An infrared temperature-appropriate pressing production process for peanut oil and peanut protein

Abstract

The present invention discloses a production process for infrared temperature-appropriate pressed peanut oil and peanut protein. This oil pressing process has a high oil yield, and its products are nutritionally safe, have a long-lasting strong fragrance, achieve the best fragrance release effect, retain the original flavor, aroma and fragrance of peanut oil, have a strong and long-lasting fragrance, a low acid value, high VE and polyphenol contents, and the obtained peanut protein has a low denaturation degree. The solubility of peanut protein powder is significantly improved, and the extraction rate of protein powder is significantly increased. It is suitable for developing high-value-added products such as peanut protein powder, peanut milk, and isolated protein, realizing the dual-protection processing of peanut oil and protein.

Description

Technical Field

[0001] The present invention belongs to the technical field of peanut oil preparation methods, and particularly relates to a production process of infrared moderate-temperature pressed peanut oil and peanut protein. Background Art

[0002] Peanuts are important oil crops, and the efficient extraction and comprehensive utilization of their oil and protein resources are the core research directions in the field of grain and oil processing. Traditional peanut oil production processes mainly include high-temperature pressing method, solvent extraction method, and cold pressing method. Although the high-temperature pressing method has a relatively high oil yield, the small-path stir-frying seed temperature exceeds 180 °C, and the pressing temperature exceeds 130 °C. The too-high processing temperature easily leads to oil oxidation and thermal degradation of nutritional active substances (such as vitamin E and phytosterols), significantly reducing the nutritional value of the oil product, and accompanied by harmful risk factors such as benzo[a]pyrene. At the same time, the peanut protein loses its functionality due to severe thermal denaturation, seriously damaging the oilseed protein and making it impossible to realize food-grade reuse, and can only be used as low-value-added feed. Although the solvent extraction method can improve the oil yield, there is a risk of solvent residue, and the subsequent solvent removal process requires high-temperature treatment, further exacerbating protein denaturation, making it difficult to achieve the coordinated high-quality development of oil and protein. Although the cold pressing method can retain more nutritional components, the oil yield is significantly reduced, and it is difficult to extract protein from the high-residual oil cake, limiting its industrial application.

[0003] Aiming at the problems commonly existing in the existing peanut processing technologies, such as the difficulty in compatibility between the temperature of the oil extraction process and the thermal denaturation threshold of the protein, the inability to balance high oil yield and high protein quality, the low thermal efficiency and uneven temperature field distribution of the traditional heating method, which are prone to cause local overheating or insufficient heating, the complex protein extraction process and insufficient retention of functionality in the pressed cake, and it is difficult to meet the requirements of food-grade applications. There is an urgent need to develop a peanut oil preparation process that can achieve the synchronous high-quality and green production of peanut oil and protein. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provides a production process for infrared moderate-temperature pressed peanut oil and peanut protein. In view of the practical problems of the traditional pressing of thick-flavor oilseeds, such as too high pressing temperature, decline in oil quality, and low utilization rate of comprehensive products, based on the physical characteristics of the oilseeds themselves and the correlation laws of the oil penetration rate of the material particles with pressure, temperature, and time during the pressing process, the influence of different physical field heat treatments on the structures of oil bodies, oils, and proteins during the oilseed processing is further explored, and a new production process for infrared moderate-temperature pressed peanut oil and peanut protein is developed. Compared with the traditional peanut pressing process, this process has a high oil yield, while maintaining the original flavor, aroma, and taste of the oil, with a strong and lasting fragrance, low acid value, high VE content, high oxidation stability, and is rich in unsaturated fatty acids, sterols, wheat germ phenols, phospholipids, and choline. In addition, the obtained peanut protein has low denaturation, and the protein powder obtained after ultrafine grinding has a light color, good flavor, and high nitrogen solubility index, realizing the dual-protection processing of peanut oil and protein.

