Method for frying crisp northern almonds by combining three-section temperature control debitterizing and dehydrating

Abstract

The invention discloses a method for stir-frying crispy northern almonds by combining three-stage temperature control debitterizing and dehydrating, and relates to the technical field of stir-frying crispy northern almonds, which comprises the following steps: performing initial debitterizing treatment on shelled red-skin northern almonds for 6 hours by adopting a 30 DEG C warm water soaking method to obtain a softened and peeled almond raw material; performing quick peeling treatment on the softened peeled almond raw material for 5 minutes by adopting a boiling method with hot water at 80 DEG C to obtain peeled clean almonds; performing deep debitterizing treatment on the peeled clean almonds for 120 hours by adopting a 30-DEG C warm water intermittent water changing method to obtain completely debittered almonds; performing curing treatment on the completely debittered apricot kernels for 1 hour by adopting a 100 DEG C boiling water boiling method, so as to obtain cured and shaped apricot kernels; performing water control treatment on the cured and shaped almonds for 8-12 hours by adopting a natural cooling method to obtain cooled and dehydrated almonds with the water content of 30-35%; and carrying out rapid dehydration treatment on the cooled and dehydrated almonds for 30 minutes by adopting a 170 DEG C high-temperature primary frying method to obtain the surface-shaped almonds.

Description

Technical Field

[0001] The invention relates to the technical field of frying crisp northern almonds, in particular to a method for frying crisp northern almonds by combining three-stage temperature control, debittering and dehydrating. Background Art

[0002] The technology of roasting crispy northern almonds is a deep processing technology specially designed for northern almonds (especially red-skinned bitter almonds). It aims to transform the originally bitter and hard almonds into a product with no obvious bitterness and an ideal crispy taste through a series of physical and chemical processing steps.

[0003] In the field of fried crispy northern almond technology, traditional processing methods often cannot effectively remove amygdalin in almonds, resulting in the final product still having a noticeable bitter taste, affecting the taste and consumer acceptance. In addition, traditional processes damage the internal structure of almonds during processing, resulting in inconsistent texture of the finished product, with some areas being too hard or too soft. At the same time, previous production processes usually take a long time to complete all steps from preliminary processing to the final product, increasing production costs. Summary of the invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method for frying crispy northern almonds by combining three-stage temperature control for debittering, dehydrating and frying, which solves the problem that traditional processing methods often cannot effectively remove amygdalin in almonds, resulting in the final product still having a significant bitter taste, affecting the taste and consumer acceptance, and the traditional process causes the internal structure of the almonds to be damaged during the processing, resulting in inconsistent texture of the finished product, and some areas are too hard or too soft.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] The present invention provides a method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating, which comprises:

[0008] The shelled red-skinned northern bitter almonds were initially debittered by soaking in warm water at 30°C for 6 hours to obtain softened and dehulled almond raw materials.

[0009] The softened peeled almond raw material is quickly peeled for 5 minutes by boiling in hot water at 80° C. to obtain peeled clean almonds;

[0010] The peeled and cleaned almonds are subjected to a deep debittering treatment for 120 hours by using 30° C. warm water intermittent water replacement method to obtain completely debittered almonds;

[0011] The completely debittered almonds are cooked in boiling water at 100° C. for 1 hour to obtain cooked and shaped almonds;

[0012] The ripened and shaped almonds are subjected to water control treatment for 8 to 12 hours by a natural cooling method to obtain cooled and dehydrated almonds having a water content of 30% to 35%;

[0013] The cooled and dehydrated almonds are rapidly dehydrated for 30 minutes by using a high temperature initial frying method at 170° C. to obtain surface-shaped almonds;

[0014] The surface-shaped almonds are subjected to a gradient crisping treatment for 40 minutes by a 150° C. low-temperature fine-frying method to obtain a crispy almond product.

[0015] As a preferred embodiment of the method for frying crispy northern almonds by combining three-stage temperature-controlled debittering and dehydrating, the crispy almond product has a water activity of ≤0.35 and amygdalin residue of ≤2 mg / 100 g.

[0016] As a preferred embodiment of the method for frying crispy northern almonds by combining three-stage temperature-controlled debittering and dehydrating, the present invention comprises the following steps: the shelled red-skinned northern bitter almonds are initially debittered for 6 hours by soaking in warm water at 30°C to obtain a softened peeled almond raw material.

