Estudo do melhoramento do sabor de cacau (Theobroma cacao L.) atraves de ação enzimatica durante a fermentação




The fermentation of cocoa beans is an indispensable activity for the development of the precursors of chocolate flavor. During this stage the pulp that surrounds the beans is metabolized by microrganisms, producing, mainly, ethanol and acetic acid which are absorbed by the cotyledons resulting in the death of the seed, with several physical-chemical changes that will have important an influence on the flavor. Among these the synthesis of amino acids and tree reducing sugars, anthocyanin oxidation and of amino acid complexation with fenolics compounds, giving rise to quinones. Ali of these contribute to the reduction of the bittemess and astringency of the beans. In order to improve of the cocoa flavor, this work deals with the use of the enzyme polyphenoloxidase (PPo) extracted trom ripe custard apple (Annona squamosa L.) pulp, which acts in the primary phase of fermentation, and of the commercial enzyme protease, known as " Protezyn Flavour ", with the aim of reducing the concentration of compounds responsible for the bittemess and astringency, and of increasing the availability of free amino acids for the reactions of flavor development. The enzymes were added after 48 hours and 96 hours of the fermentation processoThe enzyme protease was added in the concentrations of 0.5% and 0.75% of the bean protein content. The ripe custrad apple pulp, rich in the enzyme PPO, was added in the concentrations of 5.0% and 7.5% of the total weight of wet beans. Eight fermentations were carried out: three with the addition of ripe custard apple pulp, three with the addition of the enzyme protease and two with no enzyme application, and in one of these fermentations water was added in the same proportion as the solutions with the enzyme protease. The fermentations were carried out simultaneously in fiberglass boxes with a capacity for 6 liters, with holes in the botton, spaced at 2.5cm for the drainage of exsudates. The boxes were placed in an acclimatized room with a meam temperature of 33°C and reiative humidity of 65%, conditions similar in those of the areas where cocoa is cultivated and fermented. The nibs were dried and ground and then defatted. Analyses were carried out on the defatted cocoa powder for the quantification of total phenols, tannins, anthocyanidins, flavan-3-ols and free amino acids. The experiments with PPO showed a reduction of form 18.64 and 20.07% in total phenols. There was na increase in the concentration of free amino acids in the range from 43.80 -79.74%. Roasting was effected on nibs in the range of size from 3 to 6 mm, in portions of 250 g, in a rotative electric oven at a temperature of 150°C. For each experiment three different times of roasting were applied: 36, 38 and 40 minutes. The roasted cocoa nibs were ground and refined for the formulation of the mixture used in the sensory tests. According to the analyses the best results were obtained with the treatments with the addition of 0.5% of the enzyme protease and 5.0% of the ripe custard apple pulp, allowing for 96 hours of fermentation


cupuaçu fermentação sabor enzimas cacau

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