[0005] Specifically, the present invention is realized through the following technologies:

[0006] A production process for infrared moderate-temperature pressed peanut oil and peanut protein, the specific steps include:

[0007] Step 1, cleaning and color sorting: The peanut kernel raw materials enter the self-balancing vibrating screen to separate large stones, shelled peanuts, and peanut broken grains in the raw materials, remove the metal objects in the peanuts through a magnetic separator, and then are transported to a grading and screening machine through an elevator to screen out plump peanut kernels, and the color sorter eliminates the mildewed grains and germinated grains in the peanut kernel raw materials;

[0008] Step 2, removing the red skin: The peanut kernels after cleaning and impurity removal are transported to an oven for baking, and after the baked peanut raw materials are cooled, they are subjected to air peeling;

[0009] Step 3, ozone sterilization: The peeled peanut kernels are transported to an ozone generator for treatment to remove Aspergillus flavus in the raw materials;

[0010] Step 4, seed material conditioning: The peanut kernels are transported into a steaming equipment for steam softening to make the moisture content of the peanut kernels reach 10% - 15%, and after softening, they are quickly added to a vacuum freezer for freezing and conditioning at -20 to 0 °C;

[0011] Step 5, infrared roasting of seeds: The conditioned peanut kernels are transported into a drum-type infrared equipment for infrared treatment;

[0012] Step 6, moderate-temperature pressing: The peanut kernels after infrared heating treatment are transported to a single-screw oil press, controlling the inlet pressing temperature at 50 - 95 °C, and the rotation speed of the single-screw oil press at 20 - 40 r / min to obtain crude pressed peanut oil and protein cake;

[0013] Step 7 Cooling and Filtration: Coarsely filter the virgin crude peanut oil through a plate and frame filter to obtain coarsely filtered peanut oil; rapidly cool the coarsely filtered peanut oil through an exchanger, add deionized water to the obtained peanut oil, stir, let stand, and then perform low-temperature physical filtration to remove impurities to obtain pure peanut oil;

[0014] Step 8 Crushing and Sterilization: Ultrafinely crush and microwave sterilize the protein cake obtained by pressing to obtain high-quality protein powder.

[0015] Preferably, in the step 2 of removing the red skin, the baking temperature is controlled at 85-105°C and the baking time is 40-50 minutes.

[0016] Preferably, in the step 3 of ozone sterilization, the ozone concentration is 80mg / L, the temperature is controlled at 30-35°C, the stirring speed is 80-100r / min, and the treatment time is 20-40min.

[0017] Preferably, in the step 4, the vacuum freezer controls the vacuum to 10-20Pa and the freezing and conditioning time is 20-50min.

[0018] Preferably, in the step 5 of infrared roasting of seeds, the temperature is 110-150°C, the treatment time is 20-30min, the infrared physical field parameters are set as the short-wave infrared wavelength range of 0.78-1.4μm and the medium-wave infrared wavelength range of 1.4-4μm, where the short-wave: medium-wave infrared power ratio is 1:1-2, the feeding amount is 10-25% of the effective volume of the drum, the infrared treatment distance is 15-22cm, and the material thickness is 3-7cm.

[0019] Preferably, in the step 7 of cooling and filtration, the coarsely filtered peanut oil is rapidly cooled to 15-20°C, the addition amount of deionized water is 0.5-1% of the weight of the peanut oil, the stirring speed is 50-60r / min, and the stirring time is 10-30min.

[0020] Preferably, in the step 8 of crushing and sterilization, the peanut protein powder is ultrafinely ground to 100-200 meshes, microwave sterilized for 2-3min, the microwave sterilization temperature is 45-55°C, and the microwave frequency is 2300-2600MHz.

