Introduction to Cacao Research

Introduction

Theobroma cocoa, named in Latin “the fruit of the Gods” is an antioxidant rich food, containing predominantly catechin, epi-catechin and polycyanidin flavonoids (Adamson et al., 1999). Cocoa’s Oxygen Radical Antioxidant Capacity (ORAC) values have gained interest, due to their relatively higher levels than that of other anti-oxidant rich foods, such as tea, wine, grapes and Goji berries (Williams, Tamburic & Lally, 2009). The ORAC values of cocoa; however, are determined according to fermented, roasted and processed cocao, in the form of cocoa powder and cocoa butter (Seligson, Krummel commonly consumed in the form of chocolate powder, chocolate candy and chocolate confectionery.

Flavonoid-rich cocoa products and chocolate consumption have been demonstrated to improve endothelial functioning which has been directly related to cocoa’s flavonoid procyanidins (Wang-Polagruto et al., 2007). Although research on the antioxidant related health benefits of cocoa has been studied (Farhat, Drummond, Fyfe & Al-Dujaili, 2013; Massolt et al., 2010); only one study has been published comparing the direct effect of dark and milk chocolate consumption and appetite suppression (Sorensen & Astrup, 2011). Results showed that participants were more satiated, less hungry when reporting, and consumed less when eating dark chocolate instead of milk chocolate. After adjusting for the energy difference of the dark chocolate, the energy intake was reported to still be 8% lower than milk chocolate (Sorensen & Astrup, 2011). From this study, one can interpret that higher cocoa mass leads to increased appetite suppression. This study however, not only based their findings on processed cocoa powder byproducts, chocolate bars, but in addition the study did not draw a direct relationship between the level of flavonoids present and appetite suppression (Sorensen & Astrup, 2011).

This study proposes to fill in the gap in research on cocoa flavonoid consumption and appetite suppression through the consumption of unprocessed cacao products. Literature has established the decrease in flavonoids with cocoa processing (Tomas-Barberán et al., 2007) and the less processed raw cacao can be expected to have higher levels of flavonoids than processed cocoa. A randomized, crossover study of appetite suppression caused by the controlled consumption of either processed cocoa beverage and raw cacao beverage will be researched. This research aims to provide valuable information relating to cocoa’s antioxidant related appetite suppression effects between chocolate products made from i) processed cocoa and ii) non-processed/raw cacao.

Literature Review

Chocolate originates from cacao beans, the fatty seeds of the fruit, Theobroma cacao, producing cacao or cocoa solids and cocoa butter. Cacao beans are from a 4-6m high tree grown in South America (Ecuador, Colombia, Brazil, Venezuela,a and Guiana) Central America, the West Indies, West Africa (Nigeria and Ghana), Ceylan and Java. (Ensminger et al., 1995). Theobroma cacao can be found in two main forms today: processed cocoa and raw cacao. These two forms differ in the amount of processing done on the cacao plant in order to achieve the byproduct. As mentioned above, the cacao fruit produces cacao or cocoa, one of the highest antioxidant foods, seen in Table 1 below. This proposed study proposes to investigate the appetite suppression of the second noted form: unprocessed raw cacao products. 📷

Table 1: “Top Antioxidant Foods”

(Kelishadi, 2010)

The cocoa fruits are collected during spring and autumn, as the largest quantities are produced then. Research shows that the country of origin of the bean, the time harvested and the harvesting process affect cocoa bean antioxidant levels (Asami, Hong, Barrett & Mitchell, 2003) The fruits have a thick rind with pulp in which the cocoa beans are embedded. The bean contents vary; however, the cocoa bean generally contains 35-50% oil, 15% starch, 15% protein, 1 to 4% theobromine, and 0.07 to 0.36 % caffeine. (Bailly et al., 2001). Theobromine, is the principle alkaloid in the cacao bean, and is used pharmaceutically as a bronchodilator and vasodilator, with a weak stimulant effect on the nervous system similar to the effect of caffeine (Blauch & Tarka, 1983). Although preparation methods of the cocoa bean may vary, the generalized method to prepare the fruit, is to open the pulp, and extract the seeds for the fermentation process. The fermentation of the seeds occur for 3-9 days in large tubs, boxes or cavities at a temperature never above 60°C (Kelishadi, 2010). It is important to note that the referred “raw” cacao products are fermented at a relatively high temperature 60°C, yet are not roasted (Kelishadi, 2010).

