Heat-sterilized chilled chinese noodles and process for producing the same

Abstract

To provide heat-sterilized chilled Chinese noodles suppressed in deterioration of palate feeling even when stored in refrigeration at ≤ 10 °C for a long period of time, and to provide a method for producing the same.SOLUTION: The problem is solved by adding α - glucosyltransferase to heat-sterilized chilled Chinese noodles. The α - glucosyltransferase is preferably heat-resistant, and is preferably added in an amount of 240 to 2400U with respect to the 1kg of the main material flour, so that degradation of the texture during cold storage can be suppressed.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to heat-sterilized chilled Chinese noodles and a method for producing the same. [Background technology]

[0002] Conventionally, there are heat-sterilized chilled noodles that can be stored refrigerated (at temperatures below 10°C) after the noodle strands have been heated and sterilized by steaming or boiling. These noodles come in a variety of types, including those that can be simply boiled and eaten, those that can be loosened in water and eaten, those that can be loosened in a loosening liquid and then eaten with a seasoning liquid, and those that can be loosened in just a seasoning liquid and eaten as is.

[0003] These noodles have problems such as the starch easily retrograding within a short period of time after refrigeration, causing them to lose their luster and become hard, brittle, and dry, and so their best-before dates are set relatively short. Techniques to improve these problems have been disclosed (for example, Patent Documents 1 and 2). These methods are excellent techniques for improving the luster and deterioration of texture caused by retrogradation of chilled noodles, but they are insufficient and are not excellent enough to maintain a good flavor, withstand long-term refrigerated storage, or significantly extend the best-before date. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-73183 [Patent Document 2] Patent No. 6004676 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide heat-sterilized chilled Chinese noodles in which deterioration of texture is suppressed even when stored in a refrigerator for a long period of time, and a method for producing the same. [Means for solving the problem]

[0006] It has been known that adding processed starches such as etherified phosphate cross-linked starch can prevent heat-sterilized chilled noodles from becoming sticky and aging in texture during refrigerated storage, but these processed starches have problems in that the texture, such as stickiness and elasticity, differs from that of wheat flour itself, and they are also inferior in flavor. Long-term storage in the refrigerator requires a large amount of processed starch, and heat-sterilized chilled Chinese noodles containing a large amount of this processed starch lack flavor and texture. Therefore, the present invention was arrived at after extensive research to develop heat-sterilized chilled Chinese noodles that are prevented from aging and have excellent Chinese noodle flavor and texture even when stored in the refrigerator for a longer period of time than conventional noodles.

[0007] That is, the noodles are heat-sterilized chilled Chinese noodles characterized by containing α-glucosyltransferase.

[0008] Furthermore, the heat-sterilized chilled Chinese noodles according to the present invention preferably contain 240 U to 2400 U of α-glucosyltransferase per 1 kg of main ingredient flour.

[0009] Furthermore, the heat-sterilized chilled Chinese noodles according to the present invention preferably have a pH of 8.0 to 10.5.

[0010] Furthermore, the method for producing heat-sterilized chilled Chinese noodles according to the present invention preferably comprises the following steps: a noodle-making process in which 240 to 2400 U of α-glucosyltransferase is added to 1 kg of main ingredient flour to prepare noodle dough, and then the noodle dough is made by a conventional method to produce fresh noodles; a heating process in which the fresh noodles produced in the noodle-making process are heated by steaming or boiling; and a heat-sterilization process in which the steamed noodles or boiled noodles heated in the heating process are sealed in packaging material and heat-sterilized at 60 to 100°C for 10 to 50 minutes. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide heat-sterilized chilled Chinese noodles in which deterioration of texture is suppressed even when stored in a refrigerator for a long period of time, and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below, but the present invention is not limited to the following description.

[0013] 1. Noodle ingredients Examples of the main raw material flour for the heat-sterilized chilled Chinese noodles of the present invention include cereal flours such as wheat flour, barley flour, and rice flour, as well as various starches such as potato starch, tapioca starch, wheat starch, and corn starch, and these may be used alone or in combination. As the starch, raw starch, pregelatinized starch, and modified starch such as acetylated starch, etherified starch, and cross-linked starch may also be used.

