Dehydration-free low-calorie konjac composite noodles and preparation method thereof

Abstract

The invention relates to a dehydration-free low-calorie konjac composite noodle and a preparation method thereof, and belongs to the technical field of konjac noodle processing, the composite noodle is composed of 40%-60% of konjac powder, 20%-40% of vital gluten, 0.2%-0.9% of trehalose, 0.05%-0.15% of edible calcium salt and less than or equal to 65% of water, and the dry weight ratio of the konjac powder to the vital gluten is 1: (0.5-1.5). The trehalose accounts for 0.5%-1.5% of the dry weight of the konjac powder. The preparation method comprises the following steps: in the premixing process, the konjac powder is sieved and then is mixed with the vital gluten in a negative pressure environment at different speeds; the hydration process adopts three-stage gradient water injection synchronous jet flow to inject a trehalose solution; in the mixing process, a network is constructed through three-section temperature control of a double-screw extruder; in the shaping process, the dough blank is soaked in 0.1%-0.3% calcium salt solidification liquid, treated for 8-12 minutes in a turbulent flow environment at the temperature of 25-35 DEG C and periodically turned over; and finally rinsing and draining to obtain a finished product.

Description

Technical Field

[0001] The invention relates to the technical field of konjac noodle processing, in particular to non-dehydrated low-calorie konjac composite noodles and a preparation method thereof. Background Art

[0002] Traditional konjac noodle production requires dehydration and shaping, which leads to two major defects:

[0003] First, hot air drying destroys the active structure of konjac glucomannan;

[0004] Secondly, the water extraction rate after rehydration is too high, resulting in a loss of firmness and elasticity. Existing improved processes use starch compounding, which improves formability but increases the heat content. Adding carrageenan, while suppressing water extraction, also increases the cooking loss rate. The fundamental contradiction lies in the inability to achieve both the water-holding capacity of the konjac gel network and the need for dehydration-free shaping. Summary of the Invention

[0005] The main purpose of the invention is to provide a non-dehydration low-calorie konjac composite noodle and a preparation method thereof, so as to solve the technical problem that the water holding capacity of the konjac gel network and the dehydration-free shaping cannot be achieved at the same time.

[0006] To achieve the above object, the dehydrated low-calorie konjac composite noodles provided by the present invention are composed of the following raw materials by dry weight percentage:

[0007] Konjac flour 40%-60%,

[0008] Gluten 20%-40%,

[0009] Trehalose 0.2%-0.9%,

[0010] Edible calcium salt 0.05%-0.15%,

[0011] The balance is water and the content is ≤65%;

[0012] The dry weight ratio of konjac flour to gluten is 1:(0.5-1.5), and the added amount of trehalose accounts for 0.5%-1.5% of the dry weight of the konjac flour.

[0013] Furthermore, the konjac flour content is 45%-55%, and the gluten content is 30%-35%;

[0014] The amount of trehalose added is 0.8%-1.2% of the dry weight of the konjac flour;

[0015] Further comprising 0.1%-0.3% of flaxseed gum and 0.5%-1.0% of oat fiber based on the total dry weight of the raw material;

[0016] The moisture content is controlled at 58%-62%.

[0017] Furthermore, 30%-50% of the gluten is replaced by pea protein;

[0018] Further comprising 1.0%-2.0% of inulin and 0.01%-0.05% of glucono-δ-lactone based on the total dry weight of the raw material;

[0019] The edible calcium salt is a compound of calcium lactate and calcium citrate in a weight ratio of 2:1-3:1.

[0020] The present invention also provides a method for preparing a non-dehydrated low-calorie konjac composite noodle, comprising:

[0021] Premixing konjac flour and gluten at a dry weight ratio of 1: (0.5-1.5) to form the main ingredient;

[0022] Add 20%-35% of 40° C.-55° C. warm water to the main ingredients, and simultaneously inject 0.5%-1.5% of trehalose solution by weight of konjac flour;

[0023] The dough was kneaded by a twin-screw extruder at a speed of 150-250 r / min for 3-5 minutes to form a homogeneous dough, and the dough was placed in an environment with a humidity of 80%-85% and allowed to stand for 10-20 minutes;

[0024] The cooked dough is rolled into strips through a mold, and immediately immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt, and treated in a shaping tank at 25°C-35°C for 8-12 minutes, during which the coagulation liquid flow rate is maintained at 0.5-1.0 m / s;

[0025] After taking out, rinse with 10-15°C room temperature water for 30-60 seconds, drain and directly package to obtain the finished composite noodles.

[0026] Furthermore, the step of premixing konjac flour and gluten at a dry weight ratio of 1: (0.5-1.5) to form the main ingredient comprises:

[0027] The konjac flour was sieved through an 80-100 mesh sieve and placed in a negative pressure environment to control the ambient humidity to ≤40%;

[0028] Add gluten in proportion and mix at a low speed of 15-25r / min for 2-4 minutes using a two-way alternating stirring method;

[0029] Increase the speed to 40-60r / min and continue mixing for 1-2 minutes until the powder becomes a uniform light camel color. Maintain the temperature at 25℃-30℃ during the mixing process.

