JP2021122250A - Method for producing sweet potato squeezed liquid and method for producing sweet potato juice - Google Patents

Abstract

To provide a sweet potato juice that uses a squeezed liquid obtained from squeezing sweet potato, and a method for producing a sweet potato squeezed liquid and a method for producing a sweet potato juice that are made so that one exhibiting moderate sweetness can be obtained.SOLUTION: In the method for producing sweet potato squeezed liquid by subjecting sweet potato to blanching, hydrolysis, and crushing, and subjecting the obtained processed product to enzymatic treatment and then to squeezing to yield a squeezed liquid, the enzymatic treatment is performed using a maltotriose-producing amylase. Further, a sweet potato juice in which the obtained sweet potato squeezed liquid is mixed with other raw material is yielded. It is preferable to further use a fibrolytic enzyme for the enzymatic treatment. As the sweet potato, it is preferable to use an anthocyanin-containing purple-color sweet potato.SELECTED DRAWING: None

Description

The present invention relates to a sweet potato juice squeezed liquid and a method for producing sweet potato juice using sweet potato as a raw material.

Conventionally, a squeezed juice obtained by squeezing sweet potato juice and sweet potato juice using the juice are known. Some of the natural oligosaccharides contained in sweet potatoes and colored sweet potatoes contain a high content of purple pigments such as anthocyanidins and yellow / orange pigments β-carotene, and these nutrients can be easily ingested. It is attracting attention as a food material.

Generally, the press method or centrifugation method is used to separate the juice from vegetables and fruits, but sweet potatoes are rich in fiber and starch, and in order to maintain an appropriate viscosity, , It was necessary to separate the juice while removing these well. However, there is a problem that the sweetness and flavor cannot be successfully extracted from the sweet potato by simply removing the fiber and starch by centrifugation or filtration, and the yield is further deteriorated.

In relation to such a problem, for example, Patent Document 1 discloses a sweet potato beverage characterized by containing an enzymatically decomposed product of sweet potato decomposed by using a fibrous degrading enzyme and a starch degrading enzyme in combination. .. Further, for example, in Patent Document 2, sweet potato is substantially inactivated by polyphenol oxidase contained therein, but its maltose content is 1.0 to 10% by weight under the condition of activating amylase. The first step of heat-treating the sweet potato, the second step of squeezing the heat-treated sweet potato, and the squeezed juice so that the viscosity due to the starch granules in the juice is reduced. A method for producing sweet potato juice is disclosed, which is characterized by undergoing a third step.

Japanese Unexamined Patent Publication No. 9-107934 Japanese Unexamined Patent Publication No. 10-215835

According to the above-mentioned Patent Documents 1 and 2, etc., a sweet potato juice or sweet potato juice having good quality can be obtained by a method using an enzyme for fiber or starch.

However, according to the research by the present inventors, it is difficult to adjust the sweetness by sugars generated by enzymatic decomposition, and there is a problem that the flavor is affected when prepared into sweet potato juice.

Therefore, an object of the present invention is a method for producing a sweet potato juice and a method for producing a sweet potato juice so as to obtain a sweet potato juice using a juice obtained by squeezing sweet potato juice and exhibiting a moderate sweetness. The purpose is to provide a manufacturing method.

The present inventors have diligently studied in order to achieve the above object, and have completed the present invention.

That is, in the first aspect of the present invention, the sweet potato juice obtained by blanching, adding water, and crushing the sweet potato and squeezing the obtained processed product after enzyme treatment to obtain a juice. The present invention provides a method for producing sweet potato juice, which comprises performing the enzyme treatment using maltotriose-producing amylase.

In the method for producing sweet potato juice, it is preferable to carry out the enzyme treatment using the maltotriose-producing amylase and a fibrous degrading enzyme.

In the above method for producing sweet potato juice, the juice contains 70% by mass or more and 98% by mass or less of carbohydrates with respect to the total solid content, and the starch content is 10% by mass or less with respect to the total solid content. , It is preferable to obtain a juice squeezed liquid having a starch content of 10% by mass or less based on the total solid content.

In the method for producing sweet potato juice, it is preferable to obtain a juice containing 0.75% by mass or more of anthocyanin compounds in terms of aglycone in terms of total solid content.

In the method for producing sweet potato juice, it is preferable to concentrate after the juice to obtain a juice having a Brix value of 45 or more and 55 or less.

The present invention provides, from the second aspect, a method for producing sweet potato juice, which comprises a step of mixing the sweet potato juice obtained by the above-mentioned production method with other raw materials. ..

In the method for producing sweet potato juice, it is preferable that the other raw material is one or more selected from the group consisting of water, lemon juice, acidulants, and flavors.

According to the present invention, since maltotriose-producing amylase was used to prepare the sweet potato juice, the content of glucose, which is a sweet component, among the sugars produced by starch decomposition without causing deterioration of flavor and nutritional components. It is possible to provide a sweet potato juice liquor in which glucose is suppressed. Therefore, this makes it possible to provide sweet potato juice having a moderate sweetness.

The variety of sweet potato used as a raw material in the present invention is not particularly limited. For example, it may be a general distribution product such as veneer zuma, benisatsuma, or Ayamurasaki, Murasakimasari, Yamakawa purple, Taneshima purple, Chiran purple, Kyushu 109, Jay red, Benihayato, Sunny red, Akemurasaki, which are rich in anthocyanin compounds. It may be a so-called colored sweet potato such as purple sweet potato such as, Benihayato rich in carotene compounds, healthy red, Kyushu No. 120, orange sweet potato such as Higashiyama. Among them, Ayamurasaki, which is rich in anthocyanin compounds known to have various physiological effects, is preferably exemplified.

In the method for producing sweet potato juice according to the present invention, first, the sweet potato is blanched, hydrated, and crushed.

By blanching the sweet potato, the enzyme contained in the sweet potato can be inactivated and the starch contained in the sweet potato can be gelatinized. As a result, it is possible to suppress the disorderly decomposition of the sweet potato component and obtain a juice squeezed liquid with stable quality. Further, by gelatinizing the starch, it becomes easy to react with the enzyme, and efficient decomposition is promoted. The conditions of the blanching treatment are not particularly limited, and typically, for example, by steaming or soaking with steam or water heated to a state of 90 to 100 ° C., the center of the sweet potato of the raw material. The temperature is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, and the treatment can be carried out for 5 to 30 minutes.

In addition, by treating sweet potatoes with water, the treatment with enzymes becomes efficient. The amount of water added is not particularly limited, and is typically, for example, 0.5 to 20 times the amount of the sweet potato raw material, more preferably 1 to 10 times the amount, and 3 to 3 to. Even more preferably, the amount is 6 times.

Further, by subjecting the sweet potato to a crushing treatment, the treatment with an enzyme can be efficiently performed. The crushing means is not particularly limited, and typically, for example, a hammer crusher, a mixer, a chopper, a millstone crusher, a disk cutter, a cutter such as a fruit cutter, an ultra-precision high-speed crusher, or the like is used. Just do it. The degree of crushing may be arbitrarily adjusted, but the treated product in the state of being subjected to the above-mentioned watering treatment should be crushed until the contents become fluid enough to be mixed and dispersed well. Is preferable. In addition, it is desirable to select a means for finer grinding in order for the enzyme to act uniformly. The term "crushing" in such a crushing process also includes cases generally referred to as "crushing", "grinding", "shredding", and the like.

The order of processing the above-mentioned raw materials is not particularly limited, but from the viewpoint of work efficiency, the blanching treatment is preferably performed first, and the blanching, watering, and crushing treatments are more preferable. These processes may be performed at timings that overlap each other.

The raw material sweet potato may be cut into an appropriate shape as appropriate. For example, it may be cut into strips having a thickness of 20 to 40 mm by a device such as a slicer, or may be cut into random pieces to a predetermined size. Further, as a raw material sweet potato treatment, peeling may be performed with a device such as a steam peeler. By subjecting the sweet potato as a raw material to a processing treatment having such a shape, it is possible to increase the efficiency of preparation of a processed product obtained through at least the above-mentioned blanching, watering, and crushing treatments. The timing at which the raw material sweet potato is subjected to the processing treatment for such a shape is not particularly limited, and typically, for example, it may be before the above-mentioned blanching treatment, and the above-mentioned water addition may be performed. It may be before the treatment of the above-mentioned crushing. However, when it is desired to recover the sweet potato skin or the components contained in the vicinity of the skin, it is preferable not to perform the peeling treatment.

