CN110951536A

CN110951536A - Cream-flavor peanut oil and preparation method thereof

Info

Publication number: CN110951536A
Application number: CN201911155813.7A
Authority: CN
Inventors: 刘国琴; 乔泽茹
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2019-11-22
Filing date: 2019-11-22
Publication date: 2020-04-03
Anticipated expiration: 2039-11-22
Also published as: CN110951536B

Abstract

The invention discloses cream-flavor peanut oil and a preparation method thereof, wherein the preparation method comprises the following steps: (1) pre-adjusting moisture of peanut kernels: selecting peeled peanut raw materials, soaking the peeled peanut raw materials in deionized water, and taking out the peeled peanut raw materials for later use after the moisture content is preset; (2) treating peanut kernels by using pulsed electric field equipment: adopting pulsed electric field extraction equipment, putting peeled peanuts with preset moisture in a treatment chamber, adding deionized water, fixing the distance between electrode plates, exhausting air bubbles, and treating peanut kernels; (3) drying the peanut kernels: drying the peanut kernels in an oven to the required moisture content; (4) low-temperature squeezing: putting the peanut kernels into a preheated oil press, and squeezing at low temperature to obtain peanut oil; (5) and (3) centrifugal clarification: and centrifuging the cold-pressed peanut oil at low temperature to prepare the clear peanut oil with cream fragrance. The method pretreats the peanut kernels through the pulse electric field, has simple preparation process, well reserves nutrient substances in the peanut oil, is easy to control cream fragrance, and is suitable for producing the milk-flavor peanut oil.

Description

Cream-flavor peanut oil and preparation method thereof

Technical Field

The invention belongs to the field of edible oil processing, and particularly relates to cream flavor peanut oil and a preparation method thereof.

Background

The peanut is one of four oil crops in the world, and is also the largest oil crop and the most important economic crop in China. The peanuts are rich in nutrition, the main component is fat, the content of the fat is about 50-60%, 80% of unsaturated fatty acid exists in the fat, and the peanut has a high-quality oil content; peanut protein with the content of about 20 percent in the peanut kernel is accepted as high-quality plant protein with higher amino acid score; in addition, the functional active substances such as phenols, vitamins, phytosterol and the like contained in the peanut milk powder enable the peanut to have physiological functions such as memory enhancement, blood vessel softening, blood fat metabolism reduction and the like.

The peanut oil has clear color, delicious taste and easy absorption, and is a main peanut product in China. In recent years, as people pay more and more attention to resources and environment and the nutrition and health of food, the production process of peanut oil is changed to a certain extent, and the early high-temperature pressing mode is gradually changed into low-temperature pressing (pressing oil at the temperature of 65 ℃ below). Although the low-temperature pressing mode is adopted, resources can be saved, the nutritional ingredients in the peanut oil can be reserved to a great extent, meanwhile, the peanut meal can be secondarily utilized and can be further processed into deep-processed products such as protein powder, short peptides and the like to be applied to the food industry, the added value and the utilization rate are high, but due to the fact that the processing temperature is low, aroma-characteristic flavor substances such as pyrazines, pyrroles and the like cannot be generated, the aroma-characteristic flavor of the low-temperature pressed peanut oil is insufficient, the requirements of consumers are difficult to meet, and the low-temperature pressed peanut oil. (Liuyunhua, research on low-temperature pressing peanut oil flavor enhancement technology [ D ]. Hebei science and technology academy, 2017.). Therefore, there is a need to develop methods for improving the flavor of peanut oil while retaining its nutritional components.

