Journal of Oleo Science

Copyright ©2016 by Japan Oil Chemists’ Society

doi : 10.5650/jos.ess16125
J. Oleo Sci. 65, (12) 957-966 (2016)

REVIEW

Vegetable Oil Deodorizer Distillate: A Rich Source of

the Natural Bioactive Components
Syed Tufail Hussain Sherazi＊ , Sarfaraz Ahmed Mahesar and Sirajuddin
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro-76080, PAKISTAN

Abstract: Deodorizer distillates are waste products of edible oil processing industries obtained during
deodorization process of vegetable oils. It is very cheap source of several health beneficial components such
as tocopherols, sterols, squalene as well as free fatty acids which have numerous industrial applications.
These valuable components are being used in different foods, pharmaceutical formulations and cosmetics.
Traditional sources of these useful components are vegetable oils, fruits, vegetables and nuts. Global need of
these important components has been exceeded than their availability. The deodorizer distillates of various
vegetable oils are considered to be a rich source of several valuable components. Present review will cover
brief introduction of common processing stages involved in all vegetable oil processing, analytical methods
for characterization of deodorizer distillates by instrumental techniques, importance and commercial value
of deodorizer distillates. Future prospective of current field may leads to cost efficient processes and
increased attention on the nutritional quality of deodorized oil and commercial applications of deodorizer
distillates as well as their valuable components.

Key words: deodorizer distillates, characterization, analytical techniques, importance, commercial value

1 Introduction odorization.
Extracted vegetable oils from the oilseeds are in crude
state. Most of the crude oils couldn’ t be used directly for 1.1 Degumming
edible purpose due to their unacceptable color and odor Removal of phospholipids from oil is known as degum-
except olive oil1, 2）. Crude oils contain undesirable compo- ming. Gums should be separated from the crude oils in the
nents such as free fatty acids（FFAs）, pigments, metals, early refining stage due to two major reasons. Firstly, these
gums, waxes, phospholipids and odoriferous materials are responsible for high refining losses because of their
which must be removed to get a stable product with a emulsifying nature. Secondly, due to the thermal instability
bland taste. Therefore, through efficient industrial process- gums are decomposed which leads to darkening the color
ing these unwanted components are removed with of oil. There are two types of phospholipids i.e. hydratable
minimum impact on nutrition value of the edible oil3, 4）. phospholipids and non-hydratable phospholipids. Hydrat-
Various processes are involved in the refining of vegetable able phospholipids contain polar groups and hence soluble
oils. These processing steps may be chemical or physical. in water. Therefore, hydratable phospholipids are removed
Main difference between these two refining procedures is with hot water and process is known as water degumming.
removal of FFAs which could be achieved either chemically Non-hydratable phospholipids are removed with acid
（caustic/alkali neutralization）or physically（steam distilla- （usually phosphoric acid）to convert all non-hydrated gums
tion）. Differentiation between physical and chemical refin- to lyso form（hydratable gums）and easily separated from
ing is very clear through a schematic diagram（Fig. 1）. the oils either in a batch process or centrifugation process.
Generally, physical refining includes three processing This process is called acid degumming. Proper amount of
stages i.e. degumming, bleaching and deodorization while acid, appropriate time in a retention tank and suitable tem-
chemical refining includes four processing stages i.e. alkali perature is necessary to achieve best results of degum-
neutralization in addition to degumming, bleaching and de- ming4）. Small quantity of phosphoric acid（0.1-0.3％）is used

＊
Correspondence to: Syed Tufail Hussain Sherazi, National Centre of Excellence in Analytical Chemistry, University of Sindh,
Jamshoro-76080, PAKISTAN
E-mail: tufail.sherazi@yahoo.com
Accepted August 8, 2016 (received for review June 30, 2016)
Journal of Oleo Science ISSN 1345-8957 print / ISSN 1347-3352 online
http://www.jstage.jst.go.jp/browse/jos/ http://mc.manusriptcentral.com/jjocs

957
 S. T. H. Sherazi, S. A. Mahesar and Sirajuddin

Fig. 1 Refining process of crude oil.

