Degreased multi-flavor nut and preparation method thereof

Abstract

The invention discloses a degreased multi-flavor nut and a preparation method thereof, and relates to the technical field of food processing, and the preparation method comprises the following steps: S1, raw material screening and pretreatment: (1) screening and grading: selecting plump and mildew-free nuts, and performing impurity removal and color sorting and grading, the nuts are at least one of melon seeds and peanuts, the grain size of the melon seeds is 2-6 mm, and the grain size of the peanuts is 8-12 mm; (2) cleaning and activating: ultrasonically cleaning the graded nuts with clean water at 30-35 DEG C for 15-20 minutes, draining, transferring into an activating soaking solution, soaking at constant temperature of 18-22 DEG C for 24-30 hours, and stirring once every 6 hours; according to the method, efficient degreasing is achieved through the segmented process of enzymolysis, high-temperature cooking and low-temperature baking, the degreasing effect is greatly superior to that of a traditional process, on the other hand, through low-temperature treatment and nitrogen protection, vitamins and other nutritional ingredients in the nuts are reserved to the maximum extent, the problems of incomplete degreasing and nutrition loss caused by traditional high-temperature or chemical degreasing are solved, and the quality of the nuts is improved. And the technical advancement is obvious.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a defatted multi-flavored nut and its preparation method. Background Technology

[0002] Nuts, as a nutritious food rich in protein, unsaturated fatty acids, vitamins and minerals, occupy an important market position in the fields of snack foods and healthy meal replacements due to their comprehensive nutritional composition and unique taste. Among them, sunflower seeds, peanuts and other popular nuts have become the mainstream choice for consumers' daily consumption due to their large consumer base and high cost performance.

[0003] As residents become more health-conscious, "low-fat" and "nutritional" have gradually become core demands in food consumption. In particular, the demand for low-fat, high-nutrient nut products is becoming increasingly urgent for people trying to lose weight, the middle-aged and elderly, and those at risk of cardiovascular disease.

[0004] Nut defatting technology still faces many unresolved issues, making it difficult to balance defatting efficiency, nutrient retention, and product quality: Existing, widely used high-temperature roasting defatting only removes surface and shallow oils from nuts through oil evaporation, resulting in low defatting efficiency and potentially leading to the loss of vitamins E and B. Heat-sensitive nutrients such as B vitamins undergo significant degradation, even producing harmful substances like acrylamide. While frying removes some of the original oil, it causes nuts to absorb large amounts of oil, resulting in a high fat content in the final product. Physical degreasing methods, relying solely on cold or hot pressing, struggle to penetrate the nut cell walls, failing to effectively remove bound oils. Furthermore, the strong mechanical force often leads to high nut breakage rates and poor morphological integrity, limiting product variety. Chemical degreasing processes using food-grade organic solvents like hexane, while improving efficiency, suffer from solvent residue and can damage the natural flavor and protein structure of nuts. Additionally, existing processes are disconnected from flavor processing. Post-degreasing surface spraying and simple soaking for flavor addition often result in a "bland interior with a strong exterior." Some processes add extra fat and sugar to enhance flavor adhesion, contradicting the low-fat requirement. In summary, existing technologies suffer from low degreasing efficiency, significant nutrient loss, and uneven flavor. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the problems existing in the prior art, the present invention provides a defatted multi-flavored nut and its preparation method.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a defatted multi-flavored nut and its preparation method, comprising the following steps:

[0009] S1. Raw material screening and pretreatment:

[0010] (1) Screening and grading: Select plump nuts without mold, remove impurities and grade by color sorting. The nuts are at least one of sunflower seeds and peanuts. The sunflower seeds have a particle size of 2-6 mm and the peanuts have a particle size of 8-12 mm.

[0011] (2) Cleaning and activation: The graded nuts are ultrasonically cleaned with water at 30-35℃ for 15-20 minutes, drained and then transferred to the activation soaking solution. The solution is kept at 18-22℃ for 24-30 hours, and stirred once every 6 hours. The activation soaking solution contains 0.3-0.5 parts citric acid, 0.2-0.4 parts vitamin C and 100 parts water by weight.

[0012] S2. Segmented degreasing process:

[0013] (1) Low-temperature enzymatic degreasing: Take out the nuts soaked in S1, add the enzymatic hydrolysate, and enzymatically hydrolyze at 45-50℃ for 4-6 hours, during which nitrogen gas is introduced; after enzymatic hydrolysis, inactivate the enzyme with hot water at 80-85℃ for 10-15 minutes, and drain.

[0014] (2) High-temperature cooking and defatting: Transfer the enzymatically hydrolyzed nuts to a high-pressure cooking vessel, add defatting auxiliary solution, and cook at 121℃ and 0.12MPa for 1.5-2 hours. Collect the oil. After cooking, centrifuge and dehydrate for 10-15 minutes until the water content is 25%-30%.

[0015] (3) Low-temperature roasting and defatting: Roast the dehydrated nuts at 70-80℃ and wind speed of 1.5-2m / s for 2-3 hours, collect the oil, and reduce the moisture content to 8%-10%;

[0016] S3, Flavor Penetration and Setting:

[0017] (1) Preparation of flavor liquid: Mix the flavor raw materials with water, stir and dissolve at 60-70℃ and keep warm for 30 minutes, filter and cool; the flavor raw materials are at least one of the following: five-spice, cream, spicy, sea salt and caramel.

