Multilayer cheese stick and preparation method thereof

Abstract

The invention provides a multi-layer cheese stick and a preparation method thereof. The multi-layer cheese rod comprises N cheese layers which are stacked, wherein N is greater than or equal to 2; the viscosities of the raw material systems of the cheese layer at the temperature of 68-75 DEG C are respectively 6000-13000cp; the multi-layer cheese rod is at least prepared through a method comprising the following steps that raw material systems of N cheese layers are sequentially subjected to filling treatment at the temperature of 68-75 DEG C, the filling speed of the raw material system of the first cheese layer is 1000-3000 rpm, and the filling speed of the raw material systems of the remaining N-1 cheese layers is 500-1500 rpm; and the filling time interval of the raw material systems of the two adjacent cheese layers is 2-16s. The viscosity of the raw materials, the filling speed and the filling interval time are limited, so that the interlayer boundary level of the product is clear, obvious color and layer crossing is avoided, and the interlayer is continuous and does not crack.

Description

Technical Field

[0001] The present invention relates to a multi-layer cheese stick, and particularly to a multi-layer cheese stick and a preparation method thereof, belonging to the food field. Background Art

[0002] Processed cheese is composed of real natural cheese combined with other non-cheese ingredients, and these non-cheese ingredients include salts, food colors, preservatives, additional dairy products, emulsifiers, flavors, etc. It is one of the fastest-growing parts of the food industry.

[0003] Snacking is a continuous development trend presented by processed cheese. For example, cheese sticks, cheese strips, etc. are processed cheese products designed specifically for ready-to-eat snacks. However, most of the current cheese sticks on the market have a single form and color, being uniformly white or light yellow. Among the few multi-color or multi-layer cheese sticks, the layer boundaries are not clear, and there are problems such as color bleeding between layers, layer separation, and layer cracking, which cannot meet people's requirements for the aesthetic appearance of cheese.

[0004] How to obtain a multi-layer cheese product with clear layer boundaries, no obvious color bleeding between layers, and continuous and non-cracking layers is one of the technical problems in this field. Summary of the Invention

[0005] The present invention provides a multi-layer cheese stick, in which the layer boundaries of the multi-layer cheese stick are horizontally clear, there is no obvious color bleeding between layers, and the layers are continuous and non-cracking.

[0006] The present invention also provides a preparation method of a multi-layer cheese stick. Through this preparation method, a multi-layer cheese stick with horizontally clear layer boundaries, no obvious color bleeding between layers, and continuous and non-cracking layers can be prepared.

[0007] The present invention provides a multi-layer cheese stick, which includes N layers of cheese layers stacked, where N≥2; the viscosity of the raw material systems of the N layers of cheese layers is independently 6000-13000 cp at 68-75°C;

[0008] The multi-layer cheese stick is prepared by at least a method including the following process:

[0009] At 68-75°C, the raw material systems of the N layers of cheese layers are sequentially subjected to filling treatment. Among them, the filling speed of the raw material system of the first layer of cheese layer is 1000-3000 rpm, and the filling speeds of the raw material systems of the remaining N-1 layers of cheese layers are 500-1500 rpm; the filling time interval between the raw material systems of adjacent two layers of cheese layers is 2-16 s, to obtain the multi-layer cheese stick.

[0010] For the multi-layer cheese stick as described above, the viscosity of the raw material systems of the N layers of cheese layers is independently 8000-10000 cp at 68-75°C.

[0011] The multi-layer cheese stick as described above, wherein the filling speed of the raw material system of the first layer of the cheese layer is 2000 - 2500 rpm, and the filling speeds of the raw material systems of the remaining N - 1 layers of the cheese layer are 500 - 900 rpm; the filling time interval between adjacent two layers of the raw material systems of the cheese layer is 4 - 10 s.

[0012] The multi-layer cheese stick as described above, wherein the raw material system of each layer of the cheese layer independently includes, by mass percentage: 15% - 62% of natural cheese, 3% - 20% of lipid products, 0% - 30% of protein powder, 0.4% - 4% of stabilizer, 0% - 0.6% of emulsifier, 0.5% - 1.5% of emulsifying salt, 0 - 0.8% of acidity regulator, 0% - 10% of fruit source, 0% - 2% of coloring substance, and the balance is water.

[0013] The multi-layer cheese stick as described above, wherein in the raw material system of each layer of the cheese layer, the stabilizer independently includes, by mass percentage: 0.3% - 0.5% of sodium carboxymethylcellulose, 0.2% - 0.5% of carrageenan, 0.2% - 0.5% of locust bean gum.

[0014] The multi-layer cheese stick as described above, wherein the emulsifying salt includes at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium dihydrogen pyrophosphate, and sodium citrate.

[0015] The multi-layer cheese stick as described above, wherein the raw material system of each layer of the cheese layer independently includes 1.5% - 17% of sweetening substance by mass percentage.

[0016] The multi-layer cheese stick as described above, wherein when N = 2, the mass ratio of the first layer of the cheese layer to the second layer of the cheese layer is (1 - 1.5):1;

[0017] When N ≥ 3, the mass ratio of the first layer of the cheese layer to the second layer of the cheese layer is (1 - 1.5):1, and the mass ratio of the (n - 1)th layer of the cheese layer to the nth layer of the cheese layer is 1:1, where 3 ≤ n ≤ N.

[0018] The present invention also provides a preparation method of the multi-layer cheese stick according to any one of the above, comprising:

[0019] At 68 - 75 °C, the raw material systems of the N layers of the cheese layer are sequentially subjected to filling treatment, wherein the filling speed of the raw material system of the first layer of the cheese layer is 1000 - 3000 rpm, and the filling speeds of the raw material systems of the remaining N - 1 layers of the cheese layer are 500 - 1500; the filling time interval between adjacent two layers of the raw material systems of the cheese layer is 2 - 16 s, to obtain the multi-layer cheese stick.

[0020] The preparation method as described above, wherein, before the filling process, it further includes sterilizing the raw material system of the N layers of cheese layers, wherein the sterilization temperature is 85 - 125 °C and the sterilization time is 15 s - 15 min.

[0021] The multi-layer cheese stick provided by the present invention includes N layers of cheese layers stacked, N≥2; by defining the viscosity of the raw material system of each cheese layer at the filling temperature, the filling speed, and the filling time interval between the raw material systems of adjacent two layers of cheese layers, the effect of clear horizontal layer boundaries, no obvious color bleeding or layer mixing, and continuous and non-cracking between layers of the above multi-layer cheese stick is achieved. Description of the Drawings

[0022] Figure 1 Photo of the sample of Example 1;

[0023] Figure 2 Photo of the sample of Example 2;

[0024] Figure 3 Photo of the sample of Example 3;

[0025] Figure 4 Photo of the sample of Example 4;

[0026] Figure 5 Photo of the sample of Example 5;

[0027] Figure 6 Photo of the sample of Example 6;

[0028] Figure 7 Photo of the sample of Comparative Example 1;

[0029] Figure 8 Photo of the sample of Comparative Example 2;

[0030] Figure 9 Photo of the sample of Comparative Example 3. Detailed Embodiments

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0032] In the first aspect of the present invention, a multi-layer cheese stick is provided. The above multi-layer cheese stick includes N layers of cheese layers stacked, N≥2; the viscosities of the raw material systems of the N layers of cheese layers are each independently 6000 - 13000 cp at 68 - 75 °C;

[0033] The above-mentioned multi-layer cheese sticks are prepared by a method that at least includes the following process:

[0034] At 68 - 75 °C, the raw material systems of the N layers of the above-mentioned cheese layers are sequentially filled. Among them, the filling speed of the raw material system of the first layer of the above-mentioned cheese layer is 1000 - 3000 rpm, and the filling speeds of the raw material systems of the remaining N - 1 layers of the above-mentioned cheese layers are 500 - 1500 rpm; the filling time interval between the raw material systems of adjacent two layers of the above-mentioned cheese layers is 2 - 16 s, obtaining the above-mentioned multi-layer cheese sticks.