with 85％ solution as surplus amount is not adsorbed on 1.3 Bleaching

surface of bleaching clay and may cause the problem of hy- Commonly oils are treated with bleaching clay following
drolysis or phosphorylation of mono- or diglycerides during neutralization and before deodorization. However, bleach-
physical refining at high temperature. In addition to tradi- ing process can be carried out at different stages according
tional degumming processes enzymatic degumming tech- to the type and quality of oil as well per requirement of in-
nology is now also available for reducing the phosphorus dustry. Bleaching eradicates soluble material from oil.
content of vegetable oils below 10 mg/kg. It was first devel- Bleaching is an adsorptive procedure to remove color pig-
oped by the German Lurgi Company, as the“EnzyMax ments, metals, residual phosphatides, soaps and oxidation
process” in the 1990s. By using different types of enzymes products. On the bases of chemical and physical properties
non-hydratable phospholipids can be changed into a hy- of adsorbed material and the bleaching clay, the nature of
dratable form, which can easily separated by centrifuga- adsorption is due to the following mechanisms14）.
tion5−7）. 1．Physical adsorption: In this process van der Waals
forces between molecules hold the adsorbed species
1.2 Chemical refining on the bleaching clay.
In chemical refining generally sodium hydroxide （caustic 2．Chemisorption: In this process there is a chemical
soda）is used. Dilute solution of sodium hydroxide reacts bond between the adsorbate and the adsorbent.
with FFA present in oil to form sodium salts of fatty acids. 3．Decomposition and dehydration: Pseudoneutraliza-
Saponification leads to formation of soap with FFA and tion of peroxides during the oil-bleaching process.
neutralization of oil, soapstock is then removed from the oil Usually bleaching clays are derived from calcium, mag-
with water washes either in a batch process or centrifuga- nesium, and aluminum silicates（60–70％ SiO2）. Bleaching
tion process. There are many disadvantages of chemical clays are usually called“bentonites”, composed of calcium
refining including loss of oil, high energy requirement, time montmorillonites（named for a region in France） and mixed
consuming and production of large amount of byproducts sepiolites, hectorites, and smectites. Whereas sodium ben-
that pollutes the environment. Despite above disadvantag- tonites are named for Fort Benton, Wyoming. Basically
es, many industries still use this process. Due to these bleaching earths are surface mined, activated, washed,
reasons physical refining method is mostly recommended dried, and ground to a powder with a particle size in
for high FFA contents4, 8−10）. Recently, various methods on between 1–100 μm with moisture content of 10–20％. Gen-
FT-IR spectroscopy have been developed for low and high erally, bleaching clays are classified in two groups i.e. natu-
contents of FFA in the vegetable oils which are rapid and rally active clays and acid-activated clays. Frequently
environment friendly11−13）. bleaching is carried out with acid-activated clays.
To reduce the color and oxidative reactants, bleaching is
subjected under vacuum（20–30 mm Hg）. Mostly, oil is
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J. Oleo Sci. 65, (12) 957-966 (2016)
 Deodorizer distillates obtained from vegetable oil processing

heated to 90℃ during bleaching. Clay to oil ratio depends ent ways（continuous, semicontinuous or batchwise）with
on the quality of input oil. The bleaching process is carried various configurations of deodorizers（horizontal or vertical
out at 80–120℃ and takes about 15–30 min. The elevated vessels, tray-type or packed columns）. Selection of the
temperature is necessary to keep a low oil viscosity to most appropriate process technology is mainly determined
improve diffusion and mass transfer rates. But, very high by the total plant capacity and the number of feedstock
temperature is not suggested since unwanted reactions changes. Principle of deodorization includes following
also become very fast1, 2, 15）. three processes20）.
（1）Stripping: Stripping of volatile components such as
1.4 Physical refining FFAs, tocopherols, sterols, odorous compounds, and
FFA and other volatile components are removed in de- contaminants（pesticides and light polycyclic aromat-
odorization at high temperature and low pressure. If total ic hydrocarbons, etc.）,
FFAs are eradicated in deodorizer through steam under （2）Actual deodorization: Removal of different off-flavor
high vacuum and temperature without using alkali neutral- components, and
ization then process is called physical refining. Deodoriza- （3）Thermal degradation: Causes destruction of color
tion is a simple process by which saponifiable matter, unsa- pigments and unwanted side reactions like polymer-
ponifiable substances and other volatile compounds are ization, cis-trans-isomerization and conjugation.
distilled. Therefore, deodorizer distillates obtained through Therefore, during deodorization volatile components are
physical refining contained greater amount of FFA（＞ evaporated from liquid to gas and subsequently back to
70％）and comparatively less quantity of unsaponifiable liquid via condensation. Generally, during processing the
matters. Consequently, such deodorizer distillates are mar- temperature of deodorizer is maintained at 180–260℃
keted as a source of fatty acids. In chemical refining, using high pressure steam boiler. High vacuum between
caustic solution is used to neutralize FFAs either in batch 2–8 mmHg is retained in the deodorizer to avert the oil
process or continuous process and soap is washed out with from oxidative damage. Optimized stripping parameters
water. Thus, deodorizer distillates obtained from chemical such temperature, time, vacuum, and amount of stripping
refining contain comparatively less quantity of FFA steam or nitrogen gas are control the specifications of the
（30-50％）and greater amount of unsaponifiables matter outgoing deodorized oil and deodorization cost. The vola-
（25-33％） 16, 17）
. Physical refining is recommended for vege- tile odoriferous compounds are stripped off by direct injec-
table oils which contain high amount of FFAs（ ＞3％）, tion of high temperature steam. These unwanted volatile
while chemical refining which include alkali neutralization compounds include FFAs, peroxides, aldehyde, ketones,
is recommended for those vegetable oils which have a alcohols, and carbohydrates are removed during deodoriza-
lower concentration of FFAs （＜3％） . Initial investment on tion. However, some bioactive components like tocopher-
physical refining is less than chemical refinery and opera- ols, sterols and squalene are also distilled during deodor-
tional cost is also less but recovery of RBD（refined, ization. The volatile fraction from deodorizer is collected
bleached and deodorized）oil is much better. Because a and is known as deodorizer distillate. Use of stainless steel
step of alkali neutralization is totally avoided in physical re- equipment and oxygen-free steam; vigilant deaeration at ＜
finery as compare to chemical refinery which involves 100℃ before heating to the final stripping temperature;
costly equipments（ such as continuous separators）and and strict feedstock specifications is implied for Good Man-
greater loss of crude oil1, 8, 18）. Physical refining is consid- ufacturing Practice（GMP） 2, 4）
.
ered to be environment friendly because no wash water is
required for physical refinery while a lot of water is needed （DD）
1.6 Deodorizer distillate
in alkali neutralization for chemical refinery to clear soap The deodorizer distillates are complex mixture of many
particles from alkali neutralized oil. The waste discharge is health beneficial constituents. Volatile compounds present
significantly reduced in this process as compared to chemi- in a very small concentration in the vegetable oils are re-
cal refining. Further advantages of physical refinery sponsible for the unacceptable odor, color, taste and flavor
include lower refining loss and better recovery of FFAs of the oil1, 21）. Commonly, vegetable fats and oils are sub-
without conversion to oil dirt. Moreover, lesser amount of jected to industrial treatments before being consumed for
steam, water, power and capital investment is needed in edible application. Industrial processing such as neutraliza-
physical refinery. Drawback of physical refinery is that it tion, bleaching and deodorization produces significant
needs more careful degumming8, 19）. amount of waste materials like soapstocks, spent bleaching
clays and deodorizer distillates, respectively. Which are
1.5 Deodorization process often wasted without being proper utilization and many
Deodorization is a simple distillation process in which valuable components are lost12）. Deodorizer distillate is an
various volatile components are separated from the oil. important by-product obtained from the deodorization
Edible oil deodorization is performed industrially in differ- process of vegetable oils. The unwanted volatile com-
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J. Oleo Sci. 65, (12) 957-966 (2016)
 S. T. H. Sherazi, S. A. Mahesar and Sirajuddin

pounds include aldehydes, ketones, alcohols, and peroxides considered to be one of the less popular methods due to
which must be removed for edible applications of the oil. high price and time consumption. Although, Snyder et al.
Volatile compounds are stripped off by direct injection of used this method for the separation and characterization of
superheated steam or nitrogen at a temperature between tocopherol, squalene and sterol of deodorizer distillate
220 and 260℃ depending upon the types of deodorizers samples but authors suggested that if in any lab facility of
and quality of input oils. From deodorizer, volatile fraction capillary supercritical fluid chromatography–mass spec-
is distilled and collected through condensers as deodorizer troscopy is available then this technique could be success-
distillate. Deodorizer distillates are a natural source of fully used for the characterization of tocopherols, squalene
valuable components such as tocopherols, tocotrienols, and sterols26）. It may be possible to entirely characterize
phytosterols, hydrocarbons, and squalene as well as mono the deodorizer distillate by this method, but further re-
and di-acylglycerols and FFAs8, 12, 22, 23）. Tocopherols are search involving temperature and pressure must be carried
very important natural antioxidants that prevent the ran- out to evaluate their effects on the separation of all the
cidity of oils during storage and improve the shelf life of components of the distillate. Another costly technique was
edible oils24）. Assessment of the each component present reported by Ramamurthi and McCurdy, which includes li-
in the deodorizer distillate is very important to evaluate the pase-catalyzed modification of fatty acids27）. This technique
value of deodorizer distillate1, 25）. was applied on canola and soybean oil deodorizer distil-
lates. The volatile fractions were separated by vacuum dis-
tillation to concentrate the fraction containing bioactive
components such as tocopherols, sterols and squalene. For
2 Analytical
‌ techniques used for the characterization the characterization, GC technique was applied. But, high
of deodorizer distillate temperature was not so suitable and resolution of peaks
In the literature, few analytical methods are reported for was also not so good. Therefore, separation of individual
comprehensive analysis of deodorizer distillates. Liquid-liq- component for accurate quantification is not an easy task.
uid extraction, esterification/transesterification, molecular In the literature some methods have been reported for the
distillation, and crystallization techniques are applied for separation of the components of deodorizer distillates.
extraction, separation and purification of different constit- Notable methods include solvent extraction and crystalliza-
uents of deodorizer distillates. Supercritical fluid fraction- （SC-CO2）
tion28, 29）, supercritical carbon dioxide extraction
ation（SFF）technology has been also applied for the recov- 30−33）
, enzymatic reaction34） and molecular distillation35, 36）.
ery of valuable compounds from deodorizer distillates. Some other separation methods have been also described
Main focus of these techniques was on the determination in the literature such as permeation of tocopherols from
and recovery of tocopherols and sterols which are most im- deodorizer distillates using a non-porous denser polymeric
portant constituents of deodorizer distillates. Some investi- membrane37） and concentration of tocopherols and sterols
gators have also studied the phase equilibria and separation by addition of melted deodorizer distillates to a solution of
behavior of deodorizer distillates. Simple and accurate ap- urea and alcohol to separate fatty acids from the mixture38）.
proaches were used for chemical characterization and But these methods were rarely used as these have no any
evaluation of different components present in the deodor- advantages over the distinguished methods.
izer distillates1, 2, 12, 22）.
Capillary gas chromatography（ GC）is a modest and
quicker technique for classification of all constituents in
deodorizer distillates. There is no need of saponification 3 Composition of deodorizer distillates
when using this method. Resolution of the peaks of eluted Deodorizer distillate obtained from palm oil refining is
components is much better than the GC analysis utilizing a known as palm fatty acid distillate（PFAD）. Variation in
packed column. Therefore, capillary GC is considered to be composition of deodorizer distillate is basically depends on
best choice for the separation of the most important com- the quality of input oil, type of deodorizer and processing
ponents present in the deodorizer distillate in one single parameters such as volume of stripping steam, vacuum,
run. Multicomponent analyses of deodorizer distillates temperature and time of deodorization. Amount of DD is
present were carried by some scientists via in situ si- independent on the types of oil but it depends on the FFAs
lylation. After silylation, the components were separated level of input oil to deodorization process. For example,
by GC with mass spectrometry （MS） for final identification. amount of PFAD obtained from processing of palm oil has
The compounds separated were tocopherols, sterols, fatty been reported about 4％39）.
acids and glycerol esters1）. For the determination of bioac- Top（ 2010）reported that PFAD is composed of FFAs
tive components in deodorizer distillates, use of costly pro- （81.7％）, glycerides（14.4％）, squalene（0.8％）, vitamin E
cedure like capillary supercritical fluid chromatography– （0.5％） , sterols（0.4％）and other substances（2.2％）40）.
mass spectroscopy is not appropriate technique and According to Saba Naz et al., concentration of phytoster-
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J. Oleo Sci. 65, (12) 957-966 (2016)
 Deodorizer distillates obtained from vegetable oil processing

ols in unsaponified part of deodorizer distillates was the of deodorizer distillate include variety of the seeds and
most abundant（21.27–25.53％）in different samples of type of extraction（mechanical or chemical） of oil and pro-
canola deodorizer distillate and PFAD samples, whereas cessing conditions of the deodorizer. High temperature, el-
squalene and tocopherol were present in concentration evated vacuum, increased steam pressure and extended
ranges between 2.89–13.21％ and 1.29–5.81％, respective- time of deodorization are responsible to increase the rate
ly1）. of volatilization and amount of deodorizer distillate. De-
Bondioli et al. reported the typical compositions（wt％） odorizer distillates obtained from chemically refined oil
of olive oil deodorizer distillate（ OODD）obtained from contain greater concentration of tocopherols（3.5-18.2％）,
chemical refining. Amount of FFA and squalene were found and phytosterols（10-21％）while lesser amount of FFAs（9-
to be dominant with the levels of 34％ and 28％, respec- 42％）. However, the distillates resulting from physically
tively whereas phytosterols were reported 4.6％41）. refined vegetable oils contain a greater amount of FFAs
Winter21）provided main components of deodorizer distil- （70-81％）and lower concentration of tocopherols（ 1.3-
lates and concentration of unsaponifiable matter expressed 7.5％）and phytosterols（3.3-10.8％）21, 43−51）. Overall PFAD
as％（w/w）. Value of deodorizer distillate depends on the was reported to be contained highest amount of FFA（∼
amount of unsaponifiables matter. In sunflower oil deodor- 82％ w/w of total distillate）and could be used for biodiesel
izer distillates, mean percentages of unsaponifiable matter, or animal feed manufacturing. However, appreciable con-
tocopherols, α-tocopherols, sterols, stigmasterol were centrations of phytosterols, squalene and tocopherol were
found to be around 39.0, 9.30, 5.70, 18.0 and 2.90％, re- also detected in PFAD. Highest level of squalene was re-
spectively. While in cotton seed oil deodorizer distillates ported in olive oil deodorizer distillate and found to be ex-
percentages of unsaponifiables, tocopherols, α-tocopherols, cellent source of squalene which is used in many cosmetics
sterols, stigmasterol were estimated to be 42.0, 11.40, 6.30, and medicines. Due to greater amount of FFA （＞3％）palm
20.0 and ＜1％, accordingly. Similarly, in soybean oil de- and corn oils are recommended for physical refining while
odorizer distillates percentages of unsaponifiables, tocoph- sunflower, soyabean, cotton seed, canola and rapeseed oils
erols, α-tocopherols, sterols, stigmasterol were detected to are recommended for chemical refining due low concentra-
be 33.0, 11.1, 0.90, 18 and 4.40％, respectively. In rapeseed tion of FFA（＜3％）in their crude oils. Soybean deodorizer
oil deodorizer distillates percentages of unsaponifiables, distillate contains greater concentration of γ-tocopherol
tocopherols, α-tocopherols, sterols, stigmasterol were （11％） and β-sitosterol（∼8％） but considered to be a good
found to be around 35.0, 8.20, 1.40, 14.60 and 1.80％, re- source of stigmasterol（∼4％）as stigmasterol is compara-
spectively as shown in Table 121）. tively low in other deodorizer distillates. In the same way
Table 2 represents composition of unsaponified deodor- cotton seed and sunflower deodorizer distillates contain
izer distillates analyzed by quantitative GC obtained during greater level of α-tocopherols（∼4％）21）.
chemical and physical refining of different soft oils. The
distillate from physical refining is a suitable source of fatty
acids, whereas chemical refining provides a better deodor-
izer distillate for the recovery of sterols and tocopherols 4 Importance of bioactive compounds
from the unsaponifiable fraction21, 42）. Unsaponified portion of deodorizer distillates contain
It is clear from the provided literature that composition greater concentration of valuable components such as to-
of deodorizer distillates depends on the nature of the vege- copherols, sterols and squalene whereas saponified part
table oil and processing parameters. Therefore, composi- contains significant amount of FFAs and acylyglycerols.
tion of different deodorizer distillates is dissimilar. Impor- Increasing interest in nutraceuticals and functional foods
tant factors which strongly influence on quantity and value has promoted food-derived phytochemicals as bioactive in-

Table 1 L evels of some bioactive compounds（％）from different saponified

deodorizer distillate sources21）.
Deodorizer Distillates
Bioactive compounds
Sunflower Cotton Soybean Rapeseed
Unsaponifiables matter 39.0 42.0 33.0 35.0
Tocopherols 9.30 11.40 11.10 8.20
α-Tocopherols 5.70 6.30 0.90 1.40
Sterols 18.0 20.0 18.0 14.60
Stigmasterol 2.90 0.30 4.40 1.80
Mean values of replicate samples
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 S. T. H. Sherazi, S. A. Mahesar and Sirajuddin

Table 2 （％）obtained from chemical or

Composition of unsaponified deodorizer distillates
physical refining of different soft oils19, 42）.
Soybean Corn Sunflower Rapeseed
Bioactive compounds
Chemical Physical Physical Chemical Physical Chemical
δ-Tocopherol 4.4–5.6 2.0 0.1 n.d*. n.d. 0.2–0.3
β-Tocopherol 0.4–0.5 n.d. 0.1 n.d. n.d. 0.1–0.2
γ-Tocopherol 10.7–11.3 5.0 1.1–2.8 0.3 0.1 2.3–2.5
α-Tocopherol 0.8 0.5 0.2–0.4 4.8 1.2 0.9–1.4
Total Tocopherols 16.3–18.2 7.5 1.5–3.4 5.1 1.3 3.5–4.4
Brassicasterol n.d. n.d. n.d. n.d. n.d. 1.6–2.8
Campesterol 5.1–5.7 1.9 0.8–1.7 1.6 0.5 2.9–4.4
Stigmasterol 4.1–4.8 1.4 0.2–0.4 2.0 0.6 n.d.
β-Sitosterol 7.9–8.3 3.0 1.7–3.4 8.6 2.6 4.1–6.2
Other sterols** n.d. n.d. n.d. 1.7 0.6 n.d.
Steryl esters 2.3–2.6 4.5 0.6 0.3 0.1 1.4–5.3
Total sterols 19.4–21.4 10.8 3.3–6.1 14.2 4.4 10.0–18.7
Mono- acylglycerols 1.2–1.9 1.9 0.1 0.9 n.d. 1.4–2.1
Diacylglycerols 2.7–3.8 8.1 0.5–1.3 1.9 0.7 3.8–3.9
Triacylglycerols 5.1–5.9 3.8 0.1–0.8 2.6 2.7 3.0–7.5
（as C18:1）
FFA 33 73.8 77–81 9.2 70.8 39–42
Squalene 1.3–2.1 0.6 0.2–1.0 0.7 1.0 0.1–0.4
n.d.*, Not detected
**∆5 avenasterol, ∆7 avenasterol and ∆5 stigmasterol