[0017] Put shelled red-skinned northern bitter almonds and 30℃ pure water into a soaking tank at a ratio of 1:5;

[0018] The initial content of amygdalin in the shelled red-skinned northern bitter almonds is ≥3.5 mg / g;

[0019] Start the variable frequency agitator and maintain the water temperature at 30±0.5℃;

[0020] The soaking time was controlled at 6±0.25 hours, and the conductivity of the soaking liquid was tested every 30 minutes;

[0021] The modified Arrhenius equation was used to quantify the debittering efficiency, which is expressed as:

[0022]

[0023] Where C is the instantaneous concentration of amygdalin, t is the time, k is the reaction rate constant, and E a is the activation energy, R is the gas constant, T is the absolute temperature, is the real-time conductivity;

[0024] When When it reaches 225 μS / cm, the automatic water change is started, and the softened blanched almond raw material is obtained.

[0025] As a preferred embodiment of the method for frying crispy northern almonds by combining three-stage temperature control for debittering and dehydrating, the method comprises: using 80° C. hot water boiling method to rapidly peel the softened peeled almond raw material for 5 minutes to obtain peeled clean almonds, and the specific steps are as follows:

[0026] Put the softened peeled almond raw materials that have been soaked at 30℃ for 6 hours into hot water at 80±0.5℃, and the mass ratio of almonds to hot water is 1:8;

[0027] Start the vortex stirring equipment and maintain the water temperature at 80±0.5℃;

[0028] The boiling time was controlled at 5 ± 0.1 minutes, and the turbidity of the hot water was monitored during the cooking process;

[0029] When the turbidity NTU value reaches 50±5, it indicates that the epidermis has fallen off in large quantities and automatic drainage is started;

[0030] After cooking, spray with 20℃ cold water for 10 seconds and stop the heat action to make the skin shrink and fall off;

[0031] Based on color recognition technology, the photoelectric sorting machine removes the remaining skin and obtains peeled and clean almonds.

[0032] As a preferred embodiment of the method for frying crispy northern almonds by combining three-stage temperature-controlled debittering and dehydration, the peeled clean almonds are subjected to a deep debittering treatment for 120 hours by intermittent water replacement with 30°C warm water to obtain completely debittered almonds, and the specific steps are as follows:

[0033] Place the peeled and cleaned almonds in a special debittering tank and mix the almonds with 30±0.3℃ debittering liquid in a ratio of 1:6;

[0034] Equipped with a water replacement system, it automatically discharges 90±2% of the old liquid and injects an equal amount of new liquid every 24±0.5 hours;

[0035] A microporous aeration device with a bottom pore size of 50 μm was installed, and intermittent aeration was performed at a flow rate of 0.8 ± 0.1 L / min·kg;

[0036] Online near-infrared spectroscopy (NIRS) was used to monitor the content of amygdalin;

[0037] When the detection value is ≤0.1 mg / g, the early termination program is triggered and completely debittered almonds are obtained.

[0038] As a preferred embodiment of the method for frying crispy northern almonds by combining three-stage temperature-controlled debittering and dehydrating, the method comprises: performing a 100° C. boiling water cooking method on the completely debittered almonds for 1 hour to obtain ripened and shaped almonds, and the specific steps are as follows:

[0039] Almonds and deionized water were placed in a ripening tank at a mass ratio of 1:10, and the temperature was raised from 30°C to 60°C at a rate of 5°C / min, and then from 60°C to 100°C at a rate of 10°C / min;

[0040] Start the propeller stirrer and set the speed to 25 rpm, maintain the water flow rate at 0.5 m / s, and control the temperature difference in the tank within the range of ±0.3°C to obtain evenly heated almonds;

[0041] Using a 100° C. constant temperature control system to perform protein denaturation treatment on the evenly heated almonds;

[0042] The water temperature was controlled at 100±0.3℃, and the treatment was continued for 60±0.5 minutes. The viscosity was tested every 10 minutes to obtain the initially ripened almonds.

[0043] The preliminarily ripened almonds are subjected to pH stabilization treatment using an ionic strength regulator, 0.05% sodium citrate is added, and the pH is maintained at 7.0±0.2 to obtain buffer system almonds;

[0044] The buffer system almonds are subjected to thermal effect termination treatment using a rapid cooling system, with 20°C pure water spraying for 5 seconds and a cooling water volume of 2L / kg almonds. The final temperature is reduced to 25-30°C, and ripened and shaped almonds are obtained.

[0045] As a preferred embodiment of the method for frying crispy northern almonds by combining three-stage temperature control for debittering and dehydrating, the method comprises: performing water control treatment on the ripened and shaped almonds for 8-12 hours by natural cooling to obtain cooled and dehydrated almonds with a water content of 30% to 35%, and the specific steps are as follows:

[0046] A layered airing system is used to perform a preliminary cooling treatment on the ripened and shaped almonds;

[0047] Spread the almonds in a single layer on a food-grade stainless steel mesh belt and place them in a clean environment at 25±1℃ and 55±5% relative humidity. Turn on a low-speed fan with a top wind speed of 0.3m / s to assist convection.

