A method for preparing compound quick-frozen rice noodles with good freeze-thaw stability

Abstract

This invention discloses a method for preparing compound quick-frozen rice noodles with good freeze-thaw stability. The method involves adding hydroxypropyl corn starch, guar gum, and a phosphate-containing compound salt. While retaining the original flavor and nutrients, it effectively improves the texture, elasticity, toughness, water retention, chewiness, and freeze-thaw stability of the quick-frozen rice noodles. This solves the problems of poor freeze-thaw stability caused by temperature fluctuations during transportation and storage, resulting in poor toughness, low chewiness, and poor rehydration. It forms a more stable starch structure, reduces the deterioration of rice noodle quality and the increase in cooking losses caused by ice crystal growth during quick-freezing, and extends the shelf life. This effectively solves the problem of short shelf life for rice noodles. The resulting product has a delicate texture, stable quality, and good rehydration. It also avoids the complicated steps of adding cooked batter in traditional rice noodle making, making the rehydration method simple and quick.

Description

Technical fields:

[0001] This invention relates to the field of food processing technology, specifically to a method for preparing compound quick-frozen rice noodles with good freeze-thaw stability. Background technology:

[0002] Kway teow is a traditional delicacy from the Chaoshan region of Guangdong. It is a gluten-free and hypoallergenic food made from rice. As a gluten-free food, it can be used to treat celiac disease patients with gluten sensitivity and aligns with modern healthy eating habits. Currently, most commercially available pre-made kway teow is quick-frozen, with fresh and dried versions being less common. Compared to fresh and dried kway teow, quick-frozen kway teow retains its original flavor and quality to the greatest extent, effectively extending its shelf life. It is also convenient and quick to reheat and eat. However, quick-freezing requires high refrigeration temperatures, and temperature fluctuations during transportation, storage, and placement in supermarkets and homes can easily lead to poor freeze-thaw stability. Currently, commercially available quick-frozen kway teow is prone to poor elasticity, low chewiness, and poor rehydration after rehydration due to these temperature changes, resulting in consumer rejection. This has become a major challenge in the production of quick-frozen kway teow. Summary of the Invention:

[0003] The purpose of this invention is to provide a method for preparing compound quick-frozen rice noodles with good freeze-thaw stability, which solves the problems of poor freeze-thaw stability caused by temperature fluctuations during the transportation and storage of existing quick-frozen rice noodles, resulting in poor toughness, low chewiness, and poor rehydration.

[0004] This invention is achieved through the following technical solutions:

[0005] A method for preparing compound quick-frozen rice noodles with good freeze-thaw stability, the method using rice (Zhengui rice), hydroxypropyl corn starch, guar gum and phosphate-containing compound salt as raw materials, includes the following steps:

[0006] (1) Washing and soaking: Take rice, wash it with clean water and drain it, then soak it in clean water for 2-3 hours;

[0007] (2) Rice milk preparation: Soaked rice and water are poured into a cell wall breaking machine to obtain rice milk, and then 7-8% hydroxypropyl corn starch, 0.3-0.4% guar gum, and 0.2-0.3% phosphate-containing compound salt are added in sequence.

[0008] (3) Pour the batter and steam: Brush a thin layer of cooking oil on the steaming tray to prevent sticking, pour in the rice batter obtained in step (2), place it in a steamer and steam for 120-180 seconds until the rice noodles on the steaming tray are slightly bubbly.

[0009] (4) Cooling and slicing: After the steaming tray is removed and cooled to room temperature, place it at 0-4℃ for 3-4 hours and cut into strips 2mm wide and 20cm long;

[0010] (5) Quick-freezing storage: Pack the cut rice noodles in vacuum packaging, quick-freeze at -40℃ for half an hour, and then store at -20℃ to obtain quick-frozen rice noodles.

[0011] When using, take out the frozen rice noodles without thawing, put them into boiling water and cook for about 90 seconds before taking them out.

[0012] In step (2), the amounts of hydroxypropyl corn starch, guar gum, and phosphate-containing compound salt added are based on the dry weight of rice, and the wet weights of the three are 5.6%, 4.95%, and 3.75%, respectively.

[0013] Preferably, the weight of the water added in step (2) is 1.8-2 times the total weight of the rice, hydroxypropyl corn starch, guar gum, and phosphate-containing compound salt.

[0014] In step (2), the hydroxypropyl corn starch, guar gum and phosphate-containing complex salt are added sequentially while stirring, one at a time, until the other is fully stirred before adding the next.

