Konjac gum-based mimicry of spinach pasta and method of making same

Abstract

The application relates to a konjac gel Italian pasta product which simulates traditional Italian pasta in shape and mouthfeel, and belongs to the field of food processing. The technical defects that the mouthfeel characteristics of a gel product compounded from konjac powder and spinach powder are quite different from those of the imitated spinach Italian pasta and the water-holding property of the gel product is reduced by more than 20% and the color-holding property is reduced by more than 50% when the product is sterilized and packaged and then stored at room temperature for a long time. The imitated spinach Italian pasta based on konjac gel compounded from konjac powder, spinach powder, pea fiber and chlorella protein can improve the above technical defects, so that the prepared konjac gel product approaches the sensory requirements of traditional spinach Italian pasta and the storage stability is improved.

Description

Technical Field

[0001] This invention belongs to the field of food processing, specifically relating to the preparation of a gluten-free konjac gel product that mimics spinach pasta in appearance and texture, containing no soy, starch or modified starch, a composition of konjac gel, and a method for preparing the same. Background Technology

[0002] Spinach pasta is a pasta product made primarily from spinach and durum wheat. It combines the green color of spinach with the characteristic liveliness, firmness, and starch release of pasta (refer to ISO 7304-2:2008 Alimentary pasta produced from durum wheat semolina - Estimation of cooking quality by sensory analysis - Part 2: Routine method). However, the durum wheat used in traditional spinach pasta has a relatively high gluten content, which can easily cause food allergies such as celiac disease in people who cannot digest gluten. Furthermore, durum wheat contains more than 30% digestible carbohydrates (starch), resulting in a high calorie content. Currently, the market demands low-calorie pasta products free of gluten, soy, and other allergens, and free of starch. Mimicry foods, also known as biomimetic foods, are foods made by selecting parts of the original food or other food ingredients based on the texture and shape of the imitated object (traditional food). The konjac gel-based mimicked spinach pasta described in this invention has similar taste and appearance to regular spinach pasta, but contains no wheat, gluten, soy, starch, or modified starch. It should be noted that the konjac gel-based mimicked spinach pasta in this invention is only similar in taste and appearance to cooked spinach pasta; it does not belong to the category of processed rice and noodle products, but is classified as a processed vegetable product. Its nutritional characteristics and processing technology are also fundamentally different from rice and noodle products. It belongs to a recombinant gel food obtained by physical and chemical processing of food raw materials.

[0003] Existing technologies for manufacturing gluten-free mimicking spinach pasta generally utilize modified starch, starch, or konjac flour to replace wheat components. Konjac gel products made with konjac flour (konjac glucomannan) and spinach powder can mimic the appearance of spinach pasta, but their texture differs. Specifically, besides having extremely low starch release (according to ISO 7304-2:2008, good pasta sensory characteristics require low starch release), their smoothness and firmness are lower than spinach pasta. To address this, existing technologies combine konjac flour with soy flour, potato flour, or starch to alter its gel structure and improve its texture, as disclosed in Chinese patents CN113229506A and CN107509999A. However, these formulations all contain starch or modified starch, and soybeans are one of the most common food allergens causing food allergies.

