Castor is one of the oldest crops cultivated in the world, suited to tropical rainfall areas. Castor plant grows well in dry climate regions with temperature around 25° C. High oil content in the seeds are owed to the warm climatic conditions. The plant is rich in toxic protein called ricin.
Castor oil:
Castor oil obtained by crushing the seeds, ranges from colorless to pale yellowish in color. India is the leading producer of castor oil in the world, contributing more than 75% of global exports. The major components of castor oil are triglyceride fatty acids like ricinoleates, oleate. There are four grades of castor oil, classified based on the oil refinement level and non-availability of sediments or suspended matter.
Castor de-oil cake:
Castor oil cake is treated in heat to nullify the toxic effects of ricin, leading to the production of de-oil cake. The nutrient content of castor de-oil cake is equivalent to the nutrients of soybean meal. De-oil cakes contain 1-3% oil in them, compared to 12-14% oil in oilcakes.
Castor cake:
Castor cake or castor meal, is the by-product of castor oil extraction process. Castor meal is rich in nitrogen content as well as ricin. Presence of ricin limits the use of castor oil cake to organic fertilizer. Castor meal is mixed with castor husk, shell of seeds, to reduce the toxicity of ricin. This mixture increases microorganism activity in the soil, in so improving the fertility of soil.
12-Hydroxy Stearic acid
12-Hydroxy Stearic acid is mixed fatty acid obtained by hydrolysis of hydrogenated castor oil. It is high melting, brittle, waxy solid at ambient temp. It should be stored away from heat to avoid deterioration. It is insoluble in water and its solubility in many organic solvents is also limited.
|
Characteristics |
Range |
Test method |
|
Appearance |
Creamish Flakes |
Visual |
|
Gardner color |
4max |
AOCS td1a-64 (97) |
|
Acid value |
175Min |
AOCS ca 5a-40(97) |
|
Melting point |
72- 76 C |
AOCS cc 3b-92(93) |
|
Iodine value |
3 – max |
AOCS cd 1-25(97) |
|
Hydroxyl value |
155min |
AOCS cd 13-60(97) |
|
Saponification value |
180-190 |
AOCS cd 3-25(97) |
|
Moisture volatiles |
0.50%max |
AOCSca 2c-25(97) |
Dehydrated Castor Oil (Pale)
Characteristics | Specification Range |
Appearance | Pale yellow Clear Oily Liquid |
Lovibond color G | 5 G MAX |
Acid value | 4 MAX |
Specific gravity@ 20 C | 0.928 to 0.967 |
Iodine value | 128 MIN |
Hydroxyl value | 25 MAX |
Sepoification value | 180-195 |
REFRACTIVE INDEX@ 20 Deg C | 1.482 -1.483 |
Viscosity @ 25 Deg C | 1.5 – 3.0 POISE |
Moisture and Volatiles | 0.15 % Max |
Uses of castor oil:
Each grade of castor oil is used for different purposes.
- Medicinal grade is aimed as ingredient for medicines and hydraulic brake fluids. Castor oil is popular for its laxative effects.
- Next grade level castor oil is focussed on preparation of cosmetics. This grade is called Firsts special grade.
- Firsts grade is meant to be used as lubricants.
- Commercial grade oil is used for making soaps, paints, inks.
- Castor oil is used as fuel for lamps and to prepare biodiesel.