[0030] Furthermore, the steps of adding 20%-35% of 40° C.-55° C. warm water to the main ingredient and simultaneously injecting 0.5%-1.5% of trehalose solution by weight of konjac flour comprises:

[0031] Inject 40℃-55℃ warm water into the main ingredients in three stages:

[0032] In the first stage, 40%-50% of the total water volume is injected, and 50%-60% trehalose solution is injected in a jet manner at the same time, with a jet pressure of 0.15-0.3 MPa;

[0033] In the second stage, the remaining water is injected and the stirring speed is maintained at 30-40r / min to form a wet base material;

[0034] In the third stage, the remaining trehalose solution is added and the mixture is subjected to osmotic treatment at a negative pressure of 0.02-0.05 MPa for 2-4 minutes in a sealed container.

[0035] Furthermore, the steps of kneading the dough by a twin-screw extruder at a speed of 150-250 r / min for 3-5 minutes to form a homogeneous dough, and placing the dough in an environment with a humidity of 80%-85% for 10-20 minutes include:

[0036] Feed the wet base material into a twin-screw extruder, control the temperature of the machine body in three sections, including a feeding section of 40°C-45°C, a mixing section of 55°C-60°C, and a discharging section of 50°C-55°C, a screw speed of 180-220 r / min, and an aspect ratio of 25:1-30:1;

[0037] The extruded dough is placed in a resting box, and the humidity in the box is regulated in two stages. The humidity is maintained at 85% ± 3% in the first 5 minutes and then reduced to 80% ± 2% in the subsequent time. The dough is spread flat with a thickness of 2-3 cm, and the air flow speed in the box is 0.1-0.3 m / s vertically through the dough.

[0038] Furthermore, the cooked dough is rolled into strips through a mold, immediately immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt, and treated in a shaping tank at 25° C.-35° C. for 8-12 minutes, during which the flow rate of the coagulation liquid is maintained at 0.5-1.0 m / s, comprising:

[0039] The cooked dough is rolled into a strip with a thickness of 0.8-1.2 mm through a mold, and immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt within 10 seconds;

[0040] The dough is laid out in a single layer in the shaping tank. A guide plate is set in the tank to allow the coagulation liquid to circulate in both directions, maintaining a flow rate of 0.5-1.0m / s.

[0041] The processing temperature is kept constant at 25℃-35℃, the time is 8-12 minutes, and the dough is turned over every 2 minutes.

[0042] The non-dehydrated low-calorie konjac composite noodles and the preparation method thereof provided by the present invention have the following beneficial effects:

[0043] The present invention achieves three major effects under the condition of moisture content ≤65% by limiting the dry weight ratio of konjac flour to 40%-60% and gluten to 20%-40% (1:0.5-1.5), and synergizing trehalose accounting for 0.5%-1.5% of the dry weight of the konjac flour and 0.05%-0.15% of edible calcium salt.

[0044] First, the traditional dehydration process is completely eliminated. Konjac glucomannan and gluten form a dense three-dimensional network under the cross-linking of calcium ions, which significantly reduces the water extraction rate and eliminates the damage to the dietary fiber structure caused by hot air drying.

[0045] Secondly, it achieves a balance between ultra-low calories and enhanced nutrition. The main ingredients are scientifically proportioned to replace high-starch formulas, and trehalose is combined to inhibit the retrogradation of konjac molecular chains, achieving a calorie value far lower than traditional noodles while retaining high dietary fiber and high-quality protein content, meeting the core needs of functional foods.

[0046] Third, it improves processing efficiency and edible quality by optimizing the calcium salt concentration to achieve a high-strength gel network. The dehydration-free process significantly shortens the production cycle. The resulting product rehydrates quickly, has low cooking loss, and has excellent elasticity, and tastes similar to wheat noodles. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The present invention is a flow chart of a process for preparing a non-dehydrated low-calorie konjac composite noodle according to an embodiment of the present invention.

[0048] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0050] A non-dehydrated low-calorie konjac composite noodle is composed of the following raw materials in percentage by dry weight:

[0051] Konjac flour 40%-60%,

[0052] Gluten 20%-40%,

[0053] Trehalose 0.2%-0.9%,

[0054] Edible calcium salt 0.05%-0.15%,

[0055] The balance is water and the content is ≤65%;

[0056] The dry weight ratio of konjac flour to gluten is 1:(0.5-1.5), and the added amount of trehalose accounts for 0.5%-1.5% of the dry weight of the konjac flour.

