JP3408919B2 - Method for producing purple sweet potato pigment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrially advantageous production of a stable purple sweet potato dye excellent in light resistance and heat resistance. [0002] Red cabbage, grapes, purple corn,
Red natural pigments produced from berries, red radish, red turnip and the like belong to anthocyanin pigments. Purple sweet potato is also a red pigment raw material containing a similar anthocyanin pigment. In recent years, purple sweet potato dyes have been increasingly used in foods because they are more excellent in heat resistance, light resistance and vividness of color tone than other anthocyanin dyes. Several methods have been proposed for producing purple sweet potato dyes. A method for producing a purple sweet potato pigment by extracting a raw or steamed purple sweet potato with water or aqueous ethanol under acidic conditions and subjecting the extract to a purification treatment (Japanese Patent Application Laid-Open Nos. 62-297363 and 62 -297364) is one such example. In addition, the method of extracting a dye from a purple sweet potato as a raw material at a temperature of 10 ° C. or less, and a method of extracting a dye from a frozen and sweetened purple sweet potato (Japanese Patent Application Laid-Open No. 4-103669) all inhibit the activity of the enzyme. This is a method for producing a purple sweet potato pigment characterized by the following. However, the production methods in these proposals are not always satisfactory in terms of dye extraction efficiency. The kind of purple sweet potato that is the raw material is Brazilian purple sweet potato with a very low content of anthocyanin pigment (Ipoea batas, Lam ..
Convolvlaceae), purple from Yamakawa, native to Tanegashima, ei purple, Chiran purple, Kiire purple, Nakamurasaki, etc.
The method of extracting a pigment by using them does not have satisfactory extraction efficiency on an industrial level. In addition, when suppressing the action of oxidase at low temperature on purple sweet potato, it is necessary to strictly control the temperature, and it is necessary to control frictional heat in grinding and the like. Therefore, the purple sweet potato variety is improved and the improved variety Kyushu No. 113 (registered name: Asho Norin 47, commonly known as "Ayamurasaki" (hereinafter referred to as "Ayamurasaki")) is used as a pigment raw material. Methods for obtaining dyes in high yield (JP-A-7-126544, JP-A-7-22
7246). However, in all of these proposals, it is premised that the raw material of purple sweet potatoes is produced at the time of harvesting, and in order to stagger the time of production of the pigment, humidification refrigeration or frozen storage usually used for storage of vegetables is used. It becomes necessary to keep it. However, if raw purple sweet potatoes are stored raw, a large storage space (volume) is required, and the decomposition of rot and purple sweet potatoes due to humidification and refrigeration progresses. I could not do it. [0005] As a method of economically storing for a long period of time, there is a method of drying a purple sweet potato as a raw material. Examples of the drying method include a method of drying with hot air, a method of drying on the sun and natural drying, and a method of drum-drying steamed purple sweet potato. However, due to the heating, the purple sweet potato also decomposes the pigment component, or the starch contained therein becomes alpha, so even if the pigment is produced using the dried purple sweet potato as a raw material by these methods, the color tone becomes yellowish. In addition, they are not industrially usable, such as clogging during the filtration process in the production process. There is also a method of drying by freezing, but since the drying step is complicated and expensive equipment is required, it cannot be used industrially advantageously in terms of economic burden. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing purple sweet potato pigment which is industrially advantageous. Means for Solving the Problems The present inventors have conducted intensive studies on a method for producing purple sweet potato pigment from purple sweet potato in an industrially advantageous manner. The present invention, which is manufactured using Ayamurasaki, has been achieved. The drying technique of purple sweet potato will be described. Cut the raw purple sweet potatoes into slices with a slicer. As for the size of the square cut, the thickness is about 2 to 5 mm and the width is about 3 to 6
mm and a length of about 10 to 100 mm. Blast drying is divided into two stages, using orthogonal ventilation drying system or rotary ventilation drying system equipment, the former stage is performed at 70-80 ° C and 15-3.
After 0 minutes, the subsequent step is dried at 55-65 ° C. for 1-4 hours.