[0035] The above-mentioned multi-layer cheese sticks refer to cheese sticks with clearly defined multiple colors. Specifically, the above-mentioned multi-layer cheese sticks include N layers of cheese layers arranged in a stacked manner, N ≥ 2, and the colors of adjacent two layers of the above-mentioned cheese layers are different, and this difference can be judged by the naked eye.

[0036] Furthermore, the taste and flavor of adjacent two layers of the above-mentioned cheese layers of the above-mentioned multi-layer cheese sticks can also be different.

[0037] The above-mentioned N layers of cheese layers arranged in a stacked manner mean that the N layers of cheese layers are arranged in a stacked manner along the same direction, and the N layers of cheese layers arranged in a stacked manner are sequentially named the first layer of cheese layer, the second layer of cheese layer... the (N - 1)th layer of cheese layer, and the Nth layer of cheese layer according to the order of filling.

[0038] In the present invention, the filling temperature of the above-mentioned multi-layer cheese sticks is limited to 68 - 75 °C because too high a filling temperature will cause the interfacial surface between layers of the multi-layer cheese sticks to be uneven, and too low a filling temperature will cause the raw material system to solidify into lumps during the filling process, reducing the texture of the product and making its taste worse.

[0039] The viscosities of the raw material systems of the N layers of the above-mentioned cheese layers at 68 - 75 °C are each independently 6000 - 13000 cp, which means that the viscosities of the raw material systems of each layer of the N layers of the above-mentioned cheese layers at 68 - 75 °C are all 6000 - 13000 cp, but the viscosities of the raw material systems of different cheese layers at 68 - 75 °C can be the same or different.

[0040] Sequentially filling the raw material systems of the N layers of the above-mentioned cheese layers means first filling the raw material system of the first layer of cheese layer, and using the upper surface of the raw material system of the first layer of cheese layer as the bottom to fill the raw material system of the second layer of cheese layer, forming the interfacial surface, that is, the demarcation surface, between the first layer of cheese layer and the second layer of cheese layer, and then sequentially filling the raw material systems of the remaining layers of the above-mentioned cheese layers.

[0041] In some embodiments, the filling equipment used is the Chunguang SGA40W ultra-clean cheese stick filling machine. Therefore, the motor speed of the above-mentioned Chunguang SGA40W ultra-clean cheese stick filling machine can be used to represent the above-mentioned filling speed.

[0042] At 68 - 75°C, the viscosity of the raw material system of the first layer of the above-mentioned cheese layer is 6000 - 13000 cp, and the filling speed is 1000 - 3000 rpm. By controlling the filling speed in combination with the viscosity, the upper surface of the raw material system of the first layer of the cheese layer can be leveled within 2 - 16 s, forming a flat and horizontal upper surface.

[0043] Then, taking the newly formed flat and horizontal upper surface of the raw material system of the first layer of the cheese layer as the bottom surface, the raw material system of the second layer of the cheese layer with a viscosity of 6000 - 13000 cp is filled at a speed of 500 - 1500 rpm. By controlling the filling speed in combination with the viscosity, the raw material system of the second layer of the cheese layer after filling will not only not damage the newly formed flat and horizontal upper surface of the raw material system of the first layer of the cheese layer, but also be conducive to forming a clear boundary level interface between the first layer of the cheese layer and the second layer of the cheese layer, and has the effects of no obvious color bleeding and layer intermixing, and continuous layers.

[0044] Similarly, the raw material system of the second layer of the cheese layer after filling can reach automatic leveling of the upper surface within 2 - 16 s, forming a flat and horizontal upper surface, so that after filling the raw material system of the third layer of the cheese layer, a clear boundary level interface can be formed between the second layer of the cheese layer and the third layer of the cheese layer, and has the effects of no obvious color bleeding and layer intermixing, and continuous layers.

[0045] The reason why the filling time interval between the raw material systems of two adjacent layers of the above-mentioned cheese layer in the present invention is limited to 2 - 16 s is that under the dual action of the impact force brought by the filling speed and the viscosity of the raw material system of each layer of the cheese layer, the raw material system of each layer of the cheese layer can generally be leveled within 2 s - 2.2 s, forming a flat and horizontal upper surface. However, the existing filling process generally does not keep the filled material warm, resulting in the solidification of the material 16 s after filling. When the lower layer of the material solidifies and then the upper layer of the material is filled, it will cause the interlayer bonding to be not tight, and the problem of interlayer cracking is likely to occur. Therefore, by limiting the filling time interval to 2 - 16 s, it is ensured that the raw material systems of each layer of the cheese layer are in an unfrozen state, and the filled product has a tight interlayer bond, further ensuring that the interlayer boundary is clear, there is no obvious color bleeding and layer intermixing, and the layers are continuous and do not crack.

[0046] The viscosity of the material is closely related to its water retention. The viscosity of the multi-layer cheese stick prepared from the raw material system of the cheese layer with a viscosity of 6000 - 13000 cp slightly increases after remelting at 68 - 75°C, and can reach 6000 - 20000 cp, improving its water retention, thereby effectively avoiding the problem of water separation in the above-mentioned multi-layer cheese stick.

[0047] The multi-layer cheese stick of the present invention comprises at least two layers of cheese layers stacked on top of each other. By adjusting the filling speed of the raw material systems of each cheese layer in combination with their viscosities, and defining the filling time interval between the raw material systems of two adjacent cheese layers as 2 - 16 s, the filling of the raw material systems of each cheese layer is completed in sequence, so that the above multi-layer cheese stick has clear interlayer boundaries, no obvious color bleeding or layer mixing, continuous and non-cracking interlayers, and no visible water separation within 4 weeks of accelerated storage at 37°C.

[0048] It can be understood that when heat preservation treatment is carried out on the above filled material, the filling time interval between the raw material systems of two adjacent cheese layers only needs to be ≥2 s to ensure that the upper surface of the raw material system of the lower cheese layer can flow flat after filling.

[0049] After filling is completed, the filled material also needs to be cooled to solidify it, so as to obtain the finally formed finished product. Generally, the above cooling temperature should be below 40°C, which can solidify the filled material.

[0050] When the central temperature of the above multi-layer cheese stick is lower than 60°C, a linear layered effect is shown between the layers. Then the above cooling temperature can be further 8 - 10°C. Cooling the filled material at this temperature can not only make the outer surface of the filled material solidify rapidly within 3 - 4 min, but also quickly reduce its central temperature below 40°C, which is beneficial to obtaining a product with clear interlayer boundary levels.

[0051] It can be understood that the slower the filling speed of the raw material systems of the remaining N - 1 cheese layers, the more beneficial it is for the surface between the layers to flow flat, and thus it is more beneficial for the layers to maintain clear boundary levels, no obvious color bleeding or layer mixing, and continuous interlayers.

[0052] Furthermore, the viscosities of the raw material systems of the N cheese layers at 68 - 75°C are independently 8000 - 10000 cp. Within this viscosity range, it is more beneficial for the above multi-layer cheese stick to maintain clear boundary levels, no obvious color bleeding or layer mixing, continuous and non-cracking interlayers, and no visible water separation within 4 weeks of accelerated storage at 37°C.