[0057] Within the above range, the preferred embodiment 1 is selected. The raw material composition of embodiment 1 (dry weight percentage) is:

[0058] Konjac flour: 50%

[0059] Gluten: 30%

[0060] Trehalose: 0.6% (1.2% of the dry weight of konjac flour)

[0061] Edible calcium salt (calcium lactate): 0.1%

[0062] Moisture: 63%

[0063] This embodiment achieves the following effects by combining 50% konjac flour and 30% gluten (dry weight ratio 1:0.6), 1.2% trehalose and 0.1% calcium lactate, accounting for the dry weight of the konjac flour, with a moisture content of up to 63%.

[0064] First, the konjac gel network formation mechanism is completely reconstructed. The carboxyl groups of konjac glucomannan and the hydrophobic regions of gluten form a double cross-linked structure mediated by calcium ions. Trehalose molecules are embedded in the network gaps and anchor free water through hydrogen bonds. This reduces the water separation rate of a high-moisture system (63%) to 3.1% without dehydration. This is a fundamental improvement over the traditional dehydration process (water separation rate is still >8% when the moisture content is ≤15%). At the same time, the hot air drying step is eliminated, and the processing energy consumption is only 1 / 3 of that of the traditional method.

[0065] Secondly, it establishes a new standard of low calorie and balanced texture. The konjac-gluten main framework accounts for 80%, significantly reducing starch dependence. Trehalose inhibits the retrogradation of glucomannan chains and blocks starch crystallization, keeping the product's caloric value at 98kcal / 100g (65% lower than wheat noodles of the same specification). At the same time, the gel strength reaches 0.28MPa to ensure chewing elasticity. The rehydration time reaches the optimal edible state within 48 seconds. The cooking loss rate of 4.5% is far lower than the industry average (>12%), achieving the core breakthrough of "low calories without reducing the taste".

[0066] Third, it has opened up a new path for industrialized and efficient production. The calcium lactate concentration only needs 0.1% to complete the network shaping (the traditional process requires more than 0.3%). Combined with the twin-screw extrusion-shaping tank turbulent flow process, the production cycle is compressed to 25 minutes (the traditional dehydration line takes 70 minutes), and the finished product has a shelf life of 90 days (the total number of colonies in the 37°C accelerated test is ≤10 4 CFU / g), solving the industry pain point of high-moisture noodle products being easily spoiled.

[0067] There is another embodiment 2, which is:

[0068] The konjac flour content is 45%-55%, and the gluten content is 30%-35%;

[0069] The amount of trehalose added is 0.8%-1.2% of the dry weight of the konjac flour;

[0070] Further comprising 0.1%-0.3% of flaxseed gum and 0.5%-1.0% of oat fiber based on the total dry weight of the raw material;

[0071] The moisture content is controlled at 58%-62%.

[0072] In Example 2,

[0073] Konjac flour: 50%

[0074] Gluten: 32%

[0075] Trehalose: 0.55% (1.1% of the dry weight of konjac flour)

[0076] Edible calcium salt (calcium chloride): 0.08%

[0077] Flaxseed gum: 0.2%

[0078] Oat fiber: 0.8%

[0079] Moisture: 60%

[0080] By limiting the optimized ratio of 50% konjac flour and 32% gluten (dry weight ratio 1:0.64), synergizing 1.1% trehalose, 0.2% flaxseed gum and 0.8% oat fiber, which account for the dry weight of konjac flour, and at a moisture content of 60%, the following effects were achieved:

[0081] First, the stability of the gel network is improved. The anionic polysaccharide chains of flaxseed gum bond with calcium ions to form a secondary cross-linked network, and the oat fiber particles fill the pores of the konjac-gluten matrix (scanning electron microscopy shows that the pore size is reduced to 2-3 μm). The centrifugal water separation rate is reduced to 1.8%, which is a further 42% reduction compared with Example 1. Moreover, no free water is precipitated after five freeze-thaw cycles at -18°C, completely solving the problem of freeze denaturation of high-moisture noodle products.

[0082] Secondly, it pioneered a balance between low calories and metabolic health. Oat fiber absorbs glucose molecules and slows the rate of enzymatic hydrolysis, synergizing with flaxseed gum to increase chyme viscosity, reducing the product's glycemic index (GI) to 32 (less than 55 is considered a low-GI food). At the same time, the caloric value remains at 96kcal / 100g, and the dietary fiber content is as high as 14.2g / 100g (AOAC991.43 method), meeting the sugar control needs of people with diabetes.

[0083] Third, the breakthrough in property structure enhancement and processing adaptability is achieved. Flaxseed gum forms nanofiber bridges (diameter ≤100 nm observed by transmission electron microscopy) at the konjac-protein interface, which increases the tensile strength to 0.35 MPa (a 25% increase over Example 1), further reduces the cooking loss rate to 3.2%, and improves the dough's ability to withstand mechanical shear by 30%, making it suitable for high-speed continuous production (line speed ≥15 m / min).

[0084] Fourthly, the product is given scalability for multi-scenario applications, and the optimized network structure allows the noodles to maintain their complete shape (length shrinkage rate ≤ 5%) after being rehydrated and soaked in 80°C hot soup for 20 minutes, breaking through the bottleneck of the boiling resistance of instant konjac noodles.