[0048] Automatically flip the machine once every 2 hours, set the flipping speed to 0.5m / min, and simultaneously detect the surface water activity;

[0049] Using a gravity drainage system to remove free water from the almonds with uniform moisture distribution;

[0050] The mesh belt is arranged at an angle of 15°, and a V-shaped guide groove with a spacing of 10 cm is set at the bottom to collect and discharge water to obtain primary dehydrated almonds;

[0051] The primary dehydrated almonds are subjected to final water balance treatment by adopting an environmental parameter control system to obtain cooled dehydrated almonds.

[0052] As a preferred embodiment of the method for frying crispy northern almonds in combination with three-stage temperature control for debittering and dehydrating, the method comprises: performing a rapid dehydration treatment on the cooled and dehydrated almonds for 30 minutes by using a high temperature initial frying method at 170°C to obtain almonds with fixed surface shape, and the specific steps are as follows:

[0053] Adjust the gas heater to 18±0.5kW, use an infrared thermometer to calibrate the preheating drum to 170±2℃, and add materials after the temperature fluctuation is ≤1℃ / 5min;

[0054] The cooling and dehydrated almonds are quantitatively fed by a variable frequency speed regulating device, the feeding speed is controlled to be 50±2kg / min, the material layer thickness is maintained at 3±0.5cm, and the drum speed is set to 8±0.3rpm;

[0055] A dual-section temperature control system is used to perform gradient dehydration treatment on the evenly spread almonds;

[0056] During dehydration, for the first 15 minutes: maintain 170±2℃;

[0057] After 15 minutes: gradually reduce to 165±2℃;

[0058] Check exhaust humidity every 5 minutes;

[0059] Using a high-pressure air sweeping device to remove free water from the surface of the primary dehydrated almonds to obtain surface-shaped almonds;

[0060] During the free water removal process, 0.6 MPa compressed air pulse jet was set, and the air flow temperature was 80±5°C, and each action time was 3±0.5 seconds.

[0061] As a preferred embodiment of the method for frying crispy northern almonds in combination with three-stage temperature control for debittering and dehydrating, the present invention comprises the following steps:

[0062] In the initial stage, set the temperature to 150±1℃, the drum speed to 6±0.2rpm, and turn on the bottom infrared auxiliary heating;

[0063] In the middle stage, the temperature was gradually lowered to 145 ± 1 °C, the rotation speed was adjusted to 5 ± 0.2 rpm, and atomized olive oil was sprayed every 5 minutes;

[0064] In the final stage, the temperature is stabilized at 140±1°C, the rotation speed is 4±0.2rpm, and the negative pressure suction system is turned on to remove free oil;

[0065] A texture feedback control system is used to precisely control the crispness of the evenly heated almonds to obtain semi-finished almonds;

[0066] The semi-finished almonds are quickly and stably processed by an airflow cooling system to obtain crispy almond finished products.

[0067] As a preferred solution of the method for frying crispy northern almonds by combining three-stage temperature control for debittering and dehydrating, the present invention comprises the following steps:

[0068] During the water balance treatment process;

[0069] Hours 4-6: Maintain 25°C / 55%RH;

[0070] Hours 6-9: gradually adjust to 28°C / 50%RH;

[0071] Hours 9-12: Stabilize at 30°C / 45%RH.

[0072] The beneficial effects of the present invention are as follows: by adopting a 30°C warm water soaking method to carry out a preliminary debittering treatment for 6 hours on shelled red-skinned northern bitter almonds, the purpose of removing part of the bitter substances is achieved, and the mild temperature condition is used to reduce the content of amygdalin in the almonds, and at the same time, the outer skin is softened for subsequent operations. Through this mild pretreatment method, the bitter substances are effectively reduced, and the loss of nutrients that may be caused by high temperature is avoided, thereby laying a good foundation for subsequent processes and ensuring the taste and nutritional value of the final product. By implementing a 30°C warm water intermittent water replacement method, the peeled almonds are subjected to a deep debittering treatment for up to 120 hours, which further reduces the residual amount of amygdalin and ensures that the product meets the food safety standard. The method can effectively reduce amygdalin to below the safe level, and at the same time, the accumulation of harmful substances is avoided by regularly changing the water body, thereby ensuring the safety and health of the product and meeting the consumer's demand for high-quality food. The completely debittered almonds are ripened by a 100°C boiling water boiling method, and the transformation process from preliminary ripening to the final crispy finished product is completed by combining natural cooling, high-temperature initial frying, low-temperature fine frying and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0074] Figure 1 The present invention is a flow chart of the method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating in Example 1. DETAILED DESCRIPTION

[0075] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0076] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0077] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0078] Example 1, reference Figure 1 , which is the first embodiment of the present invention, provides a method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating, comprising the following steps:

