CN106720299A - A kind of physical fresh-keeping method of peanut - Google Patents

Abstract

The invention discloses a physical fresh-keeping method for peanuts, which solves the problems of pest damage and low nutritional value of peanuts in the existing storage process. The technical solution is to refrigerate fresh peanuts after soaking, cleaning, draining, high-pressure osmosis treatment, vacuum high-voltage electric field corona discharge treatment and vacuum packaging. In the critical state, it has a strong penetrating ability, can penetrate into the inside of peanuts, and has an effective antibacterial and insecticidal effect. Through vacuum high-voltage electric field corona discharge treatment, the molecular structure of volatile components in mugwort can be broken and further removed. No peculiar smell, the preservation period of the peanuts after the above treatment has been greatly improved, and the color, aroma and taste are all good.

Description

A kind of physical fresh-keeping method of peanut

technical field

The invention belongs to the field of food preservation, and in particular relates to a physical preservation method for peanuts.

Background technique

Peanut, also known as groundnut, belongs to the annual herb of Papilionaceae. Peanuts have high nutritional value and are rich in fat and protein. According to the determination, the fat content in peanuts is 44%-45%, the protein content is 24-36%, and the sugar content is about 20%. Peanuts are also rich in vitamin B ₂ , PP, A, D, E, calcium and iron. And contains thiamine, riboflavin, niacin and other vitamins. The mineral content is also very rich, especially the amino acids necessary for the human body, which can promote the development of brain cells and enhance memory. Peanuts also have the functions of strengthening the body and tonifying deficiency, pleasing the spleen and stomach, moistening the lungs and reducing phlegm, nourishing and regulating qi, diuresis and swelling, hemostasis and milk production, clearing the throat and relieving malaria. "Medicinal Test" contains: "Eating peanuts nourishes the stomach and refreshes the spleen, smooths the intestines and moistens dryness." Therefore, peanuts are an agricultural product suitable for all ages.

Nowadays, according to the nutritional characteristics of peanuts, relevant researchers have developed a variety of methods for preserving freshness of peanuts, for example: Chinese Patent Application No. CN201310375255.1 "A Method for Preserving Peanuts", Chinese Patent Application No. CN201310375256.6 " A fresh-keeping method for frying peanuts", etc. The content of the research is to use the method of soaking with chemical substances to keep fresh. However, chemical substance immersion treatment inevitably has food safety hazards.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned technical problems and provide a physical fresh-keeping method for peanuts with simple and reliable process, long-term freshness, color retention, good taste, no chemical reagent residue, and high nutritional value.

The physical fresh-keeping method for peanuts of the present invention is as follows: firstly use the mugwort essential oil gas in a supercritical state to perform high-pressure osmosis treatment on the shelled fresh peanuts, then use high-voltage electric field corona discharge treatment on the peanuts, and finally vacuum pack the peanuts Refrigerate afterwards.

Specifically include the following steps:

(1) Soaking and cleaning: immerse fresh peanuts in ultra-pure water to remove impurities and dust on the surface of peanuts, and then sonicate for 1 to 1.5 hours;

(2), draining: quickly drain the peanuts after ultrasonic treatment in the dark and at low temperature, and then put them into a high-pressure air chamber;

(3) High-pressure osmosis treatment: Add mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 100-120°C, and use a high-pressure pump to pump the volatilized mugwort essential oil gas into the high-pressure chamber containing peanuts. In the air chamber, pressurize the high-pressure air chamber and keep it at 10-15MPa, so that the gas density of mugwort essential oil reaches an approximate supercritical state of 0.68-0.85g/ ^cm3 , and the treatment time is 20-45min;

(4), vacuum high-voltage electric field corona discharge treatment: the peanuts after high-voltage infiltration treatment are packed into a high-voltage electric field corona discharge device, and high-voltage electric field corona discharge treatment is carried out in a vacuum state;

(5) Vacuum-pack the peanuts that have been treated by corona discharge in an empty high-voltage electric field, put them in a deoxidizer, and keep them refrigerated and kept fresh at 1-5°C.