[0085] Example 3:

[0086] 30%-50% of the gluten is replaced by pea protein;

[0087] Further comprising 1.0%-2.0% of inulin and 0.01%-0.05% of glucono-δ-lactone based on the total dry weight of the raw material;

[0088] The edible calcium salt is a compound of calcium lactate and calcium citrate in a weight ratio of 2:1-3:1.

[0089] By replacing 30% gluten with pea protein, introducing 1.5% inulin and 0.03% glucono-δ-lactone (GDL), and combining calcium lactate: calcium citrate = 2.5:1, the following effects were achieved at a moisture content of 62%:

[0090] First, it creates a new system of hypoallergenicity and nutritional fortification. The lysine in pea protein supplements the amino acid deficiency in gluten, raising the protein's PDCAAS score to 0.97 (0.92 in Example 1), while completely avoiding the risk of gluten allergy. Inulin, as a prebiotic fiber, simultaneously increases dietary fiber to 15.8g / 100g, meeting the health needs of special groups.

[0091] Secondly, the gel kinetics process was optimized. The hydrolysis of GDL released H+ ions in a gradient manner, which synergized with the sustained-release properties of calcium citrate (the ion release half-life was extended to 8 minutes). This allowed the calcium cross-linking depth to be evenly advanced from the surface to the inside (frozen sections showed a core cross-linking degree difference of ≤5%). The noodle cooking loss rate was reduced to 2.8%, a further 38% reduction compared to Example 1.

[0092] Third, the breakthrough expands the adaptability of the application temperature range. Inulin inhibits the growth of ice crystals at -18°C (electron microscopy shows that the ice crystal size is ≤30μm), and the compound calcium salt improves thermal stability, so that the product can still maintain an elastic modulus ≥80kPa after high-temperature sterilization at 121°C (traditional konjac noodles will collapse at ≥100°C), meeting the process requirements for canned food circulation at room temperature.

[0093] The comparison table of core technologies of the embodiment is as follows:

[0094]

[0095] Reference Attachment Figure 1 The process flow diagram of a kind of dehydration-free low-calorie konjac composite noodle preparation method that the present invention proposes comprises:

[0096] S1, premixing konjac flour and gluten at a dry weight ratio of 1: (0.5-1.5) to form a main ingredient;

[0097] S2, adding 20%-35% of 40° C.-55° C. warm water to the main ingredients, and simultaneously injecting 0.5%-1.5% of trehalose solution by weight of konjac flour;

[0098] S3, kneading for 3-5 minutes at a speed of 150-250 r / min using a twin-screw extruder to form a homogeneous dough, and placing the dough in an environment with a humidity of 80%-85% for 10-20 minutes;

[0099] S4, the cooked dough is rolled into strips through a mold, and immediately immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt, and treated in a shaping tank at 25°C-35°C for 8-12 minutes, during which the coagulation liquid flow rate is maintained at 0.5-1.0 m / s;

[0100] S5, after taking out, rinse with water at room temperature of 10°C-15°C for 30-60 seconds, drain and directly package to obtain the finished composite noodles.

[0101] In step S1, konjac flour and gluten are premixed in a dry weight ratio of 1: (0.5-1.5) to form a main ingredient, comprising:

[0102] The konjac flour was sieved through an 80-100 mesh sieve and placed in a negative pressure environment to control the ambient humidity to ≤40%;

[0103] Add gluten in proportion and mix at a low speed of 15-25r / min for 2-4 minutes using a two-way alternating stirring method;

[0104] Increase the speed to 40-60r / min and continue mixing for 1-2 minutes until the powder becomes a uniform light camel color. Maintain the temperature at 25℃-30℃ during the mixing process.

[0105] Specifically, konjac flour is sieved through an 80-100 mesh sieve. This mesh size ensures that the powder particle size is controlled to be below 150 μm (sieve residue ≤ 3%), effectively breaking the caking formed during transportation and storage. After sieving, the powder is immediately transferred to a negative pressure environment (vacuum degree -0.05~-0.08MPa) and strictly maintained at an ambient humidity of ≤40%. Under this condition, the konjac flour moisture content is stabilized at 5.5% ± 0.3% (Karl Fischer determination), blocking the local gelation caused by premature hydration of glucomannan. Subsequently, gluten is added at a dry weight ratio of 1: (0.5-1.5), and a two-way alternating stirring mode (clockwise 10 seconds / counterclockwise 10 seconds cycle) is adopted with a low speed mixing of 15-25 r / min for 2-4 minutes. At this stage, the powder electrostatic adsorption layer is broken, and the hydrophobic area of ​​gluten is initially contacted with the surface of the konjac particles. The speed is then increased to 40-60 rpm and mixing is continued for 1-2 minutes to induce a pre-crosslinking reaction driven by van der Waals forces. The end point is marked by a uniform light camel color (colorimetric values ​​L78±2, b15±1), indicating that the gluten protein has coated the konjac particles at a coverage rate of ≥95% (verified by microscopic imaging). The entire process is maintained at a temperature of 25°C-30°C by circulating jacket water. This temperature range not only prevents thermal denaturation of gluten (DSC detection of denaturation onset at >30°C) but also ensures the flexibility of the konjac molecular chains (the rheological phase angle δ is >45° at <25°C, inhibiting pre-crosslinking).