[0079] S1. Preliminary debittering treatment is performed on shelled red-skinned northern bitter almonds by soaking them in warm water at 30° C. for 6 hours to obtain softened peeled almond raw materials;

[0080] Furthermore, shelled red-skinned northern bitter almonds and 30°C pure water are put into a soaking tank at a ratio of 1:5;

[0081] The initial content of amygdalin in shelled red-skinned northern bitter almonds is ≥3.5 mg / g;

[0082] Start the variable frequency agitator and maintain the water temperature at 30±0.5℃;

[0083] The soaking time was controlled at 6±0.25 hours, and the conductivity of the soaking liquid was tested every 30 minutes;

[0084] The modified Arrhenius equation was used to quantify the debittering efficiency, which is expressed as:

[0085]

[0086] Where C is the instantaneous concentration of amygdalin, t is the time, k is the reaction rate constant, and E a is the activation energy, R is the gas constant, T is the absolute temperature, is the real-time conductivity;

[0087] when When it reaches 225 μS / cm, the automatic water change is started, and the softened peeled almond raw material is obtained;

[0088] It should be noted that by adopting the modified Arrhenius equation to quantify the debittering efficiency and automatically adjusting the water exchange cycle according to the real-time conductivity, the removal rate of amygdalin can be accurately controlled, ensuring the high efficiency and stability of the debittering process. This method not only improves the processing efficiency, but also can adapt to the changes in the content of amygdalin in different batches of raw materials, thereby ensuring the quality consistency of the final product.

[0089] S2, using 80° C. hot water boiling method to quickly peel the softened peeled almond raw material for 5 minutes to obtain peeled clean almonds;

[0090] Furthermore, the softened blanched almond raw material, which has been soaked at 30°C for 6 hours, is put into hot water at 80±0.5°C, and the mass ratio of almond to hot water is 1:8;

[0091] Start the vortex stirring equipment and maintain the water temperature at 80±0.5℃;

[0092] The boiling time was controlled at 5 ± 0.1 minutes, and the turbidity of the hot water was monitored during the cooking process;

[0093] When the turbidity NTU value reaches 50±5, it indicates that the epidermis has fallen off in large quantities and automatic drainage is started;

[0094] After cooking, spray with 20℃ cold water for 10 seconds and stop the heat action to make the skin shrink and fall off;

[0095] Based on color recognition technology, the photoelectric sorting machine removes the remaining skin and obtains peeled and clean almonds;

[0096] It should be noted that the use of vortex stirring equipment and the method of monitoring the turbidity of hot water during the peeling process can not only accelerate the shedding of the skin, but also effectively monitor the degree of peeling to ensure that the surface of the peeled almonds is clean and free of residue. In addition, the use of cold water spray to quickly terminate the heat effect and the removal of residual skin based on color recognition technology further improve the peeling effect and product appearance quality, and reduce impurities in subsequent processing.

[0097] S3, using 30°C warm water intermittent water change method to perform deep debittering treatment on the peeled clean almonds for 120 hours to obtain completely debittered almonds;

[0098] Furthermore, the peeled and cleaned almonds are placed in a special debittering tank, and the almonds are mixed with 30±0.3℃ debittering liquid in a ratio of 1:6;

[0099] Equipped with a water replacement system, it automatically discharges 90±2% of the old liquid and injects an equal amount of new liquid every 24±0.5 hours;

[0100] A microporous aeration device with a bottom pore size of 50 μm was installed, and intermittent aeration was performed at a flow rate of 0.8 ± 0.1 L / min·kg;

[0101] Online near-infrared spectroscopy (NIRS) was used to monitor the content of amygdalin;

[0102] When the detection value is ≤0.1mg / g, the early termination procedure is triggered and completely debittered almonds are obtained;

[0103] It should be noted that the content of amygdalin is monitored in real time through online near-infrared spectroscopy (NIRS) technology, and the early termination procedure is triggered accordingly, thereby achieving precise control of the deep debittering process. This method can not only effectively reduce amygdalin to below the safe level, but also avoid the loss of nutrients caused by excessive processing, thereby ensuring the safety and nutritional value of the product.

[0104] S4, using 100° C. boiling water to ripen the completely debittered almonds for 1 hour to obtain ripened and shaped almonds;

[0105] Furthermore, almonds and deionized water were put into a ripening tank at a mass ratio of 1:10, and the temperature was increased from 30°C to 60°C at a rate of 5°C / min, and then from 60°C to 100°C at a rate of 10°C / min;

[0106] Start the propeller stirrer and set the speed to 25 rpm, maintain the water flow rate at 0.5 m / s, and control the temperature difference in the tank within the range of ±0.3°C to obtain evenly heated almonds;

[0107] A 100℃ constant temperature control system was used to denature the protein of the evenly heated almonds;

[0108] The water temperature was controlled at 100±0.3℃, and the treatment was continued for 60±0.5 minutes. The viscosity was tested every 10 minutes to obtain the initially ripened almonds.

[0109] The pH of the pre-ripened almonds was stabilized by using an ionic strength regulator, adding 0.05% sodium citrate and maintaining the pH at 7.0±0.2 to obtain buffer system almonds;

[0110] The buffer system almonds were treated with thermal effect termination by using a rapid cooling system, with 20°C pure water spraying for 5 seconds and a cooling water volume of 2L / kg almonds. The final temperature dropped to 25-30°C, and ripened and shaped almonds were obtained.

[0111] It should be noted that the use of a propeller agitator to maintain the water flow rate and temperature difference control in the tank ensures that the almonds are evenly heated during the ripening process, which is crucial for protein denaturation treatment. In addition, the addition of ionic strength regulators to maintain a stable pH value helps to maintain the integrity of the almond structure and prevent texture changes caused by excessively high or low pH, thereby improving the taste and texture of the final product.

[0112] S5, using a natural cooling method to control the water of the ripened and shaped almonds for 8-12 hours to obtain cooled and dehydrated almonds with a water content of 30% to 35%;

[0113] Furthermore, a layered airing system is used to initially cool the ripened and shaped almonds;

[0114] Spread the almonds in a single layer on a food-grade stainless steel mesh belt and place them in a clean environment at 25±1℃ and 55±5% relative humidity. Turn on a low-speed fan at a top speed of 0.3m / s to assist convection.

[0115] Automatically flip the machine once every 2 hours, set the flipping speed to 0.5m / min, and simultaneously detect the surface water activity;

[0116] A gravity drainage system is used to remove free water from almonds with uniform moisture distribution;

[0117] The mesh belt is arranged at an angle of 15°, and a V-shaped guide groove with a spacing of 10 cm is set at the bottom to collect and discharge water to obtain primary dehydrated almonds;

[0118] The primary dehydrated almonds are subjected to a final water balance treatment using an environmental parameter control system to obtain cooled dehydrated almonds;

[0119] It should be noted that the combined use of the layered spreading system and the environmental parameter control system can ensure uniform distribution of moisture in the almonds while accurately controlling the temperature and humidity conditions during the cooling process, promoting the effective discharge of free water and achieving the ideal moisture content target. It plays a key role in forming the appropriate water activity inside the almonds, which is beneficial to the formation of a crispy taste in the subsequent frying process.

[0120] S6, using a high temperature initial frying method at 170° C. to rapidly dehydrate the cooled and dehydrated almonds for 30 minutes to obtain surface-shaped almonds;

[0121] Furthermore, the gas heater was adjusted to a power of 18±0.5kW, and the preheating drum was calibrated to 170±2°C using an infrared thermometer, and the material was added after the temperature fluctuation was ≤1°C / 5min;

[0122] The frequency conversion speed regulating device is used to quantitatively feed the cooled and dehydrated almonds, the feeding speed is controlled to be 50±2kg / min, the material layer thickness is maintained at 3±0.5cm, and the drum speed is set to 8±0.3rpm;

[0123] A dual-zone temperature control system is used to perform gradient dehydration on evenly spread almonds;

[0124] During dehydration, for the first 15 minutes: maintain 170±2℃;

[0125] After 15 minutes: gradually reduce to 165±2℃;

[0126] Check exhaust humidity every 5 minutes;

[0127] The high-pressure air sweeping device is used to remove the free water on the surface of primary dehydrated almonds to obtain surface-shaped almonds;

[0128] During the free water removal process, set the compressed air pulse jet at 0.6MPa and the air flow temperature at 80±5℃, with each action time of 3±0.5 seconds;

[0129] It should be noted that the use of a dual-zone temperature control system for gradient dehydration treatment can effectively reduce the free water on the surface of almonds while avoiding damage to the internal structure of almonds caused by high temperature, ensuring that they maintain a good appearance and taste. The use of a high-pressure air sweeping device further enhances the surface drying effect, laying the foundation for subsequent fine frying and helping to achieve better crispness.

[0130] S7, using a 150° C. low-temperature fine frying method to perform a gradient crisping treatment on the surface-shaped almonds for 40 minutes to obtain a crispy almond product;

[0131] Furthermore, the water activity of the finished crisp almond product is ≤0.35, and the residual amygdalin is ≤2mg / 100g;

[0132] In the initial stage, set the temperature to 150±1℃, the drum speed to 6±0.2rpm, and turn on the bottom infrared auxiliary heating;

[0133] In the middle stage, the temperature was gradually lowered to 145 ± 1 °C, the rotation speed was adjusted to 5 ± 0.2 rpm, and atomized olive oil was sprayed every 5 minutes;

[0134] In the final stage, the temperature is stabilized at 140±1°C, the rotation speed is 4±0.2rpm, and the negative pressure suction system is turned on to remove free oil;

[0135] The texture feedback control system is used to precisely control the crispness of evenly heated almonds to obtain semi-finished almonds;

[0136] The airflow cooling system is used to quickly and stably process the semi-finished almonds to obtain crispy almonds.

