JP7626421B2 - Food performance improver and method for producing food using the same - Google Patents

Description

The present invention relates to a food performance improver for improving food performance such as taste and taste stability , and a method for producing food using the same.

In the food industry, improving food performance, such as improving taste, is an important theme. For example, flour products such as bread and baked goods are required to have a moist texture and a crispy texture during production. One method for achieving this good texture is to add modified starch. However, this method does not change the texture sufficiently, and there are problems with this method, as it requires the product to be labeled as modified starch, which puts consumers off using it.

Another important issue is that good or improved taste at the time of production changes over time. For example, wheat flour products such as bread and baked goods have the problem of their texture becoming hard when stored after production. This is thought to be due to the so-called aging process, in which wheat flour starch that is alpha-converted during cooking changes to beta-converted over time. In this regard, even when modified starch is used in production, aging continues, and improvements were needed.

Foods that contain a lot of water are also considered to have a low shelf life. For example, bread, souffle cheesecake and choux pastry that are stored in the refrigerator, and pound cake stored at room temperature have a water activity Aw (an index of food preservation) of 0.7 or more, and are considered to have a low shelf life. Furthermore, these foods that contain a lot of water are also subject to aging, which means they gradually harden, so they are required to maintain a moist texture.

On the other hand, similar problems exist not only in wheat flour products but also in rice products. For example, cooked rice is chewy, moist and has a good taste. However, cooked rice also becomes hard in texture and loses taste over time after cooking. This is also thought to be due to retrogradation caused by the beta-conversion of starch.

Methods of maintaining good texture over time after cooking include the combined use of pH adjusters, rice cooking oil, and starch-modifying enzymes (α-amylase). However, there are problems with this, such as insufficient texture change, imparting an unpleasant taste, and requiring food additive labeling. Although many studies have been conducted on methods using starch-modifying enzymes and they have been evaluated to a certain extent, they are not sufficient in terms of preventing staling when stored in the refrigerator.

In addition, the following Patent Document 1 proposes a novel starch composition and a method for producing the same. This method is intended to artificially change the amylose and amylopectin content in starch by enzyme treatment. In other words, it is believed that by removing only the amylose from starch, starch that is less prone to retrogradation will be produced. According to this method, instead of simply treating the starch with α-amylase, the starch is treated with an enzyme that has a unique effect on the amylose and amylopectin in the starch.

JP 2001-103991 A

However, in the above-mentioned Patent Document 1, a special enzyme different from conventional α-amylase must be used. Also, in the application to food in the examples, the effects on warabimochi, cooked rice, and mochi are explained, but the sensory evaluation is done on the texture immediately after production, and no evaluation is done on aging over time.

Therefore, the present invention aims to address the above-mentioned problems and to provide a food performance improver that can improve the taste of foods produced using raw materials consisting of grains or potatoes and improve the taste stability over time, and a method for producing foods using the same.

In order to solve the above problems, the inventor conducted extensive research and discovered that the taste and taste stability of foods can be improved by using pectin contained in raw materials consisting of grains or potatoes in combination with a specific enzyme that modifies pectin, thereby completing the present invention.

That is, the food performance improver according to the present invention has the following features according to claim 1:
A food performance improver for improving the taste and/or taste stability of a food produced using raw materials consisting of grains or potatoes without adding any additional pectin, when the food is eaten after storage at room temperature, refrigeration or freezing without being heated in a microwave oven,
It is characterized by containing pectinase as an enzyme.

According to claim 2, the present invention provides a food performance improver according to claim 1,
The pectinase is characterized in that it is an enzyme having pectin methylesterase activity.

According to claim 3, the present invention provides a food performance improver according to claim 1 or 2,
The raw material made of grains or potatoes is characterized in that it contains starch as a main component and also contains pectin.

According to claim 4 , the method for producing food according to the present invention comprises the steps of:
A method for producing a food product using raw materials consisting of grains or potatoes , without adding any additional pectin , which improves the taste and/or taste stability of the food product when it is eaten after being stored at room temperature, refrigerated or frozen, without being heated in a microwave oven,
The raw material made of the grain or potato contains starch as a main component and also contains pectin,
An application step of applying a food performance improver containing pectinase as an enzyme to the raw material or in-process product consisting of the grain or potato;
and an activation step of activating the enzyme in the raw material or the in-process product after the application step,
The activation step is characterized in that the pectin contained in the food is modified.