[0021] Advantages of the present invention:

[0022] The oil extraction rate of the oil pressing process of the present invention is high, its products are nutritious, safe, and have a long-lasting strong fragrance, achieving the best fragrance release effect, retaining the original flavor, fragrance, and aroma of peanut oil, with a strong and long-lasting fragrance, low acid value, high VE and polyphenol content, and the obtained peanut protein has low denaturation, the solubility of peanut protein powder is significantly improved, the extraction rate of protein powder is significantly increased, which is suitable for developing high-value-added products such as peanut protein powder, peanut milk, and isolated protein, realizing the dual protection processing of peanut oil and protein. Detailed implementation manners

[0023] The present invention will be further described below by way of examples. Unless otherwise specified, the test methods used in the following examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, are reagents and materials that can be obtained from commercial channels.

[0024] Example 1

[0025] 1) Take 10 kg of peanut raw materials and add them to a self - balancing vibrating screen to separate large stones, shelled peanuts, and broken peanut grains in the raw materials. Remove the metal objects in the peanuts through a magnetic separator, and then transport them to a grading and screening machine through an elevator to screen out plump peanuts. Use a color sorter to remove mildewed grains and germinated grains in the peanut raw materials;

[0026] 2) Transport the cleaned and impurity - removed peanut kernels to an oven and bake them at 95 °C for 45 min. After cooling the baked peanut raw materials, perform air peeling;

[0027] 3) Transport the peeled peanut kernels to an ozone generator for treatment. Set the ozone concentration to 80 mg / L, the temperature to 32 °C, the stirring speed to 90 r / min, and the treatment time to 30 min to remove Aspergillus flavus in the raw materials;

[0028] 4) Transport the peanut kernels to a steamer equipment for steam softening treatment to make the moisture content of the peanut kernels reach 12%. After softening, quickly add them to a vacuum freezer, set the vacuum pressure to 15 Pa and the temperature to - 10 °C, and perform freezing and conditioning for 30 min;

[0029] 5) Transport the conditioned peanut kernels to a drum - type infrared equipment and perform infrared treatment at a temperature of 135 °C for 25 min;

[0030] 6) Transport the peanut kernels after infrared heating treatment to a single - screw oil press, control the temperature of entering the press to 80 °C, and the rotation speed of the single - screw oil press to 30 r / min to obtain crude peanut oil and protein cake;

[0031] 7) Coarsely filter the crude peanut oil obtained from the initial pressing through a plate - and - frame filter to obtain coarsely filtered peanut oil. Quickly cool the coarsely filtered peanut oil to 15 °C through an exchanger, add deionized water to the obtained peanut oil, stir, let it stand, and then perform low - temperature physical filtration to remove impurities to obtain crystal - clear pure peanut oil;

[0032] 8) Ultra - micro - pulverize the protein cake obtained by pressing to peanut protein powder of 100 - 200 meshes, set the microwave sterilization temperature to 50 °C, the wave frequency to 2500 MHz, and perform microwave sterilization for 3 min to obtain protein powder.

[0033] Example 2

[0034] 1) Take 10 kg of peanut raw materials and add them to a self - balancing vibrating screen to separate large stones, shelled peanuts, and broken peanut grains from the raw materials. Remove the metal objects in the peanuts through a magnetic separator, and then transport them to a grading and screening machine through an elevator to screen plump peanuts. Use a color sorter to remove mildewed and germinated grains from the peanut raw materials;

[0035] 2) Transport the cleaned and impurity - removed peanut kernels to an oven and bake them at 100 °C for 40 min. After cooling the baked peanut raw materials, perform air peeling;

[0036] 3) Transport the peeled peanut kernels to an ozone generator for treatment. Set the ozone concentration at 80 mg / L, the temperature at 30 °C, the stirring speed at 90 r / min, and the treatment time at 30 min to remove Aspergillus flavus in the raw materials;

[0037] 4) Transport the peanut kernels to a steaming equipment for steam softening treatment to make the moisture content of the peanut kernels reach 10%. Immediately after softening, add them to a vacuum freezer, set the vacuum pressure at 10 Pa and the temperature at - 5 °C, and perform freezing and conditioning for 40 min;