[0137] It should be noted that the crispness of almonds during the frying process can be precisely controlled through the texture feedback control system, and parameters such as the heating temperature and drum speed can be adjusted according to real-time data to ensure that each batch of products meets consistent quality standards. The intelligent control method greatly improves production efficiency and product quality stability, meeting the market demand for high-quality food.

[0138] In summary, the present invention achieves the purpose of removing some bitter substances by using a 30°C warm water immersion method to perform a preliminary debittering treatment on shelled red-skinned northern bitter almonds for 6 hours, and utilizes mild temperature conditions to reduce the content of amygdalin in almonds, while softening the outer skin for subsequent operations. Through this mild pretreatment method, bitter substances are effectively reduced, and the loss of nutrients that may be caused by high temperature is avoided, which lays a good foundation for subsequent processes and ensures the taste and nutritional value of the final product. By implementing a 30°C warm water intermittent water change method, the peeled almonds are subjected to a deep debittering treatment for up to 120 hours, which further reduces the residual amount of amygdalin and ensures that the product meets food safety standards. The method can effectively reduce amygdalin to below a safe level, and at the same time, the accumulation of harmful substances is avoided by regularly changing the water body, thereby ensuring the safety and health of the product and meeting consumers' demand for high-quality food. The completely debittered almonds are ripened by a 100°C boiling water cooking method, and the transformation process from preliminary ripening to the final crispy finished product is completed by combining natural cooling, high-temperature initial frying, low-temperature fine frying and other steps.

[0139] Example 2, referring to Table 1, is the second example of the present invention. To further verify the technical solution of the present invention, experimental simulation data of a method for frying crispy northern almonds by combining three-stage temperature control for debittering and dehydrating is provided.

[0140] In this example, wild bitter almonds were selected as raw materials, and the initial amygdalin content was 3.8±0.2 mg / g. The experiment was carried out in a standardized food processing workshop, and all equipment passed the metrological certification. The implementation process strictly followed the process parameters of the invention content, and parallel sample detection was set at key nodes:

[0141] Initial debittering stage: Use a 200L stainless steel soaking tank, load 40kg of almonds and 200L of 30.0±0.3℃ pure water; the variable frequency agitator runs at 15rpm, and the conductivity monitor records data every 30 minutes; after 6 hours, the test shows that the amygdalin content has dropped to 2.7mg / g, and the cell integrity rate is 98.5% (confocal microscopy observation).

[0142] Peeling treatment: Transfer to 80.2±0.3℃ hot water (almond: water = 1:8), the turbidity monitor reaches NTU 52 at 4 minutes and 50 seconds, and the drainage is immediately triggered; after cold water spraying and detection by CCD sorting machine, the epidermis residue rate is only 2.3%.

[0143] Deep debittering: carried out in a 500L debittering tank, with the microporous aeration system running for 30 minutes every 2 hours. The NIRS model predicted a value of 0.09 mg / g at the 116th hour, and the treatment was terminated early; the final LC-MS detection residue was 0.07 mg / g.

[0144] Ripening and curing: Using a step-by-step temperature program, the viscosity reached 36.2 cP at 58 minutes (Brookfield viscometer); after rapid cooling, the protein denaturation degree was measured to be 86.3% (differential scanning calorimetry).

[0145] Water control treatment: Spread and air in a constant temperature and humidity room (25-30°C / 45%-55% RH) for 10 hours, and the final moisture content is 32.7% (halogen moisture meter).

[0146] Frying process: In the initial frying stage (170°C), the surface moisture is reduced to 11.2%. Infrared temperature measurement feedback control is adopted in the fine frying stage. The main frequency of acoustic emission of the final product is 368Hz (detected by brittleness instrument).

[0147] The details are shown in Table 1 below:

[0148]

[0149] Table 1: Process parameter comparison table

[0150] From the comparative data, it can be seen that the three-stage temperature control system of the present invention shows significant advantages in multiple dimensions: in terms of detoxification efficiency, the residual amount of amygdalin is only 21.9% to 25.0% of that in the traditional process, which is mainly due to the precise debittering control achieved by the conductivity-NIRS combined monitoring system. The application of microporous aeration technology in the deep debittering stage increases the mass transfer efficiency by 35%.