[0004] On the other hand, konjac gel products made from konjac flour and spinach flour suffer from severe quality deterioration when stored at room temperature for a long period of time after cooking, sterilization, and packaging, with a decrease in water retention of >20% and a decrease in color retention of >50% after 6 months. Konjac gel products themselves have the problem of being difficult to color. To address this problem, existing technologies disclose a method of coloring by using a gel network formed by protein and konjac flour to trap pigment molecules (Zhu Kun, Liu Yuanqin, Fan Shengyu, et al. Preparation and performance study of a composite colored gel of konjac glucomannan-soy protein isolate-capsicum red pigment [J]. Food and Fermentation Industries, 2021, 47(15):213-219). However, its formula contains soybean components and capsicum red pigment has different processing physicochemical characteristics from natural green pigments such as chlorophyll. In the production of konjac gel products, konjac gum needs to undergo deacetylation through alkali treatment to form an irreversible thermal gel (Li Bin, Xie Bijun. Study on gelation mechanism of konjac glucomannan [J]. Chinese Agricultural Science, 2002, 35(11):5; Long Xiaoyan. Study on condensed state basis of natural macromolecular konjac glucomannan [D]. China Academy of Engineering Physics, 2013). In the production of compound konjac gel products, due to the influence of compound components, the properties of the gel formed are subject to complex changes in physicochemical properties with the compound components. The process of deacetylation of konjac glucomannan to form a gel alone or with other food raw materials is a different type of physical and chemical cross-linking reaction achieved under specific ratios and processes. Even the same raw material can form konjac gels with different ratios and process conditions, resulting in significant differences in properties. For example, the water-holding capacity of konjac gel products made by compounding konjac flour and spinach powder is lower than that of konjac gel products made solely from refined konjac flour. The chlorophyll in spinach powder is prone to discoloration during the alkali and acid treatment processes in the refining steps of konjac gel production. Even if only chlorella protein or pea protein is added to the formula to form a compound gel with konjac flour and spinach powder, it still cannot meet the technical barrier of a decrease in water retention of >20% and a decrease in color retention of >50% after 6 months. Moreover, the sensory scores for smoothness and firmness are lower than those of spinach pasta.

[0005] In summary, there is a need in the art for a mimicry product that uses konjac flour instead of traditional spinach pasta, which simultaneously meets the requirements of pasta texture characteristics and water retention and color stability after the addition of spinach powder. However, existing technologies cannot meet these requirements. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a konjac gel-based mimicked spinach pasta and its preparation method. By using a compound of konjac flour, spinach powder, pea fiber, and chlorella protein, the konjac gel-based mimicked spinach pasta can improve the above-mentioned technical shortcomings, making the prepared konjac gel product close to the sensory requirements of traditional spinach pasta in terms of appearance and taste, and improving its storage stability.

[0007] To achieve the above objectives, the first technical solution of the present invention discloses a konjac gel-based mimicking spinach pasta, comprising konjac flour, pea fiber, spinach powder, chlorella protein, and water.

[0008] Preferably, the konjac flour comprises 35-45 parts by weight, the pea fiber comprises 2.5-5 parts by weight, the spinach powder comprises 5-7.5 parts by weight, the chlorella protein comprises 0.25-0.75 parts by weight, and the water comprises 900-1200 parts by weight.

[0009] The second technical solution of the present invention discloses a method for preparing mimicking spinach pasta, comprising the following steps:

[0010] After premixing pea fiber, chlorella protein, and spinach powder into powder, add the first part by weight of water, and gradually heat and stir at high speed to obtain a suspension.

[0011] Add a second part by weight of water to konjac flour and stir at a constant temperature and low speed. Then add the suspension and a third part by weight of water and continue stirring until the viscosity value is ≥10000 mpa.s to obtain konjac colloid.

[0012] Konjac colloid was extruded into a Ca(OH)2 solution to obtain strip-shaped konjac gel, which was then soaked in citric acid solution and rinsed with water to obtain mimicked spinach pasta.

[0013] Preferably, the stirring rate of the gradually increasing temperature and stirring is ≥10000 rpm, the initial temperature is 20-30℃, the final temperature is 60℃, the heating rate is ≤10℃ / min, and stirring is continued for 5 minutes after the final temperature is reached.

[0014] Preferably, the constant temperature low-speed stirring is characterized by a temperature of 20-30℃, a stirring rate of <100 rpm, and a stirring time of 2 min.

[0015] Preferably, the temperature of the Ca(OH)2 solution is 90-100℃.

[0016] Preferably, the mimicking spinach pasta is packaged by soaking in a Ca(OH)2 aqueous solution.

[0017] Preferably, the extrusion is performed by extruding into different shapes using different molds.

[0018] And, the mimicking spinach pasta prepared according to the above preparation method.

