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Cadmium (Cd) is a non-essential trace metal, highly toxic to plants, animals and humans. Its mobility in the soil is high and it is transferred with relative ease to crops. European Food Safety Agency (EFSA) has identified the consumption of chocolate as a source of Cd contamination, and established maximum Cd limits allowed in cacao-based products. Therefore, research related to tolerance and reduction of Cd toxicity in a cacao becomes important. The main objective of the present study was to systematize the main factors that interfere in the uptake of soil Cd by the cacao tree and its strategies for tolerance to toxicity. A systematic review of the literature was conducted using six databases for academic research (Google Academic, PubMed, Springer, CAPES Periodical, Scielo and Science Direct). To avoid publication bias, a previously established protocol and inclusion and exclusion criteria were used. The main factors related to the uptake of soil Cd by the cacao tree were soil pH, soil Cd availability, genotype, the geographical location, agronomic factors such as phosphate fertilizersand Cd interaction with other minerals/metal nutrients such as Zn and Mn present in the soil. To reduce the toxicity of this metal, cocoa promotes some tolerance strategies such as uptake and transfer of Cd from the root to the shoot, molecular and biochemical changes, Cd partition between plant organs and Cd sequestration at the cellular level. So, this systematic review contributed to the acquisition of knowledge for the genetic improvement of cacao tree, concerning toxicity tolerance strategies and reduction of soil Cd uptake.

The cacao tree (Theobroma cacao L.) is the only source for the key raw material in chocolate manufacturing. However, fresh cocoa seeds do not develop any chocolate flavour during chocolate manufacturing because they do not contain the precursors necessary. The latter are formed only during the fermentation process that the seeds are subjected to in the countries of origin. During this in most cases spontaneous fermentation of the fruit pulp surrounding the seeds, the pulp is degraded by yeasts and bacteria. This degradation results in heat and organic acid formation. Heat effect and tissue acidification are the key parameters guiding flavour precursor formation. Accordingly, not microorganisms themselves but exclusively their metabolites are necessary for successful fermentation. In the present study we subjected fresh cocoa seeds to three types of fermentation-like incubation with defined amounts of acetic acid, controlled temperature regime and in the absence of microorganisms. All raw cocoa samples were of high reproducible quality as determined by biochemical quality parameter analysis. We conclude that control of the heat effect and the acidity is the reason for these quality characteristics and that application of this technique may permit standardization and mechanization of cocoa fermentation.

Agricultural land conversion and climate change play a major role in shaping tropical landscapes, but the direct and indirect links to biodiversity and species community composition remain little understood. We tested how landscape and environmental factors and management techniques, affect the diversity of ground and tree living ants in cacao plantations in Sulawesi (Indonesia). In addition, we investigated the occurrence of an aggressive, numerically dominant dolichoderine ant species (genus Philidris). Half of the 43 study plots, which differed in canopy cover, shade tree diversity, cacao tree age and their distance to the nearest rainforest, were weeded manually every 3 month, the others biannually. Each plot was divided into two subplots, one was fertilized twice a year whereas the other remained unfertilized. Using protein and sugar-solution baits, we examined species richness, abundances and interspecific interactions of ants on the ground and in cacao trees. In total we collected 160 ant morphospecies. Reduced ant species richness on the ground and in the trees was significantly correlated with higher mean temperatures while the other factors, including number of shade trees did not have any significant influence. The abundant and aggressive Philidris species, reduced arboreal ant species richness. It occurred more frequently in warmer, less shaded plots and on older cacao trees, which offer more nesting sites. In our study we show, that micro-climatic conditions and the occurrence of single ecologically dominant species are the major factors predicting species diversity in tropical agricultural ecosystems.

The impact of epiphytes on cacao productivity was investigated in agroforests in Central Sulawesi, Indonesia. Effects of epiphyte removal on fruit-set success and eventual yields were studied on 80 trees in an experiment with a balanced full factorial design. The removal treatment had no significant effect on the eventual harvest of the cacao trees. Pollinator availability had the greatest impact on fruit-set success, whereas yields were mainly determined by site-specific factors that mediate fruit-abortion and occurrence of fungal diseases. The results illustrate that epiphytic flora dominated by non-vascular species may have no effects on cacao tree functioning and removal of non-vascular epiphytes is unnecessary for improving the productivity of cacao. Hence, farmers’ labour can be reduced and conservation of the rich biodiversity outside natural forests supported.

Trichoderma theobromicola and T. paucisporum spp. nov. are described. Trichoderma theobromicola was isolated as an endophyte from the trunk of a healthy cacao tree (Theobroma cacao, Malvaceae) in Amazonian Peru; it sporulates profusely on common mycological media. Trichoderma paucisporum is represented by two cultures that were obtained in Ecuador from cacao pods partially infected with frosty pod rot, Moniliophthora roreri; it sporulates sporadically and most cultures remain sterile on common media and autoclaved rice. It sporulates more reliably on synthetic low-nutrient agar (SNA) but produces few conidia. Trichoderma theobromicola was reintroduced into cacao seedlings through shoot inoculation and was recovered from stems but not from leaves, indicating that it is an endophytic species. Both produced a volatile/diffusable antibiotic that inhibited development of M. roreri in vitro and on-pod trials. Neither species demonstrated significant direct in vitro mycoparasitic activity against M. roreri.

The current evidence on the vasculoprotective effects of flavonoid-rich cocoa and chocolate is reviewed. Cocoa flavonoids are derived from the cacao bean, found in the fruit pod of the cacao tree, Theobroma cacao . There is growing evidence that dietary supplementation with flavonoid-rich cocoa and chocolate may be cardioprotective because of their interference in many pathophysiological mechanisms associated with atherosclerosis. Possible beneficial effects by cocoa flavonoids include: antioxidant properties, improvement in endothelial function, blood pressure lowering, decreased platelet activation and function, and modulation of immune function and inflammation. Larger, long-term clinical trials investigating the potential beneficial effects of purified flavonoids and food sources rich in flavonoids, including cocoa and chocolate, are certainly warranted.

Rainwater and throughfall water were evaluated nutrient sources for a cacao (Theobroma cacao L.) ecosystem in Ilheus, Bahia, Brazil. Rainwater was collected for 35 months in an open area. Throughfall was collected on shaded and unshaded cacao plots. The shade trees were Erythrina and some species of Ficus. In evaluating the results, the agricultural year was subdivided into winter (April–September) and summer (October–March). It was found that the concentrations of N, P, K, Ca and Mg, in both rainwater and throughfall varied between and for periods within years. The nutrient concentrations in the throughfall also varied with the presence or absence of shade trees in the cacao plantation. The rainwater contributions of N, Ca, Mg, K, and P reached averages of 43, 21, 9, 9 and nearly 1 kg ha−1 year−1, respectively. The averages of annual throughfall recycling to the soil in the unshaded and shaded plots, respectively, were 141 and 47 kg K ha−1, 28.4 and 21 kg Ca ha−1, 21 and 12.2 kg Mg Ha−1, and 13 and 8 kg P ha−1. The throughfall K and P appears to be rapidly absorbed by the cacao roots, whilst most of the Mg, Ca, and N are retained in the soil. The throughfall and leaf fall constitute the most important nutrient recycling processes in the cacao ecosystem, which appears to be self-sufficient in terms of its nutrient requirements.