[0053] Furthermore, the filling speed of the raw material system of the first cheese layer is 2000 - 2500 rpm, and the filling speeds of the raw material systems of the remaining N - 1 cheese layers are 500 - 900 rpm; the filling time interval between the raw material systems of two adjacent cheese layers is 4 - 10 s, so that the multi-layer cheese stick has better effects of clear interlayer boundary levels, no obvious color bleeding or layer mixing, and continuous and non-cracking interlayers.

[0054] In some embodiments, the raw material system of each layer of cheese layer independently includes, by mass percentage: 15%-62% of natural cheese, 3%-20% of lipid products, 0%-30% of protein powder, 0.4%-4% of stabilizer, 0%-0.6% of emulsifier, 0.5%-1.5% of emulsifying salt, 0-0.8% of acidity regulator, 0%-10% of fruit source, 0%-2% of coloring substance, and the balance is water.

[0055] The above-mentioned "independently" means that the raw materials of the raw material system of each layer of cheese layer can be the same or different. Generally, in order to strengthen the difference between different cheese layers, the raw material systems of adjacent two layers of cheese layers do not simultaneously include fruit source or coloring substance. For example, the first layer of cheese layer does not include fruit source or coloring substance, while the second layer of cheese layer includes fruit source or coloring substance; or, both of the raw material systems of adjacent two layers of cheese layers include fruit source or coloring substance, but their contents are different, so that the adjacent two layers of cheese layers can also show different tastes or colors.

[0056] That is to say, the raw material system of each layer of cheese layer can be independently selected and matched from the above-mentioned raw material types and contents, but the result of the above selection and matching should make the above-mentioned multi-layer cheese sticks show different colors, tastes and textures between layers, so as to avoid the problem that most of the cheese sticks on the market at present have a single shape and color.

[0057] The above-mentioned natural cheese includes at least one of fresh cheese, cream cheese, quark, and mascarpone.

[0058] The above-mentioned lipid products include at least one of cream, light cream, anhydrous cream, coconut oil, and palm oil.

[0059] When the above-mentioned natural cheese is cream cheese, because it contains fat, the mass percentages of natural cheese and lipid products in the above-mentioned raw material system should be calculated according to the actual contents of cheese and lipid products in cream cheese and lipid products. That is to say, when the above-mentioned natural cheese is cream cheese, the corresponding mass percentage of lipid products can be reduced accordingly. When the content of cream cheese in the above-mentioned raw material system is relatively high, the fat it contains can meet the requirements of lipid products in the above-mentioned formula. Therefore, cream does not need to be added separately.

[0060] The above-mentioned protein powder includes at least one of whole milk powder, skim milk powder, concentrated milk protein powder, and whey powder.

[0061] The above-mentioned stabilizer includes at least one of sodium carboxymethyl cellulose, xanthan gum, carrageenan, locust bean gum, guar gum, and agar.

[0062] The above-mentioned emulsifier includes any one or more of mono- and diglycerol fatty acid esters, phospholipids, and propylene glycol alginate.

[0063] For the above-mentioned emulsifying salts, internationally common emulsifying salts can be selected, such as at least one of sodium hexametaphosphate, disodium dihydrogen pyrophosphate, trisodium phosphate, and sodium citrate.

[0064] The above-mentioned acidity regulators include at least one of lactic acid, citric acid, and concentrated lemon juice, which can maintain the pH value of the raw material system of each cheese layer at 4.9 - 5.6, facilitating the raw material system to maintain stable viscosity and also conducive to maintaining the quality stability of the product.

[0065] The above-mentioned fruit source can be at least one of jam, fruit juice, fruit puree, and fruit and vegetable powder. The present invention does not make specific limitations on the types of fruits in the fruit source.

[0066] The present invention does not make specific limitations on the types of the above-mentioned coloring substances, as long as they meet the relevant standards and regulations in the food field.

[0067] The synergistic combination of the above-mentioned raw materials can not only achieve the differences in color and taste of different cheese layers, making the cheese stick have a delicate and soft taste, but also make the raw material system of each cheese layer have an independent viscosity of 6000 - 13000 cp at 68 - 75 °C, which is conducive to achieving the effect of clear horizontal boundaries between layers of the multi-layer cheese stick, no obvious color bleeding and layer mixing, and continuous and non-cracking between layers, making the product have good product performance, and having no visible water separation problem within 4 weeks of accelerated storage at 37 °C, improving the stability of the product.

[0068] When adjusting the viscosity of the raw material system of the above-mentioned cheese layer, factors such as raw material dosage, cost, operation convenience, and product nutritional value, taste, stability, and inter-layer difference need to be considered simultaneously. In order to simplify the operation and achieve a high-cost performance combination of the above-mentioned various factors, it can be specified that the dry matter content in the raw material system of each cheese layer is 37 - 45%, preferably 42%, and then by adjusting the mass ratio of protein and carbohydrate in the raw material system of each cheese layer, the adjustment of the raw material system viscosity is realized, which is conducive to further improving the taste of the product.

[0069] It can be understood that the raw material system of the above-mentioned cheese layer also includes 0.05% - 0.1% preservative by mass percentage, preferably 0.08% by mass percentage. The types of preservatives commonly used in the art can be selected, for example, sorbic acid.

[0070] In some embodiments, in the raw material system of each layer of the above-mentioned cheese layer, the above-mentioned stabilizers independently include, by mass percentage: sodium carboxymethylcellulose 0.3%-0.5%, carrageenan 0.2%-0.5%, and locust bean gum 0.2%-0.5%. The above mass percentages all refer to the mass ratios in the raw material system of each layer of the above-mentioned cheese layer. When the stabilizers meet the above conditions, not only can the multi-layer cheese sticks have no water separation problem within 4 weeks of accelerated storage at 37°C, but also the quality stability of the product can be further improved, the texture of the product can be kept stable, and the effects such as clear horizontal layer boundaries, no obvious color bleeding or layer mixing, and continuous and non-cracking between layers can be maintained stably.

[0071] In some embodiments, the above-mentioned emulsifying salts include at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium dihydrogen pyrophosphate, and sodium citrate. These types of emulsifying salts are suitable for building the texture of cream products, such as cheese sticks, and have little impact on the pH value of the raw material system, avoiding the problem that other types of emulsifying salts cause a large impact on the raw material system, resulting in a significant increase or decrease in the pH value, and an increase in the hardness of the product cheese sticks.

[0072] In some embodiments, the raw material system of each layer of the above-mentioned cheese layer independently includes, by mass percentage, a sweetening substance of 1.5%-17%, which is beneficial to increasing the sweet taste of the product and improving the taste of the product. At the same time, the above-mentioned sweetening substance can also be used as a substance to adjust the viscosity of the raw material system, which is beneficial to stably maintaining the viscosity of the raw material system at 6000-13000 cp, and further maintaining a good layering effect between the above-mentioned multi-layer cheese sticks.

[0073] For the above-mentioned multi-layer cheese sticks, when N = 2, the mass ratio of the first layer of the above-mentioned cheese layer to the second layer of the above-mentioned cheese layer is (1-1.5):1;

[0074] When N≥3, the mass ratio of the first layer of the above-mentioned cheese layer to the second layer of the above-mentioned cheese layer is (1-1.5):1, and the mass ratio of the (n-1)th layer of the above-mentioned cheese layer to the nth layer of the above-mentioned cheese layer is 1:1, where 3≤n≤N.