[0014] Typically, pre-cooked chilled Chinese noodles are either reheated at the time of consumption, such as yakisoba or ramen, or consumed without reheating, such as hiyashi chuka or hiyashi ramen. In cases where retrogradation is severe or to extend the shelf life, modified starches such as etherified phosphate cross-linked starch are used. In particular, when noodles are consumed without reheating, they are thoroughly cooked in advance so that they can be consumed immediately, and as a result, the starch is highly gelatinized and prone to retrogradation, making it necessary to use a large amount of modified starch to prevent retrogradation. The use of modified starch affects the flavor and texture of Chinese noodles, but according to the present invention, the amount of modified starch used can be reduced to improve flavor and texture, and retrogradation can be further suppressed even with the same amount of modified starch added, thereby extending the shelf life.

[0015] Other powdered auxiliary ingredients that can be added include egg powders such as whole egg powder and egg white powder, alginic acid, calcined calcium, and calcium preparations.

[0016] In the present invention, other noodle ingredients besides the noodle raw material flour can be added, such as salt, alkaline agents, phosphates, noodle quality improvers, edible oils and fats, pH adjusters, emulsifiers, enzymes, thickeners, antibacterial agents such as protamine, various pigments such as carotene pigments, and preservatives that are commonly used in the production of Chinese noodles. These can be added by dissolving or suspending them in the kneading water. In the present invention, it is preferable to adjust the pH of the heat-sterilized chilled Chinese noodles to 8.0 to 10.5 using an alkaline agent known as kansui, phosphates, and calcined calcium. If the pH of heat-sterilized chilled Chinese noodles is less than 8.0, the flavor of Chinese noodles will be weak and they will lack shelf life, while if the pH exceeds 10.5, the effects of α-glucosyltransferase will be difficult to obtain, and a larger amount will need to be added.

[0017] The cooked chilled Chinese noodles of the present invention contain α-glucosyltransferase. The α-glucosyltransferase of the present invention is an enzyme that cleaves starch into units of approximately three sugars and then transfers the sugar chain to another sugar chain, such as 4-α-glucanotransferase. The α-glucosyltransferase of the present invention is preferably heat-resistant, and is preferably one that is not inactivated even when subjected to heat sterilization treatment at 80°C for 30 minutes in the noodles.

[0018] α-Glucosyltransferase can be added by mixing the powder with the main raw material flour or by dissolving it in mixing water. When dissolved in mixing water, the pH of the mixing water may become 11 or higher, and the activity of the enzyme decreases if the mixture is stored in the mixing water for a long period of time. Therefore, it is preferable to use the mixture as soon as possible after preparing the mixing water.

[0019] The amount of α-glucosyltransferase according to the present invention to be added is preferably 240 to 2400 U per 1 kg of main ingredient flour. If the amount of α-glucosyltransferase added is too small, the effect of the enzyme will be reduced, while if it is too large, the texture of the noodles will be soft, which is undesirable.

[0020] 2. Noodle making process The noodle dough (dough) according to the present invention can be prepared in the usual manner, namely by kneading a mixture of the main ingredient flour and auxiliary ingredient flour with kneading water in a batch mixer, flow jet mixer, vacuum mixer, or the like until the mixture is uniformly mixed, producing a crumbly dough.

[0021] Fresh noodles are then produced from the dough thus produced. Production methods may be conventional, including a method in which the dough is extruded using an extruder or the like to produce fresh noodles, or a method in which the dough is rolled into a coarse noodle sheet, which is then formed into a noodle sheet by compounding or the like, and further rolled multiple times using a roll to produce a predetermined noodle sheet thickness, and then the noodle sheet is cut out using a cutting roll known as a cutting blade to produce fresh noodles. When producing a noodle sheet and then producing fresh noodles, the noodle sheet may be produced using an extruder, and then rolled and cut out, or multiple noodle sheets may be combined to produce a noodle sheet with a multilayer structure, and then rolled and cut out. When producing extruded noodle sheets or extruded noodle strands using an extruder or the like, it is preferable to do so under reduced pressure.

[0022] 3.Heating process The fresh noodles are heated by steaming or boiling to produce steamed or boiled noodles so that they can be easily eaten. Steaming can be achieved, for example, by passing the noodle strands through a steam chamber that emits saturated steam for approximately 5 to 15 minutes. To increase heating efficiency, the noodle strands may be heated while being hydrated by spraying or immersing them in the steamer chamber. Boiling can be achieved by immersing the fresh noodles for approximately 60 to 180 seconds in a boiling tank whose boiling water temperature has been adjusted to 90°C or higher. Because boiling involves a higher degree of heating than steaming, steaming is preferred in the present invention because it minimizes enzyme inactivation due to heating.

[0023] 4. Heat sterilization process Next, the steamed or boiled noodles produced in the heating step are cut into pieces of approximately 15 to 35 cm, washed with water by showering or immersion if necessary, and cooled. After that, each predetermined amount is sealed and packaged in a packaging film made of polyethylene, polypropylene, or the like, and heat sterilized.

[0024] Methods for water-washing and cooling include showering with cold water at about 4 to 20°C, or immersing the heated noodle strands in a water tank filled with cold water. In this case, multiple water tanks can be prepared and the noodle strands can be water-washed and cooled in stages. Additionally, by spraying air into the water tank, the noodle strands can be moved while being water-washed and cooled.

[0025] Next, the steamed or boiled noodles, which have been washed and cooled as necessary, are sealed and packaged in predetermined weight portions in packaging film made of polyethylene, polypropylene, or the like to produce packaged noodles. At this stage, a loosening agent can be added to prevent the noodle strings from sticking together. Various loosening agents can be used, including aqueous solutions of soy-derived water-soluble hemicellulose, gum arabic, xanthan gum, and the like, as well as oils and fats such as edible oils and fats, and emulsified oils and fats. The amount of loosening agent added is preferably 3 to 15% by weight of the weight of the noodle strings to be packaged.

[0026] The heat sterilization method according to the present invention preferably involves heat sterilization of the sealed packaged noodles at a temperature of 60 to 100°C for 10 to 50 minutes. Temperatures above 100°C are not preferred because, even if the noodles are heat-resistant, the enzymes will be inactivated. Temperatures below 60°C take a long time to sterilize the noodles, which can affect the texture. For example, heat sterilization can be carried out for 10 to 50 minutes in a heat sterilization cabinet adjusted to 60 to 100°C with saturated steam.

[0027] The heat-sterilized packaged noodles are then cooled. The cooling method is not particularly limited, and the noodles can be cooled by showering them with cold water, leaving them to cool naturally, or applying a fan or cold air, and then storing them in a refrigerator at a temperature of 10°C or below for refrigeration.

[0028] 5. Other processes The cooled packaged noodles can be further packaged in a container or bag together with packaged liquid soup and condiments to produce a heat-sterilized chilled Chinese noodle product.

[0029] Heat-sterilized chilled Chinese noodles can be stored in a refrigerated temperature range of 10°C or below (0°C or above), known as the chilled zone, and then sold. The heat-sterilized chilled Chinese noodles of the present invention are less likely to deteriorate in texture even when stored in a refrigerator for a longer period than regular products, making it possible to provide heat-sterilized chilled Chinese noodles with a significantly longer shelf life than conventional noodles. In addition, it is possible to reduce the amount of processed starch used to prevent aging, making it possible to provide heat-sterilized chilled Chinese noodles with better flavor and texture than conventional noodles. [Example]

[0030] The present embodiment will be described in more detail below with reference to examples.

[0031] <Experiment 1> Study on steamed Chinese noodles Example 1 1 g of an α-glucosyltransferase preparation (Mochi Soft (registered trademark) Miyabi: Oriental Yeast Co., Ltd., 240 U / g) was added to 1 kg of noodle raw material flour consisting of 950 g of wheat flour (all-purpose flour) and 50 g of potato starch and the powder was mixed. A mixing water (pH 11.0) prepared by dissolving 10 g of salt, 4 g of kansui preparation (sodium carbonate 5: potassium carbonate 4: polyphosphate 1), 0.8 g of gardenia pigment, and 5 g of antibacterial agent (glycine 9: milt protein 1) in 380 ml of water was added, and the mixture was kneaded in a normal pressure mixer for 15 minutes to prepare dough (noodle dough).

[0032] The dough thus prepared was combined to form a 12 mm noodle sheet, which was then rolled to a thickness of 1.8 mm using a roll, and then cut with a No. 16 square roll cutting blade to form noodle strands.

[0033] The cut noodle strands were steamed for 5 minutes in a steam oven (over 99°C) with an inflow of saturated steam at 400 kg / hr, and given two water showers (6 L / min) while supplying moisture to the noodle strands. The steamed noodle strands were cut into lengths of approximately 20 cm, immersed in 10°C cold water for 20 seconds to rinse and cool, and after the noodles had cooled sufficiently, 150 g portions were placed in polyethylene containers, 5 g of salad oil was added, and the containers were sealed.

[0034] The sealed packaged noodle strings were heat-sterilized for 20 minutes in a heat sterilization cabinet adjusted to 85°C with steam, then cooled with a blower to remove the heat, and stored overnight in a low-temperature cabinet at 10°C or below to produce heat-sterilized chilled Chinese noodle samples (pH 8.5). Furthermore, to evaluate the staling sensation, the heat-sterilized chilled Chinese noodle samples were stored in a refrigerator at 10°C or below for up to 41 days.

[0035] Example 2 A heat-sterilized chilled Chinese noodle sample was prepared according to the method of Example 1, except that the amount of α-glucosyltransferase added was 5 g.

[0036] Example 3 A heat-sterilized chilled Chinese noodle sample was prepared according to the method of Example 1, except that the amount of α-glucosyltransferase added was 10 g.

[0037] (Comparative Example 1) A heat-sterilized chilled Chinese noodle sample was prepared according to the method of Example 1, except that α-glucosyltransferase was not added.

[0038] (Comparative Example 2) A heat-sterilized chilled Chinese noodle sample was prepared according to the method of Comparative Example 1, except that the main raw material flour was 700 g of wheat flour (medium-strength flour) and 300 g of hydroxypropyl etherified starch.

[0039] The samples from each test group were cooked and subjected to a sensory evaluation. The cooking method was to place each sample in a frying pan, add 60 ml of water, and heat over medium heat for 1 minute while stirring. Once the water had evaporated, add 10 g of powdered sauce, mix, and heat over medium heat for another 1 minute. When the sample started to sizzle, the heat was turned off and the sample was ready for consumption.

[0040] Sensory evaluation involved evaluating the texture and flavor of samples stored in the refrigerator for one day, and further evaluating the texture of samples stored in the refrigerator for 15, 20, 27, 32, 38, and 42 days. The evaluation was based on a rating of 5 for very good, 4 for good, 3 for acceptable as a product, 2 for edible but not acceptable as a product, and 1 for inedible. Regarding texture, the samples stored in the refrigerator for one day were evaluated for their texture as fried noodles, while samples stored in the refrigerator for 11 days or more were evaluated for aging, such as ease of cutting the noodles, surface smoothness, surface hardness, and lack of stickiness in the core. The evaluation results are shown in Table 1 below.

[0041] [Table 1]

[0042] As shown in Table 1, the regular product, Comparative Example 1, had a good texture and flavor after 1 day of refrigeration, but after 15 days of refrigeration, the surface became hard and the core lost its stickiness, resulting in a so-called aged texture, and after 27 days of refrigeration, the aged texture became even more pronounced and the noodles began to break. Further storage in the refrigerator caused the texture to become hard and brittle, and the noodle breakage became more pronounced.

[0043] In contrast, the addition of α-glucosyltransferase was able to suppress deterioration of texture due to aging after refrigerated storage, as shown in Examples 1 to 3. As shown in Examples 1 to 3, when the amount added was small, the enzyme was inactivated by heat sterilization, reducing the enzyme's effectiveness, and when the amount added was increased, the texture after production became sticky.

[0044] As shown in Comparative Example 2, the addition of hydroxypropylated phosphate cross-linked starch, an etherified phosphate cross-linked starch, can suppress deterioration in texture due to retrogradation during refrigerated storage, but the flavor and texture after production were inferior to those of Comparative Example 1, in which hydroxypropylated phosphate cross-linked starch was not added, and the product reached its marketable limit earlier than in Examples 1 to 3. This is thought to be because α-glucosyltransferase acts on starch throughout the noodles, whereas in Comparative Example 2, starch derived from wheat flour other than hydroxypropylated phosphate cross-linked starch retrograded. In order to prevent retrogradation and extend the shelf life, it is conceivable to further reduce the amount of wheat flour added and increase the amount of hydroxypropylated phosphate cross-linked starch added, but this is expected to result in even worse flavor and texture after production than in Comparative Example 2.

[0045] <Experiment 2> Study on boiled Chinese noodles (hiyashi chuka) The steamed Chinese noodles in Experiment 1 were reheated during cooking, so the degree of starch gelatinization due to the heating process was low. However, we also tested whether the same effect could be achieved with boiled Chinese noodles (hiyashi chuka), which are not reheated before eating and have a high starch gelatinization and moisture content due to the heating process.