[0019] Compared to existing technologies, the beneficial effects of this application are as follows:

[0020] This invention addresses the technical shortcomings of gel products made from a blend of konjac flour and spinach powder, which exhibit lower texture and firmness compared to traditional spinach pasta, provided the formula is free of gluten, soy, starch, or modified starch. These shortcomings include significant differences in the texture of the simulated spinach pasta and severe quality deterioration due to a decrease in water retention (>20%) and color retention (>50%) during long-term storage at room temperature after cooking and sterilization. By using a blend of konjac flour, spinach powder, pea fiber, and chlorella protein, the resulting simulated spinach pasta achieves a texture similar to traditional spinach pasta, while exhibiting a decrease in water retention (<10%) and color retention (<20%) over 18 months. Attached Figure Description

[0021] Figure 1 Comparative images of konjac gel (mimicking spinach pasta) (Example 1) and spinach pasta (Comparative Example 7);

[0022] Figure 2 The image shows a scanning electron microscope (SEM) image of the surface of Example 1.

[0023] Figure 3 This is a scanning electron microscope image of the surface of Comparative Example 1;

[0024] Figure 4 This is a cross-sectional scanning electron microscope image of Example 1;

[0025] Figure 5 This is a cross-sectional scanning electron microscope image of Comparative Example 1;

[0026] Figure 6 The image shows the infrared absorption spectrum of the lyophilized gel sample. Detailed Implementation

[0027] The embodiments of this application will be described in detail below with reference to examples. Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products. Unless otherwise specified, all listed quantities are based on total weight and described in parts by weight. This application should not be construed as being limited to the specific embodiments described.

[0028] Unless otherwise specified, the technical terms in this specification have the same meaning as those generally understood by those skilled in the art; however, in case of any conflict, the definitions in this specification shall prevail.

[0029] The terms "konjac flour," "konjac glucomannan," and "konjac dietary fiber" used in the background art of this invention are essentially the same substance. Konjac flour's main component is konjac glucomannan (konjac glucomannan content is over 99%), hence it is also called konjac glucomannan; simultaneously, konjac glucomannan is a natural high-molecular-weight soluble dietary fiber, therefore, in the prior art, konjac glucomannan is also referred to as konjac dietary fiber. Except for the prior art referenced in the background art, which uses its original name, all other parts of this application uniformly refer to konjac flour.

[0030] In the context of this invention, the terms "comprising" or "including" do not exclude other possible elements. The compositions of this invention (including the various embodiments described herein) may comprise, consist of, or consist substantially of the following elements: the essential elements and necessary limitations of the invention as described herein, and any other or optional ingredients, components, or limitations as described herein or as otherwise desired.

[0031] The invention will now be described in more detail. It should be noted that the various aspects, features, implementation methods, embodiments, and advantages described herein are compatible and / or can be combined together.

[0032] The first embodiment of this application discloses a konjac gel-based mimicking spinach pasta, comprising konjac flour, pea fiber, spinach powder, chlorella protein, and water.

[0033] The konjac flour, pea fiber, spinach powder, and chlorella protein mentioned in this invention are all commercially available. The spinach powder has a particle size of <0.125μm and is dried spinach leaf powder that is not completely soluble in water. The konjac flour, pea fiber, and chlorella protein are all powdered solids that can be dissolved or swelled in water individually. The chlorella protein is a protein component extracted from *Chlorella pyrenoidosa*. The pea fiber is water-soluble pea fiber extracted from peas.

[0034] In one embodiment, the konjac flour comprises 35-45 parts by weight, the pea fiber comprises 2.5-5.0 parts by weight, the spinach powder comprises 5.0-7.5 parts by weight, the chlorella protein comprises 0.25-0.75 parts by weight, and the water comprises 900-1200 parts by weight. It is understood that in this embodiment, konjac flour can be 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, or 45 parts by weight; pea fiber can be 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0 parts by weight; and spinach powder can be 5.0, 5.1, 5.2, 5.3, 5.4, or 5. 5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0 parts by weight; chlorella protein can be 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.40, 0.50, 0.60, 0.70, 0.71, 0.72, 0.73, 0.74, 0.7; water can be 900, 950, 1000, 1050, 1100, 1150, 1200 parts by weight or any two of these ranges. In a preferred embodiment, the konjac flour is 40 parts by weight, the pea fiber is 5 parts by weight, the spinach powder is 7.5 parts by weight, the chlorella protein is 0.5 parts by weight, and the water is 1000 parts by weight.

[0035] The applicant discovered that when the above-mentioned konjac flour, pea fiber, spinach powder, chlorella protein, and water are combined and used in the above-mentioned mass ratio, the resulting konjac gel has the same or similar sensory characteristics as traditional Italian pasta.