[0075] The purpose of making the above-mentioned limitations on the mass of each layer of the cheese layer of the multi-layer cheese sticks is, on the one hand, to make each layer of the cheese layer maintain an appropriate mass ratio, making the structure of the multi-layer cheese sticks more regular and giving consumers a comfortable visual enjoyment; on the other hand, the above-mentioned mass ratio of each layer of the cheese layer is beneficial to further improving the stability of the multi-layer cheese sticks, making the connection between layers tighter and avoiding cracking between layers.

[0076] The second aspect of the present invention provides a preparation method of the multi-layer cheese sticks of the first aspect, including:

[0077] At 68 - 75°C, the raw material systems of the N - layer cheese layers are successively filled. Among them, the filling speed of the raw material system of the first - layer cheese layer is 1000 - 3000 rpm, and the filling speeds of the raw material systems of the remaining N - 1 layer cheese layers are 500 - 1500 rpm; the filling time interval between the raw material systems of adjacent two - layer cheese layers is 2 - 16 s, thus obtaining the above - mentioned multi - layer cheese sticks.

[0078] Successively filling the raw material systems of the above - mentioned N - layer cheese layers means first filling the raw material system of the first - layer above - mentioned cheese layer, then using the upper surface of the raw material system of the first - layer above - mentioned cheese layer as the bottom surface to fill the raw material system of the second - layer above - mentioned cheese layer, and then successively filling the raw material systems of the remaining layers above - mentioned cheese layers.

[0079] At 68 - 75°C, the viscosity of the raw material system of the first - layer above - mentioned cheese layer is 6000 - 13000 cp, and the filling speed is 1000 - 3000 rpm. By controlling the filling speed in combination with the viscosity, the raw material system of the first - layer above - mentioned cheese layer can achieve self - leveling on the upper surface within 2 - 16 s, forming a flat and horizontal upper surface.

[0080] Then, taking the newly formed flat and horizontal upper surface of the raw material system of the first - layer above - mentioned cheese layer as the bottom surface, the raw material system of the second - layer above - mentioned cheese layer with a viscosity of 6000 - 13000 cp is filled at a speed of 500 - 1500 rpm. By controlling the filling speed in combination with the viscosity, the raw material system of the second - layer above - mentioned cheese layer after filling will not damage the newly formed flat and horizontal upper surface of the raw material system of the first - layer above - mentioned cheese layer. The interface between layers remains clearly horizontal, without obvious color bleeding and layer mixing, and the layers are continuous. Also, because the raw material systems of the first - layer above - mentioned cheese layer and the second - layer above - mentioned cheese layer are not solidified, the two - layer cheese layers can be closely bonded, avoiding interface cracking.

[0081] Similarly, the raw material system of the second - layer above - mentioned cheese layer can achieve self - leveling on the upper surface within 2 - 16 s, forming a flat and horizontal upper surface. After filling the raw material system of the third - layer above - mentioned cheese layer, the effect that the interfaces between the second - layer and the third - layer cheese layers remain clearly horizontal, without obvious color bleeding and layer mixing, and the layers are continuous and do not crack can be achieved.

[0082] The reason for the present invention to limit the filling time interval between the raw material systems of adjacent two - layer above - mentioned cheese layers to 2 - 16 s is that under the dual action of the impact force brought by the filling speed of the raw material system of each cheese layer and its own viscosity, each raw material system of the cheese layer can generally be leveled within at least 2 s - 2.2 s. Generally, the filled material is not thermally insulated during filling, and it will solidify after 16 s of filling, which will lead to problems such as loose bonding between layers and easy interface cracking. Therefore, by limiting the filling time interval to 2 - 16 s, it is ensured that the interfaces between layers remain clearly defined, without obvious color bleeding and layer mixing, and the layers are continuous and do not crack.

[0083] Through the above preparation method, without changing the existing preparation process and without increasing the difficulty of the filling process, multi-layer cheese sticks with the advantages of clear interlayer boundaries, no obvious color bleeding or layer intermixing, continuous and non-cracking interlayers, and no visible water separation to the naked eye can be prepared within 4 weeks of accelerated storage at 37°C.

[0084] The above preparation method also includes the preparation process of the raw material system of the above N-layer cheese layer. The raw material system of the above N-layer cheese layer is prepared by a method that at least includes the following processes: separately complete the formulation of the raw materials of the N-layer cheese layer, and separately melt and sterilize the formulated raw materials of the N-layer cheese layer to obtain the raw material system of the N-layer cheese layer.

[0085] The melting process of the above raw material system of the N-layer cheese layer can be carried out in a melting device, and the melting device includes a melting pot or a heating pot.

[0086] Generally, N melting pots are required to simultaneously prepare the raw material systems of the N-layer cheese layer; in order to reduce the number of melting pots, the raw material system of a certain prepared cheese layer can be fed into a buffer tank for standby, and the emptied melting pot can be used to prepare the raw material systems of other cheese layers. The buffer tank and pipelines can be insulated at ≥80°C to avoid solidification of the raw material system.

[0087] In order to improve the melting quality, the stirring cutter in the melting pot can be turned on and stirred according to the set stirring conditions until it is stirred evenly to the point where there are no visible particles to the naked eye.

[0088] The above melting process is to put the formulated raw materials of the N-layer cheese layer into the melting pot, stir at a rotational speed of 1000 - 3000 rpm for 1 - 3 min; then keep the rotational speed at 1000 - 2500 rpm, slowly heat the material to 85 - 125°C, stop heating, and continue to stir for 0.5 - 2 min. The above process is beneficial to improving the melting effect.

[0089] The above sterilization treatment can be direct steam heating to 85°C - 125°C, keep it for 15 s - 15 min for sterilization, or pasteurization at 105°C for 15 s. In order to further improve the sterilization effect and maintain the high quality of the raw material system of the cheese layer, stirring can be continuously carried out during the sterilization process, and the stirring rotational speed is 1000 - 2500 rpm.

[0090] Since the causal source and the coloring substance are heat-sensitive, when the raw materials of the above N-layer cheese layer include the causal source or the coloring substance, they can be added after the sterilization treatment is completed.

[0091] It is understandable that when the above-mentioned filled material is subjected to heat preservation treatment, the filling time interval of the raw material systems of two adjacent layers of the above-mentioned cheese layers only needs to be ≥2 s, so as to ensure that the upper surface of the raw material system of the lower cheese layer can flow smoothly after filling.

[0092] After filling is completed, the filled material is cooled to solidify it, and the final product can be obtained. The above-mentioned cooling temperature should meet the requirement of being below 40 °C, which can make the filled material solidify and take shape. Generally, the filled material can be cooled to below 40 °C through an online cooling tunnel.

[0093] Furthermore, the filled material can be cooled at 8-10 °C. The outer surface of the filled material can quickly solidify and take shape within 3-4 minutes after filling, and the central temperature quickly drops below 40 °C. Since when the central temperature of the above-mentioned multi-layer cheese sticks is lower than 60 °C, a linear stratification effect appears between the layers, cooling at 8-10 °C is beneficial to obtaining a product with clear horizontal boundaries between layers.

[0094] In some embodiments, the filling equipment used is the ChunGuang SGA40W ultra-clean cheese stick filling machine. Therefore, the motor speed of the above-mentioned ChunGuang SGA40W ultra-clean cheese stick filling machine can be used to characterize the above-mentioned filling speed.