[0015] Preferably, based on a total mass percentage of 100%, the phosphate-containing complex salt contains 20% sodium tripolyphosphate, 30% sodium pyrophosphate, 20% sodium hexametaphosphate, 10% sodium dihydrogen phosphate, 10% sodium carbonate, and 10% sodium chloride.

[0016] The amount of rice batter added in step (3) depends on the size of the steaming pan. For a steaming pan with a length × width × height of 23cm × 15cm × 1.5cm, the amount of batter poured is 165-175ml, which can produce rice noodles with a thickness of 1.5-2.5mm.

[0017] The oil used in step (3) is edible cooking peanut oil.

[0018] Significant advantages of this invention:

[0019] 1) This invention adds hydroxypropyl corn starch, guar gum, and phosphate-containing compound salts, which effectively improves the taste while retaining the original flavor and nutrients. It enhances the elasticity, toughness, water retention, chewiness, and freeze-thaw stability of the frozen rice noodles. It solves the problems of poor freeze-thaw stability caused by temperature fluctuations during the transportation and storage of frozen rice noodles in the prior art, resulting in poor toughness, low chewiness, and poor rehydration. It forms a more stable starch structure, reduces the deterioration of rice noodle quality and the increase in cooking losses caused by ice crystal growth during the quick-freezing process, and extends the shelf life. It effectively solves the problem of short shelf life of rice noodles. The resulting product has a delicate taste, stable product quality, and good rehydration. It also avoids the complicated steps of adding cooked batter in traditional rice noodles, and the rehydration method is simple and quick.

[0020] 2) The quick-frozen rice noodles prepared by this invention are different from those on the market that contain gluten additives. They can be used to treat celiac disease patients who are sensitive to gluten, and are also suitable for children, pregnant women, the elderly, and postoperative patients with weak digestive abilities.

[0021] 3) The preparation process of this invention is simple, involves fewer steps, and has low raw material costs, making it suitable for industrial production. Attached image description:

[0022] Figure 1 This is a graph showing the textural changes of quick-frozen rice noodles under freeze-thaw cycles in Embodiment 1 and Comparative Examples 1-4 of the present invention, where a), b) and c) represent comparison graphs of elasticity, hardness and chewiness, respectively.

[0023] Figure 2 This is a graph showing the changes in cooking characteristics of quick-frozen rice noodles under freeze-thaw cycles in Embodiment 1 and Comparative Examples 1-4 of the present invention, where a), b) and c) represent comparison graphs of water absorption rate, cooking loss and breakage rate, respectively.

[0024] Figure 3 This is a graph showing the change in the freezeable water content of quick-frozen rice noodles under freeze-thaw cycles in Embodiment 1 and Comparative Examples 1-4 of the present invention.

[0025] Figure 4 This is a graph showing the change in moisture state of quick-frozen rice noodles under freeze-thaw cycles in Embodiment 1(e) and Comparative Examples 1(a), 2(b), 3(c), and 4(d) of the present invention.

[0026] Figure 5 These are scanning electron microscope images of quick-frozen rice noodles under freeze-thaw cycles of Embodiment 1(e) and Comparative Examples 1(a), 2(b), 3(c), and 4(d) of the present invention. Detailed implementation method:

[0027] The following is a further description of the invention, but not a limitation thereof.

[0028] Example 1: A method for preparing compound quick-frozen rice noodles with good freeze-thaw stability

[0029] (1) Washing and soaking: Take 75g of rice, wash it with clean water and drain it, then add 150g of clean water and soak for 2-3 hours;

[0030] (2) Rice milk preparation: Pour the soaked rice and water into a cell wall breaking machine to obtain rice milk, and then add 7.91% hydroxypropyl corn starch by weight of rice, 0.37% guar gum by weight of rice, and 0.23% phosphate-containing compound salt (20% sodium tripolyphosphate, 30% sodium pyrophosphate, 20% sodium hexametaphosphate, 10% sodium dihydrogen phosphate, 10% sodium carbonate, and 10% sodium chloride) by weight of rice.

[0031] (3) Pour the batter and steam: Brush a thin layer of cooking oil on the steaming tray (length × width × height is 23cm × 15cm × 1.5cm) to prevent sticking, pour in 170ml of the rice batter obtained in step (2), place it in a steamer and steam for 130s in boiling water until the rice noodles on the steaming tray are slightly bubbly.

[0032] (4) Cooling and slicing: After the steaming tray is removed and cooled to room temperature, place it at 4℃ for 3 hours and cut into strips 2mm wide and 20cm long;

[0033] (5) Quick-freezing storage: Pack the cut rice noodles in vacuum packaging, quick-freeze at -40℃ for half an hour, and then store at -20℃ to obtain quick-frozen rice noodles.

