HIGHLIGHTS FROM THE TOP 5
DISCUSSIONS IN 2017
Does anyone know the concentration of citric acid used
in the oil industry, and how it is added to the oil?
25–50 ppm of citric acid is added to oil to remove or inactivate metals which could lead to oxidation. The lowest
possible amount should be used because excess citric acid
raises the acidity of the oil, adding to the apparent amount
of free fatty acid present. Citric acid also degrades at high
temperatures, so it is usually added to the oil just before
it leaves the deodorizer or after deodorization once the oil
What is the maximum storage temperature and time for
soybean oil to maintain quality?
Refined soybean oil should be stored at 30°C with nitrogen
blanketing. It should be stored in CS/SS storage tanks with
positive pressure of N2 70 mm H2O, so that when you
pump out the oil, nitrogen will move into the tank. This
will prevent an increase in peroxide value, and lead to better stability and control color/flavor reversion.
How do you calculate the calories per gram in an oil?
Multiply the number of grams of fat by 9. So,
10g of fat/oil x 9 = 90 calories.
Does anybody have any ideas or suggestions to improve
crude oil content analysis on whole canola seed?
Oil extraction efficiency is a function of particle size.
AOCS Official Methods define the particle size for these
extraction methods. Am 2-93 is the internationally recognized method for exhaustive oil extraction from oilseeds.
Other oil extraction methods give lower values, though
empirical in nature, these may be better aligned expected
values from oilseed processing. Due to the difference in
particle size, changing grinders or the type of grinders is
likely to cause a difference in results. Although measuring particle size is ideal, a possible alternative would be to
devote a single grinder to the oil content test, and ensure
that the duration of grinding is consistent.
What is the importance of Stigmasta- 3,5-diene analy-
sis when determining if an extra virgin or pure olive oil is
The Stigmastadiene test will tell you if a cold-pressed oil
has been adulterated with a refined oil. Stigmasta- 3,5-
diene is a hydrocarbon derived from sterols during refining (by means of the dehydration of beta-sitosterol). The
process is thermally activated, which is why the method
explicitly states not to heat the sample solution during
testing. Since no heat is to be applied during the pressing
of EVOO, little to no stigmastadiene should be present in a
virgin olive oil.
It is theoretically possible to remove the sterols of an
oil with a similar fatty acid profile—particularly sunflower
oil—using bleaching clay during the refining process. This
would eliminate the ability to detect adulteration via differences in the sterols profiles. If this were done, the
sterols would convert to sterenes during the bleaching
process, which can be detected because the biggest sterol
peak is the betasitosterol, the biggest sterene peak would
be the stigmasta- 3,5-diene. Consequently, a Stigmasta-
3,5-diene analysis is a useful method of detecting adulter-ation.See http://lib3.dss.go.th/fulltext/Journal/J.AOCS/J.
The ratio of the degradation products of sitosterol
(stigmastadienes) and campesterol (campestadienes) is
also good marker for desterolized sunflower, soybean,
palm, or grape seed oil.
Tips from inform|connect is a regular Inform column that features tips and other
discussion highlights from the community forum board at www.informconnect.org.
inform|connect is the gateway to the new AOCS Premium Content Library, which
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• Future Impact of Technological Changes in Oilseed
Processing & Oil Refining https://tinyurl.com/
• Application of Gas Chromatography Mass
Spectrometry (GC MS) in Food Science and
• Natural fats and oils in cosmetics https://tinyurl.