JPH07126544A - Production of purple sweet potato color - Google Patents

Abstract

PURPOSE:To obtain a stable purple sweet potato color excellent in resistances to light and heat by extracting a specific improved variety of purple sweet potato with water or water-contg. ethanol under an acidic condition. CONSTITUTION:The objective color is obtd. by extracting an improved variety of purple sweet potato, Kyushu No.113, with water or water-contg. ethanol under an acidic condition. Kyushu No.113 is produced by crossing Satsumahikari as the father with Kyushu No.109 as the mother; Kyushu No.109 is produced by crossing Yamakawamurasaki as the father with Chiranmurasaki as the mother. In producing the color, Kyushu No.113 is cut into chips with a cutter in a nitrogen-purged, almost tightly sealed space, thus preventing the oxidation by an oxidase and enabling the treatment at room temp. The sweet potato chips are pressed with a press purged with nitrogen to give juice without allowing the oxidation by an oxidase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a stable purple sweet potato dye excellent in light resistance and heat resistance. More specifically, using improved purple sweet potato cultivar "Kyushu 113", processing such as crushing, extraction, adsorption and concentration under the condition that the activity of oxidase such as polyphenol oxidase contained in purple sweet potato is suppressed. To produce a purple sweet potato pigment excellent in yield and color tone.

[0002]

2. Description of the Related Art Red natural pigments such as red cabbage, grapes and purple corn belong to anthocyanin pigments. Purple sweet potato is also a pigment raw material containing a similar anthocyanin pigment. Recently, this dye has superior heat and light resistance compared to other anthocyanin dyes,
It is a pigment that is increasingly used in food. Several proposals have been made regarding the production of this purple sweet potato pigment. A method for producing a purple sweet potato dye by extracting raw or steamed purple sweet potato under acidic conditions with water or hydrous ethanol, and adsorbing and concentrating the extract (JP-A-62-297363). JP-A-62-29364) is one such example. A method for producing a purple potato pigment by adsorbing, concentrating, etc., an extract extracted with water or hydroalcohol from a product obtained by controlling the enzyme activity at 10 ° C. or below or using a freeze-pulverized product (Japanese Patent Laid-Open No. Hei 4) -103696) and the like have been proposed.

[0003]

However, the above-mentioned conventional manufacturing methods are not always satisfactory in terms of the extraction efficiency of the dye. The kind of purple sweet potato that is the raw material is purple sweet potato (Ip
oea batas, Lam. ． Convolvla
ceae), Yamakawa purple, Tanegashima native, Eimura purple, Chiran purple, Kiiri purple, Nakamurasaki, etc., and if these are used to extract the pigment, the amount of anthocyanin contained in the potato is extremely small. However, the extraction efficiency at the industrial level was not satisfactory. In addition, in order to suppress the action of the oxidase in purple sweet potato at a low temperature, it is necessary to strictly control the temperature, and there is a problem in that it is necessary to manage heat generation such as crushing.

Therefore, the present inventors improved the purple sweet potato varieties and used the improved varieties "Kyushu 113" as the dye raw material to obtain the purple sweet potato dyes in high yield. In addition, considering the suppression of oxidase in the extraction of purple sweet potato pigments, there was no need to control the temperature by replacing air with nitrogen during crushing, and after crushing, extraction with water or hydrous alcohol under acidic conditions was carried out. However, the anthocyanin pigment contained in the purple sweet potato could be recovered in high yield by producing the purple sweet potato pigment. It was found that this could solve the problems all at once. The object of the present invention is to improve the color tone in a high yield by using an improved purple sweet potato variety "Kyushu 113" as a pigment raw material and pulverizing it under conditions not affected by oxidases such as polyphenol oxidase present in the purple sweet potato. Another object of the present invention is to provide a method for producing a purple sweet potato dye which is stable and has excellent heat resistance and light resistance.