[0034] (6) Rehydration cooking: Take out the frozen rice noodles without thawing, put them into boiling water and cook for about 90 seconds before taking them out.

[0035] (7) Freeze-thaw cycle treatment: The product prepared in step (5) was stored at -20℃ for 22 hours and then thawed at 25℃ for 2 hours as part of the freeze-thaw cycle. The freeze-thaw cycle was repeated for 0, 1, 3, 5 and 7 times respectively, and the index was measured. Before the measurement, the product was rehydrated according to step (6) and then measured. The texture of the compound quick-frozen rice noodles was measured by sampling. The results are shown in [link to relevant documentation]. Figure 1 The changes in the cooking characteristics of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 2 The changes in the freezeable water content of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 3 The changes in moisture state of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 4 Scanning electron microscopy (SEM) images of the compound quick-frozen rice noodles after multiple freeze-thaw cycles were obtained. See attached images. Figure 5 .

[0036] Comparative Example 1:

[0037] Referring to Example 1, the difference is that step (2) does not add 7.91% hydroxypropyl corn starch, 0.37% guar gum and 0.23% phosphate-containing complex salt, but only rice.

[0038] Includes the following steps:

[0039] (1) Cleaning and soaking: Same as in Example 1.

[0040] (2) Rice milk preparation: Same as in Example 1.

[0041] (3) Pouring and steaming: Same as in Example 1.

[0042] (4) Cooling and slicing: Same as in Example 1.

[0043] (5) Quick-freezing storage: Same as in Example 1.

[0044] (6) Rehydration cooking: Same as Example 1.

[0045] (7) Freeze-thaw cycle treatment: Same as in Example 1; samples were taken and the texture of the compound quick-frozen rice noodles was measured, and the results are shown in [reference]. Figure 1 The changes in the cooking characteristics of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 2 The changes in the freezeable water content of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 3 The changes in moisture state of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 4 Scanning electron microscopy (SEM) images of the compound quick-frozen rice noodles after multiple freeze-thaw cycles were obtained. See attached images. Figure 5 .

[0046] Comparative Example 2:

[0047] Referring to Example 1, the difference is that step (2) does not contain 0.37% guar gum and 0.23% phosphate-containing complex salt, but only rice and 7.91% hydroxypropyl corn starch.

[0048] Includes the following steps:

[0049] (1) Cleaning and soaking: Same as in Example 1.

[0050] (2) Rice milk preparation: Same as in Example 1.

[0051] (3) Pouring and steaming: Same as in Example 1.

[0052] (4) Cooling and slicing: Same as in Example 1.

[0053] (5) Quick-freezing storage: Same as in Example 1.

[0054] (6) Rehydration cooking: Same as Example 1.

[0055] (7) Freeze-thaw cycle treatment: Same as in Example 1; samples were taken and the texture of the compound quick-frozen rice noodles was measured, and the results are shown in [reference]. Figure 1 The changes in the cooking characteristics of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 2 The changes in the freezeable water content of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 3 The changes in moisture state of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 4 Scanning electron microscopy (SEM) images of the compound quick-frozen rice noodles after multiple freeze-thaw cycles were obtained. See attached images. Figure 5 .

[0056] Comparative Example 3:

[0057] Referring to Example 1, the difference is that step (2) does not add 7.91% hydroxypropyl corn starch and 0.23% phosphate-containing complex salt, but only rice and 0.37% guar gum.

[0058] Includes the following steps:

[0059] (1) Cleaning and soaking: Same as in Example 1.

[0060] (2) Rice milk preparation: Same as in Example 1.

[0061] (3) Pouring and steaming: Same as in Example 1.

[0062] (4) Cooling and slicing: Same as in Example 1.

[0063] (5) Quick-freezing storage: Same as in Example 1.

[0064] (6) Rehydration cooking: Same as Example 1.

[0065] (7) Freeze-thaw cycle treatment: Same as in Example 1; samples were taken and the texture of the compound quick-frozen rice noodles was measured, and the results are shown in [reference]. Figure 1 The changes in the cooking characteristics of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 2 The changes in the freezeable water content of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 3 The changes in moisture state of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 4 Scanning electron microscopy (SEM) images of the compound quick-frozen rice noodles after multiple freeze-thaw cycles were obtained. See attached images. Figure 5 .

[0066] Comparative Example 4:

[0067] Referring to Example 1, the difference is that step (2) does not add 7.91% hydroxypropyl corn starch and 0.37% guar gum, but only rice and 0.23% phosphate-containing compound salt.

[0068] Includes the following steps:

[0069] (1) Cleaning and soaking: Same as in Example 1.

[0070] (2) Rice milk preparation: Same as in Example 1.

