JPH0122815B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a membrane for edible oil regeneration,
In particular, the present invention relates to an edible oil regeneration membrane for domestic use or small-scale commercial use, which adsorbs and passes impurities generated due to deterioration of frying oil, etc., and regenerates the frying oil. Edible oil used for deep-fried foods such as tempura and fries not only deteriorates due to chemical changes such as oxidation and polymerization, but also causes odors to be transferred from fried foods such as fish, meat, and vegetables. If used repeatedly, the taste of the prepared product will be impaired. Conventionally, commercially available household cooking oil regeneration equipment for regenerating fried oil containing degraded components as described above mainly removes solids mixed in fried oil, that is, used cooking oil, resulting in deterioration of the oil. However, there is a defect that various deterioration and deterioration components, fine particulate products, and odors mainly caused by thermal oxidation, thermal polymerization, thermal decomposition, and hydrolysis dissolved in oil are hardly removed. The fine particles themselves are overheated and decomposed, and the decomposed products affect the quality of the fried oil, such as coloring. As a result of various studies on the regeneration of fried oil, the present inventors have found that by applying a cup-shaped edible oil regeneration membrane mainly made of activated clay and pulp as an adsorbent, degraded components in fried oil can be removed. It was discovered that the oil could be substantially removed by adsorption and regenerated to a condition almost unchanged from that of the oil before use, and a patent application was filed in 1982.
No. 68495 and Japanese Patent Application No. 130462/1984. In these cases, as adsorbents, activated clay and acid clay have the best adsorption effect, and exhibit excellent adsorption properties in terms of decolorizing, deodorizing, defoaming, and smoke removal of deteriorated oil, but on the other hand, adsorption The slight odor of the agent itself, generally referred to as clay odor or clay odor, may transfer into fried foods and cooking oil, impairing the taste of tempura and other fries.Activated clay has a particularly sulfur odor. Purification methods using regeneration membranes were still unsatisfactory. As a result of further intensive research, the present inventors solved the above-mentioned problem by manufacturing a membrane for edible oil regeneration from pulp and a modified adsorbent obtained by treating the acidic components in activated clay with an alkaline substance. It has been discovered that it is not necessary to add any fine powder, and therefore, it is possible to refine edible oil without stirring, and that it is possible to obtain recycled oil that does not have a clay odor, which is also said to be the foul odor of activated clay. As is well known, edible oil has a high viscosity, and at room temperature the overspeed caused by a membrane material such as paper or cloth is extremely slow, but at high temperatures the viscosity decreases and the overspeed increases. On the other hand, adsorption and purification of oil is carried out more effectively at higher temperatures. The present inventors have proposed in Japanese Patent Application No. 55-68495 that the improvement in adsorption purification rate due to this temperature increase is more effective than the increase in overrate, so heated oil immediately after being used for cooking is used as an adsorbent. It was discovered that the adsorbent could be sufficiently purified by passing it once through a layer formed into a film, and it was found that it was most convenient to form the adsorbent into a film and use it as a material, and to form the film into a cup. I'm finding out. The present invention is characterized in that the adsorbent used in the regeneration membrane used in Japanese Patent Application No. 55-68495 is activated clay treated with an alkaline substance. It is intended to include not only the shape but also the original sheet shape. The present invention is a membrane for edible oil regeneration which includes one or more layers comprising 5 to 95 parts by weight of pulp and 95 to 5 parts by weight obtained by treatment with an alkaline substance. When degraded oil used for tempura is placed on top of this membrane, the oil permeates through the porous layer, and during this process, the degraded components and odor coloring in the oil are adsorbed. Solids such as fried crumbs and charred substances in the oil are also separated, and a refined oil without a clay odor is obtained as a liquid. The adsorbent used in the present invention is mainly a porous inorganic solid adsorbent obtained by treating the acidic component in activated clay with an alkaline substance, and may be used alone or in combination of two or more. The particle size of the granule and powder adsorbent is not particularly limited, but it is usually preferred to have a particle size of 500 μm or less. The alkaline substances used in the present invention are permitted for food hygiene and are safe even if contained in small amounts in the modifier, such as soda carbonate, sodium hydrogen carbonate, caustic soda, sodium pyrophosphate,
Slaked lime, quicklime, calcium oxide, calcium carbonate and other known inorganic alkaline substances,
They can be used alone or in combination of two or more. Although these alkaline substances may be added directly to the aqueous solution of activated clay as a solid, they are usually added to the dispersed aqueous solution in the form of a dilute alkaline solution for treatment. The degree of treatment of the adsorbent according to the present invention with an alkaline substance varies depending on the type of alkaline substance used and the content of acidic components in the activated clay, but the hydrogen ion concentration of the modified adsorbent dispersion in water ( PH) is preferably 7.0 or less, and if only clay odor is to be prevented, