ABSTRACT: The physicochemical characteristics and minor
component contents of blended oils packed in pouches in rela-
tion to starting oils used for blending were studied over a pe
-
riod of 6 mon at two storage temperatures and humidity condi-
tions: 27°C/65% RH and 40°C/30–40% RH. Color, PV, FFA
value,
β-carotene content, tocopherol content, and oryzanol
content of the oils were monitored at regular intervals. The
color, PV (0.6–20.7 meq O
2
/kg , FFA value (0.08–2.1%), toco-
pherol content (360–1700 ppm%), oryzanol content
(460–2,000 mg%), and sesame oil antioxidants (400–2,000
mg%) were not changed in either the starting oils or their
blends. Oils and oil blends containing a higher initial PV
(18.9–20.7 meq O
2
/kg) showed a slight reduction in value at
40°C, whereas oils having lesser PV of 5-10 showed a slight in-
crease during the storage period. Among the minor components
studied, only
β-carotene showed a reduction, 8.9–60.2% at
27°C and 48–71% at 40°C, for the different oil blends studied.
The observed results indicated that the packed oil blends stud-
ied were stable under the conditions of the study, and the minor
components, other than
β-carotene, remained unaltered in the
package even at the end of 6 mon of storage.
Paper no. J10772 in
JAOCS 81, 1125–1129 (December 2004).
KEY WORDS: Blended oil, micronutrients, minor compo-
nents, minor constituents, packaging, storage stability, veg-
etable oil blends.
India occupies an important place in the world in production
of major oilseeds (1). About 60% of the oil extracted from
these oilseeds contains 40% or more of unsaturated FA. Edi-
ble oil quality is defined mainly by organoleptic parameters
such as flavor
, odor, and color for expeller-pressed unrefined
vegetable oils; and certain other physicochemical characteris-
tics such as FFA value, saponification value, iodine value,
Bellier turbidity test, refractive index, unsaponifiable matter
,
and FA composition are being used for determining the qual-
ity of refined vegetable oils. However, more emphasis is
placed on the PUFA content and natural antioxidants present
as minor components in the oil. The minor constituents,
which are uniquely present in certain vegetable oils, are asso-
ciated with medicinal qualities and hence helpful in prevent-
ing diseases and promoting health. These include the oryzanol
present in rice bran oil (RBO), which has been shown to have
hypocholesterolemic activity (2,3). The β-carotene found in
palm oil, which functions as provitamin A and a scavenger of
oxygen free radicals, has health benefits of its own (4). Toco-
pherols and tocotrienols present in unrefined and physically
refi
ned oils, such as palm oil and RBO, have antioxidative and
hypocholesterolemic properties and are benefi
cial in preventing
cardiovascular diseases (5). Sesame oil (SESO) contains
sesamin, which acts as an antioxidant and a hypocholes
-
terolemic agent (6). W
ith the growing awareness of health
and fitness among consumers, the health-improving minor
components of vegetable oils are being isolated and used as
nutritional supplements.
With this background, the present study was undertaken to
incorporate health-improving minor components, found in
underutilized vegetable oils, into more widely used oils
through blending. The major vegetable oils commonly used
in different regions of India are groundnut oil (GNO), sun-
flowerseed oil (SFO), and mustardseed oil (MO). These oils
do not contain the health-improving minor components such
as oryzanol, tocotrienols, and lignan antioxidants. Indian food
laws do not permit external addition of minor components as
concentrates/isolates to vegetable oils, but a vegetable oil (un-
refined or refined grade) containing minor components can be
incorporated at a level of 20 to 80% in any other vegetable oil
(7,8). Previous reports on oil blends have focused on compo-
nent tocopherols (9), F
A composition in relation to stability
(10), and storage stability of oil blends (1
1). No data regard
ing
stability during storage under packed conditions of oil blends
containing minor components such as
β-carotene, tocoph-
erols, oryzanol, and SESO lignan antioxidants are available.
In this communication, we report the preparation and storage
stability of oil blends enriched with minor components with
reference to the starting oils used for the preparation of oil
blends.
MATERIALS AND METHODS
Refined vegetable oils, GNO, and SFO and expeller-pressed,
unrefined mustard oil (MO) and SESO, were purchased from
the local market of Mysore city; RBO (physically refined,
from Eastman Agro Mills, Ltd., New Delhi, India) and unre-
fined palm oil (Palm Tech India, Ltd., Mysore, India) were
obtained from the manufacturers. The unrefined palm oil was
fractionated into olein and stearin fractions by using a sus-
pended basket centrifuge followed by a mild treatment of
olein fraction with alkali to yield deacidified red palm olein
*To whom correspondence should be addressed.
E-mail: aggk_55@yahoo.com.
Storage Stability Evaluation
of Some Packed Vegetable Oil Blends
P.M. Shiela, Y.N. Sreerama, and A.G. Gopala Krishna*
Department of Lipid Science and Traditional Foods, Central Food Technological Research Institute (CFTRI), Mysore 570 020, Karnataka, India
Copyright © 2004 by AOCS Press 1125 JAOCS, Vol. 81, no. 12 (2004)