In recent years, scholars at home and abroad have researched a series of methods for increasing the flavor of vegetable oil. For example, xuyuehua and the like adopt protease hydrolysis liquid of low-temperature pressed walnut cakes to heat and simulate the flavor of high-temperature pressed walnut oil, and are used for solving the problem of weak flavor of the low-temperature pressed walnut oil (Xuyuehua, research on flavor enhancement and walnut milk stability of cold-pressed walnut oil [ D ]. Jiangnan university, 2014.). Hu et al used Microwave pretreatment technology to treat peanut raw materials, increased the content of Flavor substances such as pyrazine in cold-pressed peanut oil, in order to improve peanut oil Flavor (Hu H., Liu H., et al. the Effect of Microwave pretreatment micro nutrient Contents, Oxidative Stability and Flavor Quality of Peanutoil [ J ]. Molles (base, Switzerland),2018,24 (1)). However, although the method improves the peanut oil flavor, the method has the problems of complex process, more loss of nutrient substances, addition of other substances and the like, is not favorable for producing the peanut oil with characteristic flavor, and is difficult to meet the requirement of people on the quality of peanut oil. The cream fragrance is widely accepted as a pleasant fragrance, and Chinese patent CN103468394B discloses a preparation method of milk-fragrance health-care peanut oil to improve the taste and quality of the peanut oil, but the temperature in the preparation process reaches more than 100 ℃, so that the odor change caused by various reactions cannot be controlled; and the cost of adding milk to improve flavor is expensive; in addition, the whole preparation process is complex and is not suitable for large-scale production.

Accordingly, there is a need to overcome the technical problems of the prior art processes for preparing characteristically flavoured peanut oil.

Disclosure of Invention

The invention overcomes the technical problems of complex preparation process and low product quality in the prior art, and aims to provide a preparation method of cream-flavor peanut oil. The invention provides a process for producing butter-flavored peanut oil by pretreating peanut raw materials through a Pulsed Electric Field (PEF) and then squeezing (cold pressing) the peanut raw materials at a low temperature.

In order to solve the problems, the invention adopts the following technical scheme.

The invention provides a preparation method of cream-flavor peanut oil, which comprises the following steps:

(1) pre-adjusting moisture of peanut kernels: soaking the peeled peanut kernels in deionized water to enable the peanut to reach the preset moisture content, filtering, and taking out to obtain soaked peanut kernels;

(2) treating peanut kernels by using a pulsed electric field: putting the soaked peanut kernels in the step (1) into a treatment chamber of a pulse electric field, adding deionized water, uniformly mixing, fixing the distance between polar plates, exhausting air bubbles to fill the whole treatment chamber with water, and performing pulse electric field treatment to obtain pulse-treated peanut kernels;

(3) drying the peanut kernels: placing the peanut kernels subjected to the pulse treatment in the step (2) in a culture dish, and drying to obtain dried peanut kernels;

(4) low-temperature squeezing: putting the dried peanut kernels obtained in the step (3) into an oil press, and performing low-temperature oil pressing treatment (the pressing temperature is less than or equal to 65 ℃) to obtain an oily mixture;

(5) centrifugal filtration: and (4) centrifuging the oily mixture obtained in the step (4), and taking supernatant (physical filtration) to obtain the milk-flavor peanut oil (clarified peanut oil).

Further, the peeled peanut kernels of step (1) are soaked in deionized water overnight.

Further, the moisture content of the soaked peanut kernels in the step (1) is 54-56%

Preferably, the distance between the fixed polar plates in the step (2) is 30 mm.

Further, the intensity of the pulsed electric field treatment in the step (2) is 1.22-1.24kV/cm, the frequency of the pulsed electric field treatment is 0-1.5Hz, and the pulse width of the pulsed electric field treatment is 250 mus; the pulse treatment times of the pulse electric field are 10-40 times.

Further, the temperature of the drying treatment in the step (3) is 55-60 ℃.

Further, the moisture content of the dried peanut kernels is 4.50-5.00%.

Further, the temperature of the low-temperature oil pressing treatment in the step (4) is less than or equal to 65 ℃.

Further, the rotation speed of the centrifugation in the step (5) is 8000 rpm.

Further, the centrifugation time in the step (5) is 10 min.

The invention provides cream-flavor peanut oil prepared by the preparation method. The cream-flavor peanut oil contains 3-hydroxy-2-butanone, and the 3-hydroxy-2-butanone accounts for 97-100% of the total content of ketones.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the cream-flavor peanut oil provided by the invention is simple in preparation process, and the cream flavor is easy to control.

(2) The preparation method of the cream-flavor peanut oil provided by the invention is environment-friendly in process, non-toxic, harmless and pollution-free, does not add any reagent except deionized water, and is high in safety.

