Special flour for rice noodles with low GI value, rice noodles, preparation method and application

Abstract

The invention belongs to the technical field of rice food processing, and particularly relates to low-GI-value special flour for rice noodles, the rice noodles, a preparation method and application, the low-GI-value special flour for the rice noodles comprises rice flour and dry particles of ampelopsis grossedentata extract, and the low-GI-value special flour for the rice noodles is low in cooking loss rate and breaking rate, low in GI value, moderate in elastic coefficient, soft in taste, moderate in viscoelasticity, good in toughness and capable of being used for preparing the rice noodles. And the rehydration time of the rice noodles is within 3 minutes, so that the rice noodles can be quickly cooked, and the quality is relatively high.

Description

Technical Field

[0001] The invention belongs to the technical field of rice-based food processing, and in particular relates to special rice noodle flour with a low GI value, rice noodles, a preparation method and uses. Background Art

[0002] Rice noodles, also known as rice noodles or rice vermicelli, are a staple food and a snack in the south. They are a rice-based food with a long history. There are many types of rice noodles, including Yunnan cross-bridge rice noodles, Guangxi Guilin rice noodles, Hunan Hengyang rice noodles, etc.

[0003] Study on the effect of some rice products on blood sugar in Yunnan, Jiang Murong et al., Journal of Kunming Medical University 2023, 44 (12): 41-45, disclosed the glycemic index of a variety of rice-based foods: rice noodle, rice block, rice noodle roll, rice noodle with sour sauce, and rice noodle with dry paste. The measured GI value of rice noodle was 63, the GI value of rice block was 64, the GI value of rice noodle roll was 46, the GI value of rice noodle with sour sauce was 38, and the GI value of rice noodle with dry paste was 33. Foods with high GI values ​​are digested and absorbed quickly by the human body, causing a rapid increase in blood sugar after a meal and a large fluctuation in insulin; while foods with low GI values ​​have a small effect on postprandial blood sugar and insulin fluctuations due to slow digestion and absorption. The size of the GI value is an important aspect of dietary guidance for diabetic patients. As starchy foods, rice noodles and rice vermicelli generally have a high GI value, which has become an important consideration for diabetic patients to choose rice noodles and rice vermicelli foods.

[0004] The quality of rice noodles is also affected by the cooking loss rate, breakage rate, elasticity coefficient, rehydration time, etc.

[0005] The cooking loss rate affects the taste of rice noodles. Generally, a low loss rate (≤5%) indicates that the rice noodles have a dense structure, strong cooking resistance, and a smooth and elastic taste. Reference: Li, H., Zhang, Y., & Wang, L. (2021). Effects of rice varieties on cooking characteristics of rice noodles. Food Chemistry, 356(3), 129678. DOI:10.1016 / j.foodchem.2021.129678.

[0006] The breakage rate is related to the taste and production cost. A low breakage rate (<8%) reflects that the rice noodles have strong resistance to mechanical damage and good toughness. Reference: Wang, T., Liu, X., Chen, J., & Li, M. (2022). Effects of starch blending on noodle breakage: A study of mechanical and structural properties. Journal of Cereal Science, 104, 103421. DOI:10.1016 / j.jcs.2022.103421.

[0007] A high elastic coefficient (>70%) indicates a good chewing feel and is a core indicator of high-quality rice noodles. Insufficient elasticity may be related to insufficient aging time or improper moisture control. Reference: Chen, Z.‌, Wu, Q.,&Huang, F. (2020).Aging time optimization for rice noodles: Texture and microstructureanalysis. Food Hydrocolloids, 108, 106512. DOI:10.1016 / j.foodhyd.2020.106512.

[0008] Rehydration too quickly may lead to a loose structure, while rehydration too slowly affects the eating experience. A short rehydration time (3-5 minutes) is more in line with the needs of rice noodles, but it needs to be balanced with the taste. Reference: Zhang, M., Zhou, R., & Li, X. (2023). Effects of drying methods on rehydration properties of rice noodles. LWT-Food Science and Technology, 185, 115203. DOI: 10.1016 / j.lwt.2023.115203.

[0009] China's national standard GB / T 23587-2009 Rice Vermicelli stipulates that the cooking loss rate is ≤8% and the breakage rate is ≤10%. Summary of the invention

[0010] The technical problem to be solved by the invention is to provide a special rice noodle flour with low GI value, rice noodle, preparation method and use, and the obtained rice noodle has low GI value and high quality.

