WO2021004000A1 - Method for producing peanut oil rich in resveratrol - Google Patents

Abstract

A method for producing peanut oil rich in resveratrol, comprising the following steps: step I, crushing washed and dried peanut roots and mixing same with peanut kernels to obtain a mixture, wherein the mass ratio of the peanut roots to the mixture is 3-11:100; and step II, performing pressing for 15-35 min at a pressure of 25-40 MPa and a temperature of 50-70°C to obtain an oil which is peanut oil rich in resveratrol. The method for producing peanut oil rich in resveratrol does not need to add a single resveratrol product, and is suitable for industrial production.

Description

Preparation method of peanut oil rich in resveratrol Technical field

The invention relates to the field of edible oil. More specifically, the present invention relates to a method for preparing peanut oil rich in resveratrol.

Background technique

Peanut oil is the fourth largest edible oil in the world, and its consumption generally shows a slow growth trend, with an average annual compound growth rate of 1.61% (2010-2016). As a major consumer and producer of peanut oil, China consumes about 53% of the total global consumption. The consumption in 2019 is expected to reach 6.19 million tons. As people pay more attention to the nutrition and health of edible oil, functional peanut oil is more and more popular with consumers. In order to obtain more profits, oil processing companies have begun to develop functional edible oils with high nutritional value, such as Duoli α-vitamin E sunflower oil, Yihai Kerry Oryzanol rice oil and plant sterol corn oil. Functional edible oil is an inevitable trend in the development of the oil processing industry. As the fourth largest edible vegetable oil in my country, peanut oil is also in urgent need of breakthrough and development.

Peanuts are rich in many beneficial substances, such as resveratrol, calcium, zinc, catechins, vitamin E, vitamin K, a variety of amino acids and unsaturated fatty acids. Peanut oil prepared from peanuts also contains phytosterols, wheat germ phenol, phospholipids, vitamin E, choline and other beneficial substances to the human body. Regular consumption of peanut oil can reduce the content of cholesterol in plasma, prevent skin from cracking and aging, protect blood vessel walls, prevent thrombosis, improve human brain memory, and delay brain function decline. More than 80% of peanut oil is unsaturated fatty acids (including about 41% of oleic acid and about 37% of linoleic acid). It has a good composition and is easily absorbed by the human body, thereby regulating blood lipids, clearing blood clots, and enhancing memory and thinking ability.

At present, the methods for preparing functional edible oil mainly include physical methods and chemical methods. The physical methods are mainly to improve the preparation process and add functional substances. Although the operation is simple, the improvement process requires expensive equipment, and it may also generate new harmful substances on the basis of destroying the functional substances; the chemical method is mainly enzymatic esterification Although the effect of increasing the solubility of functional substances is significant, there may be problems such as reagent residues. In order to solve the above problems, this research provides a simple and efficient method for preparing peanut oil rich in resveratrol.

Summary of the invention

An object of the present invention is to solve at least the above-mentioned problems and provide at least the advantages described later.

Another object of the present invention is to provide a method for preparing peanut oil rich in resveratrol, which adopts microwave-assisted processing of raw materials to effectively promote the generation of free resveratrol and other trace components in the raw materials, and to increase the resveratrol in peanut oil The content of alcohol.

In order to achieve these objectives and other advantages according to the present invention, a method for preparing peanut oil rich in resveratrol is provided, which includes the following steps:

Step 1. The washed and dried peanut roots are crushed and mixed with peanut kernels to obtain a mixture. The mass ratio of the peanut roots to the mixture is 3-11:100;

Step 2: Pressing for 15 to 35 minutes under the conditions of a pressure of 25-40 MPa and a temperature of 50-70°C, the oil obtained is peanut oil rich in resveratrol.

Preferably, it further includes: before step two, microwave treatment of the mixture under the condition of 300-600W power for 2-8min.

Preferably, the mass ratio of peanut root to the mixture in step one is 9:100.

Preferably, in step two, the pressure for pressing the oil is 40 MPa, the temperature is 60° C., and the pressing time is 20 min.