According to this drying method, the water content is 10% or less, and the decomposition of the dye can be suppressed to about 20%. Examination of the degree of pigment decomposition in hot air drying and sun drying, which are conventional techniques, revealed that the pigment was decomposed in the former by 50 to 60% and in the latter by 60 to 70%. Moreover, compared to the dried product dried by the orthogonal ventilation drying method or the rotary ventilation drying method of the present invention, the color tone of the dried product subjected to hot-air drying or solar drying is lower than that of the dried product having a bright red color. Turns yellowish brown. Although the dried purple sweet potato may be used as it is, it is more preferable to make it into a powder with a pulverizer. The size of the pulverization can be freely adjusted, and is adjusted to 3.5 to 200 mesh, preferably 20 to 70 mesh. In the case where the pigment is not immediately produced, the dried purple sweet potato is dried or pulverized as it is, or the pulverized powder obtained by pulverizing and pulverizing is made of polyethylene, polyvinyl chloride, aluminum packaging or the like having a low oxygen permeability. It can be stored for a long time in a container with a relatively constant temperature by putting it in a packaging container such as a container. Also, the dried and ground purple sweet potato has a very small volume as compared with the raw purple sweet potato. Assuming that the volume of the raw purple sweet potato before the dry pulverization is 1, the volume of the dried and ground purple sweet potato after the dry pulverization is reduced to 1/2 to 1/5 depending on the size of the pulverization. Further, the dried and ground purple sweet potato has a water content of 10% or less and can suppress the growth of bacteria and fungi, so that it can be stored for a long time as compared with the raw purple sweet potato. By drying and pulverizing the purple sweet potato in this method, the resulting dried and dried purple sweet potato can be stored for a long period of time, so that the time of producing the pigment does not have to be concentrated on harvesting the purple sweet potato. . Next, as a solvent for extracting the dried and ground purple sweet potato, water or aqueous ethanol under acidic conditions is used. The extract is acidified to have a pH of about 5 or less, and an amount is prepared for immersing the dried and crushed product. P at this time
The reason for setting it to H5 or less is that if the anthocyanin dye is more than this, it will be unstable and fade. The pH adjuster used at this time may be any of organic acids such as citric acid, tartaric acid, malic acid, and inorganic acids such as hydrochloric acid and sulfuric acid. The ratio of the dry pulverized product to the extract is, for example, 2 to 20 parts of the extract, preferably 5 to 10 parts per 1 part of the dry pulverized product.
Department. The temperature of the system may be room temperature, and the starch may be α
At a temperature (64 ° C. or less) at which no gelatinization (gelatinization) occurs,
By setting the temperature at 60 ° C., the extraction efficiency is improved, for example, the time can be reduced. As for the anthocyanin pigment contained in the dried and ground product, the entire amount of the pigment is transferred to the extract in a short time in the extract. When the transfer of the anthocyanin dye is completed, the extraction operation is stopped, the residue is removed, and only the anthocyanin dye is collected. The residue may be removed by using a means for separating a solid and a liquid, such as filtration and centrifugation. [0015] For example, 100 kg of raw sweet potato is added to 0.1 kg.
Extraction was carried out at 20 ° C. with 1 ton of 5% by weight sulfuric acid aqueous solution, and the time from preparation to extraction when press filtration (1 m × 1 m × 10 sheets) was carried out was measured. Extraction took 3 hours, and press filtration took 1 hour due to clogging of the sweet potato, and took about 5 hours to complete. On the other hand, when purple sweet potatoes were prepared by drying and pulverized under the same conditions, during extraction, the anthocyanin dye contained in the dried and pulverized products was
Compared to when using raw sweet potatoes, the whole amount of pigment was transferred to the extract in a short time in the extract, so it finished in 1 hour,
Filtration was completed in 40 minutes without clogging, and it took about 2 hours from extraction to completion of the filtration process. Compared with the use of raw purple sweet potatoes, the time required for extraction to filtration was reduced to less than half when using the dried and ground product. The filtered extract is subjected to heat treatment such as batch sterilization or plate sterilization to prevent discoloration and proliferation of bacteria. These temperatures are sufficient to heat about 80 to 100 ° C. for about 30 to 60 minutes in batch sterilization, and about 100 to 120 in plate sterilization.