According to claim 5 , the present invention provides a method for producing the food product according to claim 4 ,
The pectinase is characterized in that it is an enzyme having pectin methylesterase activity.

According to claim 6 , the present invention provides a method for producing the food according to claim 4 or 5 ,
The activation step includes a heating step of subjecting the raw material or the in-process product after the imparting step to a heat treatment,
In the heating step, the food raw materials or in-process products to which the food performance improving agent has been added are subjected to a heat treatment at a temperature in the range of 15°C to 75°C.

According to the above configuration, the food performance improver of the present invention improves the taste and/or taste stability of a food produced using raw materials made of grains or potatoes without adding any additional pectin, when the food is stored at room temperature, refrigerated or frozen and then eaten without heating in a microwave oven after storage . The pectinase may be an enzyme having pectin methylesterase activity. The raw materials made of grains or potatoes may contain starch as a main component and also pectin . As a result , it is possible to provide a food performance improver that can improve the taste of a food produced using raw materials made of grains or potatoes and improve the taste stability over time, and a food using the same.

According to the above configuration, the food manufacturing method of the present invention includes an application step and an activation step. In the application step, a food performance improver containing pectinase as an enzyme is applied to raw materials or in-process products made of grains or potatoes. In the activation step, the pectin contained in the food is modified. Here, the raw materials made of grains or potatoes contain starch as a main component and also contain pectin, and in the activation step, this pectin is modified.

According to the above configuration, the pectinase may be an enzyme having pectin methylesterase activity. The activation step may include a heating step in which the raw materials or in-process product after the application step is heat-treated. In this heating step, the raw materials or in-process product of the food to which the food performance improving agent has been applied may be heat-treated at a temperature range of 15°C to 75°C. As a result, it is possible to provide a method for producing a food that uses raw materials consisting of grains or potatoes and that can improve the taste of the food after production and improve the taste stability over time.

The present invention will be described in detail below. In the present invention, the food to be improved in taste or taste stability utilizes raw materials made of grains or tubers. Here, grains (including beans) generally refer to plants of the Poaceae family, Fabaceae family, and Polygonaceae family, and are defined as plants whose seeds are mainly starchy and are edible. Examples of grains include wheat, barley, rice, buckwheat, foxtail millet, millet, barnyard millet, corn, and other beans. In addition, tubers include potatoes, sweet potatoes, cassava, konjac, taro, taro, yam, and many others.

These grains and potatoes contain starch as a main component and also pectin. The pectinase contained in the food performance improving agent of the present invention acts on this pectin. In particular, the pectin methylesterase contained in the pectinase uses pectin contained together with starch as a substrate, and demethylates methoxyl groups to carboxyl groups without decomposing the pectin molecular chain. Therefore, in the present invention, the pectin contained together with starch can be modified to pectin with a low methyl ester content (high galacturonic acid content).

The pectinase used in the present invention may be in the form of a crude enzyme, or may be a composite enzyme pectinase. It may also be an enzyme fractionated as pectin methylesterase. When using pectinase, a composite enzyme such as polygalacturonase, pectin lyase, pectin esterase, or pectin methylesterase may also be used. In the present invention, it is preferable to use an enzyme with particularly strong pectin methylesterase activity.

Furthermore, the pectinase used in the present invention is not particularly limited in terms of its origin. Examples of pectinase sources include Aspergillus kawachii, Aspergillus usamii mutant shirousamii, Aspergillus oryzae, Aspergillus sojae, Aspergillus tamarii, Aspergillus niger, Aspergillus awamori, Aspergillus pulverulentus, Aspergillus aculeatus, Trichoderma viride, and Rhizopus oryzae.

In the present invention, it is believed that the enzyme activity is expressed in the stage (activation step) where a food performance improver containing an enzyme having pectinase, particularly pectin methylesterase activity, is added to the ingredients in the food manufacturing stage (cooking stage) and the ingredients are mixed during cooking to activate the enzyme. In the present invention, the activation step refers to a state in which the enzyme function is expressed by a specific pH or temperature. Therefore, it is not necessarily required to be near the optimum pH or temperature for the enzyme. For example, it may be in the temperature range of 0°C to 15°C, or a higher temperature range, or conversely, it may be in a temperature range below 0°C.

