Influência da espessura de lâminas e do teor de umidade da massa expandida na eficiência da extração de óleo de soja

Abstract

Soybean (Glycine max) is one of the most relevant agricultural commodities worldwide, with Brazil being the largest global producer and exporter, responsible for approximately 160 million tons per year. In the soybean processing industry, several products and by-products are obtained, among which soybean oil stands out, typically extracted using hexane as the solvent. In this context, Brazil also ranks among the world’s largest producers of soybean oil. This study aimed to analyze the influence of soybean flake thickness and the moisture content of the expanded meal on the efficiency of soybean oil extraction, considering the industrial relevance of this process and the need to understand how preparation parameters affect the solid–liquid extraction stage, with the objective of increasing productivity and reducing losses. To this end, samples were collected from a soybean oil industry and analyzed for moisture through gravimetric methods, while flake thickness was determined using a micrometer. Oil extraction was carried out using the Soxhlet method, allowing quantification of the extracted oil under the selected operating conditions. The results showed that the moisture content of the expanded meal ranged from 7% to 13%, while the flakes presented thicknesses between 0.200 mm and 0.650 mm. For the selected samples, a trend was observed in which increasing moisture content gradually reduced extraction yield, indicating that values above approximately 11% could impair the process. However, statistical analysis indicated no significant difference among the values, despite the evident downward trend in extraction performance. Additionally, industrial data on residual oil content in the meal were examined, reinforcing the relationship between higher moisture levels and lower extraction efficiency. With respect to flake thickness, thinner flakes tended to enhance extraction yield, likely due to the increased contact area between the solid material and the solvent. Conversely, thicker flakes likely reduced solvent diffusion, decreasing the amount of oil extracted. In conclusion, even considering the limitation of statistical non-significance, both moisture content and flake thickness influence the performance of the solid–liquid extraction process. Ultimately, the results provided indications of operational ranges that may support process optimization and industrial decision-making aimed at improving productivity.