Preferably, the peanut roots in step 1 are crushed to a size smaller than 80 mesh.

Preferably, it further includes: adding vitamin E and mixing uniformly after microwave treatment and before pressing, and then freezing treatment at -10°C for 30 minutes, wherein the mass ratio of the mixture to vitamin E is 100:1.

The present invention includes at least the following beneficial effects:

First, almost no resveratrol can be detected in peanut oil. The present invention uses peanut roots and peanuts to be squeezed simultaneously, which can enrich resveratrol in peanut oil without external addition, and is suitable for industrial production.

Second, the present invention adopts microwave assisted processing of raw materials, which effectively promotes the dissolution of free resveratrol and other trace components in the raw materials, and increases the content of resveratrol in peanut oil.

Third, the microwave-assisted low-temperature pressing process of the present invention has simple operation, short time-consuming, and low cost; and the process temperature is lower than 70° C., and no harmful substances such as trans fatty acids are produced in the prepared peanut oil.

Fourth, the peanut oil rich in resveratrol prepared by the present invention, except for the rich resveratrol and other beneficial components in peanuts, its color, acid value, peroxide value, moisture volatile content and heavy metal content are all consistent with The national standard of edible vegetable oil has good nutrition fortification function, good application value and market prospect.

Other advantages, objectives and features of the present invention will be partially embodied by the following description, and partly will be understood by those skilled in the art through the research and practice of the present invention.

Description of the drawings

Figure 1 shows the effect of the mass ratio of peanut root to the mixture on resveratrol in peanut oil;

Figure 2 shows the effect of microwave treatment time on resveratrol in peanut oil;

Figure 3 shows the effect of microwave processing power on resveratrol in peanut oil;

Figure 4 shows the effect of pressing time on resveratrol in peanut oil;

Figure 5 shows the effect of pressing temperature on resveratrol in peanut oil;

Figure 6 shows the effect of pressing pressure on resveratrol in peanut oil;

Figure 7 is a response surface diagram showing the influence of the interaction of microwave processing time and pressing temperature on the content of resveratrol in peanut oil;

Figure 8 is a response surface diagram showing the effect of the interaction of the ratio of peanut root to the mixture mass and the pressing temperature on the content of resveratrol in peanut oil.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it with reference to the text of the description.

It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials, unless otherwise specified, can be obtained from commercial sources.

The reagents and instruments used in the present invention are as follows:

Peanut roots: picked from Xinjiang peanut raw material base in October 2018;

Peanuts: picked from Xinjiang peanut raw material base in October 2018;

All other reagents are chromatographically pure.

Centrifuge: Model LXJ-IIB, Shanghai Anting Scientific Instrument Factory;

Ultra high performance liquid chromatograph: ACQUITY H Class, Waters;

Vortex oscillator: Vortex-Genie 2, Scientific Industries;

Microwave oven: MG720KG3-NA1, Guangdong Midea Microwave Electric Manufacturing Co., Ltd.

<Example 1>

The preparation method of peanut oil rich in resveratrol includes the following steps:

Step 1. The washed and dried peanut roots are crushed to less than 80 mesh, and mixed with peanut kernels to obtain a mixture. The mass ratio of the peanut roots to the mixture is 3:100;

Step 2: Pressing for 15 minutes under the conditions of a pressure of 25MPa and a temperature of 50°C, the oil obtained is peanut oil rich in resveratrol.

<Example 2>

The preparation method of peanut oil rich in resveratrol includes the following steps:

Step 1. The washed and dried peanut roots are crushed to less than 80 mesh, and mixed with peanut kernels to obtain a mixture. The mass ratio of the peanut roots to the mixture is 11:100;

Step 2: Pressing for 35 minutes under the conditions of a pressure of 40MPa and a temperature of 70°C, the oil obtained is peanut oil rich in resveratrol.