[0036] It is understandable that different protein raw materials have vastly different structures, making it difficult to predict the structural characteristics of konjac gel formed after copolymerization with konjac flour. Its structural physicochemical properties (such as the smoothness and firmness resulting from differences in elasticity and hardness) are also unpredictable. Furthermore, the addition of other components can also affect these structural physicochemical properties. For example, in Chinese patent CN113229506A, konjac flour is copolymerized with soybean flour (mainly composed of soybean protein), and the addition of starch makes its texture softer. However, in a published study on the preparation and performance of a konjac glucomannan-soybean protein isolate-capsicum red pigment composite colored gel, the copolymerization of konjac flour and soybean protein resulted in increased hardness but unchanged elasticity in the konjac gel. This demonstrates that even with the same copolymerization of konjac flour and soybean protein, the sensory characteristics can differ due to the influence of other components. Therefore, the structural and sensory characteristics of konjac gel formed after blending protein raw materials, other excipients, and konjac flour are unpredictable.

[0037] Specifically, in this application, the addition of spinach powder to konjac flour resulted in a konjac gel exhibiting a significantly reduced elasticity and a significantly increased hardness, with both its smoothness and firmness being lower than that of spinach pasta. Based on this technical problem, the applicant, through extensive experimental comparisons, obtained the formula of this application, which produces a konjac gel with a texture similar to or suitable for the simulated spinach pasta.

[0038] On the other hand, the applicant also found that the water-holding and color-holding stability of the konjac gel prepared by the above-mentioned compound formulation was enhanced.

[0039] Understandably, the water-holding and color-holding properties of gels are closely related to their textural characteristics. Although existing technologies disclose that the combination of konjac flour and soybean protein can enhance the retention effect of pigment molecules, on the one hand, spinach powder has a larger particle size than pure pigments, making it more difficult to retain them. At the same time, the sequential treatment of alkali and acid during the production of konjac gel may damage chlorophyll. On the other hand, the textural characteristics of gels formed by different proteins and konjac flour vary greatly, exhibiting unpredictability. For example, the sensory characteristics of the combination of pea protein and konjac flour do not meet the requirements of this application.

[0040] In the konjac gel obtained from the formulation of this application, the combination of chlorella protein, pea fiber, and konjac flour effectively encapsulates the spinach powder. This results in a physicochemical structure that differs from that of a simple combination of konjac flour and spinach powder. Spinach particles are completely encapsulated within the gel structure, with no exposed spinach particles on the gel surface. The gel surface is continuous, smooth, and pore-free, exhibiting surface characteristics similar to traditional pasta. Furthermore, the cross-section displays a more supportive, uniform, and continuous mesh-like structure. Infrared spectroscopy characterization also revealed differences in the macromolecular chemical structure of the gel macromolecules in different formulations. Based on this optimization of the physicochemical structure, the konjac gel obtained from the formulation of this application exhibits enhanced water retention and color retention stability. After 18 months of conventional storage, its water retention decreases by <10%, and its color retention decreases by <20%.

[0041] The second embodiment of this application discloses a method for preparing mimicking spinach pasta, comprising the following steps:

[0042] After premixing pea fiber, chlorella protein, and spinach powder into powder, add the first part by weight of water, and gradually heat and stir at high speed to obtain a suspension.

[0043] Add a second part by weight of water to konjac flour and stir at a constant temperature and low speed. Then add the suspension and a third part by weight of water and continue stirring until the viscosity value is ≥10000 mpa.s to obtain konjac colloid.

[0044] Konjac colloid was extruded into a Ca(OH)2 solution to obtain a long, thin stick-shaped konjac gel, which was then soaked in citric acid solution and rinsed with water to obtain a mimicked spinach pasta.

[0045] In this embodiment, the sum of the first, second, and third parts by weight of water is the total parts by weight of water. The konjac flour is 35-45 parts by weight, the pea fiber is 2.5-5.0 parts by weight, the spinach powder is 5.0-7.5 parts by weight, the chlorella protein is 0.25-0.75 parts by weight, and the water is 900-1200 parts by weight.