gredients. Tocopherols are fat-soluble vitamins which are ucts family known as triterpene and these could be con-
nutritionally very important components and exhibit high verted to phytostanols through chemical hydrogenation.
antioxidant activity. Commercially vitamin E is available as Therefore, phytostanols are a fully hydrogenated subgroup
food supplement in the form of α-tocopheryl acetate. The of phytosterols. Both, phytostanols and phytosterols are
synthetic and natural forms of vitamin E are labeled as considered to be very effective in lowering low density li-
“D,L”and“D” , respectively. But activity of synthetic form poprotein serum cholesterol. Vitamin E and sterols are also
is approximately half as compared to natural form52）. It has considered to be good candidates for corticoid drug and
been reported that α-tocopherol has highest vitamin E ac- hormone synthesis. Similarly use of stigmasterol has been
tivity and prevents cardiovascular disease, cancer, infec- reported in the preparation of corticoids and progester-
tion, and inflammation as well as decreases the risk of de- one59） while sitosterol is used for the production of estro-
generative diseases. Higher bioactivity of tocopherols as gens, contraceptives, diuretics, and male hormones60）. Due
antioxidants is mainly due to their ability to donate a hy- to effective physiological activity of phyotosterols, these
drogen atom to free radicals to prevent lipid from auto oxi- are used in many functional foods like margarine blended
dation. The relative antioxidant activities of tocopherol with steryl esters and salad oils and dressings with added
isomers are in the order of α＞β＞γ＞δ53−55）. Each form of sterols61）. Yang et al. reported that phytosterols possess
tocopherol has its particular biological activity which is di- anti-inflammatory, anti-atherogenic, anti-cancer and anti-
rectly related with potency or functional use in the body. oxidative activities. Moreover, phytosterols can be used in
Such action is directly related with platelet aggregation pharmaceuticals（production of therapeutic steroids）, nu-
and antioxidant functions56−58）. In each refining stage espe- trition（ anti-cholesterol additives in foods, anti-cancer
cially during deodorization, these valuable compounds are properties）, and cosmetics（creams, lipstick） 62, 63）
.
reduced. FDA recommended daily vitamin E allowances Nutritional importance of phytosterols is due to their
for humans are: infants, 6.7 mg; adults, children, and lac- ability of lowering serum cholesterol and thereby reducing
tating and pregnant women, 20.1 mg while daily intake of risk of cardiovascular diseases. Analysis of unsaponifiable
α-tocopherol is about 5–9 mg50, 51）. extracts of deodorizer distillates reveals the presence of
Phytosterols are important members of the natural prod- the following phytosterols: β-sitosterol, brassicasterol, stig-
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 Deodorizer distillates obtained from vegetable oil processing

