in milk chocolate. Nutritive carbohydrate sweeteners (including sucrose) are permitted for use in chocolate products in the USA, under Food and Drug Authority (FDA) Standards of Identity, section 163 of CFR Title 21. In Europe, sucrose may also be present up to 55% in accordance with the EC directive on cocoa and chocolate products and consequential national legislation

(17), although typically it is present at about 45%. Glucose syrups are not normally used in the manufacture of chocolate and indeed can create great problems in processing if present in more than small amounts, as they cause an increase in the viscosity of the molten chocolate. In plain chocolate, which does not contain milk solids, lactose is not normally included, the only sugar normally used being sucrose, which typically may be present at about 50%.

The use of sugar in chocolate manufacture is vital to provide bulking properties and to offset the bitterness of raw cocoa; it is also essential to chocolate's unique sensory experience. Nonetheless, sugar in our diet has been questioned in regard to the potential for health problems such as obesity, cardiovascular disease and cancer. The reader is directed to chapters in this book dealing specifically with these conditions in respect to chocolate consumption (Chapters 5, 6, 8 and 11). Additionally, the report of a expert consultative body appointed by the World Health Organization/Food and Agriculture Organization (WHO/FAO) to study carbohydrates in human nutrition has recently been released (18). Its findings further reinforce the already strongly held view within the scientific community that properly designed scientific studies have been unable to find any link between sucrose consumption and the prevalence of such chronic diseases.

It is permissible within the EU to use other sugars in chocolate as well as sucrose. Dextrose, fructose, lactose and maltose are specifically permitted up to 5% of the weight of the product without declaration. Dextrose may be incorporated at levels between 5 and 20%, in which case the name of the product has to be accompanied by a declaration of its presence. In Europe,

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