C. and heating for about 20 seconds to 30 minutes is sufficient. The dye solution thus obtained may be used as it is, or may be concentrated to a concentrated dye. Further, the powder can be made into a powder by a spray drying method or the like. In addition, concentrated purple sweet potato can also emulsify the pigment. The emulsification method can be usually carried out by adding an emulsifier such as gum arabic, sucrose fatty acid ester, glycerin fatty acid ester, and emulsifying. The purple sweet potato pigment obtained according to the present invention can be used for coloring foods, pharmaceuticals, cosmetics and the like. Foods include beverages, jellies, frozen desserts, ice creams, candy, tablets, chocolate confections, pickles, and the like. Pharmaceuticals include tablets, poultices, solutions, and cosmetics include soaps, detergents, shampoos, and lipsticks. The present invention will be described below in more detail with reference to examples. Example 1 5 kg of Ayamurasaki purple sweet potato was sliced into slices having a thickness of 3 mm, a width of 2 mm, and a length of 20 mm using a slicer, and a rotary ventilation dryer at 70 to 75 ° C. for 20 minutes, followed by 1 hour at 60 ° C. Dried for hours. The obtained dried product was pulverized using a pulverizer and passed through a 32-mesh sieve to obtain 2 kg of a dried and pulverized purple sweet potato. The water content of the dried and ground purple sweet potato obtained was 7.5%. 1 kg of the dried and ground purple sweet potato is added to a 0.5 wt% sulfuric acid aqueous solution 10
of the extract, extracted at 18 ° C. for 60 minutes, filtered after the extraction to remove insoluble solids, to obtain 8.3 kg of the extract.
This solution was adsorbed on 500 ml of Diaion HP-20 (adsorption resin manufactured by Mitsubishi Kasei Kogyo Co., Ltd.), washed with water, and the adsorbed dye was eluted with 500 ml of 58% by volume ethyl alcohol. The obtained dye solution was concentrated to 150 g with a vacuum concentrator, and then 15 g of 95% ethyl alcohol, 1 g of citric acid and 34 g of water were added to obtain 200 g of a purple sweet potato dye solution. The acquired purple sweet potato pigment presents a clear red color and when colored into carbonated beverages,
One month storage at room temperature did not produce any color change or insolubles. Comparative Example 1 1 kg of purple sweet potato "Ayamurasaki" was washed and 100
After steaming with steam at 30 ° C. for 30 minutes, the product was dried with a drum dryer and pulverized with a pulverizer to obtain 150 g of a steamed powder product having passed through a 32 mesh. The steamed powdered product and the raw purple sweet potato were sliced into slices having a thickness of 3 mm, a width of 2 mm, and a length of 20 mm using a slicer, and the same treatment as in Example 1 was carried out to obtain respective pigments. Citric acid 0.1% by weight 10
To a 0 g aqueous solution, 0.05 g of each of the pigment obtained from the dried and ground product of Example 1, the pigment obtained from the steamed powdered product, and the pigment obtained from raw purple sweet potato (in terms of a color value of 80) was added, and the color tone was visually observed Observed. Table 1 shows the results. Further, the color value of each raw material was calculated from the amount of the collected dye. [Table 1] Color value: It means the density (color strength) of a dye, generally measured by a spectrophotometer, and expressed by converting the measured value to a value of 10% density. In general, the measurement of the spectrophotometer is performed by adjusting the concentration of the dye so that the absorbance at the maximum absorption wavelength is in the range of 0.2 to 0.7. For example, when the absorbance (λmax OD) at the maximum absorption wavelength is 0.5 at a dye concentration of 0.1 volume / weight%, 10 ÷ 0.1 =
100 Color value = 0.5 × 100 = 50 From Table 1, it can be seen that the dye prepared by the method of the present invention exhibited a bright red color tone similar to the dye prepared from raw purple sweet potato, and also showed a high pigment content. In comparison, the steamed powder did not become a bright red pigment. The reason why the pigment content of the steamed powder product showed a high value was that a change due to heat was observed, the color tone became yellow, and the yellow component was also included in the raw material color value. Comparative Example 2 5 kg of purple sweet potato "Ayamurasaki" was sliced into slices having a thickness of 3 mm, a width of 2 mm and a length of 20 mm using a slicer, and dried for 5 days by the sun to obtain 2 kg of a sun-dried purple sweet potato. In addition, 5 kg of the above-mentioned “Ayamurasaki” square shredded material was dried with hot air of 80 ° C. for 3 hours using a dryer,
1.8 kg of hot-air dried purple sweet potato was obtained. Using a sun-dried product and a hot-air dried product as a dye raw material, a dye was produced by the method of Example 1, and the color tone was visually observed. Table 2 shows the results. [Table 2] From Table 2, the dye produced by the method of the present invention turned bright red. However, the pigment produced from the extracted raw material subjected to sun drying and hot air drying did not become bright red because the color tone was changed by drying. Comparative Example 3 The purple sweet potato of Example 1 "Ayamurasaki" 70 g of the pulverized powder obtained by passing the dried and pulverized product through a 32-mesh sieve, and the raw purple sweet potato having the same amount of pigment as 70 g of the pulverized powdered product Ayamurasaki ”1Kg is cut into 3-5mm squares,
Pour into 10 l of 0.5% by weight sulfuric acid aqueous solution and extract
The dye was extracted at 60 ° C for 60 minutes. FIG. 1 shows the relationship between the time and the amount of the extracted pigment. From FIG. 1, it was found that in the production method according to the present invention, the extraction was completed in about 1/6 of the production method using raw purple sweet potato. Comparative Example 4 Dry Sweet Potato "Ayamurasaki" of Example 1
00 g was added to an extract of 1 liter of a 0.5% by weight aqueous sulfuric acid solution, and purple sweet potato was extracted at 45 ° C. for 10 minutes to obtain 800 g of an extracted pigment solution. Similarly, 100 g of the steamed powdered product which had been steamed by the method of Comparative Example 2 and then turned into a dry powder, and 300 g of fresh purple sweet potato were similarly extracted at 45 ° C. for 10 minutes to obtain a pigment solution. These extracts were filtered through a filter paper with a Φ9 cm suction filter (ADVANTEC FILTER PAPER).
