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1.TBHQ’s stability in vegetable crude oil
According to the third edition of “Food Additive Manual”, a majority
of vegetable crude oils can prolong their induction periods due
to rich natural antioxidants such as VE, lipoid and carotene they
contain, but their quality may be lowered during the process of
storage, transportation and refinery. Proper addition of antioxidants
in the crude oils can delay the deterioration so as to regulate
the relationship between production season and market supply and
demand. The stability effect can be seen in Figure 5 after TBHQ
is added in soybean crude oil.
Carotene in crude oils (such as palm oil and soybean oil) may be
decomposed to turn out some color developing substances in the process
of alkali refinery and decolorization, which costs more decoloring
time and bigger consumption of decoloring bleach earth。After TBHQ
is added, it has a protective effect on carotene, so simple bleaching
can achieve decolorization effect as expected. In this way, the
consumption of carclazyte can be saved. The effect can be seen in
Figure 6 and 7.
Figure 8 shows that the amount of peroxides in sunflower crude oil
is lowered evidently after the oil is protected by（generally the
amount should be lower than 20mmol/kg; the oil tastes rancidity
when the amount reaches 50mmol/kg）. The above instance illuminates
the following advantages with the use of antioxidants (such as TBHQ)：
① to prevent superoxide from forming；
② to protect natural antioxidants such as carotene and VE contained
in crude oil from losing；
③ to prolong storage period and shelf life of crude oil；
④ to decrease loss of substances during oil refinery；
⑤ to lower consumption of decoloring carclazyte；
⑥ to guarantee stability of refined oil.
Furthermore, after TBHQ is added in crude oil, the amount of VE
in leavings in deodorization can be increased obviously. After deodorization,
TBHQ added can be erased from crude oil completely so refined oil
will not contain TBHQ. At the same time, the amount of VE suffers
little loss so the refined oil has higher stability than common
refined oil. “No compound antioxidants” can also be marked in trademarks.
2. Comparison between anti-oxidation effects of antioxidants
on edible vegetable oils
Comparison
in detail is seen in Table 2. AOM value in Table 2 refers to
the time(hour) when peroxide value reaches rancidity critical point
of vegetable oil 70mmol/kg as the experiment is carried out in AOM
Stability Experiment Instrument in blast and at 97.5℃. Oven method
refer to the time(day) when vegetable oil reach rancidity critical
point 70mmol/kg in heat preservation experiment at 62.8℃.It can
be seen from the table that, with respect to vegetable oils, the
order of anti-oxidation effects of current antioxidants under the
condition of all countries’ largest allowed dosage nowadays is:
TBHQ+ citric acid>TBHQ>PG>BHT>BHA。
3、 Comparison between anti-oxidation effects of antioxidants
on edible animal oils
Results
can be seen in Table 3. AOM value in the table means the time
(hour) when peroxide value in oil reaches rancidity critical point
of animal oil 20mmol/kg.Oven method refers to storage time (days)
of oil when the oil reaches the critical point 20mmol/kg at 62.8℃。It
can be seen from Table 3 that, with respect to animal oils, the
basic order of anti-oxidation effects of current antioxidants is:
TBHQ>PG>BHA>VE
4. Detailed comparison between anti-oxidation effects of
ntioxidants on essence oils.
see Table
4.
5. Comparison between anti-oxidation effects of antioxidants
on fried food
see Table
5. Fried food such as potato chips and corn chips may contain
50% oil while instant noodle made by means of frying generally contains
over 20% oil. At the same time, such food has a large surface, so
it is easy to lead to rancidity. Experiments show that TBHQ in various
vegetable oils used from frying can prevent oxidation of food.
6、 Comparison between anti-oxidation effects of antioxidants
on baked or roasted food
Seee Table
6. In baked or roasts products, anti-oxidation effect of BHA,
BHT and VE is distinct. Generally speaking, vegetable oils bought
have been added with TBHQ or PG so as to increase stability of the
oils. Therefore, in the production process of vegetable oils, a
little bit more BHA, BHT or PG, or BHA, BHT and TBHQ in the oils
will achieve a better effect. Experiment results in Table
9 and table
10 are for reference. Seen from the results in table
9 when it comes to lard, anti-oxidation effect will be extremely
good when TBHQ and BHA are used together.
Comparison of anti-oxidation stability of food baked or roasted
with lard（See
Table 7）
7、 Comparison between anti-oxidation effects of antioxidants
on nut food
Antioxidants are usually mixed into alcohol solutions and sprayed
on nuts. TBHQ is more effective than other antioxidants. Comparison
of effects can be seen in Table
8.
8、 Comparison between anti-oxidation effects of antioxidants
on cereal products
Cereal products refer broadly to candies, snacks and cereals for
breakfast. Though the products contain low level of oil and fat,
the oil and fat is basically composed of unsaturated fatty acid,
so their stability falls distinctively when they are processed in
the heating process of baking, pressing and frying. If they are
protected with some antioxidants, their stability will be increased.
（See Table
9.）
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