[0005]

[Means for Solving the Problems] In the present invention, as a variety of purple sweet potato which is a pigment raw material, an improved variety "Kyushu 113" which was successfully developed in an exchange joint research with the Kyushu Agricultural Experiment Station Field Utilization Sweet Potato Breeding Laboratory of the Ministry of Agriculture, Forestry and Fisheries No. "(during product registration)
A high-purity purple sweet potato dye can be easily produced by crushing the crushed product in a nitrogen-displaced cutting machine and extracting the crushed product with water or hydroalcohol under acidic conditions. The purple sweet potato, which is the raw material of the present invention,
Improved cultivar with Chiran purple as mother and Yamakawa purple as father "Kyushu 1"
It is characterized by using an improved cultivar "Kyushu 113" which is obtained by crossing "09" as a mother and Satsuma Hikari as a father. It was confirmed that the pigment content had anthocyanin pigment about 4 to 5 times that of the conventional varieties of purple sweet potato, and about 2 to 3 times as much as the recollection. (Ministry of Agriculture, Forestry and Fisheries Kyushu Agricultural Experiment Station, San-Ei Gen F.F.I Co., Ltd., Honbo Shuzo Co., Ltd. Joint research “Development of high anthocyanin varieties of sweet potato and development of utilization of pigment”, interim report, 1992 1
Published in February).

[0006] This new variety "Kyushu 113" is used as a raw material, and this is cut into chips with or without the epidermis. In this cutting machine, the air and the one to be cut are in contact with each other at the time of normal cutting, but use a cutting machine that can replace the air in the space close to the closed state with nitrogen with nitrogen. It is characterized in that it can prevent oxidation by oxidase and can be processed at room temperature. The purple sweet potato chips cut here were quickly added to the extract, so that the change in color tone due to the oxidase of the anthocyanin dye was reduced compared to the conventional case. Moreover, the pigment can be suppressed from the oxidase by squeezing the raw material coming out of the cutting machine which has been replaced with nitrogen with a squeezing machine which can be replaced with nitrogen. Here, the juicer is a centrifugal separator, a press machine, a decanter, or the like.

The above method is easier to manufacture than the conventional method, and the workability and the extraction rate can be improved. Next, water or hydrous ethanol is used as a solvent for extracting the cut chips. The pH of the extract is adjusted to an acidity of about 5 or less, and an amount is prepared so that the entire amount of the chips can be immersed. The pH at this time is set to 5 or less because if the anthocyanin dye is higher than this, the color is unstable and fading occurs. The pH adjusting acid used at this time may be an organic acid such as citric acid, tartaric acid or malic acid, or an inorganic acid such as hydrochloric acid or sulfuric acid. As for the temperature of the system, the higher the room temperature is, the higher the extraction efficiency is because the time can be shortened. By doing so, almost all of the dye contained in the chip is transferred to the extract.

When the transfer of the dye is completed, the extraction operation is stopped, the residue is removed, and only the red dye is collected. For removing the residue, a means for separating a solid and a liquid such as filtration or centrifugation may be used. By subjecting the filtered extract to heat treatment such as batch sterilization or plate sterilization for the purpose of sterilization and enzyme inactivation, discoloration and bacterial growth can be prevented.
These temperatures range from about 80 to 100 ° C for batch sterilization.
Heating for about 30 to 60 minutes is sufficient, and for plate sterilization, heating at about 100 to 120 ° C. 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 give a concentrated dye. Further, it can be pulverized by a spray drying method or the like. This is the end of the object of the present invention.

[0009]

【Example】

Example 1 1 kg of an improved purple sweet potato "Kyushu 113"
% Crushed with a cutter replaced with nitrogen to about 1 to 5 mm, and immediately added to 3 l of a 0.5 wt% sulfuric acid aqueous solution to obtain a purple sweet potato extract dye solution. After extraction, the insoluble solid matter was removed by filtration to obtain 3.5 kg of an extract. This liquid
After being adsorbed in 100 ml of Diaion HP-21 (adsorption resin manufactured by Mitsubishi Kasei Co., Ltd.), washed with water and then 58
The adsorbed dye was eluted with 150 ml of volume% ethanol. The obtained dye solution is vacuum-concentrated to 5
Concentrated to 0 g, 95 vol% ethanol 15 g, citric acid 1
g, 34g of water is added, and 100g of purple sweet potato pigment liquid
Got The obtained purple sweet potato pigment showed a clear reddish purple color, and when the carbonated beverage was colored, no change in color tone and no insoluble matter were generated even if it was left at room temperature for 1 month.

Experimental Example 1 A raw material of a conventional variety was treated in the same manner as in Example 1, the dye concentration of the raw material was measured, and the results are shown in Table 1.

[0011]

[Table 1] Color value: It means the density (color strength) of a dye, and is generally measured by a spectrophotometer, and the measured value is converted into a 10% density value.