5C) was performed, and the time from the start of filtration of the extract to the end of filtration was measured. [Table 3] As shown in Table 3, the time required for filtration was shorter in the production method according to the present invention than in the production method using steamed powder or raw purple sweet potato. As is evident from Comparative Examples 3 and 4, the production method according to the present invention can greatly reduce the time required for production as compared with other production methods, and can be produced industrially advantageously. . COMPARATIVE EXAMPLE 5 The dried and crushed purple sweet potato "Ayamurasaki" of Example 1 and the steamed purple sweet potato "Ayamurasaki" were dried with a drum dryer and then stored in a warehouse at 15 ° C. or lower. Table 4 shows the relationship between the residual ratio (%) of the contained pigment and the rot by the naked eye when the sweet potato was stored in a humidified refrigerator at 15 ° C. in a supersaturated state. [Table 4] From Table 4, it can be seen that the pigment produced by the production method according to the present invention has almost no deterioration in the quality of the pigment as compared with the pigment produced by the production method using raw sweet potato, and can be stored for a long time. I understand. Example 2 1 kg of the dried and ground purple sweet potato "Ayamurasaki" of Example 1 was poured into an extract of 10 l of a 50% by volume aqueous alcohol solution containing 0.01% by weight of sulfuric acid, extracted at 25 ° C for 60 minutes, and filtered. Thus, 8.5 kg of an extract was obtained by removing insoluble solids. The solution was concentrated to 5 liters, and Diaion HP-20 was added.
(Adsorption resin manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) After adsorbing on 500 ml, washing with water was performed, and the adsorbed dye was eluted using 500 ml of 58 vol% ethyl alcohol. The obtained dye solution was concentrated to 80 g with a vacuum concentrator, 3 g of glycerin fatty acid ester and 2 g of sucrose fatty acid ester
g, edible oil 16 g, gum arabic 40 g, 95% ethyl alcohol 20 g, citric acid 10 g, glycerin 20
g of water and 9 g of water were added and stirred and mixed with a homodisper to obtain 200 g of a double emulsified dye liquid of purple sweet potato. The obtained purple sweet potato pigment was colored in jelly and exhibited a clear red color when immersed in syrup, and did not cause any color change or color flow to the syrup even after being kept at room temperature for one month. According to the present invention, the time required for the production of purple sweet potato can be greatly reduced as compared with the conventional method for producing a pigment, and the interference by oxidase which has been involved in the discoloration and discoloration of the pigment can be obtained. Disappears. Moreover, since the purple sweet potato can be stored for a long period of time by making it into a dry and pulverized product, it is not necessary to concentrate the production of the pigment, and the purple sweet potato with excellent color tone can be produced efficiently and industrially advantageously. I can do it. [0039]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing a transfer amount of a dye to an extract over time in an extraction step, wherein the vertical axis indicates the amount of the dye and the horizontal axis indicates time. [Explanation of Signs] (1) Extraction raw material: dried and dried purple sweet potato (2) Extracted raw material: raw purple sweet potato t Time (minutes) V Pigment amount Color value of extraction liquid x liquid amount

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Claims (1)

(57) [Claims] [Claim 1] Moisture content in the production of purple sweet potato
A method for producing a purple sweet potato pigment, comprising using sweet potato Norin 47 dried and crushed to an amount of 10% or less .