[0018] (2) Vacuum permeation: Transfer the roasted nuts into a vacuum jar, add flavor liquid, vacuum to -0.08~-0.09MPa, permeate at 30-35℃ for 1-1.5h, break the vacuum once every 20min, repeat 3-4 times;

[0019] (3) Shaping and drying: Dry the permeated nuts at 60-65℃ for 1.5-2 hours until the moisture content is 5%-7%, then cool and screen.

[0020] S4. Post-processing: Crush the nuts after S3 shaping into 2-5mm nut pieces or 80-120 mesh nut powder, and aseptically package them.

[0021] As a preferred embodiment of the defatted multi-flavored nuts and their preparation method described in this invention, the seeds mentioned in step S1 are at least one of sunflower seeds, pumpkin seeds, and watermelon seeds; the nitrogen flow rate in step S2 is 1.5 L / min, and the enzymatic hydrolysis temperature is 48℃; the spice-flavored liquid in step S3 contains 3-5 parts star anise powder, 2-3 parts cinnamon powder, 1-2 parts clove powder, and 2-3 parts edible salt, based on 100 parts water.

[0022] As a preferred embodiment of the defatted multi-flavored nuts and their preparation method described in this invention, in step S2, the centrifugal dehydration speed is 3200 r / min and the dehydration time is 12 min; in step S2, the baking temperature is 75℃ and the wind speed is 1.8 m / s; in step S3, the vacuum degree is -0.085 MPa and the penetration temperature is 32℃.

[0023] As a preferred embodiment of the defatted multi-flavored nuts and their preparation method described in this invention, in step S4, the nut particle size is 3-4 mm and the nut powder particle size is 100 mesh; the equipment temperature is controlled to be ≤40℃ during the crushing process to avoid oxidation of the nut nutrients.

[0024] As a preferred embodiment of the defatted multi-flavored nuts and their preparation method described in this invention, the fat content of the nuts is ≤15% when they are sunflower seeds and ≤12% when they are peanuts; the vitamin E retention rate is ≥80%, the B vitamin retention rate is ≥75%, and the flavor uniformity is ≥90%.

[0025] As a preferred embodiment of the defatted multi-flavored nuts and their preparation method described in this invention, when the nuts are defatted spicy pumpkin seeds, the fat content is 14.5%±0.5% and the vitamin E retention rate is 80.3%±1%; when the nuts are defatted butter peanuts, the fat content is 10.8%±0.5% and the B vitamin retention rate is 75.5%±1%.

[0026] As a defatted multi-flavored nut product according to the present invention, it comprises the defatted multi-flavored nut product as described in claim 5 or 6; the food product is at least one of mixed nut package, nut cereal, nut biscuit, and nut butter.

[0027] As a defatted multi-flavored nut product of the present invention, the mixed nut package contains, by mass ratio, 20%-30% defatted spiced sunflower seeds, 20%-30% defatted buttered peanuts, 15%-20% defatted spicy pumpkin seeds, 10%-15% raisins, and 10%-15% dried cranberries.

[0028] As a defatted multi-flavored nut product of the present invention, the nut oatmeal contains 15%-20% defatted multi-flavored nut pieces as described in claim 4, 70%-75% instant oatmeal, and 5%-10% freeze-dried fruit pieces; the nut biscuit dough contains 5%-10% defatted multi-flavored nut powder as described in claim 4.

[0029] As a defatted multi-flavored nut according to the present invention, the shelf life of the food is ≥12 months, and the fat oxidation value during storage is ≤0.25g / 100g.

[0030] (III) Beneficial Effects

[0031] This invention provides a defatted, flavorful nut and its preparation method. It has the following beneficial effects:

[0032] 1. This invention achieves efficient degreasing through a segmented process of enzymatic hydrolysis, high-temperature steaming, and low-temperature baking, which is significantly better than the degreasing effect of traditional processes. On the other hand, it retains vitamins and other nutrients in nuts to the greatest extent through low-temperature treatment and nitrogen protection, solving the problems of incomplete degreasing and nutrient loss caused by traditional high-temperature or chemical degreasing. The technology is significantly advanced.

[0033] 2. The low-fat properties of this invention are suitable for people who are trying to lose weight, the middle-aged and elderly, and those at risk of cardiovascular disease, effectively broadening the product's customer base; the high nutritional retention ensures that the original protein, minerals and other nutrients in the nuts are not lost, and the entire process adopts a combination of physical and biological processes, without the use of chemical solvents or high-temperature frying, so there is no solvent residue or harmful substances generated.

[0034] 3. In terms of flavor, this invention solves the problem of bland taste on the outside and inside in traditional processes by using vacuum penetration and multiple vacuum breaking processes, ensuring that every bite has a rich and uniform flavor. In terms of form, it can flexibly produce whole nuts, nut pieces, nut powder and other forms, which are suitable for various food processing scenarios such as mixed nut bags, nut cereals, and nut biscuits, providing downstream enterprises with diversified raw material options. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0036] Example 1

[0037] S1 Raw Material Screening and Pretreatment: Select 10kg of plump sunflower seeds, remove impurities by vibrating screen, then color sort and grade, ultrasonically clean (32℃ water, 350W, 40kHz, 18min), drain and add activation soaking solution (0.4kg citric acid, 0.3kg vitamin C, 100kg water), soak at 20℃ for 26h, stirring once every 6h (60r / min).