[0106] The composite powder treated in this process achieved peak viscosity in the subsequent hydration phase in 35 seconds (measured by a rapid viscosity analyzer), a 40% improvement in efficiency compared to conventional unidirectional mixing processes. Extrusion mixing torque fluctuation was ≤8% (compared to ≥25% in the control group), demonstrating the formation of a pre-crosslinked network. Parameter boundaries were set with uncompromising certainty: Sieving below 80 mesh retained agglomerates >0.5 mm, leading to a hydrated white core; ambient humidity >40% resulted in a moisture content >8% within 30 minutes, causing localized gelation; speeds exceeding 25 rpm triggered centrifugal delamination in the low-speed range; and temperatures below 25°C significantly increased mixing energy consumption by 50%. Tests on a 3,000-ton annual production line showed that, using a conical double-motion mixer (500 L capacity) and maintaining a jacket water temperature of 26.5°C, the output powder temperature was 28.3°C, with a color ΔE ≤1.0, and a coefficient of variation (CV) of 3.8% for powder mixing uniformity.

[0107] In step S2, 20%-35% of 40° C.-55° C. warm water is added to the main ingredient, and a trehalose solution accounting for 0.5%-1.5% of the dry weight of konjac flour is simultaneously injected, comprising:

[0108] Inject 40℃-55℃ warm water into the main ingredients in three stages:

[0109] In the first stage, 40%-50% of the total water volume is injected, and 50%-60% trehalose solution is injected in a jet manner at the same time, with a jet pressure of 0.15-0.3 MPa;

[0110] In the second stage, the remaining water is injected and the stirring speed is maintained at 30-40r / min to form a wet base material;

[0111] In the third stage, the remaining trehalose solution is added and the mixture is subjected to osmotic treatment at a negative pressure of 0.02-0.05 MPa for 2-4 minutes in a sealed container.

[0112] Specifically, in the hydration process, warm water at 40°C-55°C is injected into the main material in three stages:

[0113] In the first stage, 40%-50% of the total water volume is injected, and 50%-60% of the trehalose solution is injected simultaneously in a jet manner (pressure 0.15-0.3MPa, nozzle aperture 0.8mm). The critical value of the jet pressure is designed to break the hydration layer on the surface of the konjac flour (when the pressure is less than 0.15MPa, the hydration layer breakdown rate is less than 80%, and when it is greater than 0.3MPa, the powder splash loss is greater than 5%). The synchronous injection strategy allows the trehalose and konjac glucomannan to preferentially form a hydrogen bond network in warm water at 40-55℃ (FTIR detection 1620cm- 1 Characteristic peak shift 12cm- 1 ), preventing the aggregation of konjac particles.

[0114] In the second stage, the remaining water is injected and the stirring speed is maintained at 30-40 r / min (the blade inclination angle is 45 degrees). This speed range ensures that the gluten is fully hydrated and swollen (swelling rate ≥300%) without shear denaturation (the tanδ value detected by the rheometer is stable at 0.38-0.42), forming a ductile wet base material (water content 28%±2%).

[0115] In the third stage, the remaining trehalose solution is added and a negative pressure of 0.02-0.05 MPa is applied in a sealed container for 2-4 minutes. This negative pressure allows the solution to penetrate to a depth of 200-300 μm (the average particle size of konjac particles is 150 μm). Nuclear magnetic resonance imaging shows that the T2 relaxation time of water is shortened to 35 ms, confirming that the trehalose is fully embedded in the interstices of the polysaccharide network.

[0116] In step S3, kneading is performed by a twin-screw extruder at a speed of 150-250 r / min for 3-5 minutes to form a homogeneous dough, and the dough is placed in an environment with a humidity of 80%-85% and left to mature for 10-20 minutes, comprising:

[0117] Feed the wet base material into a twin-screw extruder, control the temperature of the machine body in three sections, including a feeding section of 40°C-45°C, a mixing section of 55°C-60°C, and a discharging section of 50°C-55°C, a screw speed of 180-220 r / min, and an aspect ratio of 25:1-30:1;

[0118] The extruded dough is placed in a resting box, and the humidity in the box is regulated in two stages. The humidity is maintained at 85% ± 3% in the first 5 minutes and then reduced to 80% ± 2% in the subsequent time. The dough is spread flat with a thickness of 2-3 cm, and the air flow speed in the box is 0.1-0.3 m / s vertically through the dough.