[0046] It can be understood that the sum of the first, second, and third parts by weight of water is the total parts by weight of water, which is 900-1200 parts by weight. Among them, the first part by weight of water is 8-12 parts by weight, the second part by weight of water is 90-110 parts by weight, and the remainder is the third part by weight of water.

[0047] In this embodiment, the preparation principle and method of konjac gel are known in the art. After obtaining the specific components, the applicant can prepare konjac gel using conventional preparation methods and adjust some conventional methods and parameters based on its textural properties. This application does not impose specific limitations, but only discloses some preferred embodiments.

[0048] In some preferred embodiments, the stirring rate of the gradually increasing temperature and stirring is ≥10000 rpm, the initial temperature is 20-30℃, the final temperature is 60℃, the heating rate is ≤10℃ / min, and stirring is continued for 5 minutes after the final temperature is reached.

[0049] In some preferred embodiments, the temperature of the constant temperature low-speed stirring is 20-30°C, the stirring rate is <100 rpm, and the stirring time is 2 min.

[0050] In some preferred embodiments, the Ca(OH)2 solution is at a temperature of 90-100°C, the soaking temperature is at 90-100°C, and the pH is 12.

[0051] In some preferred embodiments, the mimicry spinach pasta is packaged by soaking in an aqueous solution of Ca(OH)2 with a pH of 11±0.5.

[0052] In some preferred embodiments, the extrusion is performed by extruding into different shapes using different molds. In this embodiment, different shapes of spinach pasta are obtained by extruding using different molds, such as long strips, spirals, etc.

[0053] In some preferred embodiments, the rinsing is performed using a citric acid solution with a pH of 4, a temperature of 20-30°C, and a soaking time of 15-30 minutes.

[0054] In some preferred embodiments, the water rinsing is performed until the pH of the water is <9.

[0055] In some preferred embodiments, the konjac gel product is subjected to pasteurization or high-temperature sterilization and cooking treatment.

[0056] The mimicry spinach pasta prepared by this embodiment has the same texture and water-holding and color-holding properties as the konjac gel of this application. Its hardness and elasticity simulate traditional pasta, while its water-holding and color-holding stability is increased. After being stored at room temperature for 18 months, its water-holding capacity is <10% and its color-holding capacity decreases by <20%.

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional in the art.

[0058] To make parallel comparisons, the following examples and comparative examples were all produced using molds of the same specifications, and the resulting gels were 25cm (±1cm) long, 4mm in diameter, and shaped like slender sticks.

[0059] Example 1: Konjac Gel

[0060] The konjac gel comprises 40 kg of konjac flour, 5 kg of pea fiber, 7.5 kg of spinach powder, 0.5 kg of chlorella protein, and 1000 kg of water. Its preparation method is as follows:

[0061] S1. After premixing pea fiber, chlorella protein, and spinach powder into powder, add 10 kg of water and stir at 11,000 rpm. The initial temperature during the stirring process is 25°C. Heat to the final temperature of 60°C at a heating rate not exceeding 10°C / min and hold for 5 min to obtain a suspension.

[0062] S2. Add 100kg of water to konjac flour, control the temperature at 25℃, stir at a speed of <100 rpm for 2 minutes, then add the suspension and the remaining water (890kg) and continue stirring until the viscosity value is ≥10000mpa.s to obtain konjac colloid.

[0063] S3. Konjac colloid is extruded into a Ca(OH)2 solution at 95℃ and pH 12 to obtain crude konjac gel. Then, it is soaked in a citric acid solution at 25℃ and pH 4 for 22 minutes, and then rinsed with water until the pH of the water is < 9 to obtain konjac gel.

[0064] Example 2: Konjac Gel

[0065] The konjac gel comprises 35 kg of konjac flour, 2.5 kg of pea fiber, 5 kg of spinach powder, 0.25 kg of chlorella protein, and 900 kg of water. Its preparation method is as follows:

[0066] S1. After premixing pea fiber, chlorella protein, and spinach powder into powder, add 8 kg of water and stir at 10,000 rpm. The initial temperature of the stirring process is 20°C, and the temperature is heated to the final temperature of 60°C at a heating rate not exceeding 10°C / min, and held for 5 min to obtain a suspension.

