Four sigma foods SCIENCE CACAO BEAN

Four sigma foods SCIENCE CACAO BEAN

2 FSF Science cacao bean CACAO BEAN Theobroma cacao Cacao bean is the seed of the cacao tree (Theobroma cacao). Theobroma cacao is a small but economically important tree. It is an evergreen, 4 8 m tall tree native to forests of Central and South America. Three subspecies are cultivated: Criollo, Forastero and Trinitario (also known as Calabacillo), all of which are interfertile. Trinitario is a hybrid of Criollo and Forastero. The use of cacao seeds to prepare drink was diffused among Aztecs, and Spanish introduced this use in Europe during the 16th century. In 1737 Linnaeus named the cacao tree Theobroma, which means food of the gods. (1-3) Today, the seeds of Theobroma cacao are used to prepare both cacao powder and chocolate. Chocolate is a highly processed form of cacao and although many forms of manufacturing process exist, they fundamentally all have the same basic steps: fermentation, roasting, and milling. When the seeds are fermented the walls of pigment cells break down and they change colour, while the typical chocolate flavour develops. After being dried and roasted, the seeds are ground and processed further to make different cacao products, including cacao powder. (1-4) The story of the biomedical interest on cacao is short, since its association with protective mechanisms only initiates in the nineties. Despite so, these last decades have witnessed the materialization of a huge amount of literature detailing the cacao content of flavanols as well as an array of evidences linking them with different protective pathways. (5) This summary reviews some of the studies made of cacao, showing that cacao with its high amount of flavanols have revealed central antioxidant, anti-inflammatory, and vasodilatory actions as well as anti-cariogenic effect.

3 Composition Each cacao seed contains a significant amount of fat (40 50% as cacao butter) and polyphenols, which make up about 10% of the whole bean s dry weight. The fat contains an average of 33% oleic acid, 25% palmitic acid, and 33% of stearic acid. But the compounds of interest in cacao are flavanols. Flavanols are a subclass of flavonoids, which in turn, are a subclass of the polyphenols. Moreover flavonoids also contain different molecular families like flavonols, flavones, flavanones, and anthocyanidins (see figure 1). The flavanol flavan-3-ol contains the monomers catechin and epichatechin (approximately 35% of the polyphenols) that are natural antioxidants. These flavanols are not specific to cacao, they can also be (1, 4-6) found in specific fruits, teas and red wine, although at lower concentrations. It should be noted that cacao is not only rich in polyphenols, but is also rich in methylxanthines. The main methylxanthines of cacao are theobromine (3.7% on a fat-free basis) and caffeine (about 0.2%). The possible synergistic interactions between flavonoids and methylxanthines are not totally clear and need further study, so the contribution of theobromine in cocoa (3, 4) products towards health benefits should be considered. FSF Science CACAO BEAN Figure 1. Structural skeleton of flavonoids and classification hierarchy of common flavonoids. *Flavanol is the predominate class of flavonoid found in cocoa and chocolate. (6)

