ABSTRACT Baru almonds and their byproducts have gained popularity in the population diet because of their high nutritional values. Despite this, there is limited information on how to store their flours properly, particularly their whole and partially defatted flours. Thus, this study aimed to use the Guggenheim–Anderson–de Boer (GAB) model to determine the thermodynamic properties of enthalpy, entropy, and Gibbs’s free energy variation, as well as the spreading pressure, all of which are inherent to the moisture adsorption process in baru flours. The oil content, ash content, moisture content, pH, and wettability of the baru flour samples were characterized. The adsorption isotherms were determined using the static gravimetric method at temperatures of 298.15, 303.15, and 308.15 K and adjusted to the GAB model. The differential enthalpy variation was positive and decreased as the moisture content in the flours increased, whereas the differential entropy variation exhibited an opposite trend. The isokinetic theory was validated, as the process was driven by entropy. The spreading pressure increased as water activity increased.

RESUMO O consumo da farinha e do óleo de baru (Dipteryx alata Vogel) tem crescido em virtude de suas características nutricionais, contudo, são escassos os estudos a respeito do beneficiamento das farinhas desta amêndoa. O presente trabalho propôs-se estudar a cinética da secagem das farinhas integral e a parcialmente desengordurada de amêndoas de baru, resíduo da extração do óleo, bem como suas propriedades termodinâmicas. A farinha integral foi obtida pela trituração de sementes e a parcialmente desengordura por extração química. Os dois produtos foram submetidos à secagem em estufa com circulação forçada de ar a 60, 70 e 80 °C. Dez modelos, comumente utilizados para secagem, foram selecionados para o ajuste. Com base em critérios estatísticos, o modelo de Midilli foi selecionado para representação do fenômeno para as farinhas de amêndoas de baru. A diferença da taxa de secagem entre as farinhas tendeu a se atenuar com a elevação da temperatura. A energia de ativação foi de 39,24 kJ mol-1 para a farinha integral e 29,01 kJ mol-1 para parcialmente desengordurada. A entalpia e entropia decresceram com o aumento da temperatura, enquanto a energia livre de Gibbs aumentou. Para a farinha com maior teor de óleo, as propriedades termodinâmicas foram superiores à de menor teor de óleo.

ABSTRACT The consumption of flour and oil of ‘baru’ (Dipteryx alata Vogel) has increased due to its nutritional characteristics; however, there are few studies on the processing of the flour of this almond. The aim of this research was to study the drying kinetics of the whole and partially defatted flours of ‘baru’ almond, the residue of the oil extraction, as well as its thermodynamic properties. The whole flour was obtained by the grinding of seeds and the partially defatted flour by chemical extraction. The products were dried with forced air circulation oven at 60, 70 and 80 °C. Ten models, commonly used for drying, were selected for fitting. Based on statistical criteria, the Midilli model was selected to represent the drying kinetics of ‘baru’ almond flour. The difference in the drying rate between the flours tended to attenuate with the elevation of the temperature. Activation energy was 39.24 kJ mol-1 for the whole flour and 29.01 kJ mol-1 for partially defatted flour. Enthalpy and entropy decreased with increasing temperature, whereas Gibbs free energy increased. For the flour with highest oil concentration, the thermodynamic properties were higher than for the one with lowest oil concentration.

Objetivou-se, com o presente trabalho, avaliar o efeito do estádio de maturação dos frutos sobre o rendimento em massa de matéria seca e óleo das sementes de pinhão-manso (Jatropha curcas L.) , e sobre a qualidade do óleo extraído. Frutos de pinhão-manso foram classificados em quatro diferentes estádios de maturação, de acordo com sua coloração: verde, amarela, marrom-amarela e marrom. Amostras dos frutos de cada estádio foram retiradas para a determinação do teor de água, dimensões principais, volume e contagem de sementes por fruto. As sementes foram extraídas para determinação do teor de água, dimensões principais, volume, massa seca de mil sementes, percentual em massa de óleo e percentual de ácidos graxos livres do óleo extraído. A colheita de frutos de pinhão-manso com coloração marrom-amarelo e marrom, proporcionou maior rendimento em massa seca das sementes e em conteúdo de óleo. A colheita dos frutos com coloração marrom-amarelo além de possibilitar bons rendimentos em óleo e em matéria seca, permite a obtenção de óleo com índice de acidez menor, sendo o estádio de maturação mais indicado para a realização da colheita dos frutos e sementes de pinhão-manso para fins industriais.

The aim of this study was to evaluate the effect of ripening stage of the fruits on the increase in dry matter and oil content of physic nut (Jatropha curcas L.) seeds. The quality of the oil was also investigated and related to the ripening stage. The fruits were classified in four classes of colors: green, yellow, brown-yellow and brown (dry fruits). Samples of fruits were collected for each ripening stage and the analysis of water content, size, volume and numbers of seeds were performed. For the seeds, water content, size, volume, mass of thousand seeds, oil content and acid value were evaluated. The harvest of brown-yellow and brown fruits provided higher yields in dry matter and oil of seeds. The brown-yellow fruits presented higher oil yield and dry matter, lower acid value, so it represent the more suitable ripening stage for harvesting fruits and seeds for industrial uses.