In the step (2), after the draining, carry out air blowing and mixing treatment, and dry for 40 to 60 minutes at 40 to 60°C with a mesh belt airflow dryer;

In the step (2), when draining, the low temperature is controlled to be 10-20°C.

In the step (4), the intensity of the high-voltage corona field is controlled to be 90-160KV, and the treatment time is 14-20h.

In step (4), the degree of vacuum is controlled at 2000-2500Pa.

The high-voltage electric field corona discharge device at least includes a metal plate and a discharge needle. The maximum tile thickness of the peanuts on the metal plate is 10-25 mm, and the minimum distance between the discharge needle and the metal plate is 42-55 mm. The spacing is 55-65mm.

Aiming at the problems existing in the background technology, the inventor conducted in-depth research on the physical fresh-keeping method of peanuts, and selected mugwort among many natural insecticidal plants, and used the volatilization of mugwort essential oil to exert antibacterial and insecticidal effects, but invented People have also found that it is difficult to make mugwort essential oil penetrate into the inside of peanuts only by ordinary fumigation or soaking. In order to solve the above problems, the inventor first uses a constant temperature environment to promote the volatilization of mugwort essential oil, and then makes the volatilized mugwort gas appear in an approximate supercritical state under high pressure conditions, so that it has a strong penetrating ability, so that it can penetrate Into the inside of peanuts to obtain excellent antibacterial and insecticidal effects.

Described mugwort has strong volatility, because also can make the residual irritating taste on peanut, affect the mouthfeel and the fragrance of peanut, to this problem, inventor carries out vacuum high-voltage electric field corona discharge treatment to peanut, utilizes electric The ion beam generated during the corona discharge increases the energy of the mugwort gas molecules remaining in the peanut fruit, causing the hydrogen bonds between the chain molecular groups to break, thereby breaking the molecular structure of the volatile components in the mugwort, which is fast and effective Eliminate the irritating taste brought by mugwort, and at the same time, the inventor also found that the vacuum high-voltage electric field corona discharge treatment also has a killing effect on the insect eggs in the peanut fruit. In the vacuum environment, on the one hand, it can strengthen the effect of the high-voltage corona field, and it can further remove odors, and completely solve various problems caused by using mugwort essential oil.

The selected temperature to promote the volatilization of mugwort essential oil is preferably 100-120°C, and the temperature selection should not be too high to avoid adverse chemical reactions of mugwort essential oil due to high temperature; the selected pressure is 10-15 MPa. High pressure capacity puts forward higher requirements, and it will increase the loss of nutrients in peanut fruit products during the high-pressure osmosis treatment process. If it is too low, the gas density of mugwort essential oil cannot reach the approximate supercritical state of 0.68-0.85g/cm ³ ; the selected The high-pressure penetration time is 20 to 45 minutes, and the high-pressure penetration time should not be too long, but it must be fully in contact with the supercritical mugwort gas with strong penetrating power, penetrate deep into the peanut fruit, and ensure the insecticidal and antibacterial effects .

Further, it is preferred that after step (2) is drained, it is then subjected to air blowing and mixing treatment to reduce the moisture content on the surface of peanuts, further inhibiting the growth of microorganisms on the surface of peanuts, preferably controlling the temperature of air blowing and mixing treatment to be 40-60°C, The drying time is 40-60 minutes. If the temperature is too high, it will not only cause the destruction of heat-sensitive nutrients, but also choose a higher temperature to meet the needs of external water evaporation. The carried soluble components are precipitated on the surface, thereby causing the hardening of the peanut surface; the selected time should not be too short, as the time is too short to be unfavorable for the drying of the peanut surface, and it is preferable to control the moisture content of the peanut to below 8%.

In step (4), the high-voltage electric field corona discharge device is a commercially available product (such as produced by Shanghai Zhizhao Environmental Protection Technology Co., Ltd.), which at least includes a metal plate and a vertically downward discharge needle above the metal plate. The maximum tile thickness on the metal plate is preferably 10-25 mm, the distance between the discharge needles is 50-65 mm, and the minimum distance between the tip of the discharge needle and the metal plate is preferably 42-55 mm. The selected maximum tiling thickness and the distance between the tip of the discharge needle and the metal plate should not be too large. Too large a distance will not be effective in killing insect eggs, and it will also prolong the time of high-voltage electric field corona discharge treatment; The piezoelectric corona field intensity is 90-160KV. If the high-voltage electric field corona discharge intensity is too high, it will put forward higher requirements for production conditions and have adverse effects on the quality of peanuts. However, the high-voltage corona field intensity is below 90KV. The effect of killing insect eggs is not significant; too long time selection is not conducive to controlling production efficiency, and long-term high-voltage electric field corona discharge treatment is not conducive to maintaining the quality of peanuts, and too short time will affect the effect of killing insect eggs;

Beneficial effect:

(1) No chemical substances are used for soaking treatment in the whole process, which avoids the food safety hazards caused by chemical substances. (2) In the high-pressure infiltration process, making mugwort essential oil behave in an approximate supercritical state can play a more significant antibacterial and insecticidal effect than simply using mugwort essential oil for fumigation. (3) Using the ion beam generated in the corona discharge process to destroy the molecular structure of the volatile components in Artemisia argyi, and also have a significant killing effect on the insect eggs in the peanut fruit. In the process of corona discharge, the temperature of the material will not be raised, and combined with the vacuum environment, it also solves the problem of the odor of the final product caused by the residual mugwort gas. (4) The peanuts prepared by the method of the present invention can be refrigerated and kept fresh for more than 90 days at 1-5° C., and their color, taste, smell and nutritional value are effectively guaranteed, and have broad market application prospects.

detailed description

The technical solutions in the present invention will be clearly and completely described below in conjunction with specific embodiments.

Example 1

(1) Raw material pretreatment: Remove the shell of fresh peanuts just unearthed with a peanut sheller, and manually remove peanuts with wormholes and mildew;

(2), soaking and cleaning: immerse the peanuts after the above treatment in ultra-pure water, remove impurities and dust on the surface of the peanuts, and then sonicate for 1 hour;

(3), draining, air blowing and mixing treatment: quickly drain the treated peanuts in the dark at a low temperature of 10°C, and then dry them for 40 minutes with a mesh belt air dryer at 40°C;

(4) High-pressure osmosis treatment: add mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 100°C, and use a high-pressure pump to pump the volatilized mugwort essential oil gas into the high-pressure air chamber containing peanuts During the process, pressurize the high-pressure air chamber to ensure that the pressure in the high-pressure air chamber is 10MPa. At this time, the mugwort essential oil gas shows an approximate supercritical state with a density of 0.68-0.85g/cm ³ , and the processing time is 20min;

(5) Vacuum high-voltage electric field corona discharge treatment: Put the peanuts on the metal plate in the high-voltage electric field corona discharge device to ensure that the thickness of the tile after loading is 10mm, and the distance between the tip of the needle electrode and the metal plate is 42mm. The corona field strength is 90KV, and the high-voltage electric field corona discharge treatment is carried out in a vacuum state for 14 hours to ensure that the vacuum degree is 2000-2500Pa;

(6), vacuum packaging: the dried peanuts are vacuum-packed in an aluminum foil bag, and a pouch with Fe powder deoxidizer is put in the package by 1% (w/w);

(7) Refrigeration: Refrigerate and keep fresh at 1°C.

Example 2

(1) Raw material pretreatment: Remove the shell of fresh peanuts just unearthed with a peanut sheller, and manually remove peanuts with wormholes and mildew;

(2), soaking and cleaning: immerse the peanuts after the above treatment in ultra-pure water, remove impurities and dust on the surface of the peanuts, and then sonicate for 1 hour;

(3), draining, air blowing and mixing treatment: quickly drain the processed peanuts in the dark, at a low temperature of 20°C, and then dry them for 60min with a mesh belt air dryer at 60°C;

(4) High-pressure osmosis treatment: Add mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 120°C, and use a high-pressure pump to pump the volatilized mugwort essential oil gas into the high-pressure air chamber containing peanuts , and pressurize the high-pressure air chamber to ensure that the pressure in the high-pressure air chamber is 15MPa. At this time, the mugwort essential oil gas is in an approximate supercritical state with a density of 0.68-0.85g/cm ³ , and the processing time is 45min;

(5) Vacuum high-voltage electric field corona discharge treatment: Put the peanuts into the high-voltage electric field corona discharge device and spread them on the metal plate. After loading the samples, the thickness of the spread is 25mm, and the distance between the tip of the needle electrode and the metal plate is 55mm. , the high-voltage corona field strength is 160KV, and the high-voltage electric field corona discharge treatment is carried out in a vacuum state for 20 hours to ensure that the vacuum degree is 2000-2500Pa;

(6), vacuum packaging: the red date after drying is vacuum-packed with an aluminum foil bag, and a pouch that is packed with Fe powder deoxidizer is put in the package by 1% (w/w);

(7) Refrigeration: Refrigerate and keep fresh at 1°C.

Example 3

(1) Raw material pretreatment: Remove the shell of fresh peanuts just unearthed with a peanut sheller, and manually remove peanuts with wormholes and mildew;

(2), soaking and cleaning: immerse the peanuts after the above treatment in ultra-pure water, remove impurities and dust on the surface of the peanuts, and then sonicate for 1 hour;

(3), draining, air blowing and mixing treatment: quickly drain the treated peanuts in the dark at a low temperature of 15°C, and then dry them for 50min at 50°C with a mesh belt type airflow dryer;

(4) High-pressure osmosis treatment: Add mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 110°C, and use a high-pressure pump to pump the volatilized mugwort essential oil gas into the high-pressure air chamber containing peanuts During the process, pressurize the high-pressure air chamber to ensure that the pressure in the high-pressure air chamber is 13MPa. At this time, the gas of mugwort essential oil shows an approximate supercritical state with a density of 0.68-0.85g/cm ³ , and the processing time is 30min;

(5) Vacuum high-voltage electric field corona discharge treatment: put the peanuts on the metal plate of the high-voltage electric field corona discharge device to ensure that the thickness of the tile after loading is 15mm, and the distance between the tip of the needle electrode and the metal plate is 48mm. The halo field strength is 130KV, and the high-voltage electric field corona discharge treatment is carried out in a vacuum state for 16 hours to ensure that the vacuum degree is 2000-2500Pa;

(6), vacuum packaging: the red date after drying is vacuum-packed with an aluminum foil bag, and a pouch that is packed with Fe powder deoxidizer is put in the package by 1% (w/w);

(7) Refrigeration: Refrigerate and keep fresh at 1°C.

Comparative Example 1: Artemisia essential oil is not added to high-pressure osmosis

(1) Raw material pretreatment: Remove the shell of fresh peanuts just unearthed with a peanut sheller, and manually remove peanuts with wormholes and mildew;

(2), soaking and cleaning: immerse the peanuts after the above treatment in ultra-pure water, remove impurities and dust on the surface of the peanuts, and then sonicate for 1 hour;

(3), draining, air blowing and mixing treatment: quickly drain the treated peanuts in the dark at a low temperature of 10°C, and then dry them for 40 minutes with a mesh belt air dryer at 40°C;

(4), high-pressure osmosis treatment: 100g peanuts are packed in the high-pressure air chamber, and the high-pressure air chamber is pressurized to ensure that the pressure in the high-pressure air chamber is at 10MPa, and the treatment time is 20min;

(5) Vacuum high-voltage electric field corona discharge treatment: Put the peanuts into the piezoelectric field corona discharge device and spread them on the metal plate. 42mm, the high-voltage corona field strength is 90KV, and the high-voltage electric field corona discharge treatment is carried out in a vacuum state for 14 hours to ensure that the vacuum degree is 2000-2500Pa;

(6), vacuum packaging: the red date after drying is vacuum-packed with an aluminum foil bag, and a pouch that is packed with Fe powder deoxidizer is put in the package by 1% (w/w);

(7) Refrigeration: Refrigerate and keep fresh at 1°C.

Comparative Example 2: Corona discharge treatment without vacuum high voltage electric field

(1) Raw material pretreatment: Remove the shell of fresh peanuts just unearthed with a peanut sheller, and manually remove peanuts with wormholes and mildew;

(2), soaking and cleaning: immerse the peanuts after the above treatment in ultra-pure water, remove impurities and dust on the surface of the peanuts, and then sonicate for 1 hour;

(3), draining, air blowing and mixing treatment: quickly drain the treated peanuts in the dark at a low temperature of 10°C, and then dry them for 40 minutes with a mesh belt air dryer at 40°C;

(4) High-pressure osmosis treatment: add mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 100°C, and use a high-pressure pump to pump the volatilized mugwort essential oil gas into the high-pressure air chamber containing peanuts During the process, pressurize the high-pressure air chamber to ensure that the pressure in the high-pressure air chamber is 10MPa. At this time, the mugwort essential oil gas shows an approximate supercritical state with a density of 0.68-0.85g/cm ³ , and the processing time is 20min;

(5), vacuum packaging: the red date after drying is vacuum-packed with an aluminum foil bag, and a pouch that is packed with Fe powder deoxidizer is put in the package by 1% (w/w);

(6) Refrigeration: Refrigerate and keep fresh at 1°C.

Comparative example 3: Using mugwort essential oil without high pressure osmotic treatment

(1) Raw material pretreatment: Remove the shell of fresh peanuts just unearthed with a peanut sheller, and manually remove peanuts with wormholes and mildew;

(2), soaking and cleaning: immerse the peanuts after the above treatment in ultra-pure water, remove impurities and dust on the surface of the peanuts, and then sonicate for 1 hour;

(3), draining, air blowing and mixing treatment: quickly drain the treated peanuts in the dark at a low temperature of 10°C, and then dry them for 40 minutes with a mesh belt air dryer at 40°C;

(4) Osmosis treatment: Add 10ml mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 100°C, and use a high-pressure pump to pump the volatilized mugwort gas into the high-pressure air chamber containing 100g red dates , the high-pressure chamber is not pressurized at this time, and the processing time is 20 minutes;

(5) Vacuum high-voltage electric field corona discharge treatment: Put the peanuts on the metal plate in the high-voltage electric field corona discharge device to ensure that the thickness of the tile after loading is 10mm, and the distance between the tip of the needle electrode and the metal plate is 42mm. The corona field strength is 90KV, and the high-voltage electric field corona discharge treatment is carried out in a vacuum state for 14 hours to ensure that the vacuum degree is 2000-2500Pa;

(6), vacuum packaging: the dried peanuts are vacuum-packed in an aluminum foil bag, and a pouch with Fe powder deoxidizer is put in the package by 1% (w/w);

(7) Refrigeration: Refrigerate and keep fresh at 1°C.

Comparative Example 4: Processing without air blowing

(1) Raw material pretreatment: Remove the shell of fresh peanuts just unearthed with a peanut sheller, and manually remove peanuts with wormholes and mildew;

(2), soaking and cleaning: immerse the peanuts after the above treatment in ultra-pure water, remove impurities and dust on the surface of the peanuts, and then sonicate for 1 hour;

(3), draining: draining the processed jujube quickly at a low temperature of 10°C in the dark;

(4) High-pressure osmosis treatment: add mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 100°C, and use a high-pressure pump to pump the volatilized mugwort essential oil gas into the high-pressure air chamber containing peanuts During the process, pressurize the high-pressure air chamber to ensure that the pressure in the high-pressure air chamber is 10MPa. At this time, the mugwort essential oil gas shows an approximate supercritical state with a density of 0.68-0.85g/cm ³ , and the processing time is 20min;

(5) Vacuum high-voltage electric field corona discharge treatment: Put the peanuts into the high-voltage electric field corona discharge device, and spread them on the metal plate, ensuring that the thickness of the tiles after loading the sample is 10mm, and the distance between the tip of the needle electrode and the metal plate is 42mm , the high-voltage corona field strength is 90KV, and the high-voltage electric field corona discharge treatment is carried out in a vacuum state for 14 hours to ensure that the vacuum degree is 2000-2500Pa;

(6), vacuum packaging: the red date after drying is vacuum-packed with an aluminum foil bag, and a pouch that is packed with Fe powder deoxidizer is put in the package by 1% (w/w);

(7) Refrigeration: Refrigerate and keep fresh at 1°C.

After the peanuts prepared in Examples 1-3 and Comparative Examples 1-4 were stored at 1°C for 30 days, 3 samples were randomly selected for each example to remove the aluminum foil packaging, and the browning degree, protein, and total fat of the 3 samples were measured by sampling , total sugar, insect repellent rate, odor and shelf life.

Table 1 Experimental results of relevant indicators in each case

Claims (7)

1. A physical fresh-keeping method for peanuts, characterized in that, first use the mugwort essential oil gas in an approximate supercritical state to carry out high-pressure osmosis treatment to peeled fresh peanuts, and then use high-voltage electric field corona discharge treatment for peanuts , and finally refrigerated after vacuum packaging. 2. the physical preservation method of peanut fruit as claimed in claim 1, is characterized in that, comprises the following steps: (1) Soaking and cleaning: immerse fresh peanuts in ultra-pure water to remove impurities and dust on the surface of peanuts, and then sonicate for 1 to 1.5 hours; (2), draining: quickly drain the peanuts after ultrasonic treatment in the dark and at low temperature, and then put them into a high-pressure air chamber; (3) High-pressure osmosis treatment: Add mugwort essential oil into the heating chamber, promote the volatilization of mugwort essential oil at a constant temperature of 100-120°C, and use a high-pressure pump to pump the volatilized mugwort essential oil gas into the high-pressure chamber containing peanuts. In the air chamber, pressurize the high-pressure air chamber and keep it at 10-15MPa, so that the gas density of mugwort essential oil reaches an approximate supercritical state of 0.68-0.85g/ ^cm3 , and the treatment time is 20-45min; (4), vacuum high-voltage electric field corona discharge treatment: the peanuts after high-voltage infiltration treatment are packed into a high-voltage electric field corona discharge device, and high-voltage electric field corona discharge treatment is carried out in a vacuum state; (5) Vacuum-pack the peanuts that have been treated by corona discharge in an empty high-voltage electric field, put them in a deoxidizer, and keep them refrigerated and kept fresh at 1-5°C. 3. The physical fresh-keeping method of peanut fruit as claimed in claim 2, is characterized in that, in described step (2), after described draining, carry out air-flow blowing and mixing treatment, use net-belt type air-flow drier at 40～60 Under the condition of ℃, dry for 40~60min. 4. The physical fresh-keeping method for peanuts as claimed in claim 2 or 3, characterized in that, in the step (2), when draining, the low temperature is controlled to be 10-20°C. The physical fresh-keeping method of peanuts as claimed in claim 2, characterized in that, in the step (4), the intensity of the high-voltage corona field is controlled to be 90-160KV, and the treatment time is 14-20h. 6. The physical preservation method for peanuts according to claim 2 or 5, characterized in that, in step (4), the degree of vacuum is controlled at 2000-2500Pa. 7. the physical preservation method of peanut as claimed in claim 2 or 5, is characterized in that, in described step (4), described high voltage electric field corona discharge device comprises metal plate and discharge needle at least, and described peanut The maximum tile thickness on the metal plate is 10-25mm, the minimum distance between the discharge needles and the metal plate is 42-55mm, and the distance between the discharge needles is 55-65mm.