Rice flour castella

Abstract

This new rice flour castella cake achieves the characteristic fluffy texture of castella while suppressing dryness, and maintains a moist texture comparable to that of castella made with wheat flour, even after being distributed in a frozen state. [Solution] The rice flour castella is made primarily from rice flour, egg, gelatinized rice flour, and sugar.

Description

Technical Field

[0004] , ,

[0001] The present disclosure mainly relates to rice flour castella manufactured using rice flour.

Background Art

[0002] Today, as products for those with, for example, wheat allergies, products using rice flour instead of wheat flour as raw materials are increasing. Such products are sold, for example, as rice flour bread or confectioneries using rice flour, and in general, bread and confectioneries made with wheat flour can be safely eaten by those with wheat allergies. Therefore, by adopting rice flour as a substitute for wheat flour, the diet of those troubled by wheat allergies can be enriched. Also, by using rice, which has a large domestic production volume instead of wheat, most of which is imported, it is possible to improve the food self-sufficiency rate and ensure a stable supply of raw materials (rice flour) without being affected by overseas production volumes and prices. As bread and confectioneries using the above rice flour, they have been proposed, for example, in JP-A-2018-108078 (Patent Document 1) and JP-A-2003-189786 (Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent documents 1 and 2 disclose that replacing wheat flour with rice flour eliminates gluten, resulting in the formation of a cross-linked network structure and insufficient rise after baking (inability to maintain the skeletal structure), as well as a tendency for the product to become dry. In particular, as is known from the phenomenon of freezer burn, moisture can evaporate from frozen foods and ingredients. In such cases, the texture after thawing becomes dry and the taste and aroma are also impaired. Therefore, when rice flour products are distributed in a frozen state, even more moisture is lost, making a decline in quality unavoidable.

[0005] In view of these problems, the inventors focused on castella, which has a relatively high sugar content among breads and baked goods, and completed the present invention.

[0006] Therefore, the objective of this disclosure is to provide a novel rice flour castella that achieves the fluffy texture characteristic of castella, suppresses dryness, and maintains a moist texture comparable to that of castella made with wheat flour, even after being distributed in a frozen state. [Means for solving the problem]

[0007] The rice flour castella disclosed herein is primarily made from rice flour, egg components which are made by adding egg yolks to whole eggs, pre-gelatinized rice flour components which are made from pre-gelatinized rice flour, and sugar components. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a rice flour castella that achieves the fluffy texture characteristic of castella, suppresses dryness, and maintains a moist texture comparable to that of castella made with wheat flour, even after being distributed in a frozen state. [Brief explanation of the drawing]

[0009] [Figure 1]Figure 1 is an explanatory diagram illustrating the properties of rice flour castella cake when the ratio of egg yolk added to whole egg is changed in Examples 1-5 and Comparative Examples 1-4. [Figure 2] Figure 2 is an explanatory diagram illustrating the properties of rice flour castella when the proportion of pregelatinized rice flour component in the main ingredients is changed, as shown in Examples 6-10 and Comparative Examples 5-8. [Figure 3] Figure 3 is an explanatory diagram illustrating the weight percentage of each component in the main raw materials. [Figure 4] Figure 4 shows the results of sensory evaluation tests for Examples 1 to 5, which assess the moistness after a predetermined number of days of storage at room temperature after thawing. [Figure 5] Figure 5 shows the results of sensory evaluation tests for Examples 6-10 and Comparative Examples 6 and 7, which assess the moistness after a predetermined number of days of storage at room temperature after thawing. [Modes for carrying out the invention]

[0010] <Description of Embodiments in this Disclosure> First, embodiments of this disclosure will be listed and described. The rice flour castella disclosed herein is (1) The main ingredients are rice flour components made from rice flour, egg components made by adding only egg yolks to whole eggs, pre-gelatinized rice flour components made from pre-gelatinized rice flour, and sugar components.