This fermentation process allows a liquid to be drawn from the cocoa seeds, changing from white/red to purple color, and changes in odor and taste are noted. Following fermentation, the roasting of cocoa beans occur with the original liquid content of bean. The roasting of the beans occur at 100-140°C, aiming to decrease the total liquid and acetic acid content of the beans (Kelishadi, 2010). Fermentation, alike roasting allows for a change in taste and odor. The cocoa seeds are cooled and dried, with the original liquid dehydrated during the drying process, then the seeds are removed from their husks by winnowing (Ensminger et al., 1995, as quoted in Kelishadi, 2010).

In comparison to the raw, unprocessed cocoa fruit, the fermented and roasted cocoa kernels and husks contain less theobromine, caffeine, and cocoa butter (Kelishadi, 2010). The cacao seeds constitute the nibs and husk (surrounding the nibs) and the nibs are enclosed in the husk, with the majority of the nutrients. The chocolate liquor is formed by grinding the roasted and cracked cocoa bean, but requires high pressure to extract the cocoa butter and result with cocoa butter and powder byproducts (Kelishadi, 2010). Interestingly enough, for processed chocolate products, this extracted cocoa butter, is actually added during the making of chocolate (Kelishadi, 2010). Chocolate products are usually a combination of sugar, cocoa butter, flavors, and today, emulsifiers and/or taste enhancers (Afoakwa, Paterson & Fowler, 2007; Miller et al., 2006).

Therefore, in the consumption of chocolate products, there is a main difference between raw and processed cocoa chocolate products. First, whereas raw cacao beans are only slightly fermented (depending on the cocoa bean’s source), and not roasted, processed cocoa beans are fully roasted, a process initially done to intensify flavor and protect against mold growth on the beans (Hansen & Welty, 1971). This extended roasting and additional roasting process, can be responsible for a change in the antioxidant properties of the bean (Rohan & Stewart, 1966). Secondly, differences occur in the chocolate making process, where raw cacao products are made primarily with the bean itself, with the cocoa butter not being separated and then re-added with high heat and pulverizing, processed chocolate products are made by extended heating and pulverizing methods. This process of separating the cocoa butter, by grinding and further roasting, then pulverizing not only can be responsible for lowering the antioxidant values, (Rohan & Stewart, 1966).

Cocoa contains the following identified chemical compounds: procyanidin dimer, epicatechin, and catechin components with antioxidant activity (Holt et al., 2002). The flavonoids in theobroma cacao, epi-catechin, catechin and polycanidin levels, have been shown to be sensitive to heat destruction (Kowalski & Shofran, 2015). Research shows the alkaline treatment of Dutch processing of cacao to cocoa solids has resulted in 38% to 86% flavonoid content depreciation (Preedy, 2015). In addition to Dutch Processing, non-alkaline treated but roasted cocoa processing has shown to cause significant flavonoid depreciation with roasting (Chin, Miller, Payne, Hurst & Stuart, 2013). Contradictions in research state that roasted natural cocoa products result in decreased, yet insignificant, flavonoid content (Hurst et al., 2011).

Research exists to suggest that the consumption of higher amounts of cocoa, can lead to appetite suppression. A total of 16 young, healthy, normal-weight men participated in a randomized, crossover study (Sorensen & Astrup, 2011). The participants were administered either 100 g of milk (30% cocoa) (2285 kJ) or dark chocolate (70% cocoa) (2502 kJ). Following this, participant appetite suppression was recorded with visual-analogue scales before and after the test meal, and for every thirty minutes for five hours thereafter.Research states that the flavanoid content of cocoa is dependent on appetite suppression (Sorensen & Astrup, 2011); therefore, we can speculate that it is the flavonoid content of the chocolate in the study and cocoa beverages in the present human trial study which is responsible for appetite suppression. We may be able to speculate that the flavonoid content may be responsible for the appetite suppressant effect of cocoa.