[0119] Specifically, in the mixing process, the wet base material is structurally reorganized through a twin-screw extruder, and the precise construction of the molecular network is achieved through the coordination of three-stage temperature gradient and screw dynamics. The feeding section is controlled at 40°C-45°C to maintain the flexibility of the konjac glucomannan molecular chain (rheological phase angle δ = 35° ± 3°). This temperature range not only avoids low-temperature brittle fracture but also prevents pre-gelation caused by >45°C (viscosity surge leading to feeding blockage); the mixing section is heated to 55°C-60°C to activate the hydrophobic crosslinking of gluten (denaturation enthalpy 8.2 J / g detected by differential scanning calorimetry). This temperature window allows gluten to unfold its β-pleated structure (circular dichroism spectrum shows a negative peak at 208nm), forming a hydrogen bond-hydrophobic double crosslinked network with the konjac molecules; the discharging section is cooled to 50°C-55°C to lock the gel structure (storage modulus G' ≥ 85kPa). Temperatures below 50°C will cause network shrinkage, resulting in an increase in porosity of >15%, while temperatures above 55°C will induce surface cracking. The screw speed is set at 180-220r / min to produce 350-450s- 1 The shear rate (conventional single screw extruder is only 120-180s-1) is in this critical range to ensure that the konjac particles are completely broken (laser particle size analyzer D90≤50μm) without cutting the glucomannan main chain (gel permeation chromatography shows molecular weight ≥1.2×10 6 The dough is then placed in a resting chamber for dynamic humidity control: For the first five minutes, a high humidity of 85% ± 3% is maintained to form a continuous water film on the dough surface (contact angle reduced to 25°), eliminating the risk of die sticking during calendering (adhesion force ≤ 0.1N). This stage also promotes the extension of the konjac molecular side chains (small-angle X-ray scattering detection increases the gyration radius to 42nm). Subsequently, the humidity is reduced to 80% ± 2% to induce internal moisture gradient migration (low-field nuclear magnetic resonance shows the T2 peak proportion increases to 65%), achieving core network densification. The box is equipped with a 0.1-0.3m / s vertical through-flow airflow (Reynolds number Re=2100-2300 turbulent zone), which effectively eliminates CO2 gas accumulation (the porosity of the traditional static process is ≥8%) and maintains the O2 diffusion rate ≥0.8mL / min·m 2To inhibit anaerobic fermentation, the dough is laid flat at a strict thickness of 2-3cm. This geometric constraint ensures synchronous core maturation (texture profile analysis shows a hardness gradient difference of ≤8%). Thicknesses below 2cm result in excessive surface area, causing moisture evaporation >1.5%. Thicknesses exceeding 3cm can cause core temperature hysteresis of ≥4°C. The supporting plate has a 15%-20% porosity to optimize airflow uniformity (computational fluid dynamics simulations confirm a velocity field standard deviation of ≤0.05m / s).

[0120] In step S4, the cooked dough is rolled into strips through a mold, immediately immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt, and treated in a shaping tank at 25° C.-35° C. for 8-12 minutes, during which the flow rate of the coagulation liquid is maintained at 0.5-1.0 m / s, comprising:

[0121] The cooked dough is rolled into a strip with a thickness of 0.8-1.2 mm through a mold, and immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt within 10 seconds;

[0122] The dough is laid out in a single layer in the shaping tank. A guide plate is set in the tank to allow the coagulation liquid to circulate in both directions, maintaining a flow rate of 0.5-1.0m / s.

[0123] The processing temperature is kept constant at 25℃-35℃, the time is 8-12 minutes, and the dough is turned over every 2 minutes.

[0124] Specifically, during the shaping process, the cooked dough is rolled into strips with a thickness of 0.8-1.2 mm (with a tolerance of ±0.05 mm). This thickness range ensures a balance between calcium ion penetration efficiency and structural integrity. For thicknesses less than 0.8 mm, the dough breakage rate is greater than 15% (tensile strength ≤ 0.1 MPa as measured by a texture analyzer), while for thicknesses greater than 1.2 mm, the core crosslinking degree is less than 30% (verified by iodine staining of frozen sections). The dough is then immersed in a coagulation solution containing 0.1%-0.3% edible calcium salt (calcium lactate or calcium chloride) within 10 seconds. This time window prevents the formation of a gel barrier caused by surface water loss (exposure for >10 seconds results in a 0.8% decrease in surface moisture content, which increases penetration resistance by 50%). A single-layer paving method is used in the shaping tank (the spacing between the dough blanks is ≥5mm), and the tank body is provided with a guide plate to construct a two-way circulation flow channel (the guide plate inclination is 45°±2°), maintaining a flow rate of 0.5-1.0m / s (Reynolds number Re=2100-2300 turbulent state). This flow rate domain breaks the concentration boundary layer (the boundary layer thickness is >200μm when it is <0.5m / s), and avoids the dough blank displacement caused by >1.0m / s (high-speed photography shows that the displacement is ≤0.2mm). The processing temperature is constant at 25℃-35℃ (thermocouple closed-loop control ±0.3℃), and the lower limit of 25℃ ensures that the cross-linking reaction rate meets the standard (Arrhenius equation calculates Q 10≥2.5), the upper limit of 35℃ blocks the unwinding of konjac glucomannan; the treatment time is 8-12 minutes, corresponding to the calcium ion diffusion depth equation (diffusion coefficient D = 2.1×10 -9 m 2 / s), achieving a crosslink depth of 150 μm (50% of the total thickness of the dough sheet) in 8 minutes, and full penetration of 300 μm in 12 minutes. During this period, the dough sheet was mechanically flipped every 2 minutes (flipping angle 180°±5°) to eliminate the concentration gradient between the contact surface and the free surface (the calcium concentration on the contact surface is 35% higher when not flipped, causing a difference in gel strength of >25%).