[0095] It is understandable that the slower the filling speed of the raw material systems of the remaining N-1 layers of the above-mentioned cheese layers, the more beneficial it is for the surface between layers to flow smoothly, and thus it is beneficial for maintaining clear horizontal boundaries between layers, no obvious color bleeding and layer mixing, and continuous layers.

[0096] Before the above-mentioned filling treatment, it also includes sterilizing the raw material systems of N layers of the above-mentioned cheese layers. Among them, the sterilization temperature is 85-125 °C, the sterilization time is 15 s-15 min or pasteurization at 105 °C for 15 s. The above-mentioned sterilization treatment is beneficial to killing the miscellaneous bacteria in the raw material systems of N layers of the above-mentioned cheese layers, avoiding product deterioration caused by the influence of miscellaneous bacteria during the shelf life, and is beneficial to improving the stability of the product during the shelf life.

[0097] Hereinafter, the multi-layer cheese sticks of the present invention and their preparation methods will be introduced in more detail through specific examples.

[0098] All raw materials used in the following examples are commercially available or can be prepared according to conventional methods.

[0099] Among them, the suppliers of sodium hexametaphosphate and disodium dihydrogen pyrophosphate: ICL, model: Joha S4SS;

[0100] The filling equipment is the ChunGuang SGA40W ultra-clean cheese stick filling machine.

[0101] Example 1

[0102] A double - layer cheese stick of this embodiment comprises raw materials with the following masses:

[0103] The first - layer cheese layer comprises, by mass percentage: cream cheese 17%, cream 13.5%, concentrated milk protein 7%, stabilizer (including carrageenan 0.3%, locust bean gum 0.4% and sodium carboxymethyl cellulose 0.4%) 1.1%, emulsifying salt (including sodium citrate 0.6%, sodium hexametaphosphate and disodium dihydrogen pyrophosphate in total 0.5%) 1.1%, lactic acid 0.3%, granulated sugar 11.5%, sorbic acid 0.08%, and the balance is water;

[0104] The second - layer cheese layer comprises, by mass percentage: cream cheese 17%, cream 13.5%, concentrated milk protein 7%, stabilizer (including carrageenan 0.3%, locust bean gum 0.4% and sodium carboxymethyl cellulose 0.4%) 1.1%, emulsifying salt (including sodium citrate 0.6%, sodium hexametaphosphate and disodium dihydrogen pyrophosphate in total 0.5%) 1.1%, lactic acid 0.3%, jam 5%, granulated sugar 11.5%, sorbic acid 0.08%, and the balance is water;

[0105] The mass ratio of the first - layer cheese layer to the second - layer cheese layer is 1:1;

[0106] The preparation method of the above - mentioned double - layer cheese stick comprises the following steps:

[0107] 1) Put the raw materials of the first - layer cheese layer including cream cheese into the first melting pot, chop - stir at a rotation speed of 1500 - 2500 rpm for 1 - 3 min, then keep the rotation speed at 1500 - 2500 rpm, slowly heat the material to 95 - 105 °C, stop heating, continue to stir for 0.5 - 2 min for melting, and then sterilize at 105 °C for 15 s to obtain the raw material system of the first - layer cheese layer;

[0108] 2) Put the raw materials of the second - layer cheese layer including cream cheese into the second melting pot, chop - stir at a rotation speed of 1500 - 2500 rpm for 1 - 3 min, then keep the rotation speed at 1500 - 2500 rpm, slowly heat the material to 95 - 105 °C, stop heating, continue to stir for 0.5 - 2 min for melting, and then sterilize at 105 °C for 15 s. After sterilization, add jam to obtain the raw material system of the second - layer cheese layer;

[0109] 3) At 68 - 75 °C, carry out filling treatment on the raw material system of the first - layer cheese layer and the raw material system of the second - layer cheese layer in sequence. Among them, the filling speed of the raw material system of the first - layer cheese layer is 2000 rpm, and the filling speed of the raw material system of the second - layer cheese layer is 700 rpm; the filling time interval is 4.8 s to obtain the above - mentioned double - layer cheese stick.

[0110] Example 2

[0111] A double-layer cheese stick of this embodiment comprises raw materials with the following masses:

[0112] The first-layer cheese layer comprises, by mass percentage: 27% cream cheese, 5% cream, 6% concentrated milk protein, 1.5% stabilizer (including 0.4% carrageenan, 0.6% locust bean gum and 0.5% sodium carboxymethyl cellulose), 0.8% emulsifying salt (including 0.6% sodium citrate, 0.2% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 15% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0113] The second-layer cheese layer comprises, by mass percentage: 27% cream cheese, 6% cream, 6% concentrated milk protein, 1.5% stabilizer (including 0.4% carrageenan, 0.6% locust bean gum and 0.5% sodium carboxymethyl cellulose), 0.8% emulsifying salt (including 0.6% sodium citrate, 0.2% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 7.5% jam, 11% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0114] The mass ratio of the first-layer cheese layer to the second cheese layer is 1:1;

[0115] The preparation method of the above double-layer cheese stick is the same as that of Example 1.

[0116] Example 3

[0117] A double-layer cheese stick of this embodiment comprises raw materials with the following masses:

[0118] The first-layer cheese layer comprises, by mass percentage: 62% cream cheese, 0.5% concentrated milk protein, 1.05% stabilizer (including 0.4% carrageenan, 0.35% locust bean gum and 0.3% sodium carboxymethyl cellulose), 0.65% emulsifying salt (including 0.15% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 9% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0119] The second-layer cheese layer comprises, by mass percentage: 62% cream cheese, 0.5% concentrated milk protein, 1.05% stabilizer (including 0.4% carrageenan, 0.35% locust bean gum and 0.3% sodium carboxymethyl cellulose), 0.65% emulsifying salt (including 0.15% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 7.5% jam, 7% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0120] The mass ratio of the first-layer cheese layer to the second cheese layer is 1:1;

[0121] The preparation method of the above double-layer cheese stick is the same as that of Example 1.

[0122] Example 4

[0123] A double-layer cheese stick in this example comprises raw materials with the following masses:

[0124] The first-layer cheese layer comprises, by mass percentage: 20% cream cheese, 16% fresh cheese, 15% cream, 3.8% concentrated milk protein, 1.5% whole milk powder, 1% stabilizer (including 0.4% carrageenan, 0.3% locust bean gum and 0.3% sodium carboxymethyl cellulose), 0.9% emulsifying salt (including 0.6% sodium citrate, 0.3% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 10% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0125] The second-layer cheese layer comprises, by mass percentage: 20% cream cheese, 16% fresh cheese, 15% cream, 3.8% concentrated milk protein, 1.5% whole milk powder, 1% stabilizer (including 0.4% carrageenan, 0.3% locust bean gum and 0.3% sodium carboxymethyl cellulose), 0.9% emulsifying salt (including 0.6% sodium citrate, 0.3% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 7.5% jam, 10% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0126] The mass ratio of the first-layer cheese layer to the second cheese layer is 1:1;

[0127] The preparation method of the above double-layer cheese stick is the same as that in Example 1.

[0128] Example 5

[0129] A double-layer cheese stick in this example comprises raw materials with the following masses:

[0130] The first-layer cheese layer comprises, by mass percentage: 16% cream cheese, 14.5% cream, 7% concentrated milk protein, 1% whole milk powder, 1.1% stabilizer (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethyl cellulose), 1.1% emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 11.5% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0131] The second-layer cheese layer comprises, by mass percentage: 17% cream cheese, 13.5% cream, 7% concentrated milk protein, 1.1% stabilizer (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethyl cellulose), 1.1% emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 5% jam, 11.5% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0132] The mass ratio of the first cheese layer to the second cheese layer is 1:1;

[0133] The preparation method of the above double-layer cheese stick is the same as that in Example 1.