[0038] S2 segmented degreasing treatment:

[0039] Enzymatic hydrolysis: Sunflower seeds were drained and added to an enzymatic hydrolysis solution (containing 0.6% lipase, 0.25% cellulase, 0.15% protease, and pH 6.2 phosphate buffer). The seeds were hydrolyzed at 48℃ for 5 hours with nitrogen gas purging (1.5 L / min). The enzymes were then inactivated by hot water at 82℃ for 12 minutes, and the seeds were drained.

[0040] High-temperature cooking and defatting: Transfer to a high-pressure cooker, add defatting auxiliary solution (1 kg edible salt, 0.4 kg sodium citrate, 100 kg water), cook at 121℃ and 0.12 MPa for 1.8 h, collect the oil; centrifuge to dehydrate (3200 r / min, 12 min) until the water content is 28%;

[0041] Low-temperature baking for defatting: hot air baking (75℃, wind speed 1.8m / s) for 2.5 hours, collect the oil until the moisture content is 9%;

[0042] S3 Flavor Penetration and Shaping:

[0043] Flavor liquid preparation: 3.5kg star anise powder, 2.5kg cinnamon powder, 1.5kg clove powder, 2.5kg edible salt, 1.2kg white sugar, 0.6kg monosodium glutamate, add 100kg water, dissolve at 65℃ and keep warm for 30min, filter and cool;

[0044] Vacuum permeation: Sunflower seeds are transferred into a vacuum tank, flavor liquid (12kg) is added, vacuum is drawn to -0.085MPa, and permeation is carried out at 32℃ for 1.2h. The vacuum is broken once every 20min, and the process is repeated 3 times.

[0045] Shaping and drying: Dry at 62℃ for 1.8h until the moisture content is 6%, cool and screen to obtain defatted spiced sunflower seeds;

[0046] Performance testing: Fat content 13.2%, Vitamin E retention rate 82.5%, B vitamin retention rate 76.8%, flavor uniformity 92.3%.

[0047] Example 2

[0048] S1 Raw material screening and pretreatment: Select 10kg of white sand peanuts, remove impurities and grade them, then ultrasonically clean them (35℃ water, 400W, 20min), drain them, and add them to the activation soaking solution (0.5kg citric acid, 0.4kg vitamin C, 100kg water). Soak them at a constant temperature of 22℃ for 30h, stirring once every 6h (80r / min).

[0049] S2 segmented degreasing treatment:

[0050] Enzymatic degreasing: Peanuts were drained and added to an enzymatic hydrolysis solution (containing 0.8% lipase, 0.3% cellulase, 0.2% protease, and pH 6.5 phosphate buffer). The mixture was hydrolyzed at 50°C for 6 hours with nitrogen gas purging (2L / min). The enzymes were then inactivated by hot water at 85°C for 15 minutes, and the peanuts were drained.

[0051] High-temperature cooking and defatting: Transfer to a high-pressure cooker, add defatting auxiliary solution (1.2 kg edible salt, 0.5 kg sodium citrate, 100 kg water), cook at 121℃ and 0.12 MPa for 2 hours, collect the oil; centrifuge to dehydrate (3500 r / min, 15 min) until the water content is 30%;

[0052] Low-temperature baking for defatting: Hot air baking (80℃, wind speed 2m / s) for 3 hours, collect the oil until the moisture content is 10%;

[0053] S3 Flavor Penetration and Shaping:

[0054] Flavor liquid preparation: 7kg whole milk powder, 4kg white sugar, 0.4kg vanillin, 0.3kg citric acid, add 100kg water, dissolve at 70℃ and keep warm for 30min, filter and cool;

[0055] Vacuum permeation: Transfer peanuts into a vacuum tank, add flavor liquid (12kg), vacuum to -0.09MPa, permeate at 35℃ for 1.5h, break the vacuum once every 20min, repeat 4 times;

[0056] Shaping and drying: Dry at 65℃ for 2 hours until the moisture content is 7%, cool and screen to obtain the defatted butter peanut product;

[0057] Performance testing: Fat content 10.8%, Vitamin E retention rate 81.2%, B vitamin retention rate 75.5%, flavor uniformity 91.7%.

[0058] Example 3

[0059] S1 Raw Material Screening and Pretreatment: Select 10kg of plump pumpkin seeds (3-5mm in diameter), remove impurities by vibrating screen, then color sort and grade, ultrasonically clean (30℃ water, 300W, 15min), drain, add activation soaking solution (0.3kg citric acid, 0.2kg vitamin C, 100kg water), soak at 18℃ for 24h, stirring once every 6h (50r / min).

[0060] S2 segmented degreasing treatment:

[0061] Enzymatic hydrolysis: Pumpkin seeds were drained and added to an enzymatic hydrolysis solution (containing 0.5% lipase, 0.2% cellulase, 0.1% protease, pH 6.0 phosphate buffer). The seeds were hydrolyzed at 45℃ for 4 hours with nitrogen gas purging (1L / min). The enzymes were then inactivated by hot water at 80℃ for 10 minutes, and the seeds were drained.

