2.4.3. Total Lipid Analysis
Total lipid content was determined following a gravimetric method. An
aliquot of oleoresins (1 g) added in a dry glass tube (15 mL) with
chloroform (2 mL) and methanol (4 mL) and sealed with Teflon-lined screw
caps. The tube was shaken well for 10 minutes at 325 rpm. Then,
additional chloroform (2 mL) and water (2 mL) were added, and the tube
was shaken for another 10 minutes. Then, the tube was centrifuged at
2300 rpm for 10 min to separate the organic phase containing the lipid
from the aqueous phase. The organic top layer was collected using a
Fisherbrand™ borosilicate glass Pasteur pipet (Fisher Scientific,
Waltham, MA, USA). Additional chloroform (4 mL) was added to the tube,
centrifuged at 2300 rpm, and the top layer with lipid collected. The
solvent was evaporated at 60 °C, and the total lipid in oleoresin sample
was calculated using Equation 2:
Total lipid content (wt%) =\(\frac{\left(W2-W1\right)x\ V[?]\ x\ 100}{(V[?]\ x\ S[?])}\)(2)
where W2 is the total weight of the glass tube and the
extract (g), W1 total weight of empty dried glass tube
(g), Vl is the total volume of chloroform layer (mL),
Va is the volume of the extract (mL) and
Sx is the weight of the oleoresin (g).