[0134] Example 6

[0135] A double-layer cheese stick in this example comprises raw materials with the following masses:

[0136] The first cheese layer comprises, by mass percentage: 25% cream cheese, 12% cream, 6% concentrated milk protein, 1.5% stabilizer (including 0.5% carrageenan, 0.5% locust bean gum and 0.5% sodium carboxymethyl cellulose), 0.8% emulsifying salt (including 0.6% sodium citrate, 0.2% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 9% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0137] The second cheese layer comprises, by mass percentage: 25% cream cheese, 10% cream, 6% concentrated milk protein, 1.5% stabilizer (including 0.5% carrageenan, 0.5% locust bean gum and 0.5% sodium carboxymethyl cellulose), 0.8% emulsifying salt (including 0.6% sodium citrate, 0.2% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.5% lactic acid, 7.5% jam, 8% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0138] The mass ratio of the first cheese layer to the second cheese layer is 1:1;

[0139] The preparation method of the above double-layer cheese stick is the same as that in Example 1.

[0140] Example 7

[0141] This example is basically the same as Example 1, the difference being:

[0142] The first cheese layer comprises, by mass percentage: 16% cream cheese, 16% cream, 6.5% concentrated milk protein, 1.1% stabilizer (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethyl cellulose), 1.1% emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 11.5% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0143] The second layer of cheese layer comprises, by mass percentage: 16% of cream cheese, 16% of cream, 6.5% of concentrated milk protein, 1.1% of stabilizer (including 0.3% of carrageenan, 0.4% of locust bean gum and 0.4% of sodium carboxymethyl cellulose), 1.1% of emulsifying salt (including 0.6% of sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% of lactic acid, 5% of jam, 11.5% of granulated sugar, 0.08% of sorbic acid, and the balance is water;

[0144] The mass ratio of the first layer of cheese layer to the second layer of cheese layer is 1:1;

[0145] The preparation method of the above double-layer cheese stick is the same as that of Example 1.

[0146] Example 8

[0147] This example is basically the same as Example 1, the difference is that:

[0148] The first layer of cheese layer comprises, by mass percentage: 18% of cream cheese, 16% of cream, 5.8% of concentrated milk protein, 1.1% of stabilizer (including 0.3% of carrageenan, 0.4% of locust bean gum and 0.4% of sodium carboxymethyl cellulose), 1.1% of emulsifying salt (including 0.6% of sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% of lactic acid, 11.5% of granulated sugar, 0.08% of sorbic acid, and the balance is water;

[0149] The second layer of cheese layer comprises, by mass percentage: 18% of cream cheese, 16% of cream, 5.8% of concentrated milk protein, 1.1% of stabilizer (including 0.3% of carrageenan, 0.4% of locust bean gum and 0.4% of sodium carboxymethyl cellulose), 1.1% of emulsifying salt (including 0.6% of sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% of lactic acid, 5% of jam, 11.5% of granulated sugar, 0.08% of sorbic acid, and the balance is water;

[0150] The mass ratio of the first layer of cheese layer to the second layer of cheese layer is 1:1;

[0151] The preparation method of the above double-layer cheese stick is the same as that of Example 1.

[0152] Example 9

[0153] This example is basically the same as Example 1, the difference is that:

[0154] In step 3) of the preparation method, the filling speed of the raw material system of the first layer of cheese layer is 2500 rpm, and the filling speed of the raw material system of the second layer of cheese layer is 900 rpm; the filling time interval is 4.8 s, and the above double-layer cheese stick is obtained.

[0155] Example 10

[0156] This embodiment is basically the same as Embodiment 1, with the difference that:

[0157] In step 3) of the preparation method, the filling speed of the raw material system of the first layer of cheese layer is 2000 rpm, and the filling speed of the raw material system of the second layer of cheese layer is 600 rpm; the filling time interval is 10 s, and the above double-layer cheese stick is obtained.

[0158] Embodiment 11

[0159] This embodiment is basically the same as Embodiment 1, with the difference that:

[0160] In step 3) of the preparation method, the filling speed of the raw material system of the first layer of cheese layer is 1000 rpm, and the filling speed of the raw material system of the second layer of cheese layer is 500 rpm; the filling time interval is 16 s, and the above double-layer cheese stick is obtained.

[0161] Embodiment 12

[0162] This embodiment is basically the same as Embodiment 1, with the difference that:

[0163] In step 3) of the preparation method, the filling speed of the raw material system of the first layer of cheese layer is 3000 rpm, and the filling speed of the raw material system of the second layer of cheese layer is 1500 rpm; the filling time interval is 3 s, and the above double-layer cheese stick is obtained.

[0164] Embodiment 13

[0165] This embodiment is basically the same as Embodiment 1, with the difference that:

[0166] The stabilizer of the first layer of cheese layer is 1.1%, including 0.4% carrageenan, 0.4% locust bean gum, and 0.3% xanthan gum; the stabilizer of the second layer of cheese layer is 1.1%, including 0.4% carrageenan, 0.3% locust bean gum, and 0.4% gelatin.

[0167] Embodiment 14

[0168] This embodiment is basically the same as Embodiment 1, with the difference that:

[0169] The emulsifying salts of the first layer of cheese layer and the second layer of cheese layer are both 1.1% sodium hexametaphosphate.

[0170] Embodiment 15

[0171] This embodiment is basically the same as Embodiment 1, with the difference that:

[0172] The emulsifying salts of the first layer of cheese layer and the second layer of cheese layer are both 1.1% sodium hexametaphosphate and trisodium phosphate in total.

[0173] Embodiment 16

[0174] This embodiment is basically the same as Embodiment 1, with the difference being that:

[0175] The mass ratio of the first layer of cheese layer to the second layer of cheese layer is 1.5:1.

[0176] Embodiment 17

[0177] A three-layer cheese stick of this embodiment comprises raw materials with the following masses:

[0178] The first layer of cheese layer comprises, by mass percentage: cream cheese 16%, cream 13.5%, concentrated milk protein 7%, stabilizer (including carrageenan 0.4%, locust bean gum 0.3% and sodium carboxymethyl cellulose 0.4%) 1.1%, emulsifying salt (including sodium citrate 0.6%, sodium hexametaphosphate and disodium dihydrogen pyrophosphate in total 0.5%) 1.1%, lactic acid 0.3%, granulated sugar 11.5%, sorbic acid 0.08%, and the balance is water;

[0179] The second layer of cheese layer comprises, by mass percentage: cream cheese 30%, cream 13.5%, concentrated milk protein 7%, stabilizer (including carrageenan 0.5%, locust bean gum 0.2% and sodium carboxymethyl cellulose 0.4%) 1.1%, emulsifying salt (including sodium citrate 0.6%, sodium hexametaphosphate and disodium dihydrogen pyrophosphate 0.5%) 1.1%, lactic acid 0.3%, granulated sugar 11.5%, sorbic acid 0.08%, and the balance is water;

[0180] The third layer of cheese layer comprises, by mass percentage: cream cheese 17%, cream 13.5%, concentrated milk protein 7%, stabilizer (including carrageenan 0.2%, locust bean gum 0.5% and sodium carboxymethyl cellulose 0.4%) 1.1%, emulsifying salt (including sodium citrate 0.6%, sodium hexametaphosphate and disodium dihydrogen pyrophosphate 0.5%) 1.1%, lactic acid 0.3%, granulated sugar 11.5%, sorbic acid 0.08%, and the balance is water;