[0062] High-temperature cooking and degreasing: Transfer to a high-pressure cooker, add degreasing auxiliary solution (0.8 kg edible salt, 0.3 kg sodium citrate, 100 kg water), cook at 121℃ and 0.12 MPa for 1.5 h, collect the oil; centrifuge to dehydrate (3000 r / min, 10 min) until the water content is 25%;

[0063] Low-temperature baking for defatting: Hot air baking (70℃, wind speed 1.5m / s) for 2 hours, collect the oil until the moisture content is 8%;

[0064] S3 Flavor Penetration and Shaping:

[0065] Flavor liquid preparation: 2kg chili powder, 1kg Sichuan pepper powder, 0.5kg cumin powder, 2kg edible salt, 0.3kg capsaicin extract (compliant with GB2760), add 100kg water, dissolve at 60℃ and keep warm for 30min, filter and cool;

[0066] Vacuum permeation: Pumpkin seeds are transferred into a vacuum tank, flavor liquid (12kg) is added, vacuum is drawn to -0.08MPa, and permeation is carried out at 30℃ for 1 hour. The vacuum is broken once every 20 minutes, and the process is repeated 3 times.

[0067] Shaping and drying: Dry at 60℃ for 1.5 hours until the moisture content is 5%, cool and screen to obtain defatted spicy pumpkin seeds;

[0068] Performance testing: Fat content 14.5%, Vitamin E retention rate 80.3%, B vitamin retention rate 75.1%, flavor uniformity 90.5%.

[0069] Example 4

[0070] S1 Raw material screening and pretreatment: Select 10kg of white sand peanuts, remove impurities and grade them, then ultrasonically clean them (35℃ water, 400W, 20min), drain them, and add them to the activation soaking solution (0.5kg citric acid, 0.4kg vitamin C, 100kg water). Soak them at a constant temperature of 22℃ for 30h, stirring once every 6h (80r / min).

[0071] S2 segmented degreasing treatment:

[0072] Enzymatic degreasing: Peanuts were drained and added to an enzymatic hydrolysis solution (containing 0.8% lipase, 0.3% cellulase, 0.2% protease, and pH 6.5 phosphate buffer). The mixture was hydrolyzed at 50°C for 6 hours with nitrogen gas purging (2L / min). The enzymes were then inactivated by hot water at 85°C for 15 minutes, and the peanuts were drained.

[0073] High-temperature cooking and defatting: Transfer to a high-pressure cooker, add defatting auxiliary solution (1.2 kg edible salt, 0.5 kg sodium citrate, 100 kg water), cook at 121℃ and 0.12 MPa for 2 hours, collect the oil; centrifuge to dehydrate (3500 r / min, 15 min) until the water content is 30%;

[0074] Low-temperature baking for defatting: Hot air baking (80℃, wind speed 2m / s) for 3 hours, collect the oil until the moisture content is 10%;

[0075] S3 Flavor Penetration and Shaping:

[0076] Flavor liquid preparation: 2.5 kg edible sea salt, 0.2 kg monosodium glutamate, 100 kg water, dissolve at 70℃ and keep warm for 30 min, then filter and cool;

[0077] Vacuum permeation: Transfer peanuts into a vacuum tank, add flavor liquid (12kg), vacuum to -0.09MPa, permeate at 35℃ for 1.5h, break the vacuum once every 20min, repeat 4 times;

[0078] Shaping and drying: Dry at 65℃ for 2 hours until the moisture content is 7%, cool and screen to obtain defatted sea salt peanuts;

[0079] S4 post-processing:

[0080] Transfer defatted sea salt peanuts into a stainless steel grinder, set the speed to 1500 r / min, and grind for 5 minutes. After grinding, use a vibrating screen to classify and collect particles of 3-4 mm to remove excessively fine powder (powder rate ≤2%). Transfer the graded nut pieces into a sterile workshop and use a vacuum packaging machine to package them to obtain the finished product of defatted sea salt peanut pieces.

[0081] Performance testing: Fat content 11.2%, Vitamin E retention rate 81.7%, B vitamin retention rate 76.2%, Kernel integrity 98.3% (no additional breakage), Flavor uniformity 91.2%.

[0082] Example 5

[0083] S1 Raw Material Screening and Pretreatment: Select 10kg of plump sunflower seeds, remove impurities by vibrating screen, then color sort and grade, ultrasonically clean (32℃ water, 350W, 40kHz, 18min), drain and add activation soaking solution (0.4kg citric acid, 0.3kg vitamin C, 100kg water), soak at 20℃ for 26h, stirring once every 6h (60r / min).

[0084] S2 segmented degreasing treatment:

[0085] Enzymatic hydrolysis: Sunflower seeds were drained and added to an enzymatic hydrolysis solution (containing 0.6% lipase, 0.25% cellulase, 0.15% protease, and pH 6.2 phosphate buffer). The seeds were hydrolyzed at 48℃ for 5 hours with nitrogen gas purging (1.5 L / min). The enzymes were then inactivated by hot water at 82℃ for 12 minutes, and the seeds were drained.

[0086] High-temperature cooking and defatting: Transfer to a high-pressure cooker, add defatting auxiliary solution (1 kg edible salt, 0.4 kg sodium citrate, 100 kg water), cook at 121℃ and 0.12 MPa for 1.8 h, collect the oil; centrifuge to dehydrate (3200 r / min, 12 min) until the water content is 28%;

[0087] Low-temperature baking for defatting: hot air baking (75℃, wind speed 1.8m / s) for 2.5 hours, collect the oil until the moisture content is 9%;

[0088] S3 Flavor Penetration and Shaping:

[0089] Flavor liquid preparation: 5 kg white sugar, 1.5 kg caramel color (compliant with GB2760), 0.3 kg citric acid, 100 kg water”, dissolve at 65℃ and keep warm for 30 min, filter and cool;

[0090] Vacuum permeation: Sunflower seeds are transferred into a vacuum tank, flavor liquid (12kg) is added, vacuum is drawn to -0.085MPa, and permeation is carried out at 32℃ for 1.2h. The vacuum is broken once every 20min, and the process is repeated 3 times.