[0011] The embodiment of the present invention provides a special rice noodle flour with a low GI value, comprising rice flour and dry particles of rattan tea extract.

[0012] In one embodiment, the low GI rice noodle flour also includes corn starch.

[0013] In one embodiment, the weight percentage of the dry particles of the rattan tea extract is 5-9%. Preferably, the weight percentage of the dry particles of the rattan tea extract is 5-15%.

[0014] In one of the embodiments, the preparation method of the rattan tea extract is to extract the rattan tea with an ethanol-water solution to obtain the rattan tea extract.

[0015] In one embodiment, the volume concentration of the ethanol aqueous solution is 30-50%, the extraction time is 12-36h, and the extraction temperature is 60-90° C. Preferably, the volume concentration of the ethanol aqueous solution is 40%, the extraction time is 24h, and the extraction temperature is 75° C.

[0016] In one embodiment, the preparation method of the rice noodles is to soak rice, dehydrate, dry and grind rice to obtain powder.

[0017] In one embodiment, the rice is early indica rice with an amylose content of 24-26%, the soaking time is 3-4 hours, and the pH value of the water during the soaking is 6-7.

[0018] The embodiment of the present invention provides a method for preparing the special rice noodle flour with a low GI value, comprising mixing rice flour and dry particles of rattan tea extract, stirring evenly, and filtering to obtain the special rice noodle flour.

[0019] The embodiment of the present invention provides a rice noodle, which is prepared by using the special rice noodle flour with a low GI value.

[0020] The embodiment of the present invention provides an application of rattan tea for preparing special rice noodle flour with low GI value.

[0021] The beneficial effect of the present invention is that the present invention first extracts effective substances such as dihydromyricetin, flavonoid compounds, etc. in rattan tea, and adopts advanced freeze-drying technology to obtain dry particles of rattan tea extract, and then compound them with special rice flour. While maintaining the high taste value of rice noodles, the present invention has the ability to flexibly adjust the nutrients of the compound formula.

[0022] The special rice noodle flour of the invention has low cooking loss rate and breaking rate, low GI value, moderate elasticity coefficient, soft taste, moderate viscoelasticity and good toughness. The rice noodle rehydration time is within 3 minutes, the rice noodle can be quickly cooked and has high quality. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0024] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0025] Example 1 The formula of the low GI rice noodle powder in this embodiment is: 5.6% of rattan tea extract freeze-dried powder, 84.4% of rice powder, and 10% of corn starch; The specific preparation steps of the special rice noodle flour in the present embodiment are: Step 1: Cleaning of raw grains: Flat rotary screen. Flat rotary screen has two layers of cleaning. The first layer: screens out debris with a diameter larger than rice. The second layer screens out rice ash and rice bran with an aperture less than 1.0MM, and retains the rice for the next process.

[0026] Step 2: Color sorting of raw grains: All the rice obtained in step 1 is passed through a color sorter to sort out impurities, yellow rice, and diseased rice. The parameter setting range of the color sorter is: 25%-35% for selecting different colors, 30%-40% for selecting diseased spots, and 30% for selecting glass (infrared parameters). Adjust the parameters according to the actual situation of the raw grains.

[0027] Step 3: The rice elevator and scraper obtained in step 2 are transported to the rice soaking tank, and the air pipe and water pipe are connected to the rice soaking tank. The air flow is used to stir the water flow to drive the rice to turn over in the tank, so as to achieve the effect of cleaning dust, bran powder and other foreign matters on the surface of the rice. The floating foreign matters overflow from the edge of the rice soaking tank with the water flow.

[0028] Step 4: Place 50.00 kg of the rice obtained in step 3 in a rice soaking tank with a pH value of 6.4 and soak for 3 hours. Open the drain valve at the bottom to drain the soaking water, and obtain loose rice with a moisture content of about 36%.

[0029] Step 5: Open the pneumatic gate at the bottom of the rice soaking tank, open the conveyor belt at the bottom of the gate, and move the rice obtained in step 4 through the conveyor belt to achieve uniform discharge of the rice soaking tank, and control the speed of the rice discharge by controlling the conveyor belt speed. The rice is transported to the vibrating screen through the conveyor belt to remove excess moisture on the surface of the rice, and obtain rice with a moisture content of about 32%.

[0030] Step 6: The rice obtained in step 5 is naturally dropped into the feed port of the grinding mill through the flow pipe under the influence of gravity for grinding. The material in the grinding mill is transported into the hopper by negative pressure. At this time, the moisture content of the material is about 26%.