4 FSF Science cacao bean Bioavailability of flavanols in cacao The bioavailability of flavanols in cacao depends on the size of the molecule. Bigger molecules have difficulty in being absorbed in the intestine. The smaller molecules, in turn, achieve a higher concentration in plasma, and potentially, a higher biological effect. Thus, it seems likely that the gastric environment has minimal effect on polyphenols and that they transit with minimal modification to the small intestine. The monomers, catechin and epicatechin, achieve micromolar concentrations and are readily adsorbed by the gut into the bloodstream. However, there are differences in the uptake of the catechin enantiomers. This is significant for the consumption of cacao, since the primary catechin enantiomer present in cacao is of the (-) form that is poorly adsorbed. Thus, it would seem that the most bioavailable antioxidant of significance in cacao is (-)-epicatechin. The absorption of monomers in cacao is fast (3, 5) after acute consumption and reaches maximal concentrations in blood by 2 h. The flavanol concentration of fresh cacao is reduced by the manufacturing process, which includes fermentation and roasting. The final concentration of flavanols depends on the treatment given to reduce their characteristic bitterness and to gain consistency. Interestingly, current data on uptake and bioavailability suggests that cacao flavonols can be readily adsorbed regardless of the background of other foodstuffs. Mixing cacao products with common chocolate making materials such as milk powder does not seem to prevent the uptake of (3, 5) epicatechin. Protection against cardiovascular diseases Epidemiological studies of long-term cacao ingestion seem to tally with the shorterterm clinical studies, suggesting that the consumption of certain cacao products have significant clinical benefit. Cacao may, through different mechanisms, protect against cardiovascular diseases (CVD). These mechanisms include antioxidant, antiplatelet and anti-inflammatory effects, as well as possibly increasing high-density lipoprotein (3, 6, 7) (HDL), lowering blood pressure, and improving endothelial function. Antioxidant effect The chemical structure of flavonoids in cacao gives the compound free radical scavenging ability, which means flavonoids may have antioxidant effects. Various studies have confirmed the role of flavanoids as antioxidants in biological systems. Flavanoids in cacao have been shown to exert potent antioxidant effects in vitro assays under artificial oxidative stress as well as increase antioxidant capacity as a part of various cacao feeding trials. Additionally, because lipid soluble flavonoids may intercalate into the membranes of lipoprotein particles, studies have shown flavonoids to decrease lipid peroxidation of

5 FSF Science CACAO BEAN biological membranes. (6) Lettieri-Barbato et al. (8) did a study where they evaluated the in vitro activity and in vivo human response in terms of antioxidant status of two chocolates with different cacao content. High-antioxidant dark chocolate (HADC), with the highest cacao content, displayed a remarkably higher in vitro antioxidant capacity than dark chocolate (DC). In vitro ferric reducing antioxidant power (FRAP) values for HADC and DC were comparable with previous results, showing a higher antioxidant capacity of chocolate than other antioxidantrich foods such as olive oil, blueberries, red wine or green tea. In vivo, both HADC and DC were able to significantly increase plasma antioxidant defences in healthy humans, measured as reducing power. Maximum peak of increase on plasma FRAP occurred at 2 h, in agreement with previous evidences in humans. (8) Antiplatelet effects Current research has shown that a number of components in cacao, particularly catechin and epicatechin, have significant antiplatelet effects, quantitatively similar to that of aspirin. Randomized trials studying platelet activation markers, microparticle formation and primary platelet aggregation as end points have found that daily intake of cacao beverages produces a significant reduction in all these endpoints among healthy volunteers. There

6 FSF Science cacao bean were also significant correlations between the reduction in these end points and the plasma (5, 6) concentrations of catechin and epicatechin. Another study showed that the consumption of cacao reduced the glycoprotein IIb/IIIa expression and both ADP/collagen stimulated and epinephrine/collagen stimulated plateletrelated primary hemostasis, as measured by a platelet function analyzer. (5) Anti-inflammatory effects Cacao polyphenols have also been shown to decrease inflammation via several mechanisms, namely: inhibition of mitogen induced activation of T cells, polyclonal activation of B cells, reduced expression of interleukin-2 (IL-2) messenger RNA, and reduced secretion of IL-2 by T cells. (6) Lowering blood pressure In a meta-analysis of randomized controlled trials in adults done by Taubert et al. (9), diets rich in cacao were associated with statistically significant reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP). The magnitude of the hypotensive effects of cacao is clinically noteworthy; it is in the range that is usually achieved with monotherapy of β-blockers or angiotensin-converting enzyme inhibitors. At the population level, a reduction of 4 to 5 mmhg in SBP and 2 to 3 mmhg in DBP would be expected to substantially reduce the risk of stroke (by about 20%), coronary heart disease (by 10%), and all-cause mortality (by 8%). The blood pressure lowering effects of cacao have a biological basis. In mechanistic studies, cacao extracts have been shown to cause arterial vasodilation by increasing endothelial production of nitric oxide. In clinical studies in healthy subjects, infusion of the nitric oxide synthase inhibitor L-NG - nitroarginine methyl ester (L- NAME) caused doubling of SBP (3, 9) and DBP responses after only 4 days of ingestion of cacao. Some more recent controlled studies have also analyzed the effect of cacao on blood pressure with mixed results. A 12-week placebo-controlled study on prehypertensive volunteers could not detect any protective effect of dark chocolate containing 70% cacao. In another study investigating whether there is a flavanol dose-related effect in individuals with mild hypertension, the investigators found no effect on seated clinic BP, but detected a significant reduction in 24-h SBP, 24-h DBP and mean BP at the highest, 1052 mg/day dose. The effect on overweight individuals was assessed in two studies, which found that the consumption of flavanol-rich cacao lowered both SBP and DBP and attenuated the BP response to exercise, but not to the pre-exercise BP. (5) A vast majority of studies about the effect of stearic acid in cacao, show that stearic acid has beneficial or neutral effects on blood pressures and clotting parameters. It appears unlikely that intake of stearic acid would negatively affect CVD risk through these risk factors. (6)