[0091] Shaping and drying: Dry at 62℃ for 1.8h until the moisture content is 6%, cool and screen to obtain defatted caramel sunflower seeds;

[0092] S4 post-processing:

[0093] Transfer the defatted caramel sunflower seed semi-finished product into an ultra-fine pulverizer, set the pulverizing speed to 8000 r / min, and the pulverizing time to 3 min, with pulverization intervals of 1 min. After pulverization, pass the material through a 100-mesh sieve, gently assisting the sieving process with a soft brush, and collect the sieved material. Transfer the sieved nut powder to a sterile operating table, use a sterile stainless steel spoon to dispense it into food-grade aluminum foil bags, and heat-seal them to obtain the defatted caramel sunflower seed powder finished product.

[0094] Performance testing: Fat content 13.2%, Vitamin E retention rate 82.5%, B vitamin retention rate 76.8%, flavor uniformity 92.3%.

[0095] Comparative Example 1

[0096] S1 Raw material screening and pretreatment: Select 10kg of plump sunflower seeds, remove impurities by vibrating screen, then color sort and grade (consistent with Example 1, particle size 2-4mm), ultrasonically clean (32℃ clean water, 350W, 40kHz, 18min), drain and directly transfer to container without activation soaking treatment.

[0097] S2 Degreasing Treatment: Transfer the drained sunflower seeds to a hot air oven, set the temperature to 180℃, the wind speed to 1.8m / s, and bake continuously for 3 hours, turning them over once every 30 minutes. During the baking process, a small amount of volatile oil is naturally collected. After baking, cool to room temperature. At this time, the moisture content of the sunflower seeds is 7%.

[0098] S3 Flavoring Processing:

[0099] Preparation of flavor liquid: According to the five-spice flavor formula in Example 1, take 3.5 kg star anise powder, 2.5 kg cinnamon powder, 1.5 kg clove powder, 2.5 kg edible salt, 1.2 kg white sugar, and 0.6 kg monosodium glutamate, add 100 kg water, dissolve at 65℃ and keep warm for 30 min, filter and cool for later use;

[0100] Spraying and seasoning: After cooling, the sunflower seeds are spread evenly on a conveyor belt. The flavor liquid is sprayed evenly onto the surface of the sunflower seeds using a high-pressure spraying device (pressure 0.3MPa, nozzle diameter 0.5mm). The spraying amount is 12kg (the same as the amount of flavor liquid used in Example 1). After spraying, the seeds are transferred to a 62℃ drying oven and dried for 1.8h until the moisture content is 6%. After cooling and screening, the traditional high-temperature roasted defatted spiced sunflower seeds are obtained.

[0101] Performance testing: Fat content 28.5%, Vitamin E retention rate 45.3%, B vitamin retention rate 38.7%, flavor uniformity 62.1%, sunflower seed surface scorch rate 5.8%.

[0102] Comparative Example 2

[0103] S1 Raw Material Screening and Pretreatment: Select 10kg of plump white sand peanuts, remove impurities by vibrating screen, then color sort and grade (particle size 8-10mm), ultrasonically clean (35℃ water, 400W, 40kHz, 20min), drain and transfer to 60℃ constant temperature drying oven to dry for 2h until the moisture content is 12% (pretreatment before pressing).

[0104] S2 Degreasing Treatment: The dried peanuts are transferred to a screw cold press (pressing temperature controlled ≤60℃, screw speed 60r / min, pressing pressure 20MPa) for single-pass cold pressing degreasing. The pressed oil is collected, and the pressed peanut kernels are transferred to a container. At this time, the moisture content of the peanut kernels is 9%.

[0105] S3 Flavoring Processing:

[0106] Flavor liquid preparation: According to the cream flavor formula in Example 2, take 7 kg of whole milk powder, 4 kg of white sugar, 0.4 kg of vanillin, and 0.3 kg of citric acid, add 100 kg of water, dissolve at 70°C and keep warm for 30 min, filter and cool for later use;

[0107] Spraying flavoring: The pressed peanut kernels are spread evenly on the conveyor belt and the flavor liquid is sprayed using a high-pressure spraying device (pressure 0.3MPa, nozzle orifice diameter 0.5mm). The spraying amount is 12kg. After spraying, the peanut kernels are transferred to a 65℃ drying oven to dry for 2 hours until the moisture content is 7%. After cooling and screening, the product of simply pressed defatted butter peanuts is obtained.

[0108] Performance testing: Fat content 18.6%, Vitamin E retention rate 62.5%, B vitamin retention rate 59.3%, flavor uniformity 68.4%.

[0109] Comparative Example 3

[0110] S1 Raw Material Screening and Pretreatment: Select 10kg of plump white sand peanuts, remove impurities by vibrating screen, then color sort and grade (particle size 8-10mm), ultrasonically clean (35℃ clean water, 400W, 40kHz, 20min), drain and transfer to container, without activation soaking treatment.

[0111] S2 Degreasing Treatment: Pour cooking oil into a deep fryer and heat to 180℃. Once the oil temperature stabilizes, add all the drained peanuts to the fryer and continue frying for 20 minutes, stirring slowly with a paddle (30 rpm) to prevent the peanuts from sticking together. After frying, remove the peanuts and place them in a draining net to drain naturally for 30 minutes. Collect the dripping oil; at this point, the peanut moisture content is 5%.

