HIGH-POLYPHENOL RAPESEED OIL AND PREPARATION METHOD THEREOF

HUILE DE COLZA HAUTE EN POLYPHENOL ET METHODE DE PREPARATION

English Abstract

A high-polyphenol rapeseed oil and a preparation method thereof are provided, the preparation method sequentially including: cyclically heating rapeseeds for 5- 30 min and until heating to reach a temperature range of 100-180 C to obtain the heated rapeseeds; squeezing the heated rapeseeds, and sequentially settling and filtering to obtain crude rapeseed oil; adding silicon dioxide into the crude rapeseed oil, stirring for 5-30 min at conditions of a temperature of 20-60 C and a stirring speed of 50-300 r/min, filtering or centrifuging to obtain refined rapeseed oil; mixing the refined rapeseed oil and oilcake, extracting for 0.5-10 hours at conditions of a temperature of 40-100 C and the stirring speed of 50-300 r/min, and filtering or centrifuging to obtain high polyphenol rapeseed oil, which can effectively solve problems of food safety risk, low polyphenol content, easy loss and low nutritional quality in the related art.

French Abstract

Une huile de colza haute en polyphénol et une méthode de préparation connexe sont décrites. La méthode comprend séquentiellement : le chauffage cyclique des colzas de 5 à 30 minutes, jusquà latteinte dune plage de températures de 100 à 180 °C pour obtenir des colzas chauffés; le pressage des colzas chauffé et le dépôt et le filtrage séquentiels pour obtenir une huile de colza brute; lajout de dioxyde de silicium dans lhuile de colza brute, le mélange de 5 à 30 minutes dans des conditions définies par une température de 20 à 60 °C et une vitesse de mélange de 50 à 300 tours par minute, le filtrage ou la centrifugation pour obtenir une huile de colza raffinée; le mélange de lhuile de colza raffinée et dun tourteau, lextraction de 0,5 à 10 heures dans des conditions définies par une température de 40 à 100 °C et une vitesse de mélange de 50 à 300 tours par minute, et le filtrage ou la centrifugation pour obtenir une huile de colza à haute teneur en polyphénol, laquelle permet de résoudre efficacement les problèmes du risque de salubrité des aliments, dune faible teneur en polyphénol, de perte alimentaire facile et de faible qualité nutritionnelle dans lart connexe.

Claims

CLAIMS
What is claimed is:
1. A preparation method of high-polyphenol rapeseed oil comprising:
step (1), cyclically heating a rapeseed raw material for 5-30 minutes at a low
temperature of 50-120 C and at a high temperature of 120-300 C, until the
heating of the rapeseed raw material reaches a temperature of 100-180 C to
obtain
a heated rapeseed raw material, wherein for each heating cycle of the
cyclically
heating, the cyclically heating of the rapeseed raw material at the high
temperature
of 120-300 C in the step (1) is perfoimed for 1-30 s at the high temperature,
and
wherein the each heating cycle is 1-5 min;
step (2), squeezing the heated rapeseed raw material at a temperature of 100-
180 C,
and then sequentially settling and filtering to obtain a crude rapeseed oil;
step (3), adding silicon dioxide into the crude rapeseed oil, stirring for 5-
30 min at
a temperature of 20-60 C and a stirring speed of 50-300 r/min, and then
filtering
or centrifuging to obtain a refined rapeseed oil; and
step (4), mixing the refined rapeseed oil and oilcake, extracting for 0.5-10
hours
at a temperature of 40-100 C and a stifling speed of 50-300 r/min, and then
filtering or centrifuging to obtain the high-polyphenol rapeseed oil.
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Date Reçue/Date Received 2023-12-21

2. The preparation method as claimed in claim 1, wherein 3 wt % of the silicon
dioxide is added.
3. The preparation method as claimed in claim 1, wherein a mass ratio
of the refined
rapeseed oil to the oilcake in the step (4) is 2-20:1.
4. A high-polyphenol rapeseed oil prepared by the preparation method of any
one of
claims 1 to 3.
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Date Reçue/Date Received 2023-12-21