Example 2 90% of 1 kg of improved purple sweet potato "Kyushu 113"
The raw material and 1 liter of a 2 wt% citric acid aqueous solution were simultaneously pulverized to 1 to 5 mm by a cutting machine in which the nitrogen was replaced as described above to obtain a juice. Solid-liquid separation was performed with a decanter to obtain 1.5 l of a pigment extract. Furthermore, this solid was added to 3 l of a 2 wt% citric acid aqueous solution to obtain 3 l of a purple sweet potato pigment extract in the same manner. After extraction, the solid-liquid separated pigment extracts were mixed and filtered to remove insoluble solids to obtain 4.8 kg of pigment extract. This dye extract was adsorbed on 100 ml of Duolite XAD-7 (adsorption resin manufactured by Diamond Shamrock, USA), washed with water and then 58% by volume of ethyl alcohol 1
The adsorbed dye was eluted with 00 ml to obtain 100 g of purple sweet potato dye.

Experimental Example 2 Extraction was carried out in the same manner as in Example 2 and comparison was made with the extraction rate when the nitrogen substitution rate was set to 0. The results are shown in Table 2.

[0014]

[Table 2] As is clear from Table 2, when the nitrogen substitution rate was 90% or more, the recovery rate increased and no change in color tone was observed.

Example 3 Frozen purple sweet potato improved variety "Kyushu 113" 10k
After thawing g to room temperature to destroy the cells, squeeze in a squeezing press machine in which 90% or more of nitrogen has been replaced, and dye juice 7
kg was recovered. 0.05 kg of sulfuric acid is immediately added to the obtained pigment juice. The squeezed lees were added to 10 l of a 0.5 wt% sulfuric acid aqueous solution, and the pigment in the lees was extracted and collected. The obtained dye extracts were mixed and centrifuged to remove insoluble solids. The dye extract was adsorbed on 200 ml of Diaion SP-207 (adsorption type resin manufactured by Mitsubishi Kasei Kogyo Co., Ltd.), washed with water, and the adsorbed dye was recovered with 100 ml of 58% by volume ethanol. The dye solution obtained by distilling off ethanol was permeated with a membrane having a molecular weight cut-off of 100,000 (Ultrafiltration membrane NTU-35100 manufactured by Nitto Denki Kogyo Co., Ltd.) to obtain proteins,
Starch and colloidal substances were removed. Then, it was concentrated using a reverse osmosis membrane (NTR1595, manufactured by Nitto Electric Industrial Co., Ltd.). Concentrated dye liquid 500g to 95% ethanol 150
g, 10 g of citric acid and 340 g of water were added to obtain 1 kg of purple sweet potato pigment liquid.

Experimental Example 3 The purple sweet potato pigment obtained in Example 3 is colored into a gum containing vitamin C (the formulation is as follows). For comparison, the same coloring with Eldaberry dye and purple corn dye was used, and 38
Table 3 shows the results obtained by observing the change with time at 14 ° C. (color computer SandM6 type manufactured by Suga Test Instruments Co., Ltd.).

(Gum prescription) Gum base 100g Vitamin C 0.1g Each pigment 0.08g (color value 80 conversion) 50% citric acid water 0.4g

[0018]

[Table 3]

L: degree of brightness: brighter as it approaches 100, and darker as it approaches 0. a: hue representing redness / greenness ratio indicated by Munsell color mark b: yellowness / blueness ratio indicated by Munsell color mark Hue Representation ΔE: Hue Difference As is apparent from Table 3, the purple sweet potatoes were excellent in stability.

[0019]

According to the present invention, by using the conventional purple sweet potato pigment content of the breed improvement "Kyushu 113", the pigment yield could be increased about 4 to 5 times. Moreover, the yield of the dye can be further increased by substituting nitrogen in the extraction step. It was confirmed that this dye had an excellent color tone and excellent heat resistance and light resistance.

Claims (2)

[Claims] 1. An improved variety of purple sweet potato "Kyushu 113".
No. ”is extracted with water or hydrous ethanol under acidic conditions, the method for producing a purple sweet potato pigment. 2. The method for producing a purple sweet potato dye according to claim 1, wherein nitrogen substitution is carried out in the next or the following production step. The purple sweet potatoes of the raw material are cut with a cutting machine. The raw material purple sweet potato is squeezed with a squeezing machine.