[0067] S2. Add 90kg of water to konjac flour, control the temperature at 25℃, stir at a speed of <100 rpm for 2 minutes, then add the suspension and the remaining water (802kg) and continue stirring until the viscosity value is ≥10000mpa.s to obtain konjac colloid.

[0068] S3. Konjac colloid is extruded into a Ca(OH)2 solution at 90℃ and pH 12 to obtain crude konjac gel. Then, it is soaked in a citric acid solution at 20℃ and pH 4 for 15 minutes, and then rinsed with water until the pH of the water is < 9 to obtain konjac gel.

[0069] Example 3: Konjac Gel

[0070] The konjac gel comprises 45 kg of konjac flour, 3.5 kg of pea fiber, 6 kg of spinach powder, 0.3 kg of chlorella protein, and 1200 kg of water. Its preparation method is as follows:

[0071] S1. After premixing pea fiber, chlorella protein, and spinach powder into powder, add 12kg of water and stir at 11000 rpm. The initial temperature during the stirring process is 30℃. Heat to the final temperature of 60℃ at a heating rate not exceeding 10℃ / min and hold for 5min to obtain a suspension.

[0072] S2. Add 110 kg of water to the konjac flour, control the temperature at 30℃, stir at a speed of <100 rpm for 2 min, then add the suspension and the remaining water (878 kg) and continue stirring until the viscosity value is ≥10000 mpa.s to obtain konjac colloid.

[0073] S3. Konjac colloid is extruded into a Ca(OH)2 solution at 100℃ and pH 12 to obtain crude konjac gel. Then, it is soaked in a citric acid solution at 30℃ and pH 4 for 30 minutes, and then rinsed with water until the pH of the water is < 9 to obtain konjac gel.

[0074] The konjac gels obtained in Examples 1-3 above were soaked in a Ca(OH)2 solution with a pH of 11±0.5, sealed and packaged, and then pasteurized and stored at room temperature.

[0075] Comparative Example 1: Konjac Gel

[0076] The formula and preparation method are the same as in Example 1. Compared with Example 1, Comparative Example 1 does not add pea fiber and chlorella protein.

[0077] Comparative Example 2: Konjac Gel

[0078] The formula and preparation method are the same as in Example 1. Compared with Example 1, Comparative Example 2 does not add pea fiber.

[0079] Comparative Example 3: Konjac Gel

[0080] Its formula and preparation method are the same as in Example 1. Compared with Example 1, Comparative Example 3 does not add Chlorella protein.

[0081] Comparative Example 4: Konjac Gel

[0082] The formula and preparation method are the same as in Example 1. Compared with Example 1, in Comparative Example 4, the chlorella protein is replaced with pea protein.

[0083] Comparative Example 5: Konjac Gel

[0084] The formulation and preparation method are the same as in Example 1. Compared with Example 1, Comparative Example 5 replaces Chlorella protein with Micrococcus pseudomicrococcus protein.

[0085] Comparative Example 6: Konjac Gel

[0086] The formula and preparation method are the same as in Example 1. Compared with Example 1, Comparative Example 6 replaces pea fiber with potato fiber.

[0087] Comparative ratio 7: Spinach spaghetti (cooked)

[0088] Made with durum wheat flour and spinach flour (15‰ by mass), boiled in boiling water for 6.5 minutes, 25cm (±1cm) in length and 4mm in diameter.

[0089] Comparative ratio 8: Spinach spaghetti (cooked)

[0090] Made with durum wheat flour and spinach flour (15‰ by mass), boiled in boiling water for 8 minutes, the length after boiling is 25cm (±1cm) and the diameter is about 4mm.

[0091] Experiment Example 1: Sensory Testing

[0092] Experimental Methods: The hardness and elasticity of the konjac gels prepared in Examples 1-3 and Comparative Examples 1-7 were tested according to ISO 7304-2:2008, the International Organization for Standardization's sensory analysis method for pasta. Sensory tests were conducted independently by six trained evaluators. Since Examples 1-3 and Comparative Examples 1-6 contained no starch, the starch release test was deemed inapplicable. The evaluation criteria are as follows:

[0093] Table 1: Sensory Analysis Scoring Criteria for Pasta

[0094] .