Description

HIGH-POLYPHENOL RAPESEED OIL AND PREPARATION METHOD
THEREOF
BACKGROUND
1. Technical Field
[0001] The
present disclosure generally relates to the technical field of rapeseed
oil preparation technologies, and especially relates to high-polyphenol
rapeseed oil and
a preparation method thereof.
2. Description of Related Art
[0002]
Vegetable oil is rich in phytosterols, tocopherols, flavonoids, phenols
and other nutrients, which are closely related to human health. Relevant
documents
report that phenolic compounds have good inoxidizability, anti-inflammation,
antibacterial, anti-anxiety and anti-cancer properties. It is beneficial for
people to take
appropriate phenolic substances every day. Therefore, it is of great
significance to study
these oilseeds.
[0003] Edible
vegetable oil is usually processed through full refining
processes such as degumming, impurity removal, desolventizing,
deacidification,
drying, decolorization, deodorization and dewaxing to obtain high-purity
triglycerides,
so that active ingredients and special flavour of the vegetable oil are lost
while
hazardous substances are removed. It causes unnecessary consumption of energy
and
materials, which takes a long time and increases possibility of wastewater
pollution
discharge.
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Date Regue/Date Received 2022-08-18

[0004] Most commercially available rapeseed oil is poor in
polyphenol
contents. Most polyphenols in rapeseed oil are lost during processing, which
causing
great waste and reducing nutritional quality of rapeseed oil. A new processing
technique
can effectively improve the polyphenol content in rapeseed oil by roasting and
microwave treatment on raw materials. The polyphenol content in rapeseed oil
can be
effectively reserved by combining technologies such as proper processing and
green
refining. However, probability of increasing of carcinogens such as
benzopyrene will
be increased while improving the polyphenol content in rapeseed oil by a
conventional
roasting method. The flavour of rapeseed oil produced by microwave is greatly
different
from that of rapeseed oil produced by conventional methods. It is worthy of
attention
to furthest improve and keep the polyphenol content, maintain original
flavour, and
simultaneously reduce the safety risk of rapeseed oil.
SUMMARY
[0005] The technical problems to be solved: in view of the
shortcomings of the
related art, the present disclosure provides high-polyphenol rapeseed oil and
a
preparation method thereof which can effectively solve problems of food safety
risk, a
low content and easy loss of polyphenol, and low nutritional quality in the
related art,
rather than reducing the nutritional quality of rapeseed oil and causing
unnecessary
consumption.
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Date Regue/Date Received 2022-08-18

[0006] The technical solution adopted for solving technical problems
of the
present disclosure is: a preparation method of high-polyphenol rapeseed oil
according
to an embodiment of the present disclosure includes the following steps:
[0007] step (1), cyclically heating rapeseeds for 5-30 minutes in a
low
temperature region of 50-120 C and a high temperature region of 120-300 C,
until
the rapeseeds reach at a temperature range of 100-180 C to obtain the heated
rapeseeds;
[0008] step (2), squeezing the heated rapeseeds that have been
obtained in the
step (1) at the temperature of 100-180 C, and then sequentially settling and
filtering to
obtain crude rapeseed oil;
[0009] step (3), adding silicon dioxide into the crude rapeseed oil
that has been
obtained in the step (2), stirring for 5-30 minutes at conditions of a
temperature of 20-60
C and a stirring speed of 50-300 r/min, and then filtering or centrifuging to
obtain
refined rapeseed oil; and
[0010] step (4), mixing the refined rapeseed oil that has been
obtain in the step
(3) and oilcake, extracting for 0.5-10 hours at conditions of a temperature of
40-100 C
and the stirring speed of 50-300 r/min, and then filtering or centrifuging to
obtain the
high-poly phenol rapeseed oil.
[0011] Wherein cyclically heating the rapeseeds for 5-30 minutes at
the high
temperature of 120-300 C in the step (1) is performed for 1-30 seconds in the
high
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Date Regue/Date Received 2022-08-18

