Method for improving heat resistance of gel-like composition

Abstract

[Problem] The purpose of the present invention is to suppress the deterioration of heat resistance of a gel-like composition containing curdlan and another thickening polysaccharide, particularly a gel-like composition in which the amount of curdlan is smaller. [Solution] In the preparation of a gel-like composition containing curdlan and another thickening polysaccharide, curdlan having an average particle diameter of 50 μm or less is used as the above-mentioned curdlan.

Description

Method for improving heat resistance of gel composition

[0001] The present invention relates to a method for improving the heat resistance of gel compositions containing curdlan and other thickening polysaccharides.

[0002] Curdlan, a heat-setting gelling agent, is used in many gel compositions because the gel compositions obtained after heat setting are heat-resistant. For example, the present applicant has disclosed a gel food for people with difficulty chewing that uses curdlan and processed starch, another thickening polysaccharide (Patent Document 1). This gel composition is characterized by its refrigeration and freezing resistance, ability to be cooked with heat, and suppressed syneresis. Furthermore, a gel composition containing curdlan and one or more thickening polysaccharides, such as native gellan gum, deacylated gellan gum, psyllium seed gum, agar, tamarind seed gum, carrageenan, xanthan gum, locust bean gum, glucomannan, guar gum, and tara gum, and / or starch, is known to retain its shape and not melt when cooked with heat (Patent Document 2).

[0003] WO2017 / 017953 JP2017-038530

[0004] The above-mentioned gel compositions containing curdlan take advantage of the advantage of curdlan, namely, its heat resistance when gelled. In other words, curdlan can be used as a heat resistance improver for gels. Curdlan is often sold as a solid, usually in powder, granule, or powder form, with an average particle size of approximately 100 μm. However, the heat resistance of curdlan with a normal particle size may be reduced when used in combination with other thickening polysaccharides. In gel compositions that allow for high gel strength, the curdlan content can be increased, so the heat resistance is unlikely to be affected even when used in combination with other thickening polysaccharides. However, in compositions that require a high content of thickening polysaccharides to impart viscosity during preparation and a low content of curdlan to reduce gel strength, the heat resistance may be affected, such as the gel composition collapsing upon heating.

[0005] Therefore, an object of the present invention is to suppress a decrease in heat resistance of a gel composition containing curdlan and other thickening polysaccharides, particularly a gel composition having a low curdlan content or a high content of other thickening polysaccharides relative to the curdlan content.

[0006] The present invention relates to the following (1) and (2): (1) a method for improving the heat resistance of a gel composition containing curdlan and other thickening polysaccharides, in which the gel composition is prepared by using curdlan having an average particle size of 50 μm or less; and (2) an agent for improving the heat resistance of a gel, the agent comprising curdlan having an average particle size of 50 μm or less.

[0007] When using curdlan having a normal particle size of about 100 μm in combination with other thickening polysaccharides, the use of curdlan having a mean particle size of 50 μm or less, preferably 30 μm or less (hereinafter sometimes referred to as fine particle curdlan) as the curdlan can make the heat resistance less affected by the thickening polysaccharide compared to when using curdlan having a normal particle size. This makes it possible to provide a gel composition with excellent heat resistance even when the curdlan content is low or when the content of other thickening polysaccharides relative to the curdlan content is high. Since curdlan is inherently heat-resistant, fine particle curdlan can be used as an even better heat resistance improver.

[0008] Photograph of the appearance of the gel in Test Group 1 after heating in a microwave oven. Photograph of the appearance of the gel in Comparison Group 1 after heating in a microwave oven. Photograph of the appearance of the gel in Comparison Group 2 after heating in a microwave oven. Photograph of the appearance of the gel in Test Group 2 after heating in a microwave oven. Photograph of the appearance of the gel in Comparison Group 3 after heating in a microwave oven.

[0009] In the present invention, curdlan is a general term for heat-coagulable polysaccharides primarily composed of β-1,3-glucosidic bonds. While such curdlan can be produced by microorganisms of the genus Alcaligenes or Acrobacterium, commercially available products are also suitable. While commercially available curdlan typically has an average particle size of approximately 100 μm, the present invention uses curdlan with an average particle size of typically 50 μm or less, preferably 30 μm or less. While there is no particular lower limit for the average particle size, considering ease of handling, a particle size of 10 μm or more is preferred, and 20 μm is even more preferred. Such fine-particle curdlan can be prepared by pulverizing conventional curdlan, but since it is also commercially available, commercially available products (e.g., manufactured by Mitsubishi Corporation Life Sciences) may also be used.

[0010] Other thickening polysaccharides that can be used in combination with the particulate curdlan in the present invention include carrageenan, xanthan gum, locust bean gum, gellan gum, tamarind seed gum, guar gum, pectin, gum arabic, hydroxymethylcellulose, karaya gum, etc. Examples of carrageenan include kappa-carrageenan, iota-carrageenan, and lambda-carrageenan, and any of these may be used. Examples of gellan gum include native gellan gum and desacyl gellan gum, and any of these may be used.

[0011] Polysaccharides not classified as the above-mentioned thickening polysaccharides may also be used in combination with curdlan. Examples include paramylon, a heat-coagulable polysaccharide mainly composed of β-1,3-glucosidic bonds like curdlan, modified starches obtained by subjecting potato starch, tapioca starch, sweet potato starch, sago starch, cornstarch, waxy cornstarch, high-amylose cornstarch, wheat starch, rice starch, etc. to etherification, esterification, oxidation treatment, etc., glucomannan, konjac flour, modified konjac flour, etc.

[0012] A gel composition containing particulate curdlan and other thickening polysaccharides (hereinafter also referred to as the gel composition of the present invention) can be prepared in accordance with a conventional method in which curdlan is dispersed or dissolved in a medium such as water by a method such as a high-speed stirring method, a high-viscosity method, or an alkali dissolution method, and then heated to form a gel composition. Since particulate curdlan has excellent water dispersibility during preparation, the stirring speed during stirring may be low. For example, to disperse curdlan of a normal particle size by a high-speed stirring method, high-speed stirring (several thousand rpm) using a homogenizer or the like is required, but in the present invention, which uses particulate curdlan, dispersion can be achieved even at a rotation speed of about 500 to 3,000 rpm in a household food processor.

[0013] Whether or not the method of the present invention is applicable is determined by preparing a gel composition using curdlan of a normal average particle size and another thickening polysaccharide, and observing whether or not the gel shape can be maintained when the resulting gel composition is heated for 1 minute in a microwave oven at 500 W. If the gel shape cannot be maintained as a result of the heating operation, the present invention is applicable, but even if the gel shape can be maintained, the use of particulate curdlan is not prohibited.

[0014] The criteria for determining whether the present invention is applicable are as described above, but for simplicity, it can be determined that the present invention is applicable when the content of curdlan in the gel composition is less than 3.0% by weight, preferably 2.5% by weight or less. There is no lower limit to the curdlan content, but it is usually 0.5% by weight or more, and from the viewpoint of imparting heat resistance, it is preferably 1.0% by weight or more.

[0015] The gel strength of the gel composition of the present invention can be measured as the hardness of the gel using a texture analyzer or the like. To effectively obtain the effects of the present invention, the hardness at a product temperature of 20°C must be 100,000 N / m 2 It is preferable that the resistance is not more than 50,000 N / m 2 Less than or equal to 30,000 N / m 2 or less, more preferably 20,000 N / m 2 Preferably less than 20,000 N / m 2 If the following conditions are met, the food is suitable for people who have difficulty chewing.

[0016] The gel composition of the present invention may contain other components to the extent that the respective effects of curdlan and other thickening polysaccharides are not impaired. For example, the dispersibility and solubility of curdlan can be improved by coexisting curdlan with chaotropic ions such as guanidinium ions, calcium ions, magnesium ions, lithium ions, thiocyanates, isothiocyanates, iodide ions, bromide ions, nitrate ions, basic peptides derived from TAT protein, di- and tri-arginine peptides, methyl isocyanate, n-butyl isocyanate, phenyl isocyanate, D / L arginine, D / L citrulline, and agmatine. The coexistence of chaotropic ions not only improves dispersibility but also enhances the gel strength of curdlan, making it possible to reduce the amount of curdlan used.

[0017] The gel composition of the present invention may contain food ingredients such as seasonings, spices, and sweeteners, as well as oils and fats, vitamins, and peptides, for the purpose of improving flavor and texture, extending shelf life, providing nutritional supplementation, etc., as long as the effects of the invention are not impaired. The gel composition of the present invention may be used as is, or may be mixed with soup, miso soup, vegetable juice, fruit juice, or liquid foods obtained by diluting or concentrating these, or pastes of vegetables, fruits, seafood, meat, eggs, or dairy products.

[0018] The gel composition of the present invention and foods using the same have improved heat resistance compared to gel compositions containing ordinary curdlan and other thickening polysaccharides, and therefore retain their shape even when cooked, i.e., have excellent shape retention. Furthermore, by utilizing the properties of curdlan, the gel composition of the present invention also has freezing resistance. Therefore, it is possible to heat and thaw the frozen product in a microwave oven.

[0019] Examples of the present invention will be described below, but the present invention is not limited to these.

[0020] (1) "Curdlan" and "Curdlan NS," products of Mitsubishi Corporation Life Sciences, Inc., were used as the curdlan and finely pulverized curdlan, respectively, and native gellan gum was used as another thickening polysaccharide, and modified starch was also used to prepare compositions having the compositions shown in Table 1. The finely pulverized curdlan, "Curdlan NS," had an average particle size of 30 μm or less.

[0021]

[0022] The prepared compositions of Test Group 1, Comparative Group 1, and Comparative Group 2 were added to a food processor with 100 parts water (6 parts by weight per 100 parts by weight for Test Group 1 and Comparative Group 1, and 7 parts by weight per 100 parts by weight for Comparative Group 2) and mixed at approximately 3,000 rpm for 2 minutes. After mixing, the entire contents were filled into bags, sealed, and heated in a steam convection oven at 95°C for 30 minutes. The resulting gel compositions using the composition of Test Group 1 contained 1.9% by weight of finely ground curdlan, the composition of Comparative Group 1 contained 1.9% by weight of curdlan, and the composition of Comparative Group 2 contained 2.8% by weight of curdlan. After heating, the gels were cooled to below 10°C, and their shapes were confirmed. If they retained their shape, they were cut into cylindrical shapes measuring 40 mm in diameter and 15 mm in height and their hardness was measured using a rheometer. Measurements were performed using a 20 mm diameter cylindrical plunger at a compression rate of 10 mm / sec. The results of the gel hardness measurements are also shown in Table 1.

[0023] As shown in Table 1, even when the type (native gellan gum) and content of the thickening polysaccharide were the same (Test Group 1 and Comparison Group 1), the gel hardness differed between the gel containing finely pulverized curdlan and the gel containing no curdlan, and it was shown that the gel using finely pulverized curdlan had higher strength.

[0024] The gels of Test Group 1, Comparative Group 1, and Comparative Group 2 were each heated in a 500W microwave oven for 1 minute. Photographs of the appearance of each gel after microwave heating are shown in Figures 1 to 3. As shown in Figures 1 to 3, the gels made with finely pulverized curdlan showed good shape retention even when heated in a microwave oven.

[0025] (2) Compositions having the compositions shown in Table 2 were prepared in the same manner as in Test Group 1 in (1), except that curdlan and finely pulverized curdlan were used and xanthan gum was used as the other thickening polysaccharide. The strengths of the resulting gels are also shown.

[0026]

[0027] As shown in Table 2, even when xanthan gum was used as the thickening polysaccharide, the strength of the gel obtained using finely pulverized curdlan was shown to be high, just like when native gellan gum was used.

[0028] Furthermore, the gel obtained was heated in a 500 W microwave oven for 1 minute, and the results, as shown in Figures 4 and 5, indicated that the gel made using finely pulverized curdlan had high shape retention.

Claims

1. A method for improving the heat resistance of a gel composition containing curdlan and other thickening polysaccharides, wherein the curdlan has an average particle size of 50 μm or less.

2. A heat resistance improver for gels made from curdlan particles with an average particle size of 50 μm or less.

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