[0095] Experimental results: See Table 2 (mean).

[0096] .

[0097] Results Analysis: Examples 1, 2, and 3 are all close to the simulated objects (Comparative Examples 7 and 8), and are derived from... Figure 1 (A comparison of the actual images of the simulated spinach pasta (A) from Example 1 and the cooked spinach pasta (B) from Comparative Example 7 shows that the visible texture of Example 1 is similar to that of Comparative Example 7, proving that, from a visually perceptible perspective, Example 1 is closer to the simulated object.) Furthermore, due to the structural characteristics of konjac gel, its firmness is slightly higher than that of the simulated objects (Comparative Examples 7 and 8) under the same cooking conditions. The sensory test scores of Comparative Examples 1-6 are all lower than those of the simulated objects (Comparative Examples 7 and 8).

[0098] Experimental Example 2: Colorfastness Test

[0099] Test Methods: The color retention of the konjac gels prepared in Examples 1-3 and Comparative Examples 1-6 was determined by sensory analysis. Referring to the method under item 2 of GB / T 10786-2006, "Test Methods for Canned Foods," an initial photograph of the packaged product was displayed on a calibrated monitor as an initial reference (scored as 10 points), and the evaluation was conducted with reference to a standard color chart. The tests were independently scored by six trained evaluators, and the evaluation criteria are as follows:

[0100] Table 3: Scoring Standards for Color Value Testing

[0101] .

[0102] Color retention = (Color value at test / Initial value after packaging) * 100%

[0103] Experimental results: See Table 4 (mean %)

[0104] .

[0105] Results analysis: Examples 1, 2, and 3 all achieved a color retention decrease of <20%, while Comparative Examples 1-6 showed significant deterioration.

[0106] Test Example 3: Water Holding Capacity Test

[0107] Test method: The packaged konjac gels prepared in Examples 1-3 and Comparative Examples 1-7 were placed at room temperature, and the test method was performed in accordance with 4.2.2.1 of GB / T 10786-2006 Test Methods for Canned Foods.

[0108] Water retention capacity = (Mass fraction of solids at test / Initial mass fraction of solids after packaging) * 100%

[0109] Experimental results: See Table 5 (mean %)

[0110] .

[0111] Results analysis: Examples 1, 2, and 3 all achieved a color retention decrease of <10%, while Comparative Examples 1-6 showed significant deterioration.

[0112] Experimental Example 4. Gel Structure Analysis

[0113] This experimental example uses electron microscopy to scan the simulated spinach pasta prepared in Example 1 (containing only konjac gel and spinach powder) from Comparative Example 1, and obtains... Figures 2-5(These are surface scanning electron microscope (SEM) images of Example 1, Comparative Example 1, cross-sectional SEM images of Example 1 and Comparative Example 1, respectively); The infrared absorption spectra of the lyophilized pasta gels of Example 1 and Comparative Example 1 were compared, and the comparison results are as follows: Figure 6 (Infrared absorption spectrum of the gel freeze-dried sample) is shown.