7 FSF Science CACAO BEAN Photos: Ahoova / Flickr.com Photos: esc.ape(d)/ Flickr.com Photos: A30_Tsitika/ Flickr.com Mental well-being and neuroprotection Flavanols in cacao readily cross the blood-brain barrier via stereoselective transport mechanisms and affect neuronal processes governing neurotransmission. Some recent studies in psychology have been carried out in healthy subjects to determine whether intake of flavanols in cacao-based beverage can improve performance in demanding tests of cognitive functions. In one study, subjects received one of three doses of flavanols on the day of tests. In that study, the subjects that received the high-dose flavanol beverage showed enhanced performance in terms of reaction times, response rates, and accuracy in certain tests, along with reduced mental fatigue. However, in a subsequent study, healthy subjects that drank a cacao-based beverage daily during one month failed to achieve clearcut benefits in tests of spatial working memory. Evidently, effects of flavanol-rich cacao drinks on performance of healthy subjects in psychological tests depend on experimental conditions. Flavanols have direct effects on cerebral blood flow. In one study, cerebral blood flow was enhanced for as long as four hours after a single dose of high-flavanol cacao, whereas one dose of low-flavanol cacao failed to affect cerebral blood flow reliably.

8 FSF Science cacao bean Photos: dannebrog/ Flickr.com Similarly, drinking cacao high in flavanols for five days increased cerebral blood flow in healthy subjects while performing a cognitive task, whereas low-flavanol cacao was without such an effect. (10) Several studies show that flavanols can have a marked impact on mood. First, they affect neurophysiological processes often associated with mood disorders. Second, they enhance behaviors that depend on motivation and emotions. Third, they stimulate cognitive performance and cerebral blood flow. Fourth, they have antidepressant properties in animal behavioral models. (10) Cacao has also attracted attention as a potentially neuroprotective natural product due to its antioxidant and potent iron-chelating activities. Some studies suggest there are beneficial effects of cacao on neurodegenerative disorders such as Alzheimer s disease (AD) and Parkinson s disease. In this sense, cacao extract, epicatechin, and catechin reduce the toxic effects of amyloid-β, a constituent of senile plaques in AD, on a neuronal cell line through membrane and mitochondrial protective mechanisms. (3)

9 Anti-cariogenic effect More recently it has been found that cacao products contain inhibitors of the enzyme dextransucrase, responsible for the formation of the plaque extracellular polysaccharides from sucrose. Subsequently it was suggested the possibility that phenolic substances could be responsible of the observed anticaries effect of cacao powder. Moreover it was showed that a water soluble extract of cacao powder significantly reduced caries scores in rats infected with Streptococcus sobrinus. According to the review of Ferrazzano et al. (2), the observed effect could be due to the inhibitory action of cacao water extract on the synthesis of waterinsoluble glucans. A following study has demonstrated that cacao polyphenols inhibit the growth of Streptococcus sanguinis, but not that of Streptococcus mutans. On the other hand, the pre-treatment of artificial saliva-coated microtiter wells with cacao polyphenol pentamer significantly reduced biofilm formation and acid production by S. mutans and S. sanguinis. So, although S. mutans appeared to be refractory to the growth-inhibitory or lethal effects of the cacao polyphenol pentamer in minimum inhibitory concentration / minimum bactericidal concentration (MIC/MBC) studies, acid production from sucrose was significantly inhibited. Cacao polyphenols seems to be effective against the adhesion (2, 11) of bacteria on the surface of teeth. FSF Science CACAO BEAN Photos: code.monk / Flickr.com