<Example 3>

The preparation method of peanut oil rich in resveratrol includes the following steps:

Step 1. The washed and dried peanut roots are crushed to less than 80 mesh, and mixed with peanut kernels to obtain a mixture. The mass ratio of peanut roots to the mixture is 9:100;

Step 2: Pressing for 20 minutes under the conditions of a pressure of 40MPa and a temperature of 60°C, the oil obtained is peanut oil rich in resveratrol.

<Example 4>

The preparation method of peanut oil rich in resveratrol is the same as that in Example 1, except that, before step 2, the mixture is subjected to microwave treatment with a power of 300 W for 2 min.

<Example 5>

The preparation method of peanut oil rich in resveratrol is the same as that in Example 2, except that, before step 2, the mixture is subjected to microwave treatment at a power of 600W for 8 minutes.

<Example 6>

The preparation method of peanut oil rich in resveratrol is the same as that in Example 3, except that, before step 2, the mixture is subjected to microwave treatment with a power of 500 W for 6 min.

<Example 7>

The preparation method of peanut oil rich in resveratrol is the same as that in Example 6, except that, after microwave treatment, before pressing, vitamin E is added and mixed well, and then frozen at -10°C for 30 minutes, where, The mass ratio of the mixture to vitamin E is 100:1.

<Comparative Example 1>

The preparation method of peanut oil rich in resveratrol includes the following steps: peanut kernels are squeezed under the conditions of a pressure of 40 MPa and a temperature of 60° C. for 20 minutes, and the obtained oil is peanut oil rich in resveratrol.

<Quality Evaluation of Peanut Oil Rich in Resveratrol>

The quality of the peanut oil prepared in Examples 1-7 was tested, and the results are shown in Table 1:

Table 1 Quality index of peanut oil rich in resveratrol

project	Quality Index
Smell and taste	Has the original smell and taste of peanuts, no peculiar smell
Moisture and volatile content/% ≤	0.10
Insoluble impurity content/%≤	0.03
Acid value (KOH)/(mg/g) ≤	1.1
Peroxide value/(mmol/kg) ≤	4.0
Residual solvent volume/(mg/kg) ≤	not detected

It can be seen from the above table that the quality of the peanut oil prepared in Examples 1-7 all meet the national edible vegetable oil standard.

<Resveratrol Content Evaluation>

The content of resveratrol in the peanut oil prepared in Examples 1-7 and Comparative Example 1 was tested, and the results are shown in the following table:

Table 2 The content of resveratrol in Examples 1-7 and Comparative Example 1

Group	Resveratrol mg/kg
Example 1	0.01
Example 2	0.48
Example 3	0.88
Example 4	0.45
Example 5	0.75
Example 6	0.97
Example 7	1.02

Comparative example 1

not detected

It can be seen from the above table that although peanut kernels contain resveratrol, after being pressed into peanut oil, the content of resveratrol in peanut oil is too small to be detected, and the peanut kernels with a small amount of peanut roots are increased after pressing. The content of peanut oil and resveratrol increased significantly, indicating that the appropriate amount of peanut root in the raw material can increase the content of resveratrol in peanut oil. From the comparison of Examples 4-6 with Examples 1-3, it can be seen that microwave treatment can further promote The dissolution of resveratrol increases the content of resveratrol in peanut oil.

<Resveratrol Stability Evaluation>

The peanut oil prepared in Examples 6 and 7 was baked in an oven at 180°C for 5 minutes, and the content of resveratrol in each group was tested after cooling. The results are shown in the following table:

Table 3 The content of resveratrol in Examples 6-7

Group	Resveratrol mg/kg
Example 6	0.35
Example 7	0.52

The content of resveratrol in the peanut oil prepared in Examples 6 and 7 was significantly reduced after high temperature treatment, but the reduction in Example 7 was the least, indicating that the combination of vitamin E and freezing treatment can reduce the heat of resveratrol loss.

