2.7. Determination of the melting point of FOG
Melting points were determined by the capillary tube method
according to the AOCS Official Method Cc 1-25 (AOCS, 1999). A portion
of molten FOG from fatty waste (see 2.5 above) was filtered
(filter paper) and three capillary tubes (i.d. 1 mm, o.d. 2 mm, length
50 mm) were filled with the filtrate to a height of 10 mm and the
ends of the tubes (at the sample end) were sealed by flaming. After
storing the filled tubes at 4–10 C for 16 h, they were immersed in
a bath whose temperature was 8–10 C below the estimated
melting point. Then the temperature of the bath was allowed to
increase at 0.5 C/min until the melting point was reached. The
melting points reported are the means of those observed in the
three tubes.