10 FSF Science cacao bean conclusions cacao bean Cacao bean is the seed of the cacao tree (Theobroma cacao). In South and Central America where the tree is native, the beans have been used for more than 3000 years. During the 16th century, the bean came to Europe, but the biomedical interest of cacao is less than 20 years old. The compounds that give cacao its natural antioxidant activity are flavonoids, more accurately the monomers catechins and epicatechins of flavanols. Several trials have shown that cacao may protect against cardiovascular diseases (CVD) through different mechanisms which include: antioxidant, antiplatelet and anti-inflammatory effects, as well as possibly increasing high-density lipoprotein (HDL), lowering blood pressure, and improving endothelial function. The chemical structure of flavonoids in cacao gives the compound free radical scavenging ability, which means flavonoids may have antioxidant effects. The results from controlled studies have also analyzed the effect of cacao on blood pressure with mixed results, some show clearly lowering activity while others don t show any particular changes in the BP. Even psychological tests have been done to see whether the flavanol-rich cacao have any well-being effects or neuroprotection. The psychological tests depend though on the experimental conditions, but may have positive effects. Moreover, cacao polyphenols seems to be effective against the adhesion of bacteria on the surface of teeth. Of note, a negative effect on bone density in mature women who consume chocolate has recently been identified (3).

11 REFERENCES cacao bean 1. Rusconi M, Conti A. Theobroma cacao L., the food of the gods: A scientific approach beyond myths and claims. Pharmacological Research. 2010 1;61(1):5-13. 2. Ferrazzano GF, Amato I, Ingenito A, De Natale A, Pollio A. Anti-cariogenic effects of polyphenols from plant stimulant beverages (cocoa, coffee, tea). Fitoterapia. 2009 7;80(5):255-62. 3. McShea A, Ramiro-Puig E, Munro SB, Casadesus G, Castell M, Smith MA. Clinical benefit and preservation of flavonols in dark chocolate manufacturing. Nutr Rev. 2008;66(11):630-41. 4. Belščak A, Komes D, Horžić D, Ganić KK, Karlović D. Comparative study of commercially available cocoa products in terms of their bioactive composition. Food Res Int. 2009 0;42(5 6):707-16. 5. Fernández-Murga L, Tarín JJ, García-Perez MA, Cano A. The impact of chocolate on cardiovascular health. Maturitas. 2011 8;69(4):312-21. 6. Ding E, Hutfless S, Ding X, Girotra S. Chocolate and prevention of cardiovascular disease: A systematic review. Nutrition & Metabolism. 2006;3(1):2. 7. Schroeter H, Heiss C, Balzer J, Kleinbongard P, Keen CL, Hollenberg NK, et al. ( )-Epicatechin mediates beneficial effects of flavanol-rich cocoa on vascular function in humans. Proceedings of the National Academy of Sciences of the United States of America. 2006 January 24;103(4):1024-9. 8. Lettieri-Barbato D, Villaño D, Beheydt B, Guadagni F, Trogh I, Serafini M. Effect of ingestion of dark chocolates with similar lipid composition and different cocoa content on antioxidant and lipid status in healthy humans. Food Chem. 2012 6/1;132(3):1305-10. 9. Taubert D, Roesen R,Schömig E. Effect of cocoa and tea intake on blood pressure: A meta-analysis. Archives of Internal Medicine. 2007 April 9;167(7):626-34. 10. Smith DF. Benefits of flavanol-rich cocoa-derived products for mental wellbeing: A review. Journal of Functional Foods. 2013 1;5(1):10-5. 11. Kim KH, Lee KW, Kim DY, Park HH, Kwon IB, Lee HJ. Extraction and fractionation of glucosyltransferase inhibitors from cacao bean husk. Process Biochemistry. 2004 10/29;39(12):2043-6. FSF Science CACAO BEAN

Find more FSF science articles online www.foursigmafoods.com/science