<Single factor test of peanut oil rich in resveratrol>

Figure 1 shows the effect of the mass ratio of peanut roots in the mixture on resveratrol in peanut oil. It can be seen from Figure 1 that the content of resveratrol in peanut oil first increases and then does not change as the mass ratio of peanut roots in the mixture increases. When the mass ratio of peanut roots in the mixture is 9%, the resveratrol content of peanut oil is 1.25mg/kg. Peanut roots are rich in resveratrol, and when the mass of peanut roots in the mixture is relatively low, as the proportion of peanut roots increases, the content of resveratrol in peanut oil after squeezing continues to increase. Since resveratrol is hard to dissolve in peanut oil, the content of resveratrol in peanut oil will not continue to increase after reaching a certain degree of saturation.

Figure 2 shows the effect of microwave treatment time on resveratrol in peanut oil. It can be seen from Figure 2 that the content of resveratrol in peanut oil increases with the extension of microwave treatment time, and the maximum content is 0.65 mg/kg at 6 min. Microwave treatment can destroy the structure of peanut cells and may promote the dissolution of free resveratrol. After reaching a certain degree of saturation, the content of resveratrol will no longer increase.

Figure 3 shows the effect of microwave processing power on resveratrol in peanut oil. It can be seen from Figure 3 that the resveratrol content in peanut oil increases with the extension of microwave processing power. At 500W, the highest resveratrol content is 0.71 mg/kg. With the increase of microwave processing power, the content of resveratrol no longer changes significantly. Since the more suitable microwave power for microwave equipment is 500W, in order to prolong the service life of the equipment, 500W is selected as the best microwave power.

Figure 4 shows the effect of pressing time on resveratrol in peanut oil. It can be seen from Figure 4 that the content of resveratrol in peanut oil does not change much with the extension of pressing time. The squeezing time is within 15 minutes, the oil is produced quickly, and the fat in the peanut is squeezed out by 65-75%. When the squeezing time is 20 minutes, the resveratrol content reaches the maximum value of 0.73 mg/kg. As the pressing time increases, the oil output is slower and is not conducive to continuous production, so 20min is selected as the best pressing time.

Figure 5 shows the influence of pressing temperature on resveratrol in peanut oil. It can be seen from Fig. 5 that the content of resveratrol in peanut oil first increases and then decreases with the increase of pressing temperature, reaching the maximum value of 0.77mg at a pressing temperature of 60℃ /kg. Suitable temperature promotes the dissolution of resveratrol, but when the temperature is too high, resveratrol is unstable, which reduces the content of resveratrol in peanut oil.

Figure 6 shows the effect of pressing pressure on resveratrol in peanut oil. It can be seen from Fig. 6 that the content of resveratrol in peanut oil first increases with the increase of pressing pressure and then does not change. When the pressing pressure is 40MPa, the maximum value is 0.66mg/kg. The increase of squeezing pressure is accompanied by the increase of physical extrusion strength, which is beneficial to the dissolution of resveratrol in the peanut mixture. 40MPa is the highest safety pressure of hydraulic equipment. In order to extend the service life of the equipment, this pressure is the best choice.

According to the principle of Box-Behnken center design, and on the basis of single factor test results, three factors that have a greater impact on the content of resveratrol in peanut oil (the ratio of peanut root to the mass of the mixture, microwave treatment time and pressing temperature) are selected as Independent variable, taking resveratrol content in peanut oil as the response value, using Design Expert software to design a three-factor three-level response surface, as shown in Table 4:

Table 4 Test factor levels

The results of the response surface test are as follows:

Table 5 Three-factor three-level Box-Behnken experiment design and results

Through the multiple regression fitting of the test data in Table 5 (Design Expert software), the second-order polynomial regression equation of the content of resveratrol in peanut oil on the mass ratio of independent variable peanut root to the mixture, the microwave processing time and the actual value of the pressing temperature is obtained. :

Y＝-177.03+6.62X ₁ +3.01X ₂ +4.65X ₃ +0.02X ₁ X ₃ +0.03X ₂ X ₃ -0.45X ₁ ² -0.40X ₂ ² -0.04X ₃ ²

Table 6 Response surface quadratic model variance analysis of resveratrol content in peanut oil

NS: no significant difference, P>0.05; *: significant difference, P<0.05; **: very significant difference, P<0.01; R ² is 0.9961; Adj R ² is 0.9910; CV% is 9.03.