masterol, campesterol and cycloartenol. β-sitosterol has ef- 5 Commercial value of deodorizer distillate
fective anticancer and antipyretic properties. The National Specifications of DD obtained from various studies as
Institutes of Health has issued guidelines regarding treat- well as national and international standards provide helpful
ment of high blood cholesterol through its National Choles- data about quality and commercial importance. However,
terol Education Program. The guidelines recommended these specifications are intended to be advisory and not to
that plant sterols could be used as therapeutic dietary be implied in any contract. The commercial value of de-
options to enhance lowering of LDL（low-density lipopro- odorizer distillates depends on the level of unsaponifiable
tein）cholesterol. Per day 2 g of phytosterols along with matters. Commonly, price of DD is based on tocopherol
10–25 g of soluble fiber has been recommended for signifi- and stigmasterol contents. However, tocopherol market has
cant reduction of cholesterol64−67）. The addition of phytos- a great impact in determining the price of deodorizer distil-
terols esters to foods is regulated by the European Union lates than sterol market. Commonly, distillate obtained
Regulation （EC） No. 258/97 of the European Parliament and through physical refining is lower in value than distillate
of the Council of 27 January 1997 concerning novel foods from caustic refined oil. Because deodorizer distillates ac-
and novel food ingredients68）. quired through physical refining are less in concentration
The name squalene for the C30H62 hydrocarbon is related of tocopherols and sterols while greater in concentration of
with its occurrence in shark liver oil（Squalus spp.）. Signifi- FFAs. Furthermore, the oxidative stability of the physically
cant amount of squalene is found in rice bran oil, olive, refinery distillate is lower as measured by carbonyl and
palm and wheat germ. Squalene is an important linear hy- peroxide values1, 21, 45）. Therefore, price of deodorizer distil-
drocarbon and abundantly found in almost all types of de- lates is reduced and this affects the total sale of distillate.
odorizer distillates. It is widely used in cosmetics and in Tocopherols and phytosterols are used as active ingredi-
the biosynthesis of cholesterol69）. Hydrogenation of squa- ents in many types of functional foods. Therefore, deodor-
lene provides another important product known as squal- izer distillates with a high concentration of these compo-
ane and not subjected to autoxidation. Squalane and squa- nents should have good market value. When market of
lene can be metabolized and have a great potential to be tocopherol and sterol is strong then disposal of deodorizer
used in toxicology studies70）. Squalene in addition to other distillate is profitable. Otherwise it is sold as soap stock or
lipids such as hexadecane with mycobacterium cell wall can be disposal issue. In some countries deodorizer distil-
enhances non-specific immunity against tumors. Due to lates are used in animal and poultry feeds.
free flowing oil ability, squalane has been used in skin lubri-
cant, pharmaceuticals, and as a transporter for lipophilic
drugs. Squalene and squalane emulsions are used in human
cancer vaccines due to their effective immune response 6 Conclusions
and antitumor activity. In the United States, average daily On the one hand deodorization process removes odorif-
intake of squalene is about 30 mg per day per person. erous components from the vegetable oil to make it accept-
Squalene has been considered to be vital dietary cancer able to the consumers for edible purpose on the other hand
chemopreventive agent and powerful antioxidant70, 71）. bioactive components are achieved in concentrated form
FFAs are product of lipid hydrolysis and are directly through deodorizer distillates. However, use of optimized
related to unpleasant flavor and taste of the edible oils. parameters is necessary to control loss of nutritionally
Therefore, for edible applications, FFAs should be removed useful components from final deodorized oil during de-
through refining process. Generally, FFAs are significant odorization process. Deodorizer distillates are rich and
contributors in the composition of deodorizer distillates. At cheap sources of many valuable and health beneficial com-
present, deodorizer distillate obtained from processing of ponents such as tocopherols, phytosterols and squalenes.
vegetable oils during deodorization has gained much atten- Deodorizer distillates have a great potential to meet the in-
tion for the production of biodiesel as a green approach40, 72）. creasing demand of consumers for these natural bioactive
FFAs could be used in the formulation of animal feed and components and may find new approaches of characteriza-
soap industries as well as in the oleochemicals industries. tion and applications in pharmaceuticals, foods and cos-
Monoglycerides, diglycerides and triglycerides are known metics industries in future.
as acylglycerols. Triacyiglycerols are the significant compo-
nents in vegetable oil deodorizer distillate. Monoglycerides
and diglycerides have detergent properties as these are
easily form miscelles in water solutions1, 16, 17, 21）. Acknowledgements
Author would like to thank National Centre of Excel-
lence in Analytical Chemistry, University of Sindh, Jamsho-
ro, Pakistan for providing the kind facilities.

963
J. Oleo Sci. 65, (12) 957-966 (2016)
 S. T. H. Sherazi, S. A. Mahesar and Sirajuddin

Author Contributions 11）Xiaobin, D.; Qinghua L.; Daijun, S.; Xiumei, C.; Xiuzhu,
Conceived and designed the experiments: Sherazi, STH Y. Direct FTIR analysis of free fatty acids in ddible oils
Analysed the data: Sherazi, STH, Sirajuddin, Mahesar, using disposable polyethylene films. Food Anal. Meth-
SA ods 8, 857-863（2015）.
Wrote the first draft of the manuscript: Mahesar, SA 12）Naz, S.; Sherazi, S.T.H.; Talpur, F.N.; Mahesar, S.A.;
Contributed to the writing of the manuscript: Sherazi, Kara, H. Rapid determination of free fatty acid content
STH; Mahesar, SA; Sirajuddin Agree with manuscript in waste deodorizer distillates using SB-ATR-FTIR. J.
results and conclusions: Sherazi, STH; Mahesar, SA; Sira- AOAC Int. 95, 1570-1573（2012）.
juddin Jointly developed the structure and arguments for 13）Mahesar, S. A.; Kandhro, A. A.; Khaskheli, A. R.; Tal-
the paper: Sherazi, STH; Mahesar SA; Sirajuddin pur, M. Y.; Sherazi, S.T.H. SB-ATR FTIR spectroscopic
Made critical revisions and approved final version: monitoring of free fatty acids in commercially available
Sherazi, STH Nigella sativa（Kalonji） oil. J. Spectrosc. 1-5（2014）.
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