[0031] Step 7: The rice obtained in step 6 is crushed by a cross bar and conveyed by an auger into an airflow drying system, and the moisture content of the material is reduced to below 14%, thereby obtaining special rice flour.

[0032] Step 8: Rice flour, corn starch and freeze-dried powder of rattan tea extract are mixed and passed through the first-level inspection sieve (100-mesh sieve). The unscreened materials enter the by-product bucket below the inspection sieve, and the qualified products are blown into the finished product bucket by the Roots blower to obtain rice noodle flour with low GI value.

[0033] The preparation method of the rattan tea extract freeze-dried powder is as follows: Step 1: Choose fresh young leaves of rattan tea (processed within 24 hours after picking) to avoid browning and loss of active ingredients.

[0034] Step 2: Rinse with running water to remove impurities and drain.

[0035] Step 3: Steam treatment at 105-110℃ for 3-5 minutes (to destroy oxidase activity, prevent browning, and retain flavonoids).

[0036] Step 4: Solvent extraction.

[0037] Solvent ratio: 70% ethanol solution (volume ratio), material-liquid ratio 1:15-20 (vine tea: solvent).

[0038] Extraction conditions: 60°C water bath reflux extraction twice, each time for 1.5 hours.

[0039] Step 5: Filtration and concentration.

[0040] The extracts were combined, coarsely filtered through gauze, and then finely filtered through a 0.45 μm microporous membrane.

[0041] Vacuum concentrate (50℃, -0.08MPa) to an extract with a relative density of 1.10-1.15.

[0042] Step 6: Pour the extract into freeze-drying trays with a thickness of ≤1cm.

[0043] Pre-freezing: Quick freezing at -40℃ for 4 hours to ensure complete crystallization.

[0044] Step 7: Freeze drying.

[0045] Parameter settings: cold trap temperature: -55℃, vacuum degree: 10-30Pa.

[0046] Heating program: The first stage: -40℃→-20℃ (6 hours, sublimation drying); The second stage: -20℃→25℃ (8 hours, analytical drying); End point judgment: material moisture content ≤ 5% (mass fraction).

[0047] The moisture content of the finished product is 13.8% and the broken starch content is 5.0%.

[0048] Preparation steps of rice noodles (the following examples and comparative examples adopt the same rice noodle preparation method, which will not be repeated): The low GI rice noodle flour is mixed with water to form a dough (0.8:1); the flour is put into an extruder for extrusion gelatinization to produce threads, the extrusion gelatinization temperature is 80-90°C, the extrusion molding temperature is 50-60°C; the flour is aged at high temperature to form rice noodles, the aging temperature is 50-60°C, and the aging time is 1-2h; and the rice noodles are obtained.

[0049] The rice noodles of the present embodiment have uniform color after cooking, no variegated color, clear soup, pure aroma, strong smell, no peculiar smell, pure taste, strong taste, no peculiar smell, soft mouthfeel, moderate viscoelasticity, good toughness, and a sensory evaluation value of 38 points.

[0050] The cooking loss rate was 3.55%, the breaking rate was 2.8%, the elastic coefficient was 45%, and the rehydration time of rice noodles was 1 min 20 s; the GI value was 32.7 when tested by glucose oxidase method.

[0051] Example 2 The formula of the low GI value rice noodle flour in this embodiment is: 9% lyophilized powder of rattan tea extract, 81% rice flour, and 10% corn starch; the specific steps of preparing the rice flour in this embodiment are: The methods of step 1 to step 8 are the same as those in Example 1; The moisture content of the finished product is 13.9% and the broken starch rate is 4.9%.

[0052] The rice noodles prepared with the special rice noodle flour obtained in this embodiment have uniform color after cooking, no mixed colors, clear soup, pure aroma, strong smell, no peculiar smell, pure taste, strong taste, no peculiar smell, soft mouthfeel, moderate viscoelasticity, good toughness, and a sensory evaluation value of 42 points.

[0053] The cooking loss rate was 2.15%, the breakage rate was 2.2%, the elastic coefficient was 48%, and the rehydration time of rice noodles was 1 min 30 s; the GI value was 30.5 when tested by glucose oxidase method.

[0054] Comparative Example 1 The formula of the special flour for rice noodles in this comparative example 1 is: 90% of special flour for rice and 10% of corn starch.

[0055] The specific steps of preparing the special rice noodle flour in the present embodiment are as follows: Steps 1 to 7 are the same as those in Example 1.