The activation process may also include a heating step in which the raw material or the in-process product after the enzyme has been added is subjected to a heat treatment. The heating step in the activation process includes temperatures particularly near the optimum pH and temperature for the enzyme, which is thought to enhance the enzyme activity. Therefore, the heat treatment should be carried out at a temperature range of 15°C to 75°C, more preferably 25°C to 65°C. Heat treatment at a temperature above 75°C can also have the effect of inactivating the enzyme that has completed its role.

Here, pectin, which is a substrate of pectinase, may be contained together with starch in the food material (raw material made of grains or potatoes) that is the subject of the present invention. Examples of starches that contain pectin together with these starches include wheat starch, rice waxy starch, non-glutinous rice starch, corn starch, potato starch, sweet potato starch, tapioca starch, etc.

There are many documents regarding the coexistence of starch and pectin in food ingredients. In the primary cell walls of plant walls, xyloglucan crosslinks the skeleton of cellulose microfibers, with pectin filling the gaps between them. For this reason, wheat bran and rice bran contain a lot of pectin. Pectin is also found in whole wheat, which is made by grinding the wheat bran, germ, and endosperm, as well as in wheat flour, which is made by grinding only the endosperm. It has also been reported that polished rice, excluding rice bran, contains 0.44% total pectin and 0.22% insoluble pectin (Kasei Gakkaishi Vol. 21 No. 2 P. 92-94 (1970)).

The present invention is also effective when starch and pectin do not coexist (e.g., refined starch), or when only a very small amount of pectin exists relative to the amount of starch due to the type of raw material used or the method of refining the flour. In these cases, it is preferable to artificially add pectin.

In addition to pectinase, other additives can be used in combination with the food performance improver. For example, α-glucans such as dextrin, maltotriose, and maltose, which are thought not to inhibit enzyme activity, may be used in combination.

By using the food performance improver of the present invention in the production of food, the taste of the food is improved and the taste stability is improved. The effects of the food performance improver will be explained in detail in each example described later, but for example, in terms of taste improvement, the bulk and moistness of baked goods and fresh Western-style pastries stored at room temperature after baking are improved, and the crispness and powdery texture of baked goods are improved. In addition, in terms of improving taste stability, the moistness of baked bread is maintained over time, and the water retention, chewy texture, and soft surface of cooked rice and dumplings are maintained over time.

The improvement in taste of foods by the present invention cannot be explained by the prevention of aging caused by the beta-conversion of starch. It is also unclear whether the improvement in taste stability over time is due solely to the prevention of aging caused by the beta-conversion of starch. However, the present inventor believes as follows. Pectin that coexists with starch is subjected to the action of pectinase, particularly pectin methylesterase activity, which demethylates the methoxyl groups to carboxyl groups and forms pectic acid. In this way, pectin is modified to pectin with a low methyl ester content (high galacturonic acid content). As a result, the negative charge of pectin that coexists with starch increases, making it more hydrophilic. It is also believed that the effects of the present invention are manifested by the action of increasing electrostatic repulsion, which inhibits hydrogen bonds between amylose and amylopectin in starch, especially between amylose.

Next, the food products using the food performance improving agent of the present invention and the method for producing the same will be specifically explained using each example. Note that the present invention is not limited to the examples described below, and is not limited to the specific foods listed here.

In the following examples, pectinase produced by Aspergillus niger was used. This pectinase is an enzyme with pectin methylesterase activity (hereinafter referred to as "PME" in each example), and is an enzyme with strong pectin methylesterase activity, with almost no polygalacturonase activity or pectin lyase activity. This enzyme has an optimum pH of 4.5 and an optimum temperature of 50°C, and the pectin methylesterase activity (potency) is defined as the enzyme activity unit (PMEU) that decomposes pectin methyl ester to generate 1 μmol of carboxyl group per minute.

The amount of food performance improver used in the present invention varies depending on the amount of starch used in the food and the amount of pectin coexisting with that starch. Therefore, it is adjusted according to the pectin methylesterase activity (PMEU) of the food performance improver. Note that in the present invention, there are no particular limitations on the amount of food performance improver added. For example, it is sufficient if it is 0.02 PMEU or more per gram of starch, preferably 0.05 PMEU or more, and even more preferably 0.1 PMEU or more.

This Example 1 is directed to fresh Western confectionery (souffle cheesecake), and the effect of a PME-containing food performance improver on fresh Western confectionery containing wheat flour was confirmed. Souffle cheesecake has a high water activity Aw (an index of food preservation) of about 0.9 to 0.8, and has issues such as a powdery wheat flour texture and poor texture.

