Physicochemical Characteristics and Composition of Indian Soybean Oil Deodorizer Distillate and the Recovery of Phytosterols

The deodoriser distillate (DOD) of Indian
soybean oil obtained from two industries processing soybean
oil was investigated for its physicochemical characteristics,
its composition of tocopherols, phytosterols, fatty
acids and recovery of phytosterols for use in nutraceutical
products. It was found that the two DOD samples studied
were dark in color and had higher amounts of free fatty
acids (22.7 and 49.9%), unsaponifiable matter (11.8 and
21.9%) (5–10 times found in soybean oil), total tocopherols
(1957–2256 mg/100 g) (20 times the amount in soybean
oil), and 6–10% of phytosterols (12–20 times the
soybean oil). The fatty acids found were palmitic (23.2–
25.5%), stearic (1.4–2.4%), oleic (23.8–26.1%), linoleic
(40.4–41.1%) and linolenic (2.7–3.2%) acids. The unsaponifiable
matter (21.9%) and phytosterols (8.7%) content
of DOD-2 were higher than in DOD-1 and hence was more
suited for isolation of phytosterols. Using hexane and water
for crystallisation, the DOD-2 yielded a phytosterol fraction
with lower recovery of 13.2–17.8% while treatment
with alkali to remove FFA and the glycerides followed by
organic solvent extraction yielded unsaponifiable matter
containing phytosterols with a recovery of 74.6%. Later the
unsaponifiable matter was purified by double crystallisation
into a mixture of phytosterols of 87% purity containing
b-sitosterol (34.3%), stigmasterol (3.1%) and campesterol
(50.1%). The product may find use in foods, pharmaceuticals,
cosmetics and allied industries probably as a
nutraceutical.