[0071] (3) Pouring and steaming: Same as in Example 1.

[0072] (4) Cooling and slicing: Same as in Example 1.

[0073] (5) Quick-freezing storage: Same as in Example 1.

[0074] (6) Rehydration cooking: Same as Example 1.

[0075] (7) Freeze-thaw cycle treatment: Same as in Example 1; samples were taken and the texture of the compound quick-frozen rice noodles was measured, and the results are shown in [reference]. Figure 1 The changes in the cooking characteristics of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 2 The changes in the freezeable water content of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 3 The changes in moisture state of compound quick-frozen rice noodles under multiple freeze-thaw cycles were measured. The results are shown in [reference needed]. Figure 4 Scanning electron microscopy (SEM) images of the compound quick-frozen rice noodles after multiple freeze-thaw cycles were obtained. See attached images. Figure 5 .

[0076] The freeze-thaw stability test results of Example 1 and Comparative Examples 1-4 of this invention are as follows:

[0077] The method for determining texture is referenced in the following literature (Yan Minghuan, He Jialiang, Wang Libo, et al. Effects of sweet buckwheat whole grain flour on the rheological properties of wheat dough and the quality of fresh wet noodles [J]. Food Science, 2024, 45(10)). Figure 1 Data a), b), and c) show that the elasticity, firmness, and chewiness of the frozen rice noodles made solely from rice decreased significantly after multiple freeze-thaw cycles, indicating that temperature fluctuations and ice crystal growth had the most severe impact on their texture. Comparative Examples 2, 3, and 4 showed some degree of inhibition of texture deterioration, with Example 1 exhibiting the most significant inhibitory effect. This indicates that the addition of 7.91% hydroxypropyl corn starch, 0.37% guar gum, and 0.23% phosphate-containing compound salt can improve the texture quality of the frozen rice noodles, especially the addition of the phosphate-containing compound salt, which improved the chewiness, elasticity, and firmness of the compound frozen rice noodles.

[0078] The method for determining the cooking characteristics is referenced in (Liang Jing, Liu Xueqiang, Xing Ruizhen, et al. Effects of edible herb powder on the quality characteristics of dough and noodles [J]. Food Industry Technology, 2024, 45(13)). Figure 2 As shown in Figure a), the frozen rice noodles with only guar gum added had the lowest rehydration water absorption rate, which may be because guar gum has good water retention. Figure 2 As shown in b), the cooking loss rate of quick-frozen rice noodles increases with the increase of the number of freeze-thaw cycles. The cooking loss of Comparative Example 1 is always at the maximum value, while the cooking loss of Example 1 is the minimum. This indicates that the compound quick-frozen rice noodles can inhibit starch dissolution during rehydration compared to the blank group. Figure 2 c) Comparative Example 1 showed the highest trend in breakage rate increase. Examples 1 and Comparative Examples 2-4 could significantly reduce breakage rate, indicating that the addition of hydroxypropyl corn starch, guar gum and phosphate-containing compound salt can significantly improve the toughness of quick-frozen rice noodles and inhibit ice crystal growth that damages starch structure.

[0079] The method for determining the freezeable water content is referenced in section 1.3.2, "Determination of Freezeable Water Content in Dough," of the literature (Du Xianfeng, Zhou Zhou, Cao Meng, et al. Effects of Different Improvers on the Quality of Frozen Dough and Noodles [J]. Food and Fermentation Industries, 2024, 50(02)). Figure 3 The results show that, in Comparative Example 1, the frozen rice noodles made from pure rice increased rapidly in terms of the number of freeze-thaw cycles, indicating a decrease in water-holding capacity and a greater likelihood of ice crystal formation. The growth trend of the frozen water content in Example 1 and Comparative Examples 2, 3, and 4 was effectively suppressed, with Example 1 showing the most gradual growth trend, indicating that the compounded frozen rice noodles can effectively inhibit water loss caused by ice crystal growth. Pairwise comparisons of Comparative Examples 2-4 show that the frozen water content changes of hydroxypropyl corn starch and guar gum are similar and stable. While the frozen water content of the phosphate-containing compound salt was 2-8% lower than that of Comparative Examples 2 and 3 in the first three freeze-thaw cycles, it increased in the later cycles, becoming 1-2% higher than that of Comparative Examples 2 and 3. This indicates that guar gum and hydroxypropyl corn starch have a stronger ability to enhance the freeze-thaw stability of rice noodles than the phosphate-containing compound salt.