[0011] As mentioned above, the inventors aimed to solve the problem that the absence of gluten prevents the formation of a cross-linked structure, resulting in the inability to obtain the fluffy, airy texture characteristic of castella cake, by forming a framework through the thermal coagulation of proteins contained in eggs. Therefore, the inventors conceived the idea of ​​using a larger amount of eggs in the production of castella cake using rice flour compared to conventional castella cakes using wheat flour. However, they encountered a new problem: simply increasing the amount of eggs resulted in an excessive amount of water in the main ingredients due to the water contained in the eggs, making it difficult to control the water activity (Aw). In light of this new problem, the inventors focused on egg yolks in particular, which have a relatively high protein content and a relatively low water content in terms of their component composition, and decided to add only egg yolks to the whole egg as an egg component.

[0012] As a result, the rice flour castella of this disclosure was able to form a framework through the thermal coagulation of egg proteins, and obtain a fluffy, airy texture characteristic of castella even after baking. Furthermore, the adjustment of water activity Aw, which occurs when adding egg yolks to whole eggs, was achieved by adding sugar components. In other words, these egg components and sugar components made it possible to achieve both control of water activity Aw and the effect of obtaining a fluffy, airy texture characteristic of castella.

[0013] Furthermore, to address the issue of dryness, we not only used rice flour made from milled rice (i.e., non-gelatinized rice flour), but also added gelatinized rice flour, which has higher water retention. In particular, by not only adding gelatinized rice flour but also incorporating a larger amount of egg yolk as described above, we were able to suppress dryness with the moisture and fat contained in the egg yolk, and the sugar components also retain moisture. As a result, the combined action of the egg components, gelatinized rice flour components, and sugar components allowed us to maintain a moist texture even after a predetermined period of time. By increasing the water retention of the main ingredients in this way, we were able to suppress deterioration in frozen conditions such as freezer burn, and produce a rice flour castella that is just as moist as castella made with wheat flour, even after being distributed in a frozen state.

[0014] (2) In (1) above, it is preferable that the ratio of the egg component to the rice flour component is within the range of 220% to 320% by weight. By setting the ratio of the egg component to the rice flour component within the above range by weight, the rise after baking of the rice flour castella is maintained. That is, if the egg component is less than 220% of the rice flour component, the amount of protein in the egg component will not be sufficient, so the skeletal structure cannot be maintained, and the center may sink after cooling. Also, if the egg component is more than 320% of the rice flour component, the amount of egg yolk added will be large, so the amount of fat in the main ingredients will be large, which may cause air bubbles to collapse easily or the heat conductivity (cooking) to be poor, and sufficient rise may not be obtained.

[0015] (3) In (1) or (2) above, it is preferable that the proportion of egg yolk added to the whole egg is within the range of 17% to 70% by weight. By setting the proportion of egg yolk added to the whole egg within the above range by weight, the rise after baking of the rice flour castella is maintained. That is, if the amount of egg yolk added is less than the above range, a sufficient amount of protein may not be obtained, and if the amount of egg yolk added is more than the above range, the amount of fat will be too high, so if the amount of egg yolk added is outside the above range, the same problems as in the embodiment of (2) above may occur.

[0016] (4) In any one of (1) to (3) above, it is preferable that the ratio of the gelatinized rice flour component to the rice flour component is within the range of 2% to 20% by weight. By setting the ratio of the gelatinized rice flour component to the rice flour component within the above range by weight, the amount of moisture in the rice sponge cake can be maintained at an appropriate level. That is, if the gelatinized rice flour component is less than 2% with respect to the rice flour component, the amount of gelatinized rice flour that can bind to the moisture in the dough decreases, and the proportion of free water not bound to substances increases, so there is a risk that the water activity Aw will become greater than a predetermined value. In addition, since the water retention capacity in the dough decreases, the rice flour is likely to become crumbly, and the sponge cake is likely to deteriorate under freezing conditions, and there is a risk that the target shelf life cannot be achieved. Furthermore, if the gelatinized rice flour component is more than 20% with respect to the rice flour component, since gelatinized rice flour has a property of being likely to develop viscosity by retaining moisture more than ordinary rice flour, there is a risk that the viscosity will increase and the texture of the sponge cake will not be achieved.

[0017] (5) In any one of (1) to (4) above, it is preferable that the sugar component contains sucrose and low-sweetness starch syrup. As described above, by adding the sugar component, the water activity Aw can be controlled and the crumbliness of the rice flour can be suppressed. However, if the total amount of the sugar component is composed of sucrose, the sweetness may become too strong. Therefore, since the sugar component contains low-sweetness starch syrup, the water activity Aw can be controlled, the crumbliness of the rice flour can be suppressed, and the intensity of the sweetness can also be adjusted.

[0018] (6) In (5) above, it is preferable that the low-sweetness starch syrup is maltodextrin. Since maltodextrin has a high ability to retain moisture, it can suppress the crumbliness of the rice flour, and even in a frozen state, the deterioration of the sponge cake is suppressed. By containing maltodextrin, a moist texture can be exhibited even after a predetermined period has passed.

[0019] <Details of Embodiments of the Present Disclosure> Specific examples of the rice flour castella of the present disclosure will be described below with reference to the drawings. It should be noted that the present disclosure is not limited to these examples, but is shown by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included.

[0020] <Embodiment 1> The rice flour castella of the present disclosure is mainly composed of a rice flour component made of rice flour, an egg component prepared by adding only egg yolks in addition to whole eggs, a gelatinized rice flour component made of gelatinized rice flour, and a sugar component.

[0021] <Rice flour component> Known rice flour is adopted as the rice flour constituting the rice flour component. The rice flour in Embodiment 1 is obtained by pulverizing rice in a dry state (i.e., not gelatinized) into powder. The type of rice is not limited, but polished rice is preferred.

[0022] As the rice milling method, known milling methods such as hulling milling, roll milling, stone mortar milling, pin mill milling, etc. can be adopted. In Embodiment 1, a milling method by air classification is adopted. In particular, in Embodiment 1, a milling method by wet air classification is adopted, and rice flour with less starch damage can be obtained compared to the milling method by dry air classification, for example.

[0023] The particle size of the rice flour is not limited. For example, it is preferably that the average particle size is 20 μm to 60 μm. The particle size of the rice flour in Embodiment 1 is set to have an average particle size of approximately 40 μm. Although there are various particle sizes of wheat flour circulating in the market and they cannot be simply compared, the particle size of general wheat flour is, for example, the average particle size is 150 μm or less. The rice flour used in Embodiment 1 has a relatively small particle size compared to general wheat flour.

[0024] <Egg component> As described above, the egg component in Embodiment 1 is formulated by adding only egg yolk to whole eggs. Ordinary chicken eggs are used to obtain the whole eggs and egg yolks. In the following description, the weight of the egg component refers to the sum of the weight of the whole egg and the weight of the egg yolk. Furthermore, in the following description, the weight ratio of the egg component to the rice flour component is varied, but the weight ratio of the whole egg to the rice flour component remains approximately constant. The weight ratio of the egg component is changed by varying the weight ratio of the egg yolk added to the whole egg. While the weight ratio of the whole egg to the rice flour component is not limited, if the weight of the rice flour component is considered 100%, it can be set to a range of 150% to 200% by weight, for example, in Embodiment 1, where the proportion of whole egg in the egg component is 188%.

[0025] Here, if the weight of the rice flour component is taken as 100%, it is preferable that the weight of the egg component be in the range of 220% to 320%. Furthermore, if the weight of the rice flour component is taken as 100%, it is even more preferable that the weight of the egg component be in the range of 250% to 300%. In other words, if the weight of the egg component is less than 220% of the rice flour component, as will be described later, the amount of protein in the egg component will not be sufficient, and the skeletal structure of the rice flour castella after baking may not be maintained. Also, if the weight of the egg component is more than 320% of the rice flour component, as will be described later, the amount of fat in the egg component will be high, which may cause air bubbles to collapse easily and reduce heat conductivity, potentially resulting in poor rise of the rice flour castella during baking.

[0026] Furthermore, in Embodiment 1, since the proportion of whole egg in the egg component is 188%, when the weight of the rice flour component is set to 100%, it is preferable that the amount of egg yolk added to the whole egg be between 32% and 132%. Moreover, when the weight of the rice flour component is set to 100%, it is even more preferable that the amount of egg yolk added to the whole egg be between 62% and 112%. In other words, when the weight of the whole egg is set to 100%, it is preferable that the amount of egg yolk added to the whole egg be in the range of 17% (≒32 / 188) to 70% (≒132 / 188) by weight. Furthermore, when the weight of the whole egg is set to 100%, it is preferable that the amount of egg yolk be in the range of 33% (≒62 / 188) to 60% (≒112 / 188) by weight. In other words, if the egg yolk accounts for less than 17% of the total egg weight, as will be explained later, the amount of protein in the egg components may not be sufficient, and the structural integrity of the rice flour castella may not be maintained after baking. Also, if the egg yolk accounts for more than 70% of the total egg weight, as will be explained later, the amount of fat in the egg components will be high, which may cause air bubbles to collapse easily and reduce heat conductivity, potentially resulting in poor rise during baking of the rice flour castella.

[0027] The inventors experimentally produced several rice flour castella cakes by varying the ratio of egg yolk added to whole eggs, and experimentally demonstrated that the above range is preferable for the ratio of egg component to rice flour component and the ratio of egg yolk to whole eggs. The properties of these experimental rice flour castella cakes are shown in Figure 1. The experimental cakes that fall within the above preferred range are designated as Examples 1 to 5, and the experimental cakes that fall outside the above preferred range are designated as Comparative Examples 1 to 4. The results of Examples 1 to 5 and Comparative Examples 1 to 4 are also shown in Figure 1. For Examples 1 to 5 and Comparative Examples 1 to 4, only the ratio of egg yolk added to whole eggs was changed; the other components remained the same.

[0028] As shown in Figure 1, in Comparative Examples 1 and 2, where the amount of egg yolk added to the whole egg was small, the height of the rice flour castella after baking was smaller than the predetermined value, indicating that the skeletal structure was not maintained. Similarly, in Comparative Examples 3 and 4, where the amount of egg yolk added to the whole egg was large, the height of the rice flour castella after baking was also smaller than the predetermined value, indicating poor rise during baking. On the other hand, in Examples 1 to 5, where the ratio of egg component to rice flour component and the ratio of egg yolk added to the whole egg were within the above-mentioned preferred range, it was confirmed that a fluffy rise characteristic of castella was obtained.

[0029] <gelatinized rice flour ingredients> The pregelatinized rice flour component consists of pregelatinized rice flour obtained by milling rice in a gelatinized state. Known methods are used to manufacture pregelatinized rice flour; for example, it can be produced by pulverizing rice under relatively high heat and pressure compared to the production of general rice flour. This pregelatinized rice flour has the characteristics of having higher water retention and being less prone to starch β-conjugation (less likely to become dry) than regular rice flour (the aforementioned non-pregelatinized rice flour).

[0030] In Embodiment 1, when the weight of the rice flour component is set to 100%, it is preferable that the pregelatinized rice flour component is in the range of 2% to 20% by weight. Furthermore, when the weight of the rice flour component is set to 100%, it is more preferable that the pregelatinized rice flour component is in the range of 3% to 10% by weight. In other words, if the pregelatinized rice flour component is less than 2% by weight relative to the rice flour component, the water retention capacity will be low, as will be described later, and the water activity Aw may exceed a predetermined value. Also, if the pregelatinized rice flour component is greater than 20% by weight relative to the rice flour component, the viscosity may become too high, as will be described later, and the texture may not meet the target quality.

[0031] The inventors experimentally produced several rice flour castella cakes by varying the proportion of pregelatinized rice flour added to the main ingredients, and demonstrated that the above range is preferable for the ratio of pregelatinized rice flour to rice flour. The properties of these experimental rice flour castella cakes are shown in Figure 2. The prototypes that fall within the above preferred range are designated as Examples 6 to 10, and the prototypes that fall outside the above preferred range are designated as Comparative Examples 5 to 8. The results of Examples 6 to 10 and Comparative Examples 5 to 8 are also shown in Figure 2. For Examples 6 to 10 and Comparative Examples 5 to 8, only the proportion of pregelatinized rice flour added to the main ingredients was changed; the other components remained the same.

[0032] As shown in Figure 2, in Comparative Examples 5 and 6, where the amount of pregelatinized rice flour in the main ingredients is low, the water activity Aw is higher than the predetermined value. This is thought to be because, in the rice flour castella after baking, the amount of pregelatinized rice flour that can bind with the water in the dough is low (low water retention capacity), and the proportion of free water that is not bound to any substance increases. Furthermore, since pregelatinized rice flour tends to develop viscosity more easily by retaining moisture than regular rice flour, in Comparative Examples 7 and 8, where the amount of pregelatinized rice flour in the main ingredients is high, the viscosity of the castella after baking exceeds the predetermined value, resulting in a texture that is not typical of castella. On the other hand, in Examples 6 to 10, where the weight ratio of pregelatinized rice flour to rice flour in the main ingredients is within a suitable range, both the water activity Aw and the viscosity of the rice flour castella meet the criteria.

[0033] <Sugar component> The sugar component consists of known sugars, and in Embodiment 1, it consists of sucrose and low-sweetness corn syrup. In Embodiment 1, the sugar component is blended into the main ingredients in a predetermined proportion. Since this sugar component has a certain degree of water retention capacity, it can also be used to adjust the moisture content in the main ingredients, contributing not only to the final flavoring of the rice flour castella but also to preventing the rice flour castella from drying out (staling) and adjusting the water activity Aw. The amount of sugar component blended into the main ingredients is set within an appropriate range, taking the above effects into consideration.

[0034] In particular, in Embodiment 1, the low-sweetness corn syrup is maltodextrin. Maltodextrin has a relatively high water retention capacity because it has a structure with many hydroxyl groups while suppressing sweetness. Therefore, when adding sugar components to adjust the water activity Aw, for example, if only sucrose is added, the final rice flour castella will become too sweet. However, by adding maltodextrin, it is possible to easily adjust both the sweetness and the water activity Aw.

[0035] <How to make rice flour castella cake> The following describes a specific example of the method for producing rice flour castella according to Embodiment 1. However, the method for producing rice flour castella according to this disclosure is not limited to the description below.

[0036] First, Figure 3 shows the composition of the main ingredients in the rice flour castella of Embodiment 1. As shown in Figure 3, the main ingredients include rice flour components, egg components, pregelatinized rice flour components, and sugar components. As mentioned above, when the weight of the rice flour components is taken as 100%, the egg components account for 182% to 332% by weight (in Embodiment 1, 188% whole egg and 32% to 132% additional egg yolk), and the pregelatinized rice flour components account for 2% to 20% by weight. The sugar components, consisting of sucrose and low-sweetness corn syrup (maltodextrin), are added in appropriate amounts for purposes such as adjusting the water activity Aw and preventing dryness (staling).

[0037] Then, the above main ingredients are thoroughly stirred and mixed, and then filled into a wooden mold and baked. This yields the rice flour castella of Embodiment 1.

[0038] For the rice flour castella of Embodiment 1 obtained in this manner, the previously described prototypes Examples 1-5, Examples 6-10, and Comparative Examples 6 and 7 were packaged with an oxygen absorber after baking, considering transportation in a frozen state. They were then frozen once, thawed, stored at room temperature for a predetermined number of days, and then opened for a sensory evaluation test of texture. For samples with a storage period of 0 days, the evaluation was conducted after freezing and thawing. In this sensory evaluation test, the degree to which the castella retained its characteristic moistness after freezing, thawing, and storage at room temperature for a predetermined number of days was scored on a scale of 5 points, with scores of 2 points or less considered a failure (not meeting the target quality). The results are shown in Figures 4 and 5. The number of evaluators was 5, and the values ​​in Figures 4 and 5 are the average scores of the 5 evaluators rounded to the nearest whole number. From the results shown in Figure 4, it can be seen that for Examples 1-5, the moistness was retained even after a certain number of days of storage at room temperature after freezing and thawing. Furthermore, as shown in Figure 5, the results indicate that while the moistness was maintained for Examples 6-10 even after a certain number of days of storage at room temperature following freezing and thawing, in Comparative Examples 6 and 7, after a certain number of days (40 days in Figure 5) of storage at room temperature following freezing and thawing, the products became dry (aged) and did not reach the target quality.

[0039] As described above, the production of rice flour castella had the following challenges. (i) The fluffy texture characteristic of castella cake cannot be maintained, or the cake does not rise sufficiently during baking. (ii) Compared to wheat flour, it ages more rapidly (loses moisture easily) and becomes dry. (iii) Control and suppress water activity Aw to below a predetermined value. (iv) To maintain moisture even after freezing and thawing, considering transportation in a frozen state.