[0151] Nutritional retention data showed that the vitamin E retention rate was 23.3% higher than the optimal traditional process. Analysis showed that the 80°C precision peeling and step-by-step ripening process effectively avoided the destruction of unsaturated fatty acids by high temperature. Texture tests showed that the crispness consistency of this product was significantly better than that of the control sample.

[0152] The improvement of epidermal integrity has important commercial value. High-speed video analysis shows that boiling in hot water at 80°C reduces epidermal peeling stress to 3.2N / cm 2 .

[0153] In summary, this embodiment achieves a dual breakthrough of quality improvement and energy consumption reduction through multi-parameter collaborative optimization while ensuring food safety. In particular, it innovatively integrates modern sensing technology with traditional processing technology to form a technical solution with significant progress.

[0154] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating, characterized in that: include: The shelled red-skinned northern bitter almonds were initially debittered by soaking in warm water at 30°C for 6 hours to obtain softened and dehulled almond raw materials. The softened peeled almond raw material is quickly peeled for 5 minutes by boiling in hot water at 80° C. to obtain peeled clean almonds; The peeled and cleaned almonds are subjected to a deep debittering treatment for 120 hours by using 30° C. warm water intermittent water replacement method to obtain completely debittered almonds; The completely debittered almonds are cooked in boiling water at 100° C. for 1 hour to obtain cooked and shaped almonds; The ripened and shaped almonds are subjected to water control treatment for 8 to 12 hours by a natural cooling method to obtain cooled and dehydrated almonds having a water content of 30% to 35%; The cooled and dehydrated almonds are rapidly dehydrated for 30 minutes by using a high temperature initial frying method at 170° C. to obtain surface-shaped almonds; The surface-shaped almonds are subjected to a gradient crisping treatment for 40 minutes by a 150° C. low-temperature fine-frying method to obtain a crispy almond product.

2. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 1, characterized in that: The water activity of the crisp almond product is ≤0.35, and the residual amygdalin is ≤2 mg / 100 g.

3. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 2, characterized in that: The method of using 30° C. warm water soaking to perform preliminary debittering treatment on shelled red-skinned northern bitter almonds for 6 hours to obtain softened peeled almond raw materials specifically comprises the following steps: Put shelled red-skinned northern bitter almonds and 30℃ pure water into a soaking tank at a ratio of 1:5; The initial content of amygdalin in the shelled red-skinned northern bitter almonds is ≥3.5 mg / g; Start the variable frequency agitator and maintain the water temperature at 30±0.5℃; The soaking time was controlled at 6±0.25 hours, and the conductivity of the soaking liquid was tested every 30 minutes; The modified Arrhenius equation was used to quantify the debittering efficiency, which is expressed as: Where C is the instantaneous concentration of amygdalin, t is the time, k is the reaction rate constant, and E a is the activation energy, R is the gas constant, T is the absolute temperature, and κ is the real-time conductivity; When κ reaches 225 μS / cm, automatic water change is started to obtain softened blanched almond raw material.

4. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 3, characterized in that: The softened peeled almond raw material is subjected to a quick peeling process for 5 minutes by boiling in hot water at 80° C. to obtain peeled clean almonds, and the specific steps are: Put the softened peeled almond raw materials that have been soaked at 30℃ for 6 hours into hot water at 80±0.5℃, and the mass ratio of almonds to hot water is 1:8; Start the vortex stirring equipment and maintain the water temperature at 80±0.5℃; The boiling time was controlled at 5 ± 0.1 minutes, and the turbidity of the hot water was monitored during the cooking process; When the turbidity NTU value reaches 50±5, it indicates that the epidermis has fallen off in large quantities and automatic drainage is started; After cooking, spray with 20℃ cold water for 10 seconds and stop the heat action to make the skin shrink and fall off; Based on color recognition technology, the photoelectric sorting machine removes the remaining skin and obtains peeled and clean almonds.

5. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 4, characterized in that: The peeled clean almonds are subjected to a 120-hour deep debittering treatment using a 30° C. warm water intermittent water replacement method to obtain completely debittered almonds, and the specific steps are: Place the peeled and cleaned almonds in a special debittering tank and mix the almonds with 30±0.3℃ debittering liquid in a ratio of 1:6; Equipped with a water replacement system, it automatically discharges 90±2% of the old liquid and injects an equal amount of new liquid every 24±0.5 hours; A microporous aeration device with a bottom pore size of 50 μm was installed, and intermittent aeration was performed at a flow rate of 0.8 ± 0.1 L / min·kg; Online near-infrared spectroscopy (NIRS) was used to monitor the content of amygdalin; When the detection value is ≤0.1 mg / g, the early termination program is triggered and completely debittered almonds are obtained.

6. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 5, characterized in that: The method of using 100° C. boiling water to ripen the completely debittered almonds for 1 hour to obtain ripened and shaped almonds comprises the following specific steps: Almonds and deionized water were placed in a ripening tank at a mass ratio of 1:10, and the temperature was raised from 30°C to 60°C at a rate of 5°C / min, and then from 60°C to 100°C at a rate of 10°C / min; Start the propeller stirrer and set the speed to 25 rpm, maintain the water flow rate at 0.5 m / s, and control the temperature difference in the tank within the range of ±0.3°C to obtain evenly heated almonds; Using a 100° C. constant temperature control system to perform protein denaturation treatment on the evenly heated almonds; The water temperature was controlled at 100±0.3℃, and the treatment was continued for 60±0.5 minutes. The viscosity was tested every 10 minutes to obtain the initially ripened almonds. The preliminarily ripened almonds are subjected to pH stabilization treatment using an ionic strength regulator, 0.05% sodium citrate is added, and the pH is maintained at 7.0±0.2 to obtain buffer system almonds; The buffer system almonds are subjected to thermal effect termination treatment using a rapid cooling system, with 20°C pure water spraying for 5 seconds and a cooling water volume of 2L / kg almonds. The final temperature is reduced to 25-30°C, and ripened and shaped almonds are obtained.

7. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 6, characterized in that: The natural cooling method is used to control the water of the ripened and shaped almonds for 8-12 hours to obtain cooled and dehydrated almonds with a water content of 30% to 35%, and the specific steps are: A layered airing system is used to perform a preliminary cooling treatment on the ripened and shaped almonds; Spread the almonds in a single layer on a food-grade stainless steel mesh belt and place them in a clean environment at 25±1℃ and 55±5% relative humidity. Turn on a low-speed fan with a top wind speed of 0.3m / s to assist convection. Automatically flip the machine once every 2 hours, set the flipping speed to 0.5m / min, and simultaneously detect the surface water activity; Using a gravity drainage system to remove free water from the almonds with uniform moisture distribution; The mesh belt is arranged at an angle of 15°, and a V-shaped guide groove with a spacing of 10 cm is set at the bottom to collect and discharge water to obtain primary dehydrated almonds; The primary dehydrated almonds are subjected to final water balance treatment by adopting an environmental parameter control system to obtain cooled dehydrated almonds.

8. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 7, characterized in that: The cooling and dehydrated almonds are rapidly dehydrated for 30 minutes by using a 170° C. high temperature initial frying method to obtain surface-shaped almonds, and the specific steps are: Adjust the gas heater to 18±0.5kW, use an infrared thermometer to calibrate the preheating drum to 170±2℃, and add materials after the temperature fluctuation is ≤1℃ / 5min; The cooling and dehydrated almonds are quantitatively fed by a variable frequency speed regulating device, the feeding speed is controlled to be 50±2kg / min, the material layer thickness is maintained at 3±0.5cm, and the drum speed is set to 8±0.3rpm; A dual-section temperature control system is used to perform gradient dehydration treatment on the evenly spread almonds; During dehydration, for the first 15 minutes: maintain 170±2℃; After 15 minutes: gradually reduce to 165±2℃; Check exhaust humidity every 5 minutes; Using a high-pressure air sweeping device to remove free water from the surface of the primary dehydrated almonds to obtain surface-shaped almonds; During the free water removal process, 0.6 MPa compressed air pulse jet was set, and the air flow temperature was 80±5°C, and each action time was 3±0.5 seconds.

9. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 8, characterized in that: The step of using a 150° C. low-temperature fine frying method to perform a gradient crisping treatment on the surface-shaped almonds for 40 minutes to obtain a crispy almond product is as follows: In the initial stage, set the temperature to 150±1℃, the drum speed to 6±0.2rpm, and turn on the bottom infrared auxiliary heating; In the middle stage, the temperature was gradually lowered to 145 ± 1 °C, the rotation speed was adjusted to 5 ± 0.2 rpm, and atomized olive oil was sprayed every 5 minutes; In the final stage, the temperature is stabilized at 140±1°C, the rotation speed is 4±0.2rpm, and the negative pressure suction system is turned on to remove free oil; A texture feedback control system is used to precisely control the crispness of the evenly heated almonds to obtain semi-finished almonds; The semi-finished almonds are quickly and stably processed by an airflow cooling system to obtain crispy almond finished products.

10. The method for frying crispy northern almonds by combining three-stage temperature control, debittering and dehydrating as claimed in claim 7, characterized in that: The environmental parameter control system is used to perform a final water balance treatment on the primary dehydrated almonds, and the specific steps are: During the water balance treatment process; Hours 4-6: Maintain 25°C / 55%RH; Hours 6-9: gradually adjust to 28°C / 50%RH; Hours 9-12: Stabilize at 30°C / 45%RH.

Images