1. Addition process of food performance improver First, 297 g of milk was mixed with 119 g of soft flour, 77 g of egg yolk, 18 g of granulated sugar, 190 g of cream cheese, and 47 g of margarine to prepare a material. The prepared material was divided into eight groups, and 0.002, 0.01, 0.05, and 0.3 PMEU of the food performance improver per 1 g of wheat flour were added to the four samples of Examples 1a to 1d. On the other hand, the four samples of Comparative Examples 1a to 1d were each added with no additive (1a), 2% less soft flour and 2% more milk (1b), 2% less soft flour and 2% more margarine (1c), and 0.3 Units of α-amylase (1d). Separately beaten meringue (148 g of egg white + 104 g of granulated sugar) was added to each of the prepared materials to obtain a soufflé cheesecake dough.

2. Food activation process (including heating process)
Next, 50 g of each sample batter was poured into a cup and baked at 170° C. for 27 minutes to prepare soufflé cheesecakes for eight samples of Examples 1a to 1d and Comparative Examples 1a to 1d. In this Example 1, it is believed that the PME acted during the preparation of the batter and during baking at room temperature to 170° C., particularly from room temperature to about 75° C.

3. Evaluation In this Example 1, after baking the souffle cheesecake, it was refrigerated for 16 hours and then evaluated by scoring its appearance (the height (bulk) of the finished product) and its texture (moistness) by sensory evaluation. Specifically, four skilled evaluators rated it on a scale of 0 (bad) to 5 (good) and took the average. Here, moistness refers to a state in which the surface is moist and the tongue does not feel rough, and the higher the score, the better and more moist it is, which is preferable. In addition, as an overall evaluation, a total of 7 points or more for the two evaluation items was rated as A, 6 points or more was rated as B, and the rest was rated as C. The evaluation results are shown in Table 1.

As can be seen from Table 1, all samples of Examples 1a to 1d, in which a PME-containing food performance improver was added, were judged to have an overall rating of A or B. In particular, Examples 1b to 1d, in which 0.01 PMEU or more was added, were given a high overall rating of A. In contrast, all samples of Comparative Examples 1a to 1d were given an overall rating of C. This confirmed that the use of a PME-containing food performance improver in wheat flour has a favorable effect on improving the taste of soufflé cheesecake.

This Example 2 is aimed at baked goods (cookies), and the effect of a food performance improver containing PME on baked goods containing wheat flour was confirmed. Cookies have a low water activity Aw of about 0.6 to 0.5, which causes the wheat flour to lose its crispiness.

1. Addition process of food performance improver First, 260g of margarine and 180g of white sugar were mixed, 70g of whole egg was mixed with this, and 500g of weak flour was further mixed to prepare the dough. The prepared material was divided into 9 parts, and 0.002, 0.01, 0.05, and 0.3 PMEU of the food performance improver per 1g of wheat flour were added to the four samples of Examples 2a to 2d. On the other hand, the five samples of Comparative Examples 1a to 1e were, respectively, no additive (2a), 10% of the weak flour was replaced with modified starch (2b), 10% of the weak flour was replaced with corn starch (2c), 7% less whole egg and 7% more weak flour (2d), and 0.3 Units of α-amylase was added (2e).

2. Food activation process (including heating process)
Next, the dough for each sample was cut into a mold and baked in an oven at 170°C for 13 minutes to produce nine cookies for Examples 2a to 2d and Comparative Examples 2a to 2e. Note that in this Example 2, it is believed that the PME acted during the preparation of the dough and baking at room temperature to 170°C, particularly from room temperature to about 75°C.

3. Evaluation In this Example 2, after the cookies were baked and cooled to room temperature, the dough properties (moldability of the finished cookies) and the texture (crispness and lack of powderiness) were scored and evaluated by sensory evaluation. Specifically, four skilled evaluators evaluated the cookies on a scale of 0 (bad) to 5 (good) and averaged the scores. Here, the crispiness refers to a texture that crumbles immediately when biting into the cookie, and the higher the score, the better and more preferable the crispiness. Furthermore, lack of powderiness refers to a state in which the cookie is not easily rough on the tongue after it crumbles. The higher the score, the better and more preferable the lack of powderiness. In addition, as an overall evaluation, a total of 10 points or more for the dough properties and sensory evaluation was rated as A, 8 points or more was rated as B, and the rest was rated as C. The evaluation results are shown in Table 2.