[0038] 5) Transport the conditioned peanut kernels to a drum - type infrared equipment and perform infrared treatment at 135 °C for 25 min;

[0039] 6) Transport the peanut kernels after infrared heating treatment to a single - screw oil press, control the temperature of the oil press at 90 °C, and the rotation speed of the single - screw oil press at 30 r / min to obtain crude peanut oil and protein cake;

[0040] 7) Coarsely filter the crude peanut oil obtained from the first - press through a plate - and - frame filter to obtain coarsely filtered peanut oil. Rapidly cool the coarsely filtered peanut oil to 20 °C through an exchanger. Add deionized water to the obtained peanut oil, stir, let it stand, and then perform low - temperature physical filtration to remove impurities to obtain crystal - clear pure peanut oil;

[0041] 8) Ultrafinely crush the protein cake obtained from pressing to 100 - 200 - mesh peanut protein powder. Set the microwave sterilization temperature at 50 °C, the wave frequency at 2500 MHz, and perform microwave sterilization for 3 min to obtain protein powder.

[0042] Comparative Example 1

[0043] 1) Take 10 kg of peanut raw materials and add them to a self - balancing vibrating screen to separate large stones, shelled peanuts, and broken peanut grains from the raw materials. Remove the metal objects in the peanuts through a magnetic separator, and then transport them to a grading and screening machine through an elevator to screen plump peanuts. Use a color sorter to remove mildewed and germinated grains from the peanut raw materials;

[0044] 2) Convey the cleaned and impurity-removed peanut kernels to an oven and bake them at 95°C for 45 minutes. After baking, cool the peanut raw materials and then perform air peeling;

[0045] 3) Convey the peeled peanut kernels to an ozone generator for treatment. Set the ozone concentration at 80 mg / L, the temperature at 32°C, the stirring speed at 90 r / min, and the treatment time at 30 minutes to remove Aspergillus flavus in the raw materials;

[0046] 4) Place the peanut kernels in an electromagnetic seed frying machine and control the seed frying temperature at 160°C for 30 minutes;

[0047] 5) After frying the seeds, convey them to a single-screw oil press. Control the temperature of the oil press inlet at 80°C and the rotation speed of the single-screw oil press at 30 r / min to obtain crude pressed peanut oil and protein cake;

[0048] 6) Coarsely filter the crude pressed peanut oil through a plate and frame filter to obtain coarsely filtered peanut oil. Rapidly cool the coarsely filtered peanut oil to 15°C through an exchanger. Add deionized water to the obtained peanut oil, stir, let it stand, and then perform low-temperature physical filtration to remove impurities to obtain pure peanut oil;

[0049] 7) Ultrafinely crush the protein cake obtained by pressing to 100 - 200 mesh peanut protein powder. Set the microwave sterilization temperature at 50°C, the wave frequency at 2500 MHz, and perform microwave sterilization for 3 minutes to obtain protein powder.

[0050] Comparative Example 2

[0051] 1) Take 10 kg of peanut raw materials and add them to a self-balancing vibrating screen to separate large stones, shelled peanuts, and broken peanut grains in the raw materials. Remove the metal objects in the peanuts through a magnetic separator, and then convey them to a grading and screening machine through a hoist to screen plump peanuts. Use a color sorter to remove mildewed grains and germinated grains in the peanut raw materials;

[0052] 2) Convey the cleaned and impurity-removed peanut kernels to an oven and bake them at 95°C for 45 minutes. After baking, cool the peanut raw materials and then perform air peeling;

[0053] 3) Convey the peeled peanut kernels to an ozone generator for treatment. Set the ozone concentration at 80 mg / L, the temperature at 32°C, the stirring speed at 90 r / min, and the treatment time at 30 minutes to remove Aspergillus flavus in the raw materials;

[0054] 4) Convey the peanut kernels to a drum-type infrared device and perform infrared treatment at 135°C for 25 minutes;