[0181] The mass ratio of the first layer of cheese layer, the second layer of cheese layer and the third layer of cheese layer is 1.5:1:1;

[0182] The preparation method of the above three-layer cheese stick comprises the following steps:

[0183] 1) Put the raw materials of the first layer of cheese layer including cream cheese into the first melting pot, chop and stir at a rotational speed of 1500 - 2000 rpm for 1 - 3 min, then keep the rotational speed at 1500 - 2000 rpm, slowly heat the material to 95 - 105 °C, stop heating, continue to stir for 0.5 - 2 min for melting, and then sterilize at 105 °C for 15 s to obtain the raw material system of the first layer of cheese layer;

[0184] 2) Put the raw materials of the second cheese layer including cream cheese into the second melting pot, chop and stir at a rotational speed of 1500 - 2000 rpm for 1 - 3 min, then keep the rotational speed at 1500 - 2000 rpm, slowly heat the material to 95 - 105 °C, stop heating, continue to stir for 0.5 - 2 min for melting, and then sterilize at 105 °C for 15 s. After sterilization, add jam to obtain the raw material system of the second cheese layer;

[0185] 3) Put the raw materials of the third cheese layer including cream cheese into the second melting pot, chop and stir at a rotational speed of 1500 - 2000 rpm for 1 - 3 min, then keep the rotational speed at 1500 - 2000 rpm, slowly heat the material to 95 - 105 °C, stop heating, continue to stir for 0.5 - 2 min for melting, and then sterilize at 105 °C for 15 s to obtain the raw material system of the third cheese layer;

[0186] 3) At 68 - 75 °C, fill the raw material systems of the first cheese layer, the second cheese layer, and the third cheese layer in sequence. Among them, the filling speed of the raw material system of the first cheese layer is 3000 rpm, the filling speed of the raw material system of the second cheese layer is 1000 rpm, and the filling speed of the raw material system of the third cheese layer is 500 rpm; the filling time intervals are all 4.8 s to obtain the above three - layer cheese sticks.

[0187] Example 18

[0188] This example is basically the same as Example 1, the difference is that:

[0189] The emulsifying salts of the first cheese layer and the second cheese layer are both 1.5% sodium hexametaphosphate.

[0190] Example 19

[0191] This example is basically the same as Example 1, the difference is that:

[0192] The emulsifying salts of the first cheese layer and the second cheese layer are both 1.4% sodium citrate.

[0193] Comparative Example 1

[0194] A double - layer cheese stick in this comparative example includes raw materials with the following masses:

[0195] The first layer of cheese layer comprises, by mass percentage: 36% cream cheese, 4.5% concentrated milk protein, 1.5% non-fat milk powder, 1.1% stabilizer (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethyl cellulose), 1.1% emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 10% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0196] The second layer of cheese layer comprises, by mass percentage: 16% cream cheese, 4.5% concentrated milk protein, 1.5% non-fat milk powder, 1.1% stabilizer (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethyl cellulose), 1.1% emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 7.5% jam, 11.5% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0197] The mass ratio of the first layer of cheese layer to the second layer of cheese layer is 1:1;

[0198] The preparation method of the above double-layer cheese stick is the same as that in Example 1.

[0199] Comparative Example 2

[0200] A double-layer cheese stick in this comparative example comprises raw materials with the following masses:

[0201] The first layer of cheese layer comprises, by mass percentage: 16% cream cheese, 0.3% cream, 1.8% whole milk powder, 4.7% stabilizer (including 1.5% carrageenan, 1.4% locust bean gum and 1.8% sodium carboxymethyl cellulose), 1.1% emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.4% lactic acid, 11.5% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0202] The second layer of cheese layer comprises, by mass percentage: 16% cream cheese, 0.3% cream, 1.8% whole milk powder, 1.1% emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate), 0.3% lactic acid, 7.5% jam, 11.5% granulated sugar, 0.08% sorbic acid, and the balance is water;

[0203] The mass ratio of the first layer of cheese layer to the second layer of cheese layer is 1:1;

[0204] The preparation method of the above double-layer cheese stick is the same as that in Example 1.

[0205] Comparative Example 3

[0206] A double-layer cheese stick in this comparative example comprises raw materials with the following masses:

[0207] The first layer of cheese layer comprises, by mass percentage: cream cheese 16%, cream 11.5%, concentrated milk protein 6.5%, stabilizer (including 0.4% carrageenan, 0.4% locust bean gum and 0.5% sodium carboxymethyl cellulose) 1.3%, emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate) 1.1%, lactic acid 0.3%, granulated sugar 11.5%, sorbic acid 0.08%, and the balance is water;

[0208] The second layer of cheese layer comprises, by mass percentage: cream cheese 16%, cream 11.5%, concentrated milk protein 6.5%, emulsifying salt (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate) 1.1%, lactic acid 0.3%, jam 7.5%, granulated sugar 11.5%, sorbic acid 0.08%, and the balance is water;

[0209] The mass ratio of the first layer of cheese layer to the second layer of cheese layer is 1:1;

[0210] The preparation method of the above double-layer cheese stick is the same as that in Example 1.

[0211] Comparative Example 4

[0212] This comparative example is basically the same as Example 1, except that:

[0213] The filling speed of the raw material system of the first layer of cheese layer is 4000 rpm.

[0214] Comparative Example 5

[0215] This comparative example is basically the same as Example 1, except that:

[0216] The filling speed of the raw material system of the first layer of cheese layer is 900 rpm.

[0217] Comparative Example 6

[0218] This comparative example is basically the same as Example 1, except that:

[0219] The filling speed of the raw material system of the second layer of cheese layer is 2000 rpm.

[0220] Comparative Example 7

[0221] This comparative example is basically the same as Example 1, except that:

[0222] The filling speed of the raw material system of the second layer of cheese layer is 200 rpm.

[0223] Comparative Example 8

[0224] This comparative example is basically the same as Example 1, except that:

[0225] The first layer of cheese layer comprises, by mass percentage: cream cheese 10%, cream 16%, concentrated milk protein 4%, stabilizers (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethylcellulose) 1.1%, emulsifying salts (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate) 1.1%, lactic acid 0.3%, granulated sugar 19%, sorbic acid 0.08%, and the balance is water;

[0226] The second layer of cheese layer comprises, by mass percentage: cream cheese 10%, cream 16%, concentrated milk protein 3%, stabilizers (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethylcellulose) 1.1%, emulsifying salts (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate) 1.1%, lactic acid 0.3%, jam 5%, granulated sugar 19%, sorbic acid 0.08%, and the balance is water;

[0227] Comparative Example 9

[0228] This comparative example is basically the same as Example 1, except that:

[0229] The first layer of cheese layer comprises, by mass percentage: cream cheese 65%, concentrated milk protein 7%, stabilizers (including 0.3% carrageenan, 0.4% locust bean gum and 0.4% sodium carboxymethylcellulose) 1.1%, emulsifying salts (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate) 1.1%, lactic acid 0.3%, granulated sugar 8%, sorbic acid 0.08%, and the balance is water;

[0230] The second layer of cheese layer comprises, by mass percentage: cream cheese 65%, concentrated milk protein 7%, stabilizers (including 0.2% sodium citrate, 0.3% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate) 0.5%, emulsifying salts (including 0.6% sodium citrate, 0.5% in total of sodium hexametaphosphate and disodium dihydrogen pyrophosphate) 1.1%, lactic acid 0.3%, jam 5%, granulated sugar 7%, sorbic acid 0.08%, and the balance is water;

[0231] Comparative Example 10

[0232] This comparative example is basically the same as Example 1, except that:

[0233] The raw material system of the first layer of cheese layer is filled immediately after filling the raw material system of the second layer of cheese layer.