(3) The preparation method of the cream-flavor peanut oil provided by the invention has no high-temperature treatment environment, the whole process is carried out at a low temperature, the nutrient substances in the peanut oil are reserved to a great extent, and the peanut meal still has higher secondary utilization value.

(4) The preparation method of the cream-flavor peanut oil provided by the invention has the advantages of low extraction process cost and suitability for large-scale popularization and application.

Detailed Description

The following examples are presented to further illustrate the practice of the invention, but the practice and protection of the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available by commercial purchase.

Example 1

The embodiment provides a preparation method of cream-flavor peanut oil subjected to pulse electric field pretreatment and 10 times of pulse treatment, which comprises the following steps of:

(1) pretreatment of raw materials: each time 50g of freshly produced peeled peanut kernels are selected and immersed in deionized water to adjust the moisture content to 54-56% for use.

(2) Treating peanut kernels by using PEF equipment: putting the prepared peeled peanuts into a treatment chamber, adding deionized water, fixing the distance between polar plates to be 30mm, pressing the polar plates, exhausting air bubbles to enable the whole treatment chamber to be filled with the deionized water, and carrying out PEF treatment on the peanut kernels under the conditions that the electric field intensity is 1.22-1.24kV/cm, the frequency is 1Hz, the pulse width is 250 microseconds, and the pulse treatment times are 10 times.

(3) Drying the peanut kernels: taking out the PEF-treated peanut kernels, putting the peanut kernels into a culture dish immediately, putting the culture dish into an oven at the temperature of 55-60 ℃ for drying until the moisture content of the peanut kernels is 4.50-5.00%, and taking out the peanut kernels for later use.

(4) Low-temperature squeezing: and (4) putting the peanut kernels reserved in the step (3) into an oil press, and squeezing at a low temperature (the squeezing temperature is less than or equal to 60 ℃) to obtain the peanut oil.

(5) Centrifugal filtration: and (3) centrifuging the low-temperature cold-pressed peanut oil obtained in the step (4) (8000rpm, 10min) to clarify the peanut oil to obtain the peanut oil with cream fragrance, wherein the content of the 3-hydroxy-2-butanone accounts for 97.87 percent of the total content of the ketone substances.

Example 2

The embodiment provides a preparation method of cream-flavor peanut oil subjected to pulse electric field pretreatment and with the pulse treatment frequency of 20 times, which comprises the following steps of:

(2) Treating peanut kernels by using PEF equipment: putting the prepared peeled peanuts into a treatment chamber, adding deionized water, fixing the distance between polar plates to be 30mm, pressing the polar plates, exhausting air bubbles to enable the whole treatment chamber to be filled with the deionized water, and carrying out PEF treatment on the peanut kernels under the conditions that the electric field intensity is 1.22-1.24kV/cm, the frequency is 1Hz, the pulse width is 250 microseconds, and the pulse treatment times are 20 times.

(5) Centrifugal filtration: and (3) centrifuging the low-temperature cold-pressed peanut oil obtained in the step (4) (8000rpm, 10min) to clarify the peanut oil to obtain the peanut oil with cream fragrance, wherein the content of the 3-hydroxy-2-butanone accounts for 100.00 percent of the total content of the ketone substances.

Example 3

(5) Centrifugal filtration: and (3) centrifuging (8000rpm, 10min) the low-temperature cold-pressed peanut oil obtained in the step (4) to clarify peanut oil to obtain the peanut oil with cream fragrance, wherein the content of the 3-hydroxy-2-butanone accounts for 99.18% of the total content of the ketone substances.

The volatile flavour substances of the cold pressed peanut oil pretreated with PEF were analysed by headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) on the peanut oil prepared in examples 1-3, matched by NIST library search, the compounds were characterised by taking the components with a degree of matching of not less than 80% and the relative content of the volatile components was quantified by peak area normalization, the results of the analysis and recorded as shown in tables 1 and 2. Table 1 is a table of the amount of volatiles for PEF pretreated cold pressed peanut oil. Table 2 is a table of the relative content of volatile materials in the PEF pretreated cold pressed peanut oil.

