2. Material and Methods
2.1. Reagents
The commercial castor bean seeds were bought from the Brazilian company
BRSeeds, and the Crambe oil was donated by the research company MS
Foundation, located in Maracaju - MS, Brazil. Ethyl ether, ethanol,
hexane, acetone, sodium hydroxide, and phenolphthalein were used with
minimum purities of 99%.
2.2. Preparation of Castor Seed Particles
2.2.1. In Natura
Seeds
In natura castor seeds were ground with a blender, and the seed
particles smaller than 4.8 mm were collected after sieving.
2.2.2. Oil-Free
Seeds
To prepare the oil-free seeds, a methodology reported elsewhere was used
with slight modifications (Cavalcanti et al., 2007). Approximately 10 g
of castor bean seeds were peeled and ground, then 50
cm3 of acetone was added to the particles and were
left under constant stirring at 4oC for 16 h.
Subsequently, the seeds were filtered under vacuum and left to dry at
room temperature for 24 h. Particles of less than 1 mm were collected
after sieving. The average of oil extracted following this methodology
was 47.4 ± 1.3%.
2.3. Quantification of FFA
Titration with NaOH solution was performed to quantify the FFA (free
fatty acids) following the AOCS official method (Ca 5a-40) (AOCS, 1996).Equation 1 was employed to calculate the mass percentage of FFA
in the samples.