[0112] S3 Flavoring Processing:

[0113] Preparation of flavor liquid: Take 2kg chili powder, 1kg Sichuan pepper powder, 2kg edible salt, and 0.3kg capsaicin, add 100kg water, dissolve at 60℃ and keep warm for 30 minutes, filter and cool for later use;

[0114] Seasoning spraying: Spread the oil-controlled peanuts evenly on the conveyor belt and spray the flavor liquid using a high-pressure spraying device (pressure 0.3MPa, nozzle orifice diameter 0.5mm). The spraying amount is 12kg. After spraying, transfer to a 60℃ drying oven to dry for 1 hour until the moisture content is 6%. Cool and screen to obtain the finished fried defatted spicy peanut product.

[0115] Performance testing: Fat content 26.3%, Vitamin E retention rate 42.8%, B vitamin retention rate 35.6%, flavor uniformity 58.9%, peanut surface charring rate 8.7%.

[0116] Comparative Example 4

[0117] S1 Raw Material Screening and Pretreatment: Select 10kg of plump sunflower seeds, remove impurities by vibrating screen, then color sort and grade (particle size 2-4mm), ultrasonically clean (32℃ clean water, 350W, 40kHz, 18min), drain and directly transfer to microwave treatment container without activation soaking treatment.

[0118] S2 Degreasing Treatment: Place the container containing sunflower seeds into a microwave oven (700W power, 2450MHz frequency), set the heating time to 15 minutes, and remove and stir once every 5 minutes during the process. A small amount of volatile oil will be collected naturally during the microwave treatment. After the treatment is completed, cool to room temperature. At this time, the moisture content of the sunflower seeds is 8%.

[0119] S3 Flavoring Processing:

[0120] Flavor liquid preparation: Take 4 kg of honey, 1 kg of white sugar, and 0.2 kg of citric acid, add 100 kg of water, dissolve at 65℃ and keep warm for 30 min, filter and cool for later use;

[0121] Soaking and flavoring: Place the cooled sunflower seeds into the flavor liquid and soak at room temperature for 30 minutes without stirring or vacuuming. After soaking, remove the seeds, drain the excess flavor liquid from the surface, and transfer them to a 60℃ drying oven to dry for 1 hour until the moisture content is 6%. Cool and screen to obtain the microwave defatted honey sunflower seeds.

[0122] Performance testing: Fat content 22.7%, Vitamin E retention rate 51.4%, B vitamin retention rate 43.8%, flavor uniformity 65.3%, local cracking rate of sunflower seeds 12.5%.

[0123] Comparative Example 5

[0124] S1 Raw Material Screening and Pretreatment: Select 10kg of plump pumpkin seeds, remove impurities by vibrating screen, then color sort and grade (particle size 3-5mm), ultrasonically clean (30℃ clean water, 300W, 40kHz, 15min), drain and transfer to a sealed degreasing tank, without activation soaking treatment.

[0125] S2 Degreasing Treatment: Add food-grade n-hexane (mass ratio of pumpkin seeds to hexane 1.5:1) to the degreasing tank, seal, and soak at room temperature for 2 hours, stirring once every 30 minutes (50 r / min). After soaking, transfer the mixture to a distillation apparatus and distill at 69℃ (boiling point of n-hexane) to recover n-hexane. After distillation, transfer the pumpkin seeds to a 60℃ drying oven to dry for 1 hour to remove residual solvent. At this point, the moisture content of the pumpkin seeds is 7%.

[0126] S3 Flavoring Processing:

[0127] Flavor liquid preparation: According to the cream flavor formula in Example 3, take 7 kg of whole milk powder, 4 kg of white sugar, 0.4 kg of vanillin, and 0.3 kg of citric acid, add 100 kg of water, dissolve at 70°C and keep warm for 30 min, filter and cool for later use;

[0128] Spraying flavoring: The dried pumpkin seeds are spread flat on a conveyor belt and sprayed with flavor liquid using a high-pressure spraying device (pressure 0.3MPa, nozzle orifice diameter 0.5mm). The spraying amount is 12kg. After spraying, the seeds are transferred to a 60℃ drying oven and dried for 1.5h until the moisture content is 5%. After cooling and screening, the chemically defatted cream pumpkin seeds are obtained.

[0129] Performance testing: Fat content 18.9%, Vitamin E retention rate 58.6%, B vitamin retention rate 52.4%, flavor uniformity 68.7%, n-hexane residue 0.005g / kg.

[0130] All test indicators in the performance comparison experiment of this invention were performed in accordance with current standards, as detailed below:

[0131] I. Basic Nutritional Component Testing

[0132] 1. Fat content

[0133] Implementation Standard: GB / T5009.6-2003 "Determination of Fat in Food"

[0134] Standard attributes: National recommended standard, applicable to the determination of crude fat content in various foods, and is the basic standard for food nutrient analysis.

[0135] Core detection method: Soxhlet extraction is used. The specific steps are as follows: Weigh 5g of uniform sample (accurate to 0.001g), use anhydrous diethyl ether or petroleum ether as the extraction solvent, reflux and extract in a Soxhlet extractor for 6-8 hours. After extraction, evaporate the extract to dryness, weigh the mass of fat residue, and calculate the fat content according to the formula (fat content = mass of residue / mass of sample × 100%).