As can be seen from Table 2, all samples of Examples 2a to 2d, which contained a PME-containing food performance improver, received a high overall rating of A. In contrast, samples of Comparative Examples 2a to 2d received an overall rating of C, and Comparative Example 2e also received an overall rating of B. This confirmed that the use of a PME-containing food performance improver in wheat flour has a favorable effect on improving the taste of cookies.

This Example 3 is directed to bread, and the effect of a food performance improver containing PME on bread containing wheat flour was confirmed. Bread has a high water activity Aw, and there is an issue of deterioration in texture due to aging over time. There is also an issue of the dough properties when water is added.

1. Addition process of food performance improver First, 371g of strong flour (Super Camellia), 7g of yeast (Saf yeast red), and 220g of city water were put into a molder, mixed at low speed for 3 minutes, and mixed at medium speed for 1 minute to obtain a dough. Then, the dough was fermented in a proofer at a temperature of 28°C and a humidity of 78% for 2 hours to obtain a sponge. Then, 159.4g and 55g of strong flour, 10g of skim milk powder, 10g of salt, and 146.2g of water were added to the sponge. Here, 0.03 PMEU of a food performance improver per 1g of flour was added to the sample of Example 3. On the other hand, nothing was added to the sample of Comparative Example 3. This kneading was performed at low speed for 30 seconds and medium speed for 3 minutes, and then 21g of margarine was added. Then, it was mixed at low speed for 1 minute, and further kneaded at medium speed for 4 minutes.

2. Food activation process (including heating process)
Next, the obtained dough was rested at 24°C for 20 minutes, and then the dough was shaped, rested again at 24°C for 20 minutes, and then rounded and shaped. The dough was then placed in a proofer and fermented for 53 minutes at a temperature of 38°C and a humidity of 85%. After fermentation, the dough was baked at 210°C for 27 minutes to produce two sample breads, Example 3 and Comparative Example 3. In this Example 3, it is believed that the PME acted during dough preparation (main kneading and resting) and during baking at room temperature to 210°C, particularly from room temperature to about 75°C.

3. Evaluation In this Example 3, the texture (moistness) of the bread 1 day and 3 days after baking was evaluated by sensory evaluation. Specifically, four skilled evaluators evaluated the texture from 0 points (bad) to 5 points (good) and took the average value. Here, moistness refers to a state in which the surface is moist and the tongue does not feel rough, and the higher the score, the better the moistness and the more preferable it is. In addition, as an overall evaluation, a sensory evaluation of 4 points or more was rated A, 2.5 points or more was rated B, and the rest was rated C. The evaluation results are shown in Table 3.

As can be seen from Table 3, the sample of Example 3, which contained the PME-containing food performance improver, received a high overall rating of A one day after baking. It also received an overall rating of B even three days after baking. In contrast, the sample of Comparative Example 3 received an overall rating of C one day after baking. This shows that the use of the PME-containing food performance improver in wheat flour gives bread a moist texture and also inhibits aging over time.

This Example 4 is directed to a curry roux containing wheat flour, and the effect of a food performance improver containing PME on a curry roux containing wheat flour was confirmed. If the curry roux is left to sit after preparation, a film forms on the surface, which causes the smooth texture to be lost.

1. Addition process of food performance improver First, heat salad oil, add onion, garlic, and ginger, and fry. Separately, heat butter, add weak flour, and fry until brown. Add the previously fried onion, cumin powder, and other seasonings and mix. Here, 0.03 PMEU of food performance improver per 1 g of wheat flour was added to the sample of Example 4. On the other hand, nothing was added to the sample of Comparative Example 4a, and 0.03 Units of α-amylase was added to the sample of Comparative Example 4b.

2. Food activation process (including heating process)
Next, each curry roux was heated at around 100°C for 20 minutes in the usual manner to produce the curry roux of Example 4 and Comparative Examples 4a and 4b. Note that in this Example 4, it is believed that the PME acted during the preparation of the curry roux and heating at room temperature to 100°C, particularly from room temperature to around 75°C.