temperature region in each heating cycle.
[0012] Wherein cyclically heating the rapeseeds for 5-30 minutes in
the step (1)
is that each circle is 1-5 minutes.
[0013] Wherein the silicon dioxide in the step (3) is added in an
amount of 0.5-
wt%.
[0014] Wherein 3 wt % of the silicon dioxide is added.
[0015] Wherein a mass ratio of the refined rapeseed oil to the
oilcake in the
step (4) is 2-20:1.
[0016] Wherein a mixing ratio of the refined rapeseed oil and the
oilcake is
11:1.
[0017] A high-polyphenol rapeseed oil prepared by the above
preparation
method is provided.
[0018] In summary, the present disclosure provides the advantages as
below:
[0019] there are many kinds of polyphenols in rapeseeds and rapeseed
oil, and
a solubility of various polyphenols in the oil is different. Therefore, in
order to improve
the polyphenol content in rapeseed oil, it is necessary to convert the
polyphenols that
are difficult to dissolve in the oil into the polyphenols that are easy to
dissolve in the
oil. It was found that the polyphenol content in rapeseed oil can be increased
by a
heating mode, and the polyphenol content tends to be increased and then
decreased with
a heating temperature and a heating time being increased. Although the
conventional
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Date Regue/Date Received 2022-08-18

heating method can also achieve the above purpose, it is easy to cause the
increase of
benzopyrene and other hazardous substances, even exceeding a standard thereof.
Therefore, the present disclosure has the following advantages:
[0020] firstly, through cyclically heating at a high temperature and
a short time,
the conversion of oil-soluble polyphenols is promoted and the hazardous
substances are
controlled to be generated, which not only improves the nutrition value of
rapeseed oil,
but also ensures food safety;
[0021] secondly, green refining is performed at the low temperature
by silicon
dioxide adsorption so that the polyphenol content can be effectively reserved,
and
phospholipids and benzopyrene in rapeseed oil are further removed, to improve
the
quality of rapeseed oil;
[0022] thirdly, the polyphenol content in rapeseed oil can be
further improved
by extracting the oilcake.
DETAILED DESCRIPTION
[0023] A first embodiment
[0024] a preparation method of the high-polyphenol rapeseed oil
sequentially
includes the following steps:
[0025] step (1), cyclically heating rapeseeds for 15 minutes at a
low
temperature of 50 C and a high temperature of 300 C, until heating the
rapeseeds to
Date Regue/Date Received 2022-08-18

reach at a temperature of 150 C, to obtain the heated rapeseeds; wherein
heating the
rapeseeds at the high temperature of 300 C is performed for 30 s each time
and each
cycle period is 5 minutes;
[0026] step (2), squeezing the heated rapeseeds that have been
obtained in the
step (1) at the temperature of 150 C, and then sequentially settling and
filtering to
obtain crude rapeseed oil;
[0027] step (3), adding 3 wt% of silicon dioxide into the crude
rapeseed oil that
has been obtained in the step (2), stirring for 30 min at conditions of a
temperature of
40 C and a stirring speed of 150 r/min, and then filtering or centrifuging to
obtain
refined rapeseed oil;
[0028] step (4), mixing the refined rapeseed oil that has been
obtain in the step
(3) and oilcake according to a mass ratio of 20:1, extracting for 5 hours at
conditions of
a temperature of 40 C and the stirring speed of 150 r/min, and then filtering
or
centrifuging to obtain high polyphenol rapeseed oil.
[0029] A second embodiment
[0030] a preparation method of the high-polyphenol rapeseed oil
sequentially
includes the following steps:
[0031] step (1), cyclically heating rapeseeds for 30 minutes at a
low
temperature of 50 C and a high temperature of 120 C, until heating the
rapeseeds to
reach at a temperature of 100 C, to obtain the heated rapeseeds; wherein
heating the
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Date Regue/Date Received 2022-08-18