[0040] In contrast, the rice flour castella of this disclosure incorporates only egg yolks in addition to whole eggs as an egg component. This ensures a sufficient amount of protein, maintains the skeletal structure after baking, and resolves the above-mentioned problem (i) of the rice flour castella sinking after cooling. In particular, egg yolks contain not only protein but also a relatively large amount of water and fat, and these water and fat components can also resolve the above-mentioned problems (ii) to (iv). Furthermore, pregelatinized rice flour components were added to further improve water retention. This also resolves the above-mentioned problems (ii) to (iv). Moreover, the main ingredients contain sugar components. Since the sugars in the sugar components can also retain water, this also resolves the above-mentioned problems (ii) to (iv). In particular, since castella contains a relatively large amount of sugars compared to bread and baked goods, it is easier to add sugar components to resolve the above-mentioned problems (ii) to (iv), in other words, it is possible to manufacture a higher quality product among products using rice flour.

[0041] In other words, the rice flour castella of this disclosure is not simply a matter of replacing the wheat flour in conventional castella with rice flour, but rather the egg component, pregelatinized rice flour component, and sugar component work together to resolve the above-mentioned problems (i) to (iv), thereby achieving a rice flour castella that is comparable to conventional castella made with wheat flour.

[0042] Furthermore, in Embodiment 1, the ratio of egg components to rice flour components was set to within the range of 220% to 320% by weight. In particular, in Embodiment 1, the ratio of egg yolk added to the whole egg in this egg component was set to within the range of 17% to 70% by weight. This ensures a sufficient amount of protein in the egg component, while preventing excessive amounts of fat derived from the egg yolk, resulting in a fluffy texture characteristic of castella.

[0043] Furthermore, rice flour loses moisture more easily than wheat flour, and one of the challenges is how to retain moisture. Therefore, in Embodiment 1, the ratio of pregelatinized rice flour component to rice flour component was set to within the range of 2% to 20% by weight. As mentioned above, pregelatinized rice flour has a higher water retention capacity than general rice flour, which helps to solve the above problems (ii) to (iv), and makes it possible to produce high-quality rice flour castella.

[0044] Furthermore, the main ingredients include sugar components containing sucrose and low-sweetness corn syrup. This not only solves the above problems (ii) to (iv), but also allows for adjustment of the final sweetness of the rice flour castella by using low-sweetness corn syrup. In particular, in Embodiment 1, the low-sweetness corn syrup is maltodextrin. Since maltodextrin has many hydrophilic groups, it has a high water retention capacity, which effectively solves the above problem of how to retain moisture.

[0045] <Variation> Although Embodiment 1 has been described in detail above as a specific example of the present disclosure, the present disclosure is not limited by this specific description. Modifications, improvements, etc., to the extent that they can achieve the purpose of the present disclosure are included in the present disclosure. For example, the following modifications of the embodiments are also included in the technical scope of the present disclosure.

[0046] (1) In the above embodiment, the composition shown in Figure 3 is the main ingredient, and known food additives may be added when manufacturing rice flour castella.

[0047] (2) In the above embodiment, the sugar component contained sucrose and low-sweetness corn syrup, but the embodiment is not limited to this, and other known sugars may be used.

[0048] (3) The numerical values ​​described in the above embodiments are merely examples, and for example, the ratio of whole eggs in the egg component to the rice flour component is not limited to 188%.

Claims

1. Rice flour components made from rice flour, In addition to whole eggs, egg yolks are added to the egg components, Pre-gelatinized rice flour component, Sugar components, Rice flour castella, which is made primarily from rice flour.

2. The rice flour castella according to claim 1, wherein the ratio of the egg component to the rice flour component is in the range of 220% to 320% by weight.

3. The rice flour castella according to claim 2, wherein the proportion of egg yolk added to the whole egg is in the range of 17% to 70% by weight.

4. The rice flour castella according to any one of claims 1 to 3, wherein the ratio of the pregelatinized rice flour component to the rice flour component is in the range of 2% to 20% by weight.

5. The rice flour castella according to any one of claims 1 to 3, wherein the sugar component comprises sucrose and low-sweetness starch syrup.

6. The rice flour castella according to claim 5, wherein the low-sweetness corn syrup is maltodextrin.

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