[0055] 5) Convey the peanut kernels after infrared heating treatment to a single-screw oil press. Control the temperature of the oil press inlet at 80°C and the rotation speed of the single-screw oil press at 30 r / min to obtain crude pressed peanut oil and protein cake;

[0056] 6) Coarsely filter the crude peanut oil by a plate and frame filter to obtain coarsely filtered peanut oil. Rapidly cool the coarsely filtered peanut oil to 15°C through an exchanger. Add deionized water to the obtained peanut oil, stir, let it stand, and then perform low-temperature physical filtration to remove impurities to obtain pure peanut oil;

[0057] 7) Ultrafinely grind the pressed protein cake into peanut protein powder with a mesh size of 100 - 200. Set the microwave sterilization temperature at 50°C, the wave frequency at 2500 MHz, and perform microwave sterilization for 3 minutes to obtain protein powder.

[0058] Comparative Example 3

[0059] 1) Take 10 kg of peanut raw materials and add them to a self-balancing vibrating screen to separate large stones, shelled peanuts, and broken peanut grains in the raw materials. Remove the metal substances in the peanuts through a magnetic separator, and then transport them to a grading and screening machine through an elevator to screen plump peanuts. Use a color sorter to remove mildewed grains and germinated grains in the peanut raw materials;

[0060] 2) Transport the cleaned and impurity-removed peanut kernels to an oven and set the baking temperature at 95°C for 45 minutes. After cooling the baked peanut raw materials, perform air peeling;

[0061] 3) Transport the peeled peanut kernels to an ozone generator for treatment. Set the ozone concentration at 80 mg / L, the temperature at 32°C, the stirring speed at 90 r / min, and the treatment time at 30 minutes to remove Aspergillus flavus in the raw materials;

[0062] 4) Transport the peanut kernels to a steamer equipment for steam softening treatment to make the moisture content of the peanut kernels reach 12%;

[0063] 5) Transport the softened peanut kernels to a drum-type infrared equipment and perform infrared treatment at a temperature of 135°C for 25 minutes;

[0064] 6) Transport the infrared-treated peanut kernels to a single-screw oil press, control the inlet temperature at 80°C, and the rotation speed of the single-screw oil press at 30 r / min to obtain crude peanut oil and protein cake;

[0065] 7) Coarsely filter the crude peanut oil by a plate and frame filter to obtain coarsely filtered peanut oil. Rapidly cool the coarsely filtered peanut oil to 15°C through an exchanger. Add deionized water to the obtained peanut oil, stir, let it stand, and then perform low-temperature physical filtration to remove impurities to obtain pure peanut oil;

[0066] 8) Ultrafinely grind the pressed protein cake into peanut protein powder with a mesh size of 100 - 200. Set the microwave sterilization temperature at 50°C, the wave frequency at 2500 MHz, and perform microwave sterilization for 3 minutes to obtain protein powder.

[0067] Comparative Example 4

[0068] 1) Take 10 kg of peanut raw materials and add them to a self - balancing vibrating screen to separate large stones, shelled peanuts, and crushed peanut grains in the raw materials. Remove the metal objects in the peanuts through a magnetic separator, and then transport them to a grading and screening machine through a hoist to screen plump peanuts. Use a color sorter to remove mildewed grains and germinated grains in the peanut raw materials;

[0069] 2) Use intelligent temperature - controlled equipment to precisely heat the cleaned and impurity - removed peanut kernels by microwave to adjust the material temperature to 130 °C, and the microwave heating time is 6 min;

[0070] 3) Transport the microwave - treated peanut kernels to a drum - type infrared device and process them at a temperature of 130 °C for 22.5 min;

[0071] 4) Air - cool the infrared - treated peanut kernels rapidly to 75 °C at a cooling rate of 12.5 °C / min. Use a peanut skin - removing machine to remove the red skins of the peanut kernels, and use a color sorter to remove the peanut kernels with incomplete skin removal. Transport the peanut kernels with the red skins removed to a steaming pot device for steam softening treatment to make the moisture content of the peanut kernels 8%;

[0072] 5) Transport the softened and conditioned peanut kernels to a twin - screw oil press, control the inlet temperature to 75 °C, and the rotation speed of the twin - screw oil press is 22 r / min to obtain peanut oil and peanut meal;

[0073] 6) The peanut oil obtained by pressing is centrifugally filtered at a centrifugal speed of 5000 r / min, transported to a heat exchanger for instant cooling at a cooling rate of 5 °C / min, cooled to 25 °C, add 0.75% water, stir for 45 min, stand and settle for 9 h, and then remove impurities by low - temperature physical filtration to obtain pure peanut oil;

[0074] 7) Ultra - micro - pulverize the protein cake obtained by pressing to 100 - 200 - mesh peanut protein powder, set the microwave sterilization temperature to 50 °C, the wave frequency to 2500 MHz, and microwave sterilize for 3 min to obtain protein powder.

[0075] Comparative Example 5

[0076] 1) Take 10 kg of peanut raw materials and add them to a self - balancing vibrating screen to separate large stones, shelled peanuts, and crushed peanut grains in the raw materials. Remove the metal objects in the peanuts through a magnetic separator, and then transport them to a grading and screening machine through a hoist to screen plump peanuts. Use a color sorter to remove mildewed grains and germinated grains in the peanut raw materials;

[0077] 2) Transport the cleaned and impurity - removed peanut kernels to an oven, set the baking temperature to 95 °C and bake for 45 min. After cooling the baked peanut raw materials, perform air peeling;

[0078] 3) Transport the peeled peanut kernels to an ozone generator for treatment. Set the ozone concentration at 80 mg / L, the temperature at 32 °C, the stirring speed at 90 r / min, and the treatment time at 30 min to remove Aspergillus flavus in the raw materials;

[0079] 4) Transport the peanut kernels to a steaming equipment for steam softening treatment to make the moisture content of the peanut kernels reach 8%. Immediately after softening, add them to a vacuum freezer. Set the vacuum pressure at 15 Pa and the temperature at -10 °C, and carry out freezing and conditioning for 30 min;

[0080] 5) Transport the conditioned peanut kernels to a drum-type infrared equipment for infrared treatment at a temperature of 135 °C for 25 min;

[0081] 6) Transport the peanut kernels after infrared heating treatment to a single-screw oil press. Control the temperature at 80 °C when feeding into the press, and the rotation speed of the single-screw oil press at 30 r / min to obtain crude pressed peanut oil and protein cake;

[0082] 7) Coarsely filter the crude pressed peanut oil through a plate-and-frame filter to obtain coarsely filtered peanut oil. Rapidly cool the coarsely filtered peanut oil to 15 °C through an exchanger. Add deionized water to the obtained peanut oil, stir, let it stand, and then filter at a low temperature physically to remove impurities to obtain crystal-clear pure peanut oil;

[0083] 8) Ultrafinely crush the protein cake obtained by pressing to peanut protein powder of 100 - 200 mesh. Set the temperature for microwave sterilization at 50 °C, the wave frequency at 2500 MHz, and carry out microwave sterilization for 3 min to obtain protein powder.

[0084] Performance detection test

[0085] Prepare peanut oil according to the methods in the examples and comparative examples, and refer to the following methods to detect the performance of the obtained peanut oil. The results are shown in Table 1 and Table 2.

[0086] 1. Oil yield of peanut oil: Let the newly pressed peanut oil stand in a constant temperature storage room at 2 °C for 48 h and then filter it, and record the mass of the residue after filtration. Collect the peanut kernel cake produced during oil pressing and weigh it. The ratio of the mass of the peanut oil obtained in each batch to the mass of the peanut kernels is the oil yield, as shown in the following formula: Y = (m1 - m2 - m3) / m1 × 100%, where m1 is the mass of the peanut kernels, m2 is the mass of the peanut protein powder, and m3 is the mass of the residue after filtration.