[0136] Applicable scenario: The fat content testing of all nuts and derivative products (crushed peanuts, sunflower seed powder, etc.) in this comparison table follows this standard, which can accurately quantify the degreasing efficiency of different degreasing processes (e.g., fat content of 13.2% in Example 1 vs. fat content of 26.3% in Comparative Example 3).

[0137] 2. Vitamin E retention rate

[0138] Implementation Standard: GB5009.82-2016 "National Food Safety Standard - Determination of Vitamin E in Food"

[0139] Standard attributes: National mandatory safety standard, replacing the original GB / T5009.82-2003, applicable to the determination of vitamin E homologues such as α-tocopherol and β-tocopherol in various foods.

[0140] Core detection method: High-performance liquid chromatography (HPLC) was used. After saponification treatment, vitamin E was extracted with diethyl ether, separated by a C18 column, and detected at a wavelength of 292 nm using methanol-water (98:2) as the mobile phase. Quantification was performed using the external standard method. The retention rate was calculated as: (vitamin E content in the sample / vitamin E content in the unprocessed raw material) × 100%.

[0141] Key requirements: The standard specifies a detection limit of 0.02 mg / 100g and a quantification limit of 0.05 mg / 100g for vitamin E to ensure the accuracy of detection in low-content samples (e.g., in Comparative Example 3, where the vitamin E retention rate is only 42.8%, it can still be accurately determined).

[0142] 3. B vitamin retention rate

[0143] B vitamins are a complex system, and the retention rate needs to be calculated as follows: Total B vitamin retention rate = (Total content of B1+B2+B6+B12 in the sample / Total content of the corresponding components in the unprocessed raw materials) × 100%, which conforms to the industry practice for testing food fortifiers.

[0144] II. Product Quality Characteristics Testing

[0145] 1. Flavor uniformity

[0146] Key Basis: Currently, there is no specific national standard for the uniformity of flavor in nuts. A composite evaluation system of "instrumental analysis + sensory verification" is adopted, referencing the following standards and technical specifications:

[0147] Instrumental analysis standard: Refer to the high performance liquid chromatography method in GB / T30986-2014 "Determination of antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ) in food" to detect the content of characteristic flavor substances on the surface and inside (central layer) of nuts (such as 5-hydroxymethylfurfural in caramel sunflower seed powder and capsaicin in spicy peanuts).

[0148] Sensory reference standard: The sensory evaluation method in LY / T2703-2016 "Quality Grades of Thin-Shelled Pecan Nuts and Kernels" is used, in which 5 professional reviewers (who have been trained and qualified in GB / T23776-2009 "Sensory Evaluation Methods for Tea") score the consistency of the flavor of the samples and take the average value.

[0149] Quantification formula: Flavor uniformity = 90% × [1 - (surface content - internal content) / surface content] + 10% × sensory score / 10. When the content difference is ≤ 10% and the sensory score is ≥ 9 points, the uniformity is ≥ 90% (e.g., the flavor uniformity of Example 5 is 90.8%).

[0150] The test results are shown in the table below:

[0151]

[0152] The table below illustrates this:

[0153] 1. Comparative Example 1 uses a traditional high-temperature baking process, relying solely on oil evaporation for degreasing, yet the final sunflower seed fat content remains as high as 28.5%; Comparative Example 3 uses 180℃ frying for degreasing, but the peanuts absorb oil, resulting in a fat content of 26.3%; Comparative Example 2 uses simple cold pressing for degreasing, but due to the limited physical pressing depth, the peanut fat content remains at 18.6%, while the degreased spiced sunflower seeds in Example 1 of this invention have a fat content of only 13.2%, and the degreased butter peanuts in Example 2 have a fat content as low as 10.8%, with a degreasing rate of 60%-70%, far exceeding the 30%-40% degreasing efficiency of traditional processes.

[0154] 2. The high-temperature baking at 180℃ in Comparative Example 1 resulted in a vitamin E retention rate of only 45.3% and a B vitamin retention rate of 38.7% for sunflower seeds; the frying process in Comparative Example 3 resulted in a vitamin E retention rate of 42.8% and a B vitamin retention rate of 35.6% for peanuts; and the chemical defatting process using n-hexane in Comparative Example 5, although compliant with regulations, still reduced the vitamin E retention rate to 58.6% and the B vitamin retention rate to 52.4%. In contrast, the vitamin C in the activated soaking solution of this invention has antioxidant properties, and the low-temperature enzymatic hydrolysis (45-50℃) and low-temperature baking (70-80℃) avoid high-temperature damage. Nitrogen gas is introduced during enzymatic hydrolysis to isolate oxygen and prevent nutrient oxidation. In the final examples 1-5, the vitamin E retention rate is ≥80% and the B vitamin retention rate is ≥74%, almost completely preserving the original protein, minerals, and vitamins of the nuts.

[0155] 3. Comparative Example 1, after baking, was sprayed with five-spice flavor liquid, and the flavor uniformity was only 62.1%; Comparative Example 4, after microwave defatting, was soaked in honey flavor liquid without vacuum-assisted penetration, and the flavor uniformity was 65.3%; Comparative Example 5, after chemical defatting, was sprayed with cream flavor liquid, and the uniformity was only 68.7%. However, the present invention places the nuts in a vacuum environment of -0.08~-0.09MPa, removes the internal air, and allows the flavor liquid to penetrate into the pores under the action of pressure difference. The vacuum is broken once every 20 minutes to enhance the penetration effect. The test results show that the flavor uniformity of Examples 1-5 is ≥90%.

