JPH0159282B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an efficient method for producing carrageenan with good thermal stability and improved gel texture. Carrageenan is derived from red algae such as Chondrus crispus, Gigartina Stellatta, Euchyuma
Eucheuma Ccttonii
It is a sulfated galactan obtained by extracting spinosum (Eucheuma Spinosum) etc. with neutral to weakly alkaline hot water. There are several types of these with different contents of sulfate groups and 3,6-anhydro-D-galactose units, but they are generally classified into κ, λ, and ι, each with a unique gelling ability and It has reactivity and is used in a wide range of fields including the food industry and the cosmetics industry. Carrageenan is significantly inferior in thermal stability compared to other polysaccharides; for example, if it is left in the air at a temperature of 100°C for 1 to 4 hours, it will change color or carbonize, resulting in a decrease in the viscosity required for carrageenan.
Physical properties such as gel strength are also significantly reduced. This change is observed over a period of 10 to 100 hours even at lower temperatures, e.g., 60 to 80 degrees Celsius, and a similar change occurs within an extremely short period of time, i.e., 5 to 50 minutes, at higher temperatures, e.g., 130 to 150 degrees Celsius. do. This means that carrageenan undergoes significant quality deterioration due to heat load during various steps before it is used, such as after the sterilization step, and that deterioration of various properties over time is unavoidable before use. In anticipation of these phenomena, the industry is currently avoiding this problem by adding carrageenan in excess of the required amount, but this increases production costs and increases the need for physical property values to understand the state of deterioration. The company is forced to go through the trouble of having to measure more frequently. As a result of repeated research on the thermal instability of carrageenan, the present inventors found that the instability lies in the chemical heterogeneity of the cations with respect to the sulfate groups bonded to the galactan skeleton of carrageenan, and that this causes the instability of the sulfate groups. It was discovered that the carrageenan was destabilized. Furthermore, according to the research conducted by the present inventors,
Carrageenan, which is produced by extraction with hot water with a pH of 5.0 to 8.0, contains a heterogeneous structure with hydrogen ions as counter cations of the sulfate group, depending on the pH value of the extract. It has become clear that this non-uniformity is the cause of significantly deteriorating the thermal stability of the produced carrageenan. And to resolve this heterogeneity,
It was confirmed that it is effective to adjust the pH of the liquid to 9.0 or higher, and that the carrageenan produced by this method has extremely good thermal stability. From the results of this study, it can be easily inferred that thermal stability will be imparted to the produced carrageenan by extracting the raw material algae with hot water with a pH of 9.0 or higher. However, this method has extremely low extraction efficiency of carrageenan and is very difficult to filter, so it is not preferred as an industrial production method from the economic point of view. The reason for this is that when the pH is above 9.0, the degree of swelling of the raw material algae is low, and the extraction efficiency of carrageenan is low.
Further, if a part of the alkaline earth metal salt becomes insolubilized and the two are applied together in a coexisting state, overload may become excessive. The present invention extracts carrageenan from raw algae at a pH of 5.0 to 8.0, filters the extract, and converts the liquid to a pH of 9.0 to 8.0.
This is a method for producing carrageenan, which is characterized by passing it through again as 12.0 and then dehydrating it. A major feature of the method of the present invention in terms of production efficiency is that the raw material algae is extracted and filtered at a pH of 5.0 to 8.0, and then the pH of the liquid is adjusted to 9.0 to 12.0. That is, by extracting raw material algae at pH 5.0 to 8.0, a decrease in the extraction efficiency of carrageenan can be completely avoided, and no difficulty will arise in the subsequent steps. Next, when the pH of the liquid is set to 9.0 to 12.0, an over-step is required to insolubilize some of the alkaline earth metal salts, but since the unextracted residue of the raw material algae has been removed in advance, overloading is not possible. significantly reduced. When carrying out the present invention, first the raw material algae is
Extract carrageenan at PH5.0-8.0. Examples of raw material algae include the above-mentioned red algae. As an extraction method, for example, a method is used in which the raw material algae is immersed in water, the pH is adjusted to 5.0 to 8.0 with acid or alkali, and then heated. The heating temperature is preferably 70 to 100°C. Heating time is 2 to 8 hours. Next, filter the extract and adjust the pH of the liquid to 9.0 to 12.0.
As will pass again. If the pH of the liquid is lower than 9.0,
The resulting carrageenan has poor thermal stability and PH
If it is higher than 12.0, the physical properties of carrageenan will deteriorate, and the pigments contained in the raw material algae will change color, resulting in a significant decrease in the quality of carrageenan. For example, the following bases are used to adjust the pH of the liquid. Hydroxides, carbonates, acetates, citrates, oxalates, tartrates, fumarates, adipates, phosphates, ammonia, amines, etc. of sodium, calcium, magnesium, potassium, etc., and two types thereof A mixture of the above. A combination of hydroxide and carbonate is particularly preferred. Carrageenan is obtained by concentrating the thus obtained liquid as necessary, dehydrating it, and drying it. As the dehydration method, for example, a method in which carrageenan is precipitated by adding a water-miscible organic solvent, a method in which the liquid is gelled and then pressurized, etc. are used. Preferred water-miscible organic solvents include methanol, ethanol, isopropanol, and acetone.
Excess alkali can be removed through a dehydration step. After dehydration, carrageenan with a pH of 7.8 to 9.5 can be obtained by drying using a conventional method. Carrageenan produced by the method of the present invention has excellent thermal stability and shows little change in physical properties over time. Also surprisingly, the gel properties of the product are significantly improved, especially in Katupa carrageenan. Gels prepared using Katupa carrageenan produced by conventional methods are extremely brittle and have a so-called dry feeling when eaten, giving an unpleasant sensation. This tendency is particularly noticeable when potassium salts such as potassium chloride are added. On the other hand, the gel prepared from Katupa carrageenan produced by the method of the present invention has no brittleness and does not cause discomfort even when potassium salts such as potassium chloride are added. This is also evidenced by various measured values using gel property evaluation instruments such as a Neocard meter (manufactured by Iio Electric Co., Ltd.) and a rheometer (manufactured by Fudo Kogyo Co., Ltd.). For example, gels prepared with carrageenan produced by the method of the present invention have a larger displacement on the gel surface before gel rupture than gels produced by conventional methods, and therefore have less brittleness and dryness. It is clear that it has been resolved. Examples 1 to 5 and Comparative Example 1 After washing 6 kg of Yukiyuma kotoni with water,
Soak in water and PH with hydrochloric acid or potassium hydroxide
After adjusting the temperature to 7.1, it was heated to 80°C and extracted. After 3 hours, add 1 kg of diatomaceous earth to the extract and filter.
I got it. The potassium solid shown in Table 1A was added to this liquid to adjust the pH to the pH shown in the second column of Table 1A, and then 300 g of diatomaceous earth was added and filtered again.
2 parts by weight of isopropanol was added to 1 part by weight of the obtained liquid to precipitate Katupa carrageenan, which was then dried at 80° C. for 30 minutes to obtain dried Katupa carrageenan. This was subjected to the following test. Thermal stability test: Leave in air at 80°C and heat-treat for a specified period of time. The viscosity and gel strength of the 1.5% solution at 75°C were measured before and after this heat treatment. In addition, the time required to reach carbonization in air at 150°C was measured. Storage stability test: The samples were left in an air-controlled room at 30°C and 60% humidity for 200 and 400 days, and changes in viscosity and gel strength were measured. Gel texture: A 1.5% solution was cooled to gel, and a tasting sensory test was conducted, and the amount of displacement of the gel surface until breakage was measured using a Neo Card meter (plunger diameter: 5.6 mm). The results are shown in Tables 1A and 1B. It is known that the Katupa carrageenan obtained by the method of the present invention is superior in thermal stability, storage stability, and gel texture as compared to Comparative Example 1.