[0125] In step S5, after taking out, the noodles are rinsed in a circulating manner with water at room temperature of 10°C-15°C for 30-60 seconds, and then directly packaged to obtain the finished composite noodles after draining:

[0126] During the rinsing process, the shaped dough is immersed in a 10-15°C water circulation tank (water temperature fluctuation ≤±1°C). This temperature range is designed to trigger a thermal shock effect. When the high-temperature gel network (25-35°C) suddenly encounters a low-temperature water flow, the konjac-gluten complex matrix undergoes volume contraction (linear shrinkage rate 0.8%±0.2%), squeezing out internal free calcium ions (atomic absorption spectroscopy detection residual calcium ≤0.03%). At the same time, the low temperature blocks the recrystallization of calcium salts (X-ray diffraction shows no characteristic peak of calcium lactate dihydrate). The rinsing time is strictly controlled between 30 and 60 seconds. The lower limit of 30 seconds ensures a calcium ion elution rate of ≥95% (verified by EDTA titration), and the upper limit of 60 seconds prevents network swelling caused by overhydration (swelling rate >10% will lead to texture softening). The water flow rate is maintained at 0.6-0.8m / s turbulent state (Reynolds number Re=2500-2800), and the ultrasonic vibration plate in the tank (frequency 40kHz, power density 0.5W / cm 2 ) Remove surface adsorbed bubbles (microscopic observation of residual bubbles ≤ 3 / cm 2 ), this synergistic effect increases the light transmittance of the product to 85%±3% (measured by spectrophotometer at 600nm). The drainage process uses an inclined vibrating screen (amplitude 2-3mm, frequency 15Hz, inclination 12°) to reduce the surface moisture content to 8.5%±0.5% within 12 seconds (online monitoring by infrared moisture meter). This critical moisture content not only avoids the precipitation of vacuum packaging droplets (water activity Aw≤0.88), but also maintains the active moisture of the gel (single layer water coverage ≥80%). The final product is packaged by nitrogen substitution (residual oxygen content ≤0.8%), and can achieve a 90-day shelf life at room temperature without secondary sterilization (accelerated test 37℃ / 90%RH total colony count ≤10 4 CFU / g).

[0127] In summary, the present invention relates to a non-dehydrated low-calorie konjac composite noodle and a preparation method thereof. The composite noodle is composed of 40%-60% konjac flour, 20%-40% gluten, 0.2%-0.9% trehalose, 0.05%-0.15% edible calcium salt, and 65% or less of moisture (dry weight percentage), wherein the dry weight ratio of konjac flour to gluten is 1:(0.5-1.5), and the trehalose accounts for 0.5%-1.5% of the dry weight of the konjac flour. The preparation method includes: pre-mixing konjac flour, which is then screened and mixed with wheat gluten at different speeds under negative pressure (humidity ≤ 40%); hydration using a three-stage gradient water injection process with simultaneous jet injection of a trehalose solution; kneading using a twin-screw extruder with three temperature-controlled sections (feeding section 40-45°C / kneading section 55-60°C / discharging section 50-55°C) to create a network; and shaping the dough by immersing it in a 0.1%-0.3% calcium salt coagulant solution at 25-35°C in a turbulent flow environment (flow rate 0.5-1.0 m / s) for 8-12 minutes with periodic rotation; and finally rinsing and draining to obtain the finished product. This solution, for the first time, achieves moisture content ≤ 65% without dehydration, resulting in a product with a water extraction rate ≤ 3.1%, a calorie count ≤ 98 kcal / 100g, and a rehydration time ≤ 50 seconds, reducing processing energy consumption by 67%.

[0128] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A non-dehydrated low-calorie konjac composite noodle, characterized in that, It is composed of the following raw materials in percentage by dry weight: Konjac flour 40%-60%, Gluten 20%-40%, Trehalose 0.2%-0.9%, Edible calcium salt 0.05%-0.15%, The balance is water and the content is ≤65%; The dry weight ratio of konjac flour to gluten is 1:(0.5-1.5), and the added amount of trehalose accounts for 0.5%-1.5% of the dry weight of the konjac flour.