[0234] Comparative Example 11

[0235] The filling interval time of the raw material systems of the two layers of cheese layer is 20 s.

[0236] Test Example

[0237] 1. Detect the following parameters for the above examples and comparative examples:

[0238] 1. Viscosity and pH value: Detect the viscosity and pH value of the raw material system of each layer of the above cheese layer. Among them, the viscosity is detected using a bookfield viscometer at a detection temperature of 72°C, rotor 93, rotation speed of 8 rpm, and detection time of 1 min; the pH is measured using a pH meter. The specific results are shown in Table 1.

[0239] 2. Sensory evaluation: Evaluate the taste of the product according to the paired comparison method. The specific results are shown in Table 2.

[0240] 3. Water separation situation: Observe the water separation situation of the product when it is just prepared and after accelerated storage at 37°C for 4 weeks. The specific results are shown in Table 2.

[0241] 4. Interlayer boundary situation: Observe the interlayer boundary situation of the product when it is just prepared and after accelerated storage at 37°C for 4 weeks. The specific results are shown in Table 2.

[0242] 5. Product pictures: Take pictures of the samples on the 0th day of the shelf life (i.e., when the product is just prepared) placed in a refrigerated environment at 2 - 8°C. The specific results are shown in Figures 1-9 .

[0243] 2. Test results

[0244] Table 1 Viscosity and pH value of the raw material system of the cheese layer

[0245]

[0246]

[0247]

[0248] The results in Table 1 prove that the viscosity of the raw material system of each example is within 6000 - 13000 cp. Among them, the content of cream cheese in Example 3 is relatively high, and the content of cream components can also meet the range of 3% - 20% of lipid products. The content of cream cheese in Comparative Example 1 is insufficient to provide enough cream components, resulting in a lower viscosity in combination with other factors.

[0249] Table 2 Sensory evaluation results of the product

[0250]

[0251]

[0252]

[0253]

[0254]

[0255] The results in Table 2 prove that the taste of each example is delicate. Due to different raw material formulas, some are firmer and some are softer, all meeting the taste requirements of the expected cheese sticks. The raw material formula and viscosity are the most important factors affecting the product stability, i.e., the water separation situation. However, the filling process also has an impact on the texture, tissue state, and demarcation line of the product. Combining Figures 1-9 with the sample photos, among which, Figure 1 is the sample photo of Example 1, Figure 2 is the sample photo of Example 2, Figure 3 is the sample photo of Example 3, Figure 4 is the sample photo of Example 4, Figure 5 is the sample photo of Example 5, Figure 6 is the sample photo of Example 6, Figure 7 is the sample photo of Comparative Example 1, Figure 8 is the sample photo of Comparative Example 2, Figure 9 is the sample photo of Comparative Example 3, and through the analysis of the results in Table 2, it is found that the viscosity of the raw material system and the filling process jointly affect the demarcation line situation of the product. Among them, acceptable water separation means that although there is water separation, it is not significant and within the acceptable range. The above demarcation line has an inclination. Acceptable means that the inclination angle of the layer separation < 10°. During the industrial production process, due to the precision of the equipment, the length of the pipelines in different production lines, the fluctuation of the filling temperature, and the market quality acceptance level, there will be a slight inclination between the layers. Generally, for multi-layer cheese products with clear layer separation between layers and an inclination angle of layer separation < 10°, the products are acceptable.

[0256] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some or all of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-layer cheese stick, characterized in that, the multi-layer cheese stick comprises N layers of cheese layers arranged in a stacked manner, N≥2; the viscosity of the raw material systems of the N layers of cheese layers is independently 6000-13000 cp at 68-75 °C; the multi-layer cheese stick is prepared by a method at least including the following process: at 68-75 °C, the raw material systems of the N layers of cheese layers are sequentially subjected to filling treatment, wherein the filling speed of the raw material system of the first layer of cheese layer is 1000-3000 rpm, and the filling speeds of the raw material systems of the remaining N-1 layers of cheese layers are 500-1500 rpm; the filling time interval between the raw material systems of adjacent two layers of cheese layers is 2-16 s, obtaining the multi-layer cheese stick.

2. The multi-layer cheese stick according to claim 1, characterized in that, the viscosity of the raw material systems of the N layers of cheese layers is independently 8000-10000 cp at 68-75 °C.

3. The multi-layer cheese stick according to claim 1 or 2, characterized in that, the filling speed of the raw material system of the first layer of cheese layer is 2000-2500 rpm, and the filling speeds of the raw material systems of the remaining N-1 layers of cheese layers are 500-900 rpm; the filling time interval between the raw material systems of adjacent two layers of cheese layers is 4-10 s.

4. The multi-layer cheese stick according to any one of claims 1-3, characterized in that, the raw material system of each layer of cheese layer independently comprises, by mass percentage: 15%-62% of natural cheese, 3%-20% of lipid products, 0%-30% of protein powder, 0.4%-4% of stabilizer, 0%-0.6% of emulsifier, 0.5%-1.5% of emulsifying salt, 0-0.8% of acidity regulator, 0%-10% of fruit source, 0%-2% of coloring substance, and the balance is water.

5. The multi-layer cheese stick according to claim 4, characterized in that, in the raw material system of each layer of cheese layer, the stabilizer independently comprises, by mass percentage: 0.3%-0.5% of sodium carboxymethylcellulose, 0.2%-0.5% of carrageenan, 0.2%-0.5% of locust bean gum.

6. The multi-layer cheese stick according to claim 4 or 5, characterized in that, the emulsifying salt comprises at least one of sodium hexametaphosphate, sodium tripolyphosphate, disodium dihydrogen pyrophosphate, and sodium citrate.

7. The multi-layer cheese stick according to any one of claims 4-6, characterized in that, the raw material system of each layer of cheese layer independently comprises 1.5%-17% of sweetening substance by mass percentage.

8. The multi-layer cheese stick according to any one of claims 1-7, characterized in that, when N = 2, the mass ratio of the first layer of cheese layer to the second layer of cheese layer is (1-1.5):1; when N≥3, the mass ratio of the first layer of cheese layer to the second layer of cheese layer is (1-1.5):1, and the mass ratio of the (n-1)th layer of cheese layer to the nth layer of cheese layer is 1:1, wherein 3≤n≤N.

9. A preparation method of the multi-layer cheese stick according to any one of claims 1-8, It is characterized in that including: At 68 - 75°C, the raw material systems of the N layers of the cheese layer are successively subjected to filling treatment. Among them, the filling speed of the raw material system of the first layer of the cheese layer is 1000 - 3000 rpm, and the filling speeds of the raw material systems of the remaining N - 1 layers of the cheese layer are 500 - 1500 rpm; the filling time interval between the raw material systems of adjacent two layers of the cheese layer is 2 - 16 s, obtaining the multi-layer cheese stick.

10. According to the preparation method described in claim 9, it is characterized in that Before the filling treatment, it further includes subjecting the raw material systems of the N layers of the cheese layer to sterilization treatment, wherein the sterilization temperature is 85 - 125°C and the sterilization time is 15 s - 15 min.

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