The raw material sweet potato after the blanching treatment described above is optionally used for the production of sweet potato juice at another time, so that it can be stored in a temporary freezing or the like.

In the method for producing sweet potato juice according to the present invention, the processed product obtained through the above-mentioned blanching, watering, and crushing treatments is subjected to enzymatic treatment with maltotriose-producing amylase.

The maltotriose-producing amylase used for the enzyme treatment may be any enzyme having an activity of acting on starch to mainly produce maltotriose. Specifically, it may be an enzyme having an activity of producing maltotriose using a polysaccharide having an α (1 → 4) -glucan structure such as amylose, amylopectin, and glycogen as a substrate, and more specifically. Is glucan
It may be an enzyme belonging to 1,4-α-maltotriohydrolase (EC 3.2.1.16, also known as maltotriose-forming enzyme). For example, Japanese Patent Publication No. 57-6915 describes maltotriose-producing amylase derived from a microorganism belonging to Streptomyces griseus. Further, Japanese Patent Publication No. 60-15315 describes a maltotriose-producing amylase derived from a microorganism belonging to the genus Bacillus. Further, Japanese Patent Application Laid-Open No. 3-251173 describes a maltotriose-producing amylase derived from a microorganism belonging to the genus Microbacterium. Further, Japanese Patent Application Laid-Open No. 2012-016309 describes maltotriose-producing amylase derived from a microorganism belonging to Streptomyces cinnamonensis. Further, as a commercially available enzyme preparation, for example, the trade name "AMT1.
2L ”(manufactured by Amano Enzyme Co., Ltd.) is on the market.

Enzymatic treatment with maltotriose-producing amylase decomposes starch contained in sweet potatoes to produce low-molecular-weight saccharides, but maltotriose-producing amylase has a low production efficiency, at least for glucose. Sweetness is suppressed.

One type of maltotriose-producing amylase may be used alone, or two or more types may be used in combination.

The conditions for the enzyme treatment are not particularly limited, and may be performed under conditions suitable for the enzyme to be used as appropriate. Typically, for example, the processed product of the raw material sweet potato is placed in a suitable container such as a tank together with the enzyme to be used, and while being stirred by the stirring means, the temperature is 35 to 65 ° C., more typically by the heating means. It can be carried out by reacting in the range of 50 to 60 ° C. for 15 to 120 minutes. After the enzyme treatment, a treatment for inactivating the used enzyme may be performed, such as raising the temperature to 70 ° C. or higher, more preferably 90 ° C. or higher. As another example, the enzyme may be added first, the liquid may be gradually accumulated over 15 to 60 minutes, and the juice may be started when the entire amount is accumulated. In addition, when two or more kinds of enzymes are used in combination, treatment with another kind of enzyme may be carried out step by step, or another kind of enzyme may be added together with the above-mentioned raw material sweet potato processed product to carry out enzyme treatment. can.

In the method for producing a sweet potato juice according to the present invention, as a preferred embodiment thereof, the enzyme treatment may be further referred to as a degrading enzyme for fiber or protein together with maltotriose-producing amylase (hereinafter, simply referred to as "fibrotic degrading enzyme"). ) May be used. According to this, the fiber of sweet potato is efficiently decomposed, the amount of juice obtained with respect to the raw material, that is, the juice ratio (yield in terms of solid content) is improved, and the yield is improved. Examples of the fibrogenic enzyme include cellulase, hemicellulase, pectinase, protease and the like. One type of fibrogenic enzyme may be used alone, or two or more types may be used in combination.

The conditions for the enzyme treatment when the above-mentioned fibrogenic enzyme is used are not particularly limited as the above-mentioned conditions for the enzyme treatment with maltotriose-producing amylase, and are suitable for the enzyme to be used as appropriate. Just do it. Typically, for example, the processed product of the raw material sweet potato is placed in a suitable container such as a tank together with the enzyme to be used, and while being stirred by the stirring means, the temperature is 35 to 65 ° C., more typically by the heating means. It can be carried out by reacting in the range of 50 to 60 ° C. for 15 to 120 minutes. After the enzyme treatment, a treatment for inactivating the used enzyme may be performed, such as raising the temperature to 70 ° C. or higher, more preferably 90 ° C. or higher. As another example, the enzyme may be added first, the liquid may be gradually accumulated over 15 to 60 minutes, and the juice may be started when the entire amount is accumulated. In addition, when two or more kinds of enzymes are used in combination, treatment with another kind of enzyme may be carried out step by step, or another kind of enzyme may be added together with the above-mentioned raw material sweet potato processed product to carry out enzyme treatment. can. When the maltotriose-producing amylase and the fibrogenic enzyme are treated separately, the order of their treatment is arbitrary, and the treatment with the maltotriose-producing amylase and the fibrogenic enzyme may be repeated.

The use of an enzyme other than the above-mentioned maltotriose-producing amylase or the above-mentioned enzyme treatment with a degrading enzyme for a fiber or protein is not excluded, and other enzymes can be arbitrarily used.

In the method for producing a sweet potato juice according to the present invention, a processed sweet potato product obtained through blanching, watering, and crushing treatment is enzymatically treated as described above and then squeezed. By the treatment of the juice, a juice liquid from which the juice residue such as pulp is removed can be obtained.

The means of squeezing the juice is not particularly limited, and for example, a centrifugal squeezing machine such as a decanter or a separator, or a squeezing type squeezing machine such as a filter press, a belt press, or a screw press is known. Therefore, it may be selected from among them as appropriate according to the purpose.

After the treatment of the juice, various treatments such as sterilization, concentration, filtration, homogenization, etc. may be performed to obtain the juice according to the present invention.

In the method for producing sweet potato juice according to the present invention, as a preferred embodiment thereof, the juice is concentrated after squeezing and has a Brix value of 45 or more and 55 or less, more preferably a Brix value of 47.5 or more and 52.5 or less, and even more. Preferably, a juice juice having a Brix value of 49 or more and 51 or less may be obtained. According to this, for example, it is convenient to use as a concentrated juice for sweet potato juice by temporarily freezing it and using it for producing sweet potato juice at an arbitrary time. In this case, the quality of the squeezed juice is inspected for each lot to control the quality of the sweet potato juice as the product, and in some cases, different lots are mixed to adjust the quality of the sweet potato juice as the product. It is also possible.

The means for concentrating is not particularly limited, and for example, a concentrator such as a single-effect can or a multi-effect can is known, and the concentrator may be appropriately selected from among them according to the purpose.

The sweet potato juice obtained as described above usually contains 70% by mass or more and 98% by mass or less of carbohydrates with respect to the total solid content, and contains 80% by mass or more and 97% by mass or less. Is more typical, and it is even more typical that the content is 90% by mass or more and 96% by mass or less. Further, it is typical that maltotriose is usually contained in an amount of 1% by mass or more and 20% by mass or less based on the total solid content as a product of the action of maltotriose-producing amylase, and is 1% by mass or more. It is more typical to contain 15% by mass or less, even more typically to contain 2% by mass or more and 7.5% by mass or less, and particularly typically to contain 3% by mass or more and 5% by mass or less. Is. The content of starch in such sweet potato juice is preferably 10% by mass or less with respect to the total amount of solids, and the content of glucose is preferably 10% by mass or less with respect to the total amount of solids. It is more preferable that the content is 7.5% by mass or less based on the total solid content, and the glucose content is 7.5% by mass or less based on the total solid content. Further, the anthocyanin compound is preferably contained in an amount of 0.75% by mass or more, more preferably 1% by mass or more, based on the total amount of solids in terms of its aglycone. The lower limit of the content of starch and glucose is not particularly limited, but in the case of starch, it is usually at least 1% by mass or more, more typically at least 3% by mass or more, based on the total solid content of sweet potato juice. Degrees may be included. Alternatively, glucose may be contained in an amount of about 0.5% by mass or more, more typically at least about 1% by mass or more, based on the total solid content of the sweet potato juice. Furthermore, the upper limit of the content of the anthocyanin compound is not particularly limited, but usually, from the content naturally contained in the sweet potato, the anthocyanin compound is at most in terms of its aglycone with respect to the total solid content of the sweet potato juice. It is considered that the upper limit is about 5% by mass, more typically about 3% by mass at most.

The sweet potato juice obtained as described above has a flavor and nutritional components derived from sweet potato, but the starch content is in the above range, so that the mouthfeel when the juice is prepared does not become powdery. Further, since the glucose content is in the above range, sweet potato juice having a moderate sweetness can be obtained without the sweetness being too strong. If the carbohydrate content per solid content of the sweet potato juice is less than the above range, it tends to be difficult to maintain the sweet potato flavor generally exhibited by the sweet potato-derived components.

On the other hand, in the method for producing sweet potato juice according to the present invention, sweet potato juice is produced using the sweet potato juice obtained as described above. The raw material used for producing the sweet potato juice may be any raw material generally used for producing a juice product, and is not particularly limited. Typically, for example, water, lemon juice, flavors, plant-derived extracts, acidulants, thickeners, sweeteners, citrus juices and the like can be mentioned. Of these, from the viewpoint of compatibility with the sweet potato flavor, it is preferable to use lemon juice, acidulants, and flavors. From the viewpoint of improving storage stability, it is preferable to add a pH adjuster such as an organic acid as necessary to adjust the pH to 3.60 to 4.00. Further, in order to obtain a straight feeling of sweet potato flavor, the sweet potato juice obtained as described above is added to the total mass of the raw materials of the sweet potato juice to be 30% by mass or more and less than 100% by mass (as a Brix value of 50). It is preferable to occupy 40% by mass or more and 80% by mass or less, and even more preferably 40% by mass or more and 70% by mass or less.

The sweet potato juice obtained as described above may be provided in a container for one serving, for example, in a container having a capacity of 65 mL or more and 300 mL or less. In this case, it is preferable that the anthocyanin compound is provided in the form of a packaged beverage containing 200 mg or more and 550 mg or less in terms of aglycone in the one container, and is provided in the form of a packaged beverage containing 230 mg or more and 450 mg or less. It is more preferable to be done.

The contents of various components in the present specification can be analyzed as follows, for example.

・ Moisture: 105 ° C constant drying method ・ Carbohydrate: Of the total mass, other than the total amount of quantitative values for water, protein (by Kjeldahl method), lipid (by acid decomposition method), and ash (by ashing method) , Treated as carbohydrate content.
・ Stardust: Modified Somogie method ・ Glucose: HPLC method ・ Anthocyanin compounds: Bilberry extract According to the food standard, the amount of anthocyanidin after glycosides are desalted by heating and refluxing under hydrochloric acid acidity, based on the amount of delphinidin. It is calculated from the specific absorptiometry by the absorptiometry.
・ Maltotriose: HPLC method

The Brix value can be measured with a commercially available sugar content meter or the like.

Hereinafter, the present invention will be specifically described with reference to examples, but these examples do not limit the scope of the present invention.

(enzyme)
The contents of the enzyme preparation used in the test are summarized in Table 1.

(Brix value)
The Brix of the sample at 20 ° C. was measured using a saccharimeter (Atago RX-5000α, manufactured by Atago).

(Preparation Example 1-1)
A concentrated juice for sweet potato juice (set Brix value: Bx50) was produced from Ayamurasaki, which is a colored sweet potato, as a raw material. Specifically, the raw sweet potato was washed with a drum-type washing machine, peeled using a steam peeler, and further cut to a thickness of 20 mm with a slicer. This was put into a blanching tank, heated at 93 ° C. for 15 minutes to be blanched, hydrated to the same amount as the raw material, and then crushed with a hammer crusher. After crushing, the liquid was sent to a tank and treated with an enzyme. Among the enzyme preparations shown in Table 1, (1) trade name "Gluczyme AF6" (manufactured by Amano Enzyme Co., Ltd.) and (2) trade name "Gluc SBG" (manufactured by Amano Enzyme Co., Ltd.) and (3) product Using the name "Hemicellulase M" (manufactured by HBI Co., Ltd.), add 0.125 parts by mass of the enzyme preparation (1) to 100 parts by mass of the raw material sweet potato, and add the enzyme preparation (2) to 100 parts by mass of the raw material sweet potato. On the other hand, 0.125 parts by mass was added, and 0.125 parts by mass of the enzyme preparation (3) was added with respect to 100 parts by mass of the raw material sweet potato. After reacting at 50-55 ° C for 15 minutes while stirring with the stirring device provided in the tank, the juice is squeezed with a decanter type juice squeezing machine, and the obtained primary juice is sterilized by UHT and then set in a triple-effect can. Concentrated to a value of Bx50 (final Brix value is approximately Bx50.10-50.30).

(Preparation Example 1-2)
A concentrated juice for sweet potato juice (set Brix value: Bx50) was produced from Ayamurasaki, which is a colored sweet potato, as a raw material. Specifically, the raw sweet potato was washed with a drum-type washing machine, peeled using a steam peeler, and further cut to a thickness of 20 mm with a slicer. This was put into a blanching tank, heated at 93 ° C. for 15 minutes to be blanched, hydrated to three times the amount of the raw material, and then crushed with a hammer crusher. After crushing, the liquid was sent to a tank and treated with an enzyme. Of the enzyme preparations shown in Table 1, (4) trade name "AMT1.2L" (manufactured by Amano Enzyme Co., Ltd.) and (5) trade name "Cellulase TP-5" (manufactured by Kyowa Kasei Co., Ltd.) are used as enzymes. Then, the enzyme preparation (4) was added by 0.125 parts by mass with respect to 100 parts by mass of the raw material sweet potato, and the enzyme preparation (5) was added by 0.125 parts by mass with respect to 100 parts by mass of the raw material sweet potato. After reacting at 50 to 55 ° C. for 15 minutes, the juice was squeezed with a decanter type juice squeezing machine, and the obtained primary juice was sterilized by UHT and then concentrated to a set brix value of Bx50 in a triple-effect can ( The final brix value is approximately Bx50.1 to 50.30).

(Preparation Example 1-3)
A concentrated juice for sweet potato juice (set Brix value: Bx50) was produced in the same manner as in Preparation Example 1-2 except that raw materials having different harvest times were used as the raw material for Ayamurasaki (final Brix value is about Bx50.10). ~ 50.30).

(Preparation Example 1-4)
A concentrated juice for sweet potato juice (set Brix value: Bx50) was produced from Ayamurasaki, which is a colored sweet potato, as a raw material. Specifically, the raw sweet potato was washed with a drum-type washing machine, peeled using a steam peeler, and further cut to a thickness of 40 mm with a slicer. This was put into a blanching tank, heated at 93 ° C. for 15 minutes to be blanched, hydrated to 6 times the amount of the raw material, and then crushed with a hammer crusher. After crushing, the liquid was sent to a tank and treated with an enzyme. Of the enzyme preparations shown in Table 1, (4) trade name "AMT1.2L" (manufactured by Amano Enzyme Co., Ltd.) and (5) trade name "Cellulase TP-5" (manufactured by Kyowa Kasei Co., Ltd.) are used as enzymes. Then, 0.125 parts by mass of the enzyme preparation (4) was added to 100 parts by mass of the raw material sweet potato, and 0.03 part by mass of the enzyme preparation (5) was added to 100 parts by mass of the raw material sweet potato. After reacting at 50 to 55 ° C. for 15 minutes, the juice was squeezed with a decanter type juice squeezing machine, and the obtained primary juice was sterilized by UHT and then concentrated to a set brix value of Bx50 in a triple-effect can ( The final brix value is approximately Bx50.1 to 50.30).

(Preparation Example 1-5)
A concentrated juice for sweet potato juice (set Brix value: Bx50) was produced in the same manner as in Preparation Example 1-4 except that raw materials having different harvest times were used as the raw material for Ayamurasaki (final Brix value is about Bx50.10). ~ 50.30).

(Preparation Example 1-6)
A concentrated juice for sweet potato juice (set brix value: Bx50) is produced in the same manner as in Preparation Example 1-5, except that the peeling treatment is not performed using the raw materials at the same harvest time as in Preparation Example 1-5. (The final brix value is approximately Bx50.1 to 50.30).

Table 2 shows the combinations and addition amounts of the enzyme preparations used for the preparation of the concentrated juices obtained in Preparation Examples 1-1 to 1-6.

<Test Example 1>
The sugar composition and anthocyanin content of the concentrated juice obtained in Preparation Examples 1-1 to 1-6 were analyzed. As an analytical method, the starch content was determined by a modified somogie method, and the content of various sugars such as glucose, fructose, galactose, sucrose, lactose, and maltose was determined by an HPLC method. In addition, the total solid content was determined by the constant moisture drying method at 105 ° C. and was determined as the difference from the total amount. Furthermore, for carbohydrates, the total of quantitative values for water (according to the 105 ° C constant weight drying method), protein (according to the Kjeldahl method), lipid (according to the acid decomposition method), and ash content (according to the ashing method) in the total mass. Other than the amount, it was treated as carbohydrate content. On the other hand, regarding the anthocyanin content, the amount of anthocyanidin after desalting the glycoside by heating and refluxing under hydrochloric acid acidity is determined by the absorbance method based on the amount of delphinidin according to the bilberry extract food standard. Calculated. The results are shown in Table 3.

As a result, in Preparation Example 1-1 in which glucoamylase and α-amylase were used for enzyme treatment, the glucose content was 29.0 g / 100 g (60.3% by mass based on the total solid content). In Preparation Example 1-2 to Preparation Example 1-6 using maltotriose-producing amylase and cellulase for enzymatic treatment, the glucose content was 1.0 g / 100 g to 2.9 g / 100 g (relative to the total solid content). It was 2.1% by mass to 6.03% by mass). The obtained concentrated juice was diluted with water to the concentration of sweet potato juice, and the taste was evaluated separately. As a result, the sweetness was strong in Preparation Example 1-1, whereas the sweetness was strong in Preparation Example 1-2 to Preparation Example 1. At -6, the sweetness was moderate. On the other hand, the anthocyanidin content was 345 mg / 100 g (0.7% by mass with respect to the total solid content) in Preparation Example 1-1, whereas it was in Preparation Example 1-2 to Preparation Example 1-6. Was 505 mg / 100 g to 669 mg / 100 g (1.0% by mass to 1.4% by mass with respect to the total solid content).

<Test Example 2>
From the results of Test Example 1, it was considered that the type of enzyme used in producing the sweet potato juice may affect the taste and anthocyanin content of the sweet potato juice. Therefore, various conditions such as the amount of water added to the raw material and the amount of the enzyme preparation added during the enzyme treatment were adjusted, and the effect of the type of enzyme was investigated. Therefore, in this test example, the sugar composition and anthocyanin content when the type of enzyme was changed were investigated for the sweet potato juice prepared on a laboratory scale, not for the equipment for producing the concentrated juice for sweet potato juice.

Specifically, 1 to 2 kg of Ayamurasaki, which is the raw material (without peeling), is hand-washed, sliced to a thickness of about 40 mm with a kitchen knife, soaked in boiling water, heated at 98 ° C for 15 minutes, and blanched. After adding water to double the amount, the mixture was blanched in a twin-screw crusher and then blanched in a mixer. After crushing, the mixture was transferred to a container and treated with the enzyme combinations and addition amounts shown in Table 4.

Among the enzyme preparations shown in Table 1, (2) trade name "Gluc SBG" (manufactured by Amano Enzyme Co., Ltd.), (4) trade name "AMT1.2L" (manufactured by Amano Enzyme Co., Ltd.), and (5) ) The trade name "Cellulase TP-5" (manufactured by Kyowa Kasei Co., Ltd.) was used, and the combination and addition amount shown in Table 4 were used. After reacting at 55 ° C. for 1 hour while stirring with a tabletop stirrer, the supernatant is collected by centrifuge (3,000 rpm, 10 minutes), sieved through a 60 mesh sieve to prepare a coarse filtrate, and then 95 ° C. The enzyme was inactivated by heat treatment at the temperature of the sweet potato, and a sweet potato juice was obtained.

The obtained juice was evaluated for each property of Brix value (Bx sugar content), pH, and juice ratio (according to the following formula (1)). In addition, in order to simply examine the presence or absence of starch decomposition, the degree of color change was sensory-evaluated using an iodine-starch reaction titrant. Furthermore, regarding the taste, the degree of off-taste and sweetness was sensory-evaluated.

(Squeezing rate)
Juice squeezing rate (%) = (mass of the obtained squeezed juice / total mass after hydration when added to the raw material) × 100… (1)

(Starch decomposition)
The color change due to the addition of the iodine-starch reaction titrator (95% hydrous ethanol solution containing 10 w / v% of iodine) was observed.

○ No change △ Slightly changed × There is a change

(taste)
○ Good △ Slightly bad × Bad

The results are shown in Table 5.

As a result, it was obtained in Preparation Example 2-1 in which maltotriose-producing amylase, cellulase, esterase and tannase were used in combination as enzymes used for enzyme treatment, and in Preparation Example 2-2 in which only maltotriose-producing amylase was used. There was no difference in the properties of the sweet potato juice, and the starch decomposition and taste were good.

On the other hand, in Preparation Example 2-3 in which only cellulase, esterase and tannase were used as enzymes used for enzyme treatment and maltotriose-producing amylase was not used, starch decomposition was poor and the viscosity was strong for use in juice. It was thought to be too much. In addition, the taste was slightly different from that of Preparation Example 2-1 and Preparation Example 2-2.

On the other hand, in Preparation Example 2-4 in which glucoamylase and α-amylase were used as the enzymes used for the enzyme treatment, the sweetness of the obtained sweet potato juice was considered to be strong, and the sweetness was considered to be too strong for use in juice ( The proportion of glucose in the solid content is 16.2% by mass).

The sugar composition and anthocyanidin content of the juice of Preparation Example 2-1 and the juice of Preparation Example 2-4 were examined in the same manner as in Test Example 1. In addition, the Bx50 conversion content when converted by multiplying by a magnification such that the Brix value of the prepared juice was Bx50 was calculated. The results are shown in Table 6.

As a result, the content of Preparation Example 2-1 using maltotriose-producing amylase as the enzyme used for the enzyme treatment was the same as that of Preparation Example 2-4 using glucoamylase in the prepared juice. Despite the degree, when converted to Bx50, the anthocyanidin content was about 1.6 times higher. It was considered that this was because the Brix value was high due to the enzyme and the concentration was low when converted to Bx50.

<Test Example 3>
A sweet potato juice was prepared on a laboratory scale in the same manner as in Test Example 2 except that the combinations and addition amounts of the enzymes shown in Table 7 were used.

The obtained juice was evaluated for each property of Brix value (Bx sugar content), pH, and juice ratio (according to the above formula (1)). The results are shown in Table 8.

As a result, in Preparation Example 3-1 in which maltotriose-producing amylase and cellulase were used in combination as the enzyme used for the enzyme treatment, the obtained sweet potato juice was obtained as compared with Preparation Example 3-2 in which only maltotriose-producing amylase was used. Although there was no significant difference in the Brix value and pH properties of the juice, the juice squeezing rate was 89.9% in Preparation Example 3-2, whereas the juice squeezing rate was high in Preparation Example 3-1. It was 97.5%, which was significantly higher.

From the above, it was clarified that the juice squeezing rate can be improved and the yield can be improved by increasing the amount of cellulase added.

Claims (7)

In the method for producing sweet potato juice obtained by blanching, adding water, and crushing sweet potato and squeezing the obtained processed product after enzymatic treatment to obtain a juice, the enzyme treatment is performed as maltotriose-producing amylase. A method for producing sweet potato juice, which is characterized by the use of. The method for producing sweet potato juice according to claim 1, wherein the enzyme treatment is further carried out using a fibrous degrading enzyme together with the maltotriose-producing amylase. A juice containing 70% by mass or more and 98% by mass or less of carbohydrates with respect to the total amount of solids. The method for producing a sweet potato juice according to claim 1 or 2, wherein the juice is obtained in an amount of 10% by mass or less. The method for producing a sweet potato juice according to any one of claims 1 to 3, wherein a juice containing 0.75% by mass or more of anthocyanin compounds in terms of aglycone is obtained. The method for producing sweet potato juice according to any one of claims 1 to 4, wherein the juice is concentrated after being squeezed to obtain a juice having a Brix value of 45 or more and 55 or less. A method for producing sweet potato juice, which comprises a step of mixing the sweet potato juice obtained by the production method according to any one of claims 1 to 5 with other raw materials. The method for producing sweet potato juice according to claim 6, wherein the other raw material is one or more selected from the group consisting of water, lemon juice, acidulants, and flavors.