【table】

[Table] Comparative example 2 After washing 6 kg of Yukiyuma kotoni with water,
The mixture was soaked in water, adjusted to pH 10.2 with potassium hydroxide, and extracted by heating at 80°C. After 3 hours, 1.3 kg of diatomaceous earth was added to the extract and filtered, but the flow rate suddenly decreased and only 15 liquids were obtained. Examples 6 to 10 and Comparative Example 3 After washing 6.2 kg of Euchyuma spinosum with water, it was immersed in 100 ml of water, adjusted to pH 7.3 with hydrochloric acid or calcium hydroxide, and then heated and extracted at 80°C. After 3 hours, add 1 kg of diatomaceous earth to the extract and filter it.
Got 91. Next, an alkaline solid was added to the liquid to adjust the pH to the pH shown in the second column of Table 2A, and 300 g of diatomaceous earth was added and filtered again. Add 2 parts by weight of isopropanol to 1 part by weight of the obtained liquid to precipitate iota carrageenan.
Dry iota carrageenan was obtained by drying at 80°C for 30 minutes. Using this, a thermal stability test and a storage stability test were conducted in the same manner as in Example 1. However, gel strength was not measured. The results are shown in Table 2A and
Shown in Table 2B. It is known that iota carrageenan obtained by the method of the present invention is superior in thermal stability and storage stability as compared to comparative examples.

【table】

【table】

【table】

Claims (1)

[Claims] 1. A method for producing carrageenan, which comprises extracting carrageenan from raw material algae at a pH of 5.0 to 8.0, filtering the extract, filtering the liquid again at a pH of 9.0 to 12.0, and then dehydrating it.