JPH0221782B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for preventing yellowing of green plants. The green color of green plants is due to chlorophyll in the chloroplasts, and this chlorophyll is an unstable compound. In weakly acidic conditions, the Mg in the molecule is substituted with 2H to form pheophytin, and the green color changes to yellow. Since this reaction is accelerated by heating, for example, vegetables such as green peppers and green onions turn yellow when heated, and their aesthetic appearance and taste are significantly reduced. A well-known method to prevent this is to replace Mg in the chemical structure of chlorophyll with Cu or Zn, fixing the green color, and treating it with copper sulfate. However, the use of copper sulfate as a food additive is prohibited, and there is currently no suitable means for preventing yellowing of green plants, so a proposal for this was desired. Based on the above, the present inventor has studied various ways to prevent yellowing of green plants, especially those used as food, and has found that they can be used in food products safely, without impairing taste, and at low cost. It has been found that the use of calcium salt as an additive has a remarkable effect on preventing fading. Examples of the calcium salt here include calcium chloride, calcium acetate, calcium gluconate, calcium pantothenate, and calcium lactate, and those that are easily soluble in water are desirable in order to facilitate the addition process. Table 1 shows the results of experiments to confirm the effect of preventing discoloration when various metals were added to frozen green peppers. The experimental method was to boil 1 part of tap water in a pot, then add and dissolve each reagent to an appropriate concentration, add 100g of cut frozen green pepper, and heat at 100°C for 4 minutes. After 4 minutes, they were immediately poured into a colander and cooled with tap water, and their color, taste, and texture were observed.

【table】

【table】

[Table] As is clear from Table 1, those treated with Ca ²⁺ were found to be superior to those treated with well-known Cu ²⁺ or Zn ²⁺ in preventing fading. Moreover, it can be stored for a long period of time. Table 2 shows the relationship between the concentration range and the fading effect when calcium chloride is used.

[Table] Next, applying calcium salt to green plant materials can be easily carried out by adding about 10 ^-2 to ^{10 -3} M of calcium chloride during the commonly performed blanching treatment. It is also highly effective when processing already blanched items; for example, in the case of food products, they are usually boiled for the purpose of sterilization or the like before processing, so it is sufficient to perform discoloration prevention treatment at the same time. In order to confirm the above effects, a test was conducted on the residual rate of chlorophyll using green pepper as a sample, and the results are shown in FIG. Curve A in the same figure
shows a rapid decrease in chlorophyll as a result of blanching at the boiling point in distilled water; curve B
Curve C shows that the reduction of chlorophyll was suppressed as a result of using a 10 ^-2 M CaCl ₂ solution as a blanching solution at the boiling point, and curve C shows that the sample was immersed in a 10 ^-2 M CaCl ₂ solution for 60 minutes and then This shows that the effect of inhibiting chlorophyll decomposition was further enhanced as a result of blanching at the boiling point in ^-2 M CaCl ₂ solution. In this case, when comparing the time required to reach 50% survival rate, it can be seen that the stability of chlorophyll is approximately doubled. In order to confirm that such an effect is due to the calcium salt, blanching was carried out using various water-soluble calcium salts, and the results are shown in Table 3.

[Table] This experiment shows the residual rate of chlorophyll when immersed in 500 ml of each calcium salt solution at room temperature for 1 hour, washed with water, and then blanched in 500 ml of each calcium salt solution at the boiling point for 4 minutes, and the blanching rate at the end of blanching. This is a measurement of the pH of the liquid. The results show that the increase in chlorophyll residual rate is due to the presence of calcium ions. However, the correlation with pH is low, and it is thought that calcium salts do not act as alkaline agents. Also, when comparing calcium salts, calcium acetate and calcium pantothenate have a large effect, but the use of calcium acetate is not permitted in Japan, and calcium pantothenate has a negative effect on taste at its effective concentration, and glucon Since calcium acid is also difficult to use in Japan due to regulations, calcium chloride and calcium lactate are preferred. Furthermore, in order to confirm the effect of calcium salts on vegetables other than green peppers, we blanched spinach, cabbage, and linden in addition to green peppers, and the results are shown in Table 4.

[Table] In this case, calcium chloride was used as the calcium salt, and it was found that the effect of calcium is universal because it increases the residual rate of chlorophyll in various vegetables. Next, an experiment was conducted to determine whether calcium chloride acts directly (chemically changes) on chlorophylls a and b to suppress their thermal decomposition. That is, isolated chlorophylls a and b were collected as an ethanol solution in a test tube, and immersed in hot water at 100°C to measure the rate of thermal decomposition of chlorophyll. On the other hand, when chlorophyll was dissolved in ethanol containing 10 ^-2 M CaCl ₂ and the same operation was performed, chlorophyll decomposed rather rapidly in ethanol containing CaCl ₂ . The results are as shown in FIGS. 2 and 3. In FIG. 2, the curve shows a solution of chlorophyll a in ethanol, and the curve shows the case where chlorophyll a was dissolved in ethanol containing 10 ^-2 M CaCl ₂ . In FIG. 3, the curve shows an ethanol solution of chlorophyll b, and the curve shows a case where chlorophyll b is dissolved in ethanol containing 10 ^-2 M CaCl ₂ . According to this, it is thought that calcium chloride does not have a direct effect on chlorophyll. Furthermore, a similar conclusion was obtained from the determination of Mg and Ca in the chlorophyll extract. When blanched at 100℃ in 500ml of distilled water and
After immersion in a 10 ^-2 M CaCl ₂ solution for 1 hour at room temperature and blanching in 500 ml of a 10 ^-2 M CaCl ₂ solution at 100°C, chlorophyll was extracted, and after dissolving in ether, the Ca of the ether-soluble fraction was extracted. and Mg were determined using an atomic absorption spectrometer, and the results shown in Figure 5 were obtained. In the figure, □ and ○ indicate blanching in distilled water, and ■ and ● indicate blanching in a 10 ⁻² M CaCl ₂ solution. According to this, when blanched in distilled water, Mg decreased rapidly, which is considered to indicate rapid decomposition of chlorophyll. On the other hand, when treated with CaCl ₂ solution, the decrease in Mg was delayed, which is thought to indicate that calcium inhibits the decomposition of chlorophyll. Furthermore, the amount of Ca in the ether-soluble fraction did not change when blanched in distilled water or treated with calcium chloride, indicating that calcium does not directly act on chlorophyll. That is, calcium inhibits thermal decomposition of chlorophyll through an indirect action, and has an excellent effect of preventing discoloration. As explained above, the method of the present invention uses calcium chloride, calcium acetate, calcium gluconate,
By using at least one calcium salt of calcium pantothenate and calcium lactate, a very remarkable anti-fading effect can be obtained,
In particular, when calcium chloride, calcium lactate, or both are added as additives, it can be safely used in foods. Moreover, since the amount added is small and it is effective at extremely low concentrations, it not only does not impair the taste, but also has a pH
It has excellent workability and does not require much effort such as adjustment. Furthermore, both calcium chloride and calcium lactate are very inexpensive, and the cost impact of implementing the method of the present invention is almost negligible.

[Brief explanation of drawings]

1 to 4 are diagrams showing the results of implementing the present invention.

Claims (1)

[Claims] 1. A green plant characterized by treating a green plant with an aqueous solution containing one or more calcium salts of calcium chloride, calcium acetate, calcium gluconate, calcium pantothenate, and calcium lactate at low concentrations. How to prevent fading of plants.