[0056] Step 8: Rice flour and corn starch are mixed and passed through the first-level inspection screen (100-mesh screen). The unscreened materials enter the by-product bucket below the inspection screen, and the qualified products are blown into the finished product bucket by the Roots blower to obtain rice noodle flour.

[0057] The moisture content of the finished product is 13.7% and the broken starch content is 5.1%.

[0058] The rice noodles prepared with the special rice noodle flour obtained in this embodiment have uniform color after cooking, no variegated color, clear soup, pure aroma, strong smell, no peculiar smell, pure taste, strong taste, no peculiar smell, soft mouthfeel, moderate viscoelasticity, good toughness, and a sensory evaluation value of 35 points.

[0059] The cooking loss rate was 4.10%, the breakage rate was 8.3%, the elastic coefficient was 40%, the rehydration time of rice noodles was 1 min 56 s, and the GI value was 64.7 when tested by glucose oxidase method.

[0060] Comparative Example 2 The formula of the special rice noodle flour in this comparative example 2 is: 9% of lyophilized powder extracted from Kudingcha tea, 81% of special rice flour, and 10% of corn starch.

[0061] The specific steps for preparing the special rice noodle flour in this comparative example 2 are as follows: Steps 1 to 7 are the same as those in Example 1.

[0062] Step 8: Rice flour, corn starch and Kudingcha extract freeze-dried powder are mixed and passed through the first-level inspection sieve (100-mesh sieve). The unscreened materials enter the by-product bucket below the inspection sieve, and the qualified products are blown into the finished product bucket by the Roots blower to obtain rice noodle flour.

[0063] The preparation method of the Kudingcha tea extract freeze-dried powder is the same as the preparation method of the rattan tea extract freeze-dried powder in Example 1, except that the rattan tea is replaced by Kudingcha tea.

[0064] The moisture content of the finished product is 13.8% and the broken starch rate is 4.7%.

[0065] The rice noodles prepared with the special rice noodle flour obtained in this embodiment have uniform color after cooking, no variegated color, clear soup, pure aroma, strong smell, no peculiar smell, pure taste, strong taste, no peculiar smell, soft mouthfeel, moderate viscoelasticity, good toughness, and a sensory evaluation value of 30 points.

[0066] The cooking loss rate was 4.10%, the breakage rate was 7.2%, the elastic coefficient was 40%, the rehydration time of rice noodles was 1 min 50 s, and the GI value was 67.5 when tested by glucose oxidase method.

[0067] Comparative Example 3 The formula of the special rice noodle flour in this comparative example 3 is: 9% of Longjing green tea extract freeze-dried powder, 81% of rice special flour, and 10% of corn starch.

[0068] The specific steps for preparing the special rice noodle flour in this comparative example 3 are as follows: Steps 1 to 7 are the same as those in Example 1.

[0069] Step 8: Rice flour, corn starch and Longjing green tea extract freeze-dried powder are mixed and passed through the first-level inspection sieve (100-mesh sieve). The unscreened materials enter the by-product bucket below the inspection sieve, and the qualified products are blown into the finished product bucket by the Roots blower to obtain rice noodle flour.

[0070] The preparation method of the Longjing green tea extract freeze-dried powder is the same as the preparation method of the rattan tea extract freeze-dried powder in Example 1, except that the rattan tea is replaced by Longjing green tea.

[0071] The moisture content of the finished product is 13.5% and the broken starch rate is 5.7%.

[0072] The rice noodles prepared with the special rice noodle flour obtained in this embodiment have uniform color after cooking, no variegated color, clear soup, pure aroma, strong smell, no peculiar smell, pure taste, strong taste, no peculiar smell, soft mouthfeel, moderate viscoelasticity, and good toughness.

[0073] The cooking loss rate was 4.25%, the breakage rate was 7.3%, the elastic coefficient was 40%, the rehydration time of rice noodles was 1 min 45 s, and the GI value was 66.7 when tested by glucose oxidase method.

[0074] In summary, it can be seen that the rice noodles prepared with the low GI value special rice noodle flour of the present invention have high taste value and excellent rice noodle performance parameters, and are significantly better than the rice noodles of the comparative example in terms of GI value.

[0075] The cooking loss rate of Example 1-2 is significantly lower than that of Comparative Example 1-3, which is 1-2% lower, an increase of about 50% year-on-year. The possible reason is that the extract of rattan tea is not easy to degrade and has lower solubility. It forms a complex with rice noodle amylose through hydrogen bonding, and the high-temperature dissolution is less.