[0046] Example 4 To 1 kg of main ingredient flour consisting of 550 g of wheat flour (all-purpose flour) and 450 g of hydroxypropylated phosphate cross-linked starch, 140 g of gluten, 5 g of calcined calcium, 5 g of alginic acid, 10 g of egg yolk powder, and 5 g of an α-glucosyltransferase preparation (Mochi Soft (registered trademark) Miyabi: Oriental Yeast Co., Ltd., 240 U / g) were added and mixed. A mixing solution of 8 g of salt, 12 g of alkaline water preparation (5 parts sodium carbonate, 4 parts potassium carbonate, 1 part polyphosphate), 4 g of carotene pigment, and 10 g of trehalose in 400 ml of water was added and kneaded for 4 minutes, and then kneaded for 8 minutes under a reduced pressure of -500 mmHg to produce a dough.

[0047] The dough thus prepared was combined to form a 12 mm noodle band, which was then rolled to 1.35 mm using a roll press. The noodle band was then cut using a No. 20 square roll cutting blade to form noodle strands, which were then cut into approximately 25 cm pieces to produce fresh noodles.

[0048] Next, the raw noodles were prepared in boiling water containing a 0.1 wt% aqueous solution of calcium chloride and boiled for 2 minutes and 30 seconds. They were then rinsed twice by immersing them in cold water at 10°C for 30 seconds. After the noodles had cooled sufficiently, 140 g of each was placed into a polyethylene container, which was filled with 10 g of a loosening agent consisting of an aqueous solution of 5 wt% soybean-derived water-soluble hemicellulose and 0.25 wt% xanthan gum, and then sealed.

[0049] The sealed packaged noodles were sterilized by steam in a heat sterilization cabinet adjusted to 75°C for 30 minutes, then cooled by blowing air to remove the heat, and stored in a low-temperature cabinet at 10°C or below for one day to produce heat-sterilized chilled Chinese noodle samples (hiyashi chuka). Furthermore, to evaluate the aging sensation, the heat-sterilized chilled Chinese noodle samples were stored in a freezer at 10°C or below for up to 18 days (pH 10.5).

[0050] Example 5 A heat-sterilized chilled Chinese noodle sample was prepared according to the method of Example 4, except that the amount of wheat flour added was 775 g and the amount of hydroxypropylated phosphate cross-linked starch was 225 g.

[0051] (Comparative Example 3) A heat-sterilized chilled Chinese noodle sample was prepared according to the method of Example 1, except that α-glucosyltransferase was not added.

[0052] 40 ml of chilled Chinese noodle sauce was added to each test sample, which was then thoroughly loosened and eaten. A sensory evaluation was conducted. The samples were evaluated for texture and flavor after 1 day of refrigeration, and the texture was further evaluated for samples after 4, 10, and 18 days of refrigeration. The evaluation results are shown in Table 2 below.

[0053] [Table 2]

[0054] Comparative Example 3, a standard boiled Chinese noodle (hiyashi chuka), is not cooked and has a high degree of gelatinization, making it prone to aging. To prevent this, hydroxypropylated phosphate cross-linked starch is used in just under half of the main ingredient flour. As a result, the Chinese noodle flavor is weak, the surface is sticky, and the texture is soft, derived from the hydroxypropylated phosphate cross-linked starch. The product shelf life is 10 days after refrigeration.

[0055] In contrast, as shown in Example 4, by adding α-glucosyltransferase, the flavor and texture remained unchanged after refrigerated storage for one day, but the surface was no longer sticky, the product was easily flaked, the progression of aging was suppressed, and the product shelf life was extended to 18 days after refrigeration.

[0056] As shown in Example 5, even when the amount of hydroxypropylated phosphate cross-linked starch added to prevent retrogradation was reduced by half compared to Comparative Example 3, the addition of α-glucosyltransferase improved the flavor and texture after 1 day of refrigerated storage, and the product limit was almost the same as that of Comparative Example 3.

Claims

1. Heat-sterilized chilled Chinese noodles containing α-glucosyltransferase.

2. 2. The heat-sterilized chilled Chinese noodles according to claim 1, wherein the α-glucosyltransferase is contained at 240 U to 2400 U per kg of main raw material flour.

3. 3. The heat-sterilized chilled Chinese noodles according to claim 1, wherein the pH of the pasteurized Chinese noodles is 8.0 to 10.

5.

4. a noodle-making process in which 240 to 2400 U of α-glucosyltransferase is added to 1 kg of main raw material flour to prepare noodle dough, which is then made into fresh noodles by conventional methods; a heating step in which the raw noodles produced in the noodle-making step are heated by steaming or boiling; a heat sterilization step of sealing the steamed noodles or boiled noodles heated in the heating step in a packaging material and sterilizing them by heat at 60 to 100°C for 10 to 50 minutes.

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