3. Evaluation In this Example 4, after preparation of the curry roux, it was stored in a refrigerator (4°C) for one day, and was evaluated when a film had formed on the surface. Although a film formed on the surface in both the Examples and Comparative Examples, the physical properties (viscosity) of the curry roux and the sensory evaluation (softness of the film, smoothness of the inside) by eating were scored and evaluated. The sensory evaluation was evaluated by four skilled evaluators on a scale of 0 (bad) to 5 (good), and the average value was taken. Here, the softness of the film is defined as a state in which there is almost no film on the surface and it is smooth, and the higher the score, the more preferable it is for there to be no film and it is smooth. In addition, the smoothness of the inside is the smoothness felt when the part under the film of the curry roux is eaten and evaluated, and the higher the score, the better the smoothness and it is preferable. In addition, a total of 10 points or more for the three evaluation items was rated as A, 8 points or more was rated as B, and the rest was rated as C. The evaluation results are shown in Table 4.

As can be seen from Table 4, the sample of Example 4, which contained a food performance improving agent containing PME, received a high overall rating of A. The sample of Example 4 had the viscosity of a curry roux, but was soft with almost no film formed on the surface, and was also exceptionally smooth inside.

In contrast, the samples of Comparative Examples 4a and 4b received an overall rating of C. In the additive-free sample of Comparative Example 4a, a film formed on the surface after one day of storage, and the inside felt rough. In the sample of Comparative Example 4b with added α-amylase, a film was hardly formed and it was soft, but it had lost the viscosity required for a curry roux in the first place, and was not suitable for use as a curry roux.

This confirmed that the use of a food performance improver containing PME in wheat flour has a favorable effect on improving the taste stability of curry roux. In addition, by using it in viscous sauces containing wheat flour or rice flour other than curry roux (e.g. cream croquettes), it is possible to achieve a smooth interior without causing a decrease in viscosity. It also suppresses the formation of a film on the surface.

This Example 5 is directed to custard filling, and the effect of a food performance improver containing PME on custard filling containing wheat was confirmed. Here, the objective is to improve the smooth texture of the custard filling.

1. Step of adding food performance improver First, 13% egg yolk, 64% milk, 15% granulated sugar, and 8% starch are mixed. The starch used was weak flour in Example 5 and Comparative Examples 5a and 5c, and modified starch (phosphate cross-linked starch) in Comparative Example 5b. In addition, 0.03 PMEU of the food performance improver per 1 g of wheat flour was added to the sample of Example 5. On the other hand, nothing was added to the samples of Comparative Examples 5a and 5b, and 0.03 Units of α-amylase was added to the sample of Comparative Example 5c.

2. Food activation process (including heating process)
Next, each sample was heated at about 100°C for 20 minutes in a normal manner to prepare the custard fillings of Example 5 and Comparative Examples 5a, 5b, and 5c. In this Example 5, it is believed that the PME acted during the preparation of the ingredients and heating at room temperature to 100°C, particularly from room temperature to about 75°C.

3. Evaluation In this Example 5, the custard filling was prepared, frozen, and then thawed before evaluation. First, the physical properties (viscosity and thickness) of the custard filling were confirmed by mixing with a spatula. In addition, the smoothness of the inside and the taste (absence of an unusual starchy flavor) were scored and evaluated as a sensory evaluation upon eating. The sensory evaluation was conducted by four experienced evaluators, who scored from 0 points (bad) to 5 points (good), and the average was calculated.

Here, internal smoothness refers to a state in which the texture when it touches the tongue is smooth, with higher scores being preferable as it is membrane-free and smooth. Additionally, taste (absence of off-flavor starch) refers to a state in which there is no flavor or taste specific to starch, with higher scores being preferable. Furthermore, the inhibition of syneresis during refrigeration/cold thawing was also evaluated. Additionally, for the overall evaluation, a total of 15 points or more for the five evaluation items was given an A, and anything less was given a C. The evaluation results are shown in Table 5.

As can be seen from Table 5, the sample of Example 5, which contained a food performance improver containing PME, received a high overall rating of A. In the sample of Example 5, PME acts on the pectin in the wheat to increase water retention, which is thought to improve smoothness and suppress syneresis when thawed in a cold state.

In contrast, the samples of Comparative Examples 5a, 5b, and 5c were given an overall rating of C. The additive-free sample of Comparative Example 5a uses weak flour and does not have an off-flavor of starch, but is prone to syneresis when thawed in the cold or stored for a long period of time. The additive-free sample of Comparative Example 4b uses modified starch (phosphate cross-linked starch), which has a good effect of suppressing syneresis, but produces an off-flavor of starch and makes it difficult to achieve height after cooking the custard filling. The sample of Comparative Example 4c with added α-amylase has a significant decrease in viscosity, making it unsuitable as a custard filling.

This confirmed that by using a food performance improver containing PME in a custard filling made with wheat flour, it is possible to achieve a smooth interior without causing a decrease in viscosity or height, and that this has a favorable effect on improving the taste of the custard filling.

This Example 6 is aimed at cooked rice, and the effect of a food performance improver containing PME on cooked rice was confirmed. Cooked rice with a high water activity Aw has two issues: suppressing hardness during refrigeration, and suppressing hardness due to heat deterioration in the rice cooker after cooking.

1. Addition process of food performance improver First, 150 g of raw rice (Aichi no Kaori) was washed with water, and then soaked in water with 150% water added so that the total amount of water and rice was 375 g. The sample of Example 6 thus prepared was added with 0.03 PMEU of food performance improver per 1 g of raw rice. The sample of Comparative Example 6 was not added.

2. Food activation process (including heating process)
Next, each sample of Example 6 and Comparative Example 6 was cooked in a normal cooking mode of a commercially available electric rice cooker (electric rice cooker). In this Example 6, it is considered that the PME acted during cooking at room temperature to 100°C after the addition of the food performance improving agent, particularly from room temperature to about 75°C.

3. Evaluation In this Example 6, the change in the texture of cooked rice over time was confirmed both in the electric rice cooker (heating deterioration) and in the refrigerator (refrigerating deterioration). To confirm the deterioration in the electric rice cooker, each sample after cooking was stored in the electric rice cooker in the warming mode, and the texture was confirmed after 4 hours and 6 hours. On the other hand, to confirm the deterioration in the refrigerator, each sample immediately after cooking was mixed with vinegar, then transferred to a plastic container and stored in a refrigerator (4°C), and the texture was confirmed after 16 hours and 24 hours. The evaluation of the texture was evaluated by scoring three items, namely, water retention, chewy texture, and surface softness, by sensory evaluation. Specifically, four evaluators who are skilled in evaluation evaluated the rice on a scale of 0 points (bad) to 5 points (good), and the average value was taken.

Here, moisture retention refers to a state in which the surface is moist but the rice grains are holding water, and the higher the score, the better and more preferable the moisture retention. Chewy texture refers to the chewy repulsive force felt on the teeth when biting into the rice, and the higher the score, the better and more preferable the chewiness. Surface softness refers to the absence of repulsive force felt on the teeth when first biting into the rice, and the higher the score, the better and more preferable the softness. In addition, as an overall evaluation, a total of 12 points or more in the three sensory evaluation items was given an A, 8 points or more was given a B, and the rest was given a C. As evaluation results, deterioration inside the electric rice cooker (heat deterioration) is shown in Table 6, and deterioration inside the refrigerator (refrigerated deterioration) is shown in Table 7.

As can be seen from Table 6, when stored in an electric rice cooker to evaluate thermal degradation, the sample of Example 6 to which the PME-containing food performance improver was added received a high overall rating of A after 4 hours of storage in the rice cooker. It also received an overall rating of B after 6 hours of storage in the rice cooker. In contrast, the sample of Comparative Example 6 received an overall rating of C after both 4 and 6 hours of storage in the rice cooker. This confirmed that the use of a PME-containing food performance improver in cooked rice also has a favorable effect against thermal degradation.

As can be seen from Table 7, when stored in a refrigerator to evaluate refrigeration deterioration, the sample of Example 6 to which the PME-containing food performance improver was added received an overall rating of B both after 16 and 24 hours of refrigerated storage. In contrast, the sample of Comparative Example 6 received an overall rating of C both after 16 and 24 hours of refrigerated storage. This confirmed that the use of a PME-containing food performance improver in cooked rice also provides a favorable effect against refrigeration deterioration.

This Example 7 is aimed at dumplings, and the effect of a food performance improver containing PME on dumplings containing glutinous rice flour was confirmed. Dumplings with high water activity Aw have the problem of suppressing hardness during refrigeration.

1. Addition of food property improver First, 100 g of water was added to 100 g of glutinous rice flour and mixed thoroughly, and 0.03 PMEU of the food property improver per 1 g of glutinous rice flour was added to the sample of Example 7 and molded into dumplings. The sample of Comparative Example 7 was molded into dumplings without any additives.