[0156] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

Claims

1. A method for preparing defatted multi-flavored nuts, characterized in that, Includes the following steps: S1. Raw material screening and pretreatment: (1) Screening and grading: Select plump nuts without mold, remove impurities and grade by color sorting. The nuts are at least one of sunflower seeds and peanuts. The sunflower seeds have a particle size of 2-6 mm and the peanuts have a particle size of 8-12 mm. (2) Cleaning and activation: The graded nuts are ultrasonically cleaned with water at 30-35℃ for 15-20 minutes, drained and then transferred to the activation soaking solution. The solution is kept at 18-22℃ for 24-30 hours, and stirred once every 6 hours. The activation soaking solution contains 0.3-0.5 parts citric acid, 0.2-0.4 parts vitamin C and 100 parts water by weight. S2. Segmented degreasing process: (1) Low-temperature enzymatic degreasing: Take out the nuts soaked in S1, add the enzymatic hydrolysate, and enzymatically hydrolyze at 45-50℃ for 4-6 hours, during which nitrogen gas is introduced; after enzymatic hydrolysis, inactivate the enzyme with hot water at 80-85℃ for 10-15 minutes, and drain. (2) High-temperature cooking and defatting: Transfer the enzymatically hydrolyzed nuts to a high-pressure cooking vessel, add defatting auxiliary solution, and cook at 121℃ and 0.12MPa for 1.5-2 hours. Collect the oil. After cooking, centrifuge and dehydrate for 10-15 minutes until the water content is 25%-30%. (3) Low-temperature roasting and defatting: Roast the dehydrated nuts at 70-80℃ and wind speed of 1.5-2m / s for 2-3 hours, collect the oil, and reduce the moisture content to 8%-10%; S3, Flavor Penetration and Setting: (1) Preparation of flavor liquid: Mix the flavor raw materials with water, stir and dissolve at 60-70℃ and keep warm for 30 minutes, filter and cool; the flavor raw materials are at least one of the following: five-spice, cream, spicy, sea salt and caramel. (2) Vacuum permeation: Transfer the roasted nuts into a vacuum jar, add flavor liquid, vacuum to -0.08~-0.09MPa, permeate at 30-35℃ for 1-1.5h, break the vacuum once every 20min, repeat 3-4 times; (3) Shaping and drying: Dry the permeated nuts at 60-65℃ for 1.5-2 hours until the moisture content is 5%-7%, then cool and screen. S4. Post-processing: Crush the nuts after S3 shaping into 2-5mm nut pieces or 80-120 mesh nut powder, and aseptically package them.

2. The preparation method according to claim 1, characterized in that: The seeds mentioned in step S1 are at least one of sunflower seeds, pumpkin seeds, and watermelon seeds; in step S2, the nitrogen flow rate is 1.5 L / min, and the enzymatic hydrolysis temperature is 48℃; in step S3, the spice-flavored liquid contains 3-5 parts star anise powder, 2-3 parts cinnamon powder, 1-2 parts clove powder, and 2-3 parts edible salt, based on 100 parts water.

3. The preparation method according to claim 1, characterized in that: In step S2, the centrifugal dehydration speed is 3200 r / min and the dehydration time is 12 min; in step S2, the baking temperature is 75℃ and the air velocity is 1.8 m / s; in step S3, the vacuum degree is -0.085 MPa and the permeation temperature is 32℃.

4. The preparation method according to claim 1, characterized in that: In step S4, the nut fragments should be 3-4 mm in size, and the nut powder should be 100 mesh. During the grinding process, the equipment temperature should be controlled to be ≤40℃ to avoid oxidation of the nut nutrients.

5. A defatted, multi-flavored nut, characterized in that: The nuts are prepared by any one of the preparation methods described in claims 1-4; the fat content is ≤15% when the nuts are sunflower seeds and ≤12% when the nuts are peanuts; the vitamin E retention rate is ≥80%, the B vitamin retention rate is ≥75%, and the flavor uniformity is ≥90%.

6. The defatted multi-flavored nuts according to claim 5, characterized in that: When the nuts are defatted spicy pumpkin seeds, the fat content is 14.5%±0.5% and the vitamin E retention rate is 80.3%±1%; when they are defatted butter peanuts, the fat content is 10.8%±0.5% and the B vitamin retention rate is 75.5%±1%.

7. A defatted, multi-flavored nut food product, characterized in that: The food comprises the defatted multi-flavored nuts as described in claim 5 or 6; the food is at least one of mixed nut packets, nut cereals, nut biscuits, and nut butter.

8. The defatted multi-flavored nut food product according to claim 7, characterized in that: The mixed nut packet contains, by weight, 20%-30% defatted spiced sunflower seeds, 20%-30% defatted buttered peanuts, 15%-20% defatted spicy pumpkin seeds, 10%-15% raisins, and 10%-15% dried cranberries.

9. The defatted multi-flavored nut food product according to claim 7, characterized in that: The nut oatmeal contains 15%-20% of the defatted multi-flavored nut crumbs as described in claim 4, 70%-75% of instant oatmeal, and 5%-10% of freeze-dried fruit pieces; the nut biscuit dough contains 5%-10% of the defatted multi-flavored nut powder as described in claim 4.

10. The defatted multi-flavored nut food product according to claim 7, characterized in that: The shelf life of the food is ≥12 months, and the fat oxidation value during storage is ≤0.25g / 100g.

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