[0076] The breaking rate of Example 1-2 is significantly lower than that of Comparative Example 1-3. The possible reason is that the rattan tea extract-starch complex can better enhance the gel structure of rice noodles and reduce the breakage caused by water penetration during cooking. The ORAC value of rattan tea is 20% higher than that of green tea, and it has better efficiency in inhibiting lipid oxidation and can effectively maintain the integrity of starch granules.

[0077] The GI value of Example 1-2 is significantly lower than that of Comparative Example 1-3. The possible reason is that the complex formed by the vine tea extract and starch can resist the decomposition of α-amylase and reduce the hydrolysis rate. The vine tea extract binds to the active site of α-amylase through hydrogen bonds, inhibiting its catalytic efficiency.

[0078] The specific scheme for determining the rehydration breaking rate of rice noodles in the above-mentioned embodiments and comparative examples is as follows: Take 30 10 cm long rice noodles without mechanical damage, put them into an electric cooker filled with 1 L of boiling water, heat and steam them, and take out the rice noodles after steaming according to the optimal steaming time (90 s), and record the total number of rice noodles.

[0079]

[0080] In the formula: D is the breaking rate (%); N is the total number of rice noodles cooked according to the optimal steaming time.

[0081] The specific implementation scheme of the cooking loss determination in the following examples and comparative examples is as follows: Weigh M1 of rice noodles, steam and remove them according to the method for determining the breakage rate, rinse them repeatedly with 100 mL of distilled water for 5 times, then put them into an aluminum box and dry them in an oven at 105°C until they reach a constant weight, weigh M2, and calculate the cooking loss of the rice noodles.

[0082]

[0083] Where: L—cooking loss (%); M1—the mass of rice noodles before cooking (g); M2—the mass of rice noodles after cooking according to the optimal cooking time (g); w —Water content of rice noodles (%).

[0084] The specific implementation scheme of the sensory evaluation determination of rice noodles in the above examples and comparative examples is as follows: The sensory evaluation was conducted by five people, and the color, aroma, flavor, and mouthfeel were analyzed. The sensory evaluation criteria are shown in Table 1.

[0085] Table 1 Sensory evaluation table for rice noodles (full score for each item is 10 points)

[0086] The specific test method for the rehydration time in the above embodiment is: Take 30 10 cm long rice noodles without mechanical damage, add them to an electric cooker filled with 1L boiling water, heat and cook, and immediately use a stopwatch to time. Observe the softening state of the rice noodles. When the rice noodles are clamped with double-sided glass and no obvious hard core is felt, stop the watch again. The time taken is the rehydration time.

[0087] The formula for calculating rice flour yield is:

[0088] Where: w is the yield of rice flour (%); M1 is the mass of rice raw material (g); M2 is the mass of the obtained rice flour.

[0089] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0090] One or more embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A low GI rice noodle flour, characterized in that: The dry granules include rice powder and rattan tea extract.

2. The special rice noodle flour as claimed in claim 1, characterized in that: Also includes corn starch.

3. The special rice noodle flour as claimed in claim 2, characterized in that: The weight percentage of the dry particles of the rattan tea extract is 5-9%.

4. The special rice noodle flour as claimed in claim 3, characterized in that: The weight percentage of the dry particles of the rattan tea extract is 5-15%.

5. The special rice noodle flour as claimed in claim 1, characterized in that: The preparation method of the rattan tea extract is to extract the rattan tea with an ethanol aqueous solution to obtain the rattan tea extract.

6. The special rice noodle flour as claimed in claim 5, characterized in that: The volume concentration of the ethanol aqueous solution is 30-50%, the extraction time is 12-36 hours, and the extraction temperature is 60-90°C.

7. The special rice noodle flour according to any one of claims 1 to 6, characterized in that: The preparation method of the rice noodles comprises the steps of soaking rice, dehydrating, drying and grinding the rice to obtain powder.

8. A method for preparing a low GI rice noodle flour according to any one of claims 1 to 7, characterized in that: The rice flour and the dry particles of rattan tea extract are mixed, stirred evenly, and filtered to obtain the special rice noodle flour.

9. A rice noodle, characterized in that: The method is prepared by using the low GI rice noodle flour according to any one of claims 1 to 7.

10. An application of rattan tea, characterized in that: Used to prepare special rice noodle flour with low GI value.

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