2. Food activation process (including heating process)
Next, boiling water was prepared in a pot, and each sample of Example 7 and Comparative Example 7 was added and simmered for 8 minutes, and then rapidly cooled in ice water. Note that in this Example 7, it is believed that the PME acted during simmering at room temperature to 100°C after the addition of the food performance improving agent, particularly from room temperature to about 75°C.

3. Evaluation In this Example 7, in order to confirm the suppression of hardness during refrigeration, the following sample dumplings were placed on a plate and stored in a refrigerator (4°C), and the texture was confirmed after 4 hours and 24 hours. The texture was evaluated by scoring three items, namely, water retention, chewy texture, and surface softness, through sensory evaluation. Specifically, four skilled evaluators rated the dumplings on a scale of 0 (bad) to 5 (good), and the average was calculated.

Here, moisture retention is defined as a state in which the surface is moist but the rice grains are holding water, with the higher the score, the better and more preferable the moisture retention. Chewy texture is defined as the springy repulsive force felt on the teeth when biting into the rice, with the higher the score, the better and more preferable the chewy texture. Surface softness is defined as the absence of repulsive force felt on the teeth when first biting into the rice, with the higher the score, the better and more preferable the softness. In addition, for the overall evaluation, a total of 12 points or more in the three sensory evaluation categories was given an A, a B for 8 points or more, and a C for anything less. The evaluation results are shown in Table 8.

As can be seen from Table 8, when stored in a refrigerator to evaluate refrigeration deterioration, the sample of Example 7 to which the PME-containing food performance improver was added received a high overall rating of A after 4 hours of refrigerated storage. It also received an overall rating of B after 24 hours of refrigerated storage. In contrast, the sample of Comparative Example 7 received an overall rating of C after both 4 and 24 hours of refrigerated storage. This confirmed that the use of a PME-containing food performance improver in glutinous rice flour provides a favorable effect against refrigeration deterioration.

As described above, according to the present invention, it is possible to provide a food performance improver that can improve the taste of foods produced using raw materials consisting of grains or potatoes and can improve the taste stability over time, and a method for producing foods using the same.

The present invention is not limited to the above-described embodiments, but may be modified in various ways as follows.
(1) In each of the above examples, pectinase produced by Aspergillus niger was used as the enzyme contained in the food performance improving agent. However, this is not limited to this, and pectinase derived from other microorganisms may also be used.
(2) In each of the above examples, the enzyme contained in the food performance improving agent was pectinase, which has little polygalacturonase activity or pectin lyase activity and has strong pectin methylesterase activity. However, the present invention is not limited to this, and an enzyme having polygalacturonase activity and pectin lyase activity may be used.
(3) In the above examples, wheat flour (wheat starch), polished rice (rice non-glutinous starch), and glutinous rice flour (rice glutinous starch) were used as the raw materials for the food on which the food performance improving agent acts. However, this is not limited to these, and other raw materials such as corn starch, potato starch, sweet potato starch, tapioca starch, etc. may also be used.

Claims (6)

A food performance improver for improving the taste and/or taste stability of a food produced using raw materials consisting of grains or potatoes without adding any additional pectin, when the food is eaten after storage at room temperature, refrigeration or freezing without being heated in a microwave oven,
A food performance improver characterized by containing pectinase as an enzyme. The food performance improver according to claim 1, characterized in that the pectinase is an enzyme having pectin methylesterase activity. 3. The food performance improver according to claim 1 or 2, characterized in that the raw material consisting of grains or potatoes contains starch as a main component and also contains pectin. A method for producing a food product using raw materials consisting of grains or potatoes , without adding any additional pectin , which improves the taste and/or taste stability of the food product when it is eaten after being stored at room temperature, refrigerated or frozen, without being heated in a microwave oven,
The raw material made of the grain or potato contains starch as a main component and also contains pectin,
An application step of applying a food performance improver containing pectinase as an enzyme to the raw material or in-process product consisting of the grain or potato;
and an activation step of activating the enzyme in the raw material or the in-process product after the application step,
A method for producing a food product, comprising modifying pectin contained in the food product in the activation step. The method for producing a food product according to claim 4 , wherein the pectinase is an enzyme having pectin methylesterase activity. The activation step includes a heating step of subjecting the raw material or the in-process product after the imparting step to a heat treatment,
The method for producing a food product according to claim 4 or 5 , characterized in that in the heating step, the raw materials or in-process products of the food product to which the food performance improving agent has been applied are subjected to a heat treatment at a temperature in the range of 15°C to 75°C.