TABLE 1

Remarking: p1 represents pulsed electric field treatment 10 times; p2 represents pulsed electric field treatment 20 times; p3 represents pulsed electric field treatment 40 times; "-" indicates no detection.

The PEF has the characteristics of uniform transmission, short treatment time and less heat generation, and can cause cell membranes to be broken under the action of an external electric field, promote cell contents to flow out and generate a series of non-heat-caused chemical reactions (the influence of a pulsed electric field assisted water substitution method for preparing sesame oil on the oil quality and the protein property [ D ] Yangzhou university, 2017.).

As shown in table 1, the volatile substances in the cold-pressed peanut oil after PEF pretreatment are reduced, probably because the pulse electric field has a large influence on the peanut cells, the substances are easily lost in the deionized water during the pulse electric field pretreatment due to the cell wall damage, and the types of flavor substance precursors of the peanut oil are reduced after the peanut oil is dried and pressed.

As shown in table 1, since the pulsed electric field pretreatment has no strong thermal effect and no loss of reactants, the characteristic volatile substances of peanut oil, such as pyrazine substances, are not generated.

TABLE 2

As shown in table 2, the ketones increase in relative content with increasing number of PEF treatments, and dominate the volatile odor of the prepared peanut oil.

As shown in Table 2, the ketones have the highest relative content of 3-hydroxy-2-butanone and dominate the volatile flavor of PEF-pretreated cold-pressed peanut oil, which imparts a unique creamy flavor to peanut oil due to its pleasant creamy flavor.

The above examples are only preferred embodiments of the present invention, which are intended to be illustrative and not limiting, and those skilled in the art should understand that they can make various changes, substitutions and alterations without departing from the spirit and scope of the invention.

Claims

1. The preparation method of the cream-flavor peanut oil is characterized by comprising the following steps:

(1) pre-adjusting moisture of peanut kernels: soaking the peeled peanut kernels in water, and filtering to obtain soaked peanut kernels;

(2) treating peanut kernels by using a pulsed electric field: adding the soaked peanut kernels obtained in the step (1) into deionized water, fixing the distance between polar plates, exhausting air bubbles, filling the whole treatment chamber with water, and performing pulsed electric field treatment to obtain pulsed peanut kernels;

(3) drying the peanut kernels: drying the peanut kernels subjected to the pulse treatment in the step (2) to obtain dried peanut kernels;

(4) low-temperature squeezing: putting the dried peanut kernels obtained in the step (3) into an oil press, and performing low-temperature oil pressing treatment to obtain an oily mixture;

(5) centrifugal filtration: and (4) centrifuging the oily mixture obtained in the step (4), and taking supernatant to obtain the milk-flavor peanut oil.

2. The method for preparing butter-flavor peanut oil as claimed in claim 1, wherein the moisture content of the soaked peanut kernels in step (1) is 54-56%.

3. The method for preparing butter-flavor peanut oil according to claim 1, wherein the electric field intensity of the pulsed electric field treatment in the step (2) is 1.22 to 1.24kV/cm, the frequency of the pulsed electric field treatment is 0 to 1.5Hz, and the pulse width of the pulsed electric field treatment is 250 μ s; the pulse treatment times of the pulse electric field are 10-40 times; the distance between the polar plates of the pulse electric field is 29-31 mm.

4. The process for the preparation of cream-flavor peanut oil as claimed in claim 1, wherein the temperature of the drying treatment in step (3) is 55-60 ℃.

5. The method of claim 1, wherein the moisture content of the dried peanut kernels is between 4.50% and 5.00%.

6. The process for the production of cream-flavor peanut oil as claimed in claim 1, wherein the temperature of the low temperature oil extraction process of step (4) is less than or equal to 65 ℃.

7. The method of claim 1, wherein the centrifugation in step (5) is carried out at 8000 rpm.

8. The process for the preparation of cream-flavor peanut oil as claimed in claim 1, wherein the centrifugation of step (5) is carried out for 10 min.

9. Butter-flavor peanut oil obtained by the process according to any one of claims 1 to 8, characterized in that it contains 3-hydroxy-2-butanone in its volatile flavor, the 3-hydroxy-2-butanone being present in a relative amount of 97 to 100% of the total content of ketones.