Cacao and cocoa’s stimulant effects are responsible for cocoa’s appetite suppresant qualities, cocoa’s levels are comparably lower than coffee or tea. Caffeine has been identified as an appetite suppressant, through research, such as green tea extract and post-ingestion levels (Belza et al., 2007). However, cocoa products’ theobromine (acting as a stimulant) and caffeine levels are lower on average than other products. Food analysis shows that commercial cocoas contained, on average, 1.89% theobromine and 0.21% caffeine; sweet chocolate 0.46% theobromine and 0.07% caffeine, while milk chocolate 0.15% theobromine and 0.02% caffeine (Zoumas, 2006). A study comparing the caffeine and theobromine levels of tea and coffee determined that caffeine is highest in coffee, tea and cocoa in descending order, in addition, theobromine is highest in cocoa products than tea, and not present in coffee (Blauch & Tarka, 2006). Caffeine contents ranged from 32.4–35.0 mg/cup in instant tea, 30.2–67.4 mg/cup in bag tea, 1.0–7.8 mg/cup in instant hot cocoa mixes, 46.7–67.6 mg/cup in instant coffee, and 93.0–163.5 mg/cup in ground coffee (Blauch & Tarka, 2006). In addition, Theobromine levels ranged from 1.4–2.3 mg/cup in instant tea, 1.2–4.4 mg/cup in bag tea, and 39.5–79.5 mg/cup in instant hot cocoa mixes (Blauch & Tarka, 2006). Therefore, in review the average levels of caffeine and theobromine are relatively lower than that of coffee and tea, and therefore, cocoa products may not be regarded as strong appetite suppresants in regards to their stimulant levels.

This research paper aims to investigate the gap between the degree of appetite suppression with the level of processing of the cocoa bean. Consuming cocoa products that are made from raw cacao, instead of processed cocoa, contain higher cocoa antioxidant levels (Kelishadi, 2010). Therefore, one would expect higher effects of the antioxidant effects, studied to be naturally found in cacoa products, such as lowering leukotriene/prostacyclin ratio, inhibiting low-density lipoprotein (LDL) oxidation, raising high-density lipoproteins (HDL) levels, reducing thrombotic tendencies, increased processing of nitric oxide, lessening of anxiety, promotion of relaxation and triggering of endorphins. This research chooses to focus on appetite suppression alone, to understand if this effect of appetite suppression is linked to cocoa’s antioxidant levels, and to understand the significance of the change in their effects between raw and processed cocoa byproducts.

Hypothesis

Do unprocessed raw cacao products more effective as an appetite suppressant in comparison to processed cocoa products?

The study aims to investigate the appetite suppressant difference between processed and unprocessed cocoa bean products. The processed cocoa bean products have considerably lower levels of antioxidant than processed cocoa products (Adamson et al., 1999). The antioxidants in cocoa bean are present in the cocoa byproducts of cacao or cocoa powder and fat, which are present in the chocolate consumed (Adamson et al., 1999). The higher temperature and extended processing of the roasting of the cacao beans to cocoa beans has been shown to decrease antioxidant levels in cocoa (Adamson). Sorensen & Astrup’s (2011) study showed a decrease in appetite suppressant effects of cocoa as the cocoa mass decreased. Therefore, this study suggests that cocoa products with equally high percentages of cocoa products in either cocoa or cacao form will have different levels of antioxidant levels and therefore different levels of working as an appetite suppressant. This study suggests that the processing of the cocoa bean destroys levels of antioxidants in the cocoa bean, which therefore, lead to decreased appetite suppressant effects of the cocoa bean.

References

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