2. the dehydration-free low-calorie konjac composite noodle according to claim 1, is characterized in that: The konjac flour content is 45%-55%, and the gluten content is 30%-35%; The amount of trehalose added is 0.8%-1.2% of the dry weight of the konjac flour; Further comprising 0.1%-0.3% of flaxseed gum and 0.5%-1.0% of oat fiber based on the total dry weight of the raw material; The moisture content is controlled at 58%-62%.

3. the dehydration-free low-calorie konjac composite noodle according to claim 1, is characterized in that: 30%-50% of the gluten is replaced by pea protein; Further comprising 1.0%-2.0% of inulin and 0.01%-0.05% of glucono-δ-lactone based on the total dry weight of the raw material; The edible calcium salt is a compound of calcium lactate and calcium citrate in a weight ratio of 2:1-3:

1.

4. A method for preparing a dehydrated, low-calorie konjac composite noodle, characterized in that: include: Premixing konjac flour and gluten at a dry weight ratio of 1: (0.5-1.5) to form the main ingredient; Add 20%-35% of 40° C.-55° C. warm water to the main ingredients, and simultaneously inject 0.5%-1.5% of trehalose solution by weight of konjac flour; The dough was kneaded by a twin-screw extruder at a speed of 150-250 r / min for 3-5 minutes to form a homogeneous dough, and the dough was placed in an environment with a humidity of 80%-85% and allowed to stand for 10-20 minutes; The cooked dough is rolled into strips through a mold, and immediately immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt, and treated in a shaping tank at 25°C-35°C for 8-12 minutes, during which the coagulation liquid flow rate is maintained at 0.5-1.0 m / s; After taking out, rinse with 10-15°C room temperature water for 30-60 seconds, drain and directly package to obtain the finished composite noodles.

5. the dehydration-free low-calorie konjac composite noodle preparation method according to claim 4, is characterized in that, The step of premixing konjac flour and gluten at a dry weight ratio of 1: (0.5-1.5) to form a main ingredient comprises: The konjac flour was sieved through an 80-100 mesh sieve and placed in a negative pressure environment to control the ambient humidity to ≤40%; Add gluten in proportion and mix at a low speed of 15-25r / min for 2-4 minutes using a two-way alternating stirring method; Increase the speed to 40-60r / min and continue mixing for 1-2 minutes until the powder becomes a uniform light camel color. Maintain the temperature at 25℃-30℃ during the mixing process.

6. the dehydration-free low-calorie konjac composite noodle preparation method according to claim 4, is characterized in that, The steps of adding 20%-35% of 40° C.-55° C. warm water to the main ingredient and simultaneously injecting 0.5%-1.5% of trehalose solution by weight of konjac flour comprises: Inject 40℃-55℃ warm water into the main ingredients in three stages: In the first stage, 40%-50% of the total water volume is injected, and 50%-60% trehalose solution is injected in a jet manner at the same time, with a jet pressure of 0.15-0.3 MPa; In the second stage, the remaining water is injected and the stirring speed is maintained at 30-40r / min to form a wet base material; In the third stage, the remaining trehalose solution is added and the mixture is subjected to osmotic treatment at a negative pressure of 0.02-0.05 MPa for 2-4 minutes in a sealed container.

7. the dehydration-free low-calorie konjac composite noodle preparation method according to claim 6, is characterized in that, The steps of kneading the dough at a speed of 150-250 r / min for 3-5 minutes using a twin-screw extruder to form a homogeneous dough, and placing the dough in an environment with a humidity of 80%-85% for 10-20 minutes for aging include: Feed the wet base material into a twin-screw extruder, control the temperature of the machine body in three sections, including a feeding section of 40°C-45°C, a mixing section of 55°C-60°C, and a discharging section of 50°C-55°C, a screw speed of 180-220 r / min, and an aspect ratio of 25:1-30:1; The extruded dough is placed in a resting box, and the humidity in the box is regulated in two stages. The humidity is maintained at 85% ± 3% in the first 5 minutes and then reduced to 80% ± 2% in the subsequent time. The dough is spread flat with a thickness of 2-3 cm, and the air flow speed in the box is 0.1-0.3 m / s vertically through the dough.

8. the dehydration-free low-calorie konjac composite noodle preparation method according to claim 4, is characterized in that, The cooked dough is rolled into strips through a mold, immediately immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt, and treated in a shaping tank at 25°C-35°C for 8-12 minutes, during which the coagulation liquid flow rate is maintained at 0.5-1.0 m / s, comprising: The cooked dough is rolled into a strip with a thickness of 0.8-1.2 mm through a mold, and immersed in a coagulation liquid containing 0.1%-0.3% edible calcium salt within 10 seconds; The dough is laid out in a single layer in the shaping tank. A guide plate is set in the tank to allow the coagulation liquid to circulate in both directions, maintaining a flow rate of 0.5-1.0m / s. The processing temperature is kept constant at 25℃-35℃, the time is 8-12 minutes, and the dough is turned over every 2 minutes.

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