There are three main genetic varieties of cocoa (Theobroma cacao L) used in chocolate making: Forastero, Trinitario and Criollo, which are distinguished by their aroma, an attribute that determines their quality. Criollo cocoa is of the highest quality and is used in the manufacture of fine chocolates because of its fruity aroma. The aroma of Criollo cocoa is defined by volatile compounds such as pyrazines and aldehydes, which are formed during roasting of the bean, from aroma precursors (reducing sugars and free amino acids) that are generated inside the bean via enzymatic reactions during fermentation; for this reason, fermentation is the most important process in the value chain. This review discusses the production of aroma precursors of Criollo and Forastero cocoa by studying the kinetics of spontaneous fermentation and the role of starter cultures to produce aroma precursors. Fine aroma precursors produced in the pulp during the fermentation phase will migrate into the bean when it's permeability is improved and then retained during the drying phase. Diffusion of aroma precursors into the cocoa bean may be possible, this process is mathematically characterized by the coefficient of molecular diffusion D, which describe the process of mass transfer via Fick's Second Law. The current state of knowledge is analyzed based on existing research and reports some gaps in the literature, suggesting future research that will be necessary for a better understanding of cocoa fermentation.

Agricultural and agroindustrial residues are major sources of cellulose, hemicellulose, and starch that can be converted into bioactive compounds, such as oligosaccharides and monosaccharides, using various chemical and biological methods. These bioactive compounds can be used as raw materials by food, cosmetic and pharmaceutical industries, as well as in the production of intermediate products and the development of biomaterials by chemical industries. In Brazil, the major industrial residues, which are corn residues, soybean residues, sugarcane bagasse, palm and coconut fibers, and grape and tomato seeds, among others, are produced at a rate of approximately of 600 million tons per year. Thus, the utilization of these residues using sustainable technology is of great interest. Hydrothermal treatment is a green technology that includes autohydrolysis as well as subcritical and supercritical hydrolysis, in which water is used at high pressures and temperatures to recover polysaccharides from complex vegetal matrices. The hydrolytic mechanisms can be improved by changing the ionic product or the polarity and electrical conductivity of water in subcritical and supercritical states. These properties promote the selective dissolution of the starch, hemicellulose and cellulose in the residues. The conversion of starch and hemicellulose into oligosaccharides and monosaccharides is preferentially performed at temperatures of less than 200°C. In contrast, the conversion of cellulose into oligosaccharides is promoted at temperatures greater than 200°C, with the highest amount oligosaccharide formation occurring at close to the critical point. In this article, the main biomass components, the properties of water under subcritical and supercritical conditions, and the latest studies of polysaccharide conversion in biomasses using hydrothermal treatments are reviewed.

Cocoa beans are the main raw material for the manufacture of chocolate and are currently gaining great importance due to their antioxidant potential attributed to the total phenolic content (TPC) and the monomeric flavan-3-ols (epicatechin and catechin). The objective of this study was to determine the degradation kinetics parameters of TPC, epicatechin, and catechin during the roasting process of Criollo cocoa for 10, 20, 30, 40, and 50 min at 90, 110, 130, 150, 170, 190, and 200 °C. The results showed a lower degradation of TPC (10.98 ± 6.04%) and epicatechin (8.05 ± 3.01%) at 130 °C and 10 min of roasting, while a total degradation of epicatechin and a 92.29 ± 0.06% degradation of TPC was obtained at 200 °C and 50 min. Reaction rate constant ( $k$ ) and activation energy ( $E_a$ ) were 0.02–0.10 min⁻¹ and 24.03 J/mol for TPC and 0.02–0.13 min⁻¹ and 22.51 J/mol for epicatechin, respectively. Degradation kinetics of TPC and epicatechin showed first-order reactions, while the catechin showed patterns of formation and degradation.

Açai is considered a functional food, and in addition to being a source of energy and fiber, it is a valuable source of bioactive compounds such as anthocyanins, minerals and fatty acids. In the present work, antioxidant-rich extracts from açai pulp were obtained using pressurized liquid extraction (PLE). The effects of the independent variables, including solvent type (pure ethanol and ethanol/water (50:50 v/v)), citric acid (0 and 0.3%, w/w), pressure (20 and 80 bar) and temperature (30 and 60 °C) were evaluated using a full factorial design. The extraction was affected primarily by the solvent type and the citric acid percentage. The results indicate that the maximum overall yield (X₀) was 64± 9 (%, d.b.) when the process was performed using ethanol (99.5%) and citric acid (0.3% w/w). The maximum total anthocyanin content and anthocyanin recovered from the raw material were 7 ± 1 (mg anthocyanin/g extract, d.b.) and 11 ± 2 (%, d.b.), respectively.