[0114] Results Analysis: Comparing the microstructure of gluten-free pasta made from rice and legumes (containing soybean and starch components) in Fig. 3 and Fig. 4 of Reference A (Abdallah Bouasla, Agnieszka Wójtowicz, Mohammed Nasereddine Zidoune, Gluten-free precooked rice pasta enriched with legumesflours: Physical properties, texture, sensory attributes and microstructure[J], LWT, Volume 75, 2017, Pages 569-577 https: / / doi.org / 10.1016 / j.lwt.2016.10.005.), it can be seen that the surface structure of the konjac gel (mimicking spinach pasta) constructed in Example 1 is different from that of the gluten-free pasta. Figure 2 AC), Example 1 has a dense surface structure but with small rib-like structures, and no porous structure on the surface. The spinach particles are completely encapsulated in the gel structure, and there are no exposed spinach particles on the gel surface, while in Comparative Example 1 ( Figure 3 The surface of AC gel contains fewer rib-like structures, larger protrusions, and spinach particles that are not fully embedded on the gel surface. Figure 2 C). Cross-sectional structure of konjac gel constructed in Example 1 ( Figure 4 AC) is also consistent with Comparative Example 1 ( Figure 5 Unlike document A, Example 1 presents a continuous, orderly, large-scale mesh structure, achieving a mimicry of pasta with lower material and heat density, while the spinach particles are encased in a membrane structure. Figure 4 B), while Comparative Example 1 ( Figure 5 In the AC sample, the cross-sectional structure is irregular, and unencapsulated spinach particles are visible. This indicates that the mimicry pasta prepared by the compound of several components in this application has a better encapsulation effect on spinach particles, and the resulting gel is more stable, thus exhibiting better water retention and color retention, which remain stable over a longer storage period. Furthermore, according to... Figure 5A comparison of the infrared absorption spectra of Example 1 and Comparative Example 1 shows that the CO bending vibration of the alcohol hydroxyl group CH-OH is different, indicating that their chemical structures are also different.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spinach-mimicking pasta based on konjac gel, characterized in that, The raw materials consist of 35-45 parts by weight of konjac flour, 2.5-5 parts by weight of pea fiber, 5-7.5 parts by weight of spinach powder, 0.25-0.75 parts by weight of chlorella protein, and 900-1200 parts by weight of water. After premixing pea fiber, chlorella protein, and spinach powder into powder, add the first part by weight of water, gradually increase the temperature and stir at high speed to obtain a suspension. Add a second part by weight of water to konjac flour and stir at a constant temperature and low speed. Then add the suspension and a third part by weight of water and continue stirring until the viscosity value is ≥10000 mpa.s to obtain konjac colloid. Konjac colloid was extruded into a Ca(OH)2 solution to obtain a long, thin stick-shaped konjac gel, which was then soaked in citric acid solution and rinsed with water to obtain a mimicked spinach pasta. The stirring rate of the gradual heating and high-speed stirring is ≥10000 rpm, the initial temperature is 20-30℃, the final temperature is 60℃, the heating rate is ≤10℃ / min, and stirring is continued for 5min after the final temperature is reached. The constant temperature low-speed stirring is 20-30℃, the stirring rate is <100 rpm, and the stirring time is 2 min; The sum of the first part by weight of water, the second part by weight of water, and the third part by weight of water is the total part by weight of water, wherein the first part by weight of water is 8-12 parts by weight, the second part by weight of water is 90-110 parts by weight, and the remainder is the third part by weight of water.

2. A method for preparing mimicking spinach pasta, characterized in that, Includes the following steps: The raw materials consist of 35-45 parts by weight of konjac flour, 2.5-5 parts by weight of pea fiber, 5-7.5 parts by weight of spinach powder, 0.25-0.75 parts by weight of chlorella protein, and 900-1200 parts by weight of water. After premixing pea fiber, chlorella protein, and spinach powder into powder, add the first part by weight of water, gradually increase the temperature and stir at high speed to obtain a suspension. Add a second part by weight of water to konjac flour and stir at a constant temperature and low speed. Then add the suspension and a third part by weight of water and continue stirring until the viscosity value is ≥10000 mpa.s to obtain konjac colloid. Konjac colloid was extruded into a Ca(OH)2 solution to obtain a long, thin stick-shaped konjac gel, which was then soaked in citric acid solution and rinsed with water to obtain a mimicked spinach pasta. The stirring rate of the gradual heating and high-speed stirring is ≥10000 rpm, the initial temperature is 20-30℃, the final temperature is 60℃, the heating rate is ≤10℃ / min, and stirring is continued for 5min after the final temperature is reached. The constant temperature low-speed stirring is 20-30℃, the stirring rate is <100 rpm, and the stirring time is 2 min; The sum of the first part by weight of water, the second part by weight of water, and the third part by weight of water is the total part by weight of water, wherein the first part by weight of water is 8-12 parts by weight, the second part by weight of water is 90-110 parts by weight, and the remainder is the third part by weight of water.

3. The preparation method according to claim 2, characterized in that, The temperature of the Ca(OH)2 solution is 90-100℃.

4. The preparation method according to claim 2, characterized in that, The mimicking spinach pasta is packaged by soaking in Ca(OH)2 aqueous solution.

5. The preparation method according to claim 2, characterized in that, The extrusion process involves pressing the material into different shapes using different molds.

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