[0087] 2. Aroma evaluation: Randomly select 10 volunteers with sensitive olfaction. Take 10 ml of the oil sample, smell the odor while stirring, and

[0088] carry out an overall flavor evaluation on the oil sample. Having the inherent aroma of peanut oil and no peculiar smell is scored 8 - 10 points; the smell is relatively light and there is no peculiar smell, scored 5 - 7 points; the smell is light and there is a slight peculiar smell, scored 1 - 4 points; the evaluation result takes the average value of the scores of 10 volunteers.

[0089] 3. Vitamin E detection: The HPLC method is adopted (C18 chromatographic column, mobile phase methanol: water = 95:5, detection wavelength 294 nm).

[0090] 4. Color: Determined according to GB / T 22460-2008 Determination of Lovibond Color of Animal and Vegetable Oils.

[0091] 5. Polyphenol content: Determined according to LS / T 6119-2017 Cereals, Oils and Foodstuffs Inspection - Determination of Polyphenols in Vegetable Oils - Spectrophotometry.

[0092] 6. Acid value and peroxide value: The acid value of peanut oil is detected according to GB / T5009.229 National Food Safety Standard - Determination of Acid Value in Foods, and the peroxide value of peanut oil is detected according to GB / T5009.227 National Food Safety Standard - Determination of Peroxide Value in Foods. Then the peanut oil is filled into a ground - glass brown glass bottle, the bottle stopper is covered, 2 bottles of peanut oil for each example or comparative example are placed in an oven at 70 °C for constant - temperature storage for 15 days, and then the acid value and peroxide value are detected again.

[0093] Table 1 Basic indicators of peanut oil

[0094] Table 2 Test results of acid value and peroxide value of peanut oil

[0095]

[0096] Table 3 Test results of acid value and peroxide value of peanut oil

[0097]

[0098] The protein powder is prepared according to the methods in the examples and comparative examples, and the performance of the obtained protein powder is detected with reference to the following methods, and the results are shown in Table 3.

[0099] 1. Oil content: The oil content in the protein powder is determined with reference to GB 5009.6 - 2016.

[0100] 2. NSI determination: Determined with reference to the Kjeldahl method (GB 5009.5).

[0101] 3. Determination of protein content and solubility: 1) Sample pretreatment: Pass the peanut protein powder sample through a 60-mesh sieve (particle size ≤ 0.25 mm) to ensure uniformity; if the oil content of the sample > 5%, it is necessary to perform Soxhlet extraction with petroleum ether (boiling range 30 - 60 °C) for 6 hours to defat, and then dry at 60 °C for later use; 2) Dissolution and centrifugation: Accurately weigh 1.5 g of the sample into a 250 mL beaker, add 75 mL of 0.03% KOH solution (pH ≈ 12.5), place it on a magnetic stirrer at 25 °C and stir for 20 minutes, transfer the solution to a centrifuge tube, centrifuge at 3000 r / min for 10 minutes, and take the supernatant and filter it through a 0.45 μm filter membrane; 3) Determination of protein content: Refer to the Kjeldahl method GB 5009.5 - 2016 "National Food Safety Standard - Determination of Protein in Foods" to determine the total protein content of the original sample; take the supernatant after centrifugation and determine the soluble protein content in the same way; 4) The solubility calculation formula is as follows:

[0102]

[0103] Table 3 Test Results of Protein Powder Performance

[0104]

[0105] The above results show that the peanut oil prepared by the process of the present invention has good color and flavor, a high oil yield, and the VE content and polyphenol content are significantly increased compared with traditional processes such as Comparative Example 1; the solubility of its peanut protein powder is significantly improved, the extraction rate of the protein powder is increased, and it is more suitable for developing high-value-added products such as peanut protein powder, peanut milk, and isolated protein.

[0106] It should be noted here that the embodiments of the present invention are only used to illustrate the present invention, rather than to limit the present invention. Therefore, any simple improvement to the present invention under the premise of the method of the present invention falls within the scope protected by the present invention.

Claims

1. A production process for infrared moderate-temperature pressed peanut oil and peanut protein, characterized in that, The specific steps include: Step 1: Cleaning and color sorting: The raw peanut kernels enter a self - balancing vibrating screen to separate large stones, shelled peanuts, and broken peanut grains from the raw materials. Metal objects in the peanuts are removed by a magnetic separator, and then they are transported to a grading and screening machine by an elevator to screen out plump peanut kernels. The color sorter removes mildewed and sprouted grains from the raw peanut kernel materials; Step 2: Removing the red skin: The peanut kernels after cleaning and impurity removal are transported to an oven for baking. After baking, the raw peanut materials are cooled and then air - peeled; Step 3: Ozone sterilization: The peeled peanut kernels are transported to an ozone generator for treatment to remove Aspergillus flavus in the raw materials; Step 4: Seed material conditioning: The peanut kernels are transported into a steaming equipment for steam softening to make the moisture content of the peanut kernels reach 10% - 15%. After softening, they are quickly added to a vacuum freezer for freezing and conditioning at - 20~0°C; The vacuum freezer controls the vacuum to be 10 - 20 Pa, and the freezing and conditioning time is 20 - 50 min; Step 5: Infrared roasting of seeds: The conditioned peanut kernels are transported to a drum - type infrared equipment for infrared treatment; Step 6: Pressing at appropriate temperature: The peanut kernels after infrared heating treatment are transported to a single - screw oil press. The inlet temperature for pressing is controlled at 50~95°C, and the rotation speed of the single - screw oil press is 20~40 r / min to obtain crude peanut oil and protein cake; Step 7: Cooling and filtering: The crude peanut oil is roughly filtered through a plate - and - frame filter to obtain roughly filtered peanut oil; The roughly filtered peanut oil is quickly cooled through an exchanger. Deionized water is added to the obtained peanut oil, stirred, allowed to stand, and then physically filtered at low temperature to remove impurities to obtain pure peanut oil; Step 8: Crushing and sterilization: The protein cake obtained by pressing is ultra - finely crushed and microwave - sterilized to obtain high - quality protein powder.

2. The production process according to claim 1, characterized in that, In step 2 of removing the red skin, the baking temperature is controlled at 85~105°C, and the baking time is 40~50 minutes.

3. The production process according to claim 1, characterized in that, In step 3 of ozone sterilization, the ozone concentration is 80 mg / L, the temperature is controlled at 30~35°C, the stirring speed is 80~100 r / min, and the treatment time is 20~40 min.

4. The production process according to claim 1, characterized in that, In step 5 of infrared roasting of seeds, the temperature is 110~150°C, the treatment time is 20 - 30 min, the infrared physical field parameters are set as the short - wave infrared wavelength range is 0.78~1.4 μm, the middle - wave infrared wavelength range is 1.4~4 μm, where the short - wave: middle - wave infrared power ratio is 1:1~2, the feeding amount is 10~25% of the effective volume of the drum, the infrared treatment distance is 15~22 cm, and the material thickness is 3~7 cm.

5. The production process according to claim 1, characterized in that, In step 7 of cooling and filtering, the roughly filtered peanut oil is quickly cooled to 15~20°C. The addition amount of deionized water is 0.5~1% of the weight of the peanut oil, the stirring speed is 50 - 60 r / min, and the stirring time is 10~30 min.

6. The production process according to claim 1, characterized in that, In step 8 of crushing and sterilization, the peanut protein powder is ultra - finely ground to 100~200 meshes, microwave - sterilized for 2~3 min, the microwave - sterilization temperature is 45~55°C, and the microwave frequency is 2300~2600 MHz.

7. Application of the high - quality protein powder prepared by the production process according to any one of claims 1 - 6 in the preparation of foods and drugs.

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