[0080] Figure 4 The display shows the moisture distribution during the freeze-thaw cycle, with red, yellow, and blue representing moisture levels from high to low. It can be seen that the moisture binding state in Comparative Examples 1 (a) and 4 (d) is generally poor, with few high-moisture areas and mostly medium to low-moisture content areas. This indicates that the quick-frozen rice noodles made from single-origin rice have poor water-holding capacity and low content of tightly bound water. In Comparative Example 4 (d), the addition of a phosphate-containing compound salt only slightly improves the water-holding capacity of the quick-frozen rice noodles in the early stages, but the water-holding capacity decreases rapidly with each freeze-thaw cycle. Comparative Examples 2 and 3 have more high-moisture areas, indicating a higher content of tightly bound water and stronger water-holding capacity. Furthermore, the presence of most high-moisture areas in the early stages of the freeze-thaw cycle in Example 1 is likely due to the strong hydrophilicity of hydroxypropyl corn starch and guar gum.

[0081] The method for determining the bound water content is based on the determination of 2,4-NMR transverse relaxation time (T2) in the reference (Liu Weicong, Jin Li, Fu Xiangjin, et al. Effect of trehalose on freeze-thaw stability of frozen fish noodles [J]. Food Science, 2017, 38(01)). Table 1 shows that after each freeze-thaw cycle, the bound water content of Example 1 was 5.95-9.89% higher than that of Comparative Example 1. This value is higher than the sum of the bound water content increases from the addition of hydroxypropyl corn starch alone, the addition of guar gum alone, and the addition of a phosphate-containing compound salt alone. It can be seen that hydroxypropyl corn starch, guar gum, and the phosphate-containing compound salt further improve the water-holding capacity of quick-frozen rice noodles through synergistic effects.

[0082] Table 1. Tightly bound water content of Examples 1 and Comparative Examples 1-4

[0083]

[0084] Figure 5 The results showed that after multiple freeze-thaw cycles, the starch structure of Comparative Example 1 exhibited numerous uneven pores, and some even cracked, indicating that ice crystal growth severely damaged the structure of the control group. In contrast, the structures of Examples 1 and Comparative Examples 2-4, after the first three freeze-thaw cycles, did not show most of the uneven pores seen in Comparative Example 1. Only a few large pores appeared in a few freeze-thaw cycles, and the small pores were relatively uniform. This suggests that the addition of hydroxypropyl corn starch, guar gum, and the phosphate-containing compound salt can improve the freeze-thaw stability of the quick-frozen rice noodles. Therefore, considering all the test results, the compounded quick-frozen rice noodles significantly improved the freeze-thaw stability and edible quality of the rice noodles compared to the control group.

[0085] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing compound quick-frozen rice noodles with good freeze-thaw stability, characterized in that, This method uses rice, hydroxypropyl corn starch, guar gum, and phosphate-containing complex salts as raw materials, and includes the following steps: (1) Washing and soaking: Take rice, wash it with clean water and drain it, then soak it in clean water for 2-3 hours; (2) Rice slurry preparation: Soaked rice and water are poured into a cell wall breaking machine to obtain rice slurry. Then, 7-8% hydroxypropyl corn starch by weight of rice, 0.3-0.4% guar gum by weight of rice, and 0.2-0.3% phosphate-containing compound salt by weight of rice are added in sequence. The phosphate-containing compound salt contains 20% sodium tripolyphosphate, 30% sodium pyrophosphate, 20% sodium hexametaphosphate, 10% sodium dihydrogen phosphate, 10% sodium carbonate, and 10% sodium chloride by weight of rice. (3) Steaming the batter: Brush a thin layer of cooking oil on the steaming tray, pour in the rice batter obtained in step (2), place it in a steamer and steam for 120-180 seconds until the rice noodles on the steaming tray are slightly bubbly. (4) Cooling and slicing: After the steaming tray is removed and cooled to room temperature, place it at 0-4℃ for 3-4 hours and cut into strips 2mm wide and 20cm long; (5) Quick-freezing storage: Pack the cut rice noodles in vacuum packaging, quick-freeze them at -40℃ for half an hour, and then store them at -20℃ to obtain quick-frozen rice noodles.

2. The method for preparing compound quick-frozen rice noodles with good freeze-thaw stability according to claim 1, characterized in that, The weight of the water added in step (2) is 1.8-2 times the total weight of the rice, hydroxypropyl corn starch, guar gum and phosphate-containing compound salt.

3. The method for preparing compound quick-frozen rice noodles with good freeze-thaw stability according to claim 1, characterized in that, The amount of rice batter added in step (3) depends on the size of the steaming pan. For a steaming pan with a length × width × height of 23cm × 15cm × 1.5cm, the amount of batter poured is 165-175ml, which can produce rice noodles with a thickness of 1.5-2.5mm.

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