Through the analysis of variance on the model, the results are shown in Table 6. The model is extremely significant (P<0.0001). The influence of each factor on Y is not a simple linear relationship; the equation determination coefficient R ² is 0.9961, indicating that the regression model can be very Explain the relationship between the independent variable and Y well. The correction coefficient of determination Adj R ² is 0.9910, indicating that the model has good fit. The lack of fit term of the model P = 0.2311> 0.05, indicating that the lack of fit term of the model is not significant. The coefficient of variation CV of the model is 9.03%<10%, indicating that the quadratic polynomial model is acceptable. Therefore, this model can more accurately analyze and predict the content of resveratrol in peanut oil.

Figure 7 shows the effect of the interaction of microwave treatment time and pressing temperature on the content of resveratrol in peanut oil. Analysis of the effect of the interaction of microwave treatment time and pressing temperature on the content of resveratrol in peanut oil shows that the microwave treatment time is certain , The content of resveratrol in peanut oil first increases and then decreases with the increase of the pressing temperature; when the pressing temperature is constant, the content of resveratrol in peanut oil first increases and then decreases with the extension of the microwave treatment time; and The influence of temperature is more significant than that of microwave processing time.

Figure 8 shows the effect of the interaction between the mass ratio of peanut roots in the mixture and the pressing temperature on the content of resveratrol in peanut oil. Analysis of the interaction between the mass ratio of peanut roots in the mixture and the pressing temperature on the content of resveratrol in peanut oil shows that : When the ratio of peanut root to the mass of the mixture is constant, the content of resveratrol in peanut oil first increases and then decreases with the increase of pressing temperature; when the pressing temperature is constant, the content of resveratrol in peanut oil increases with the mass ratio of peanut root to the mass of the mixture. Increase first increase and then decrease.

The results show that the best parameters obtained by analysis and prediction using Design Expert software are: the ratio of peanut roots to the mixture is 9.03%, the microwave processing time is 6.05 min, and the pressing temperature is 59.82℃. However, considering the actual operation and equipment errors, the process conditions were adjusted as follows: peanut roots accounted for 9% of the mixture, microwave treatment time 6min and pressing temperature 60℃, and the resveratrol content in peanut oil reached 1.00mg/kg. The predicted results are not significantly different from the actual results, indicating that the model is more reliable and can be used to predict the preparation process.

Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. For those familiar with the field, it can be easily Therefore, without departing from the general concept defined by the claims and equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims (6)

1. The preparation method of peanut oil rich in resveratrol is characterized in that it comprises the following steps:

   Step 1. The washed and dried peanut roots are crushed and mixed with peanut kernels to obtain a mixture. The mass ratio of the peanut roots to the mixture is 3-11:100;

   Step 2: Pressing for 15 to 35 minutes under the conditions of a pressure of 25-40 MPa and a temperature of 50-70°C, the obtained oil is peanut oil rich in resveratrol.
2. The method for preparing peanut oil rich in resveratrol according to claim 1, characterized in that it further comprises: before step 2, microwave processing the mixture under the condition of 300-600W power for 2-8min.
3. The method for preparing peanut oil rich in resveratrol according to claim 1, wherein the mass ratio of peanut root to the mixture in step 1 is 9:100.
4. The method for preparing peanut oil rich in resveratrol according to claim 1, characterized in that in step 2, the oil squeezing pressure is 40 MPa, the temperature is 60° C., and the squeezing time is 20 min.
5. The method for preparing peanut oil rich in resveratrol according to claim 1, wherein the peanut root in step one is crushed to a size smaller than 80 mesh.
6. The method for preparing peanut oil rich in resveratrol according to claim 2, characterized in that it further comprises: after microwave treatment and before pressing, adding vitamin E and mixing uniformly, wherein the mass ratio of the mixture to the vitamin E It is 100:1.

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