rapeseeds at the high temperature of 120 C is performed for 1 s each time and
each
cycle period is 1 minute;
[0032] step (2), squeezing the heated rapeseeds that have been
obtained in the
step (1) at the temperature of 100 C, and then sequentially settling and
filtering to
obtain crude rapeseed oil;
[0033] step (3), adding 0.5 wt% of silicon dioxide into the crude
rapeseed oil
that has been obtained in the step (2), stirring for 5 min at conditions of a
temperature
of 20 C and a stirring speed of 50 r/min, and then filtering or centrifuging
to obtain
refined rapeseed oil;
[0034] step (4), mixing the refined rapeseed oil that has been
obtain in the step
(3) and oilcake according to a mass ratio of 2:1, extracting for 0.5 hours at
conditions
of a temperature of 40 C and the stirring speed of 50 r/min, and then
filtering or
centrifuging to obtain high polyphenol rapeseed oil.
[0035] A third embodiment
[0036] a preparation method of the high-polyphenol rapeseed oil
sequentially
includes the following steps:
[0037] step (1), cyclically heating rapeseeds for 5 minutes at a low
temperature
of 120 C and a high temperature of 300 C, until heating the rapeseeds to
reach at a
temperature of 180 C, to obtain the heated rapeseeds; wherein heating the
rapeseeds at
the high temperature of 300 C is performed for 30 s each time and each cycle
period
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Date Regue/Date Received 2022-08-18

is 1 minute;
[0038] step (2), squeezing the heated rapeseeds that have been
obtained in the
step (1) at the temperature of 180 C, and then sequentially settling and
filtering to
obtain crude rapeseed oil;
[0039] step (3), adding 5 wt% of silicon dioxide into the crude
rapeseed oil that
has been obtained in the step (2), stirring for 30 min at conditions of a
temperature of
60 C and a stirring speed of 300 r/min, and then filtering or centrifuging to
obtain
refined rapeseed oil;
[0040] step (4), mixing the refined rapeseed oil that has been
obtain in the step
(3) and oilcake according to a mass ratio of 20:1, extracting for 10 hours at
conditions
of a temperature of 100 C and the stirring speed of 300 r/min, and then
filtering or
centrifuging to obtain high polyphenol rapeseed oil.
[0041] First comparative example
[0042] A difference between the first comparative example and the
first
embodiment is that the heating time of each cycle in the step (1) in the high
temperature
region is 3 min.
[0043] Second comparative example
[0044] The second comparative example is different from the first
embodiment
in that a total heating time in the step (1) is 5 min.
[0045] Third comparative example
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Date Regue/Date Received 2022-08-18

[0046] A preparation method of rapeseed oil includes the following
steps:
roasting rapeseeds for 20 min at a temperature of 150 C, and squeezing at the
temperature of 150 C, removing phospholipids from crude oil by hydration, and
then
settling or filtering to obtain rapeseed oil.
[0047] Rapeseed oil that has been obtained in the first to third
embodiments,
and the first to third comparative examples are measured for their nutrient
contents, and
results thereof are shown in table 1.
[0048] Table 1
Determination results of nutrient components of rapeseed oil
Polyphenol Benzo [a] pyrene Phospholipid
Embodiments content content content Special
flavour
(mg/kg) ( g/kg) (mg/kg)
First
3977 1.5 1284 strong
fragrance
embodiment
Second
523 Not detected 244 delicate fragrance
embodiment
Third
3069 4.2 2118 strong
fragrance
embodiment
Comparative
2673 9.7 2155 strong
fragrance
example 1
Comparative
398 Not detected 256 delicate fragrance
example 2
Comparative
2821 6.8 2594 strong
fragrance
example 3
[0049] It can be seen from table 1 that if a duration of the high
temperature is
too long, the polyphenol content in rapeseed oil will decrease due to
decomposition, the
phospholipid content will increase due to an increase of solubility, and the
content of
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Date Regue/Date Received 2022-08-18

benzopyrene will increase. If the rapeseeds are not cyclically heated, the
heating time
is insufficient, both a conversion rate of the polyphenol and the polyphenol
content in
rapeseed oil are low. By cyclically heating for a short time at the high
temperature, it
can effectively improve the polyphenol content in rapeseed oil and effectively
control
benzopyrene to be generated.
[0050]
Although the present disclosure has been described in detail with
reference to specific embodiments thereof, it should not be construed as
limiting the
protection scope of the present disclosure, each feature or element can be
used alone or
in other various combinations within the principles of the present disclosure
to the full
extent indicated by the broad general meaning of the terms in which the
appended
claims are expressed.
Date Regue/Date Received 2022-08-18