No abstract

No abstract

The effects of temperature and contact time on lipid extraction from sunflower collets was investigated in a batch extractor with hexane as solvent. The total removed material varied in quantity and composition due to changes in temperature and contact time. Higher temperatures enhanced oil extraction as well as increased the tocopherol and phospholipid contents of the oil. The kinetic data for triglycerols, phospholipid and tocopherols extraction were interpreted by using an equation that considers extraction as the sum of two components: diffusion and washing. Effective diffusion coefficients for oil, tocopherols and phospholipid at different temperatures were determined. Control of temperature and contact time are essential to obtain good quality oil and reduce refining costs. Extraction at 60°C and short contact times (30 min) obtained high oil yield (98%) accompanied by significant tocopherol extraction ([99%) and reduced phospholipid extraction (66%). List of symbolsA Model constant A 1 ,…, A n Model coefficients B Model constant B 1 ,…, B n Model coefficients (1/s) c Solute concentration (kg solute/kg miscella) D Diffusivity (m 2 /s) D o Constant in Arrhenius equation (m 2 /s) D e Effective-diffusion coefficient (m 2 /s) E a Activation energy (kJ/mol) J 0 (R k 1 ) Bessel function L Collet length (m) M t Solute mass diffused at time t (kg of solute/kg of inert solid) M 0 Solute mass already diffused during the washing stage (kg solute/kg inert solid) M inf Solute mass diffused at infinite time (kg solute/kg inert solid) r Radial coordinate (m) r 2 Correlation coefficient R Collet radius (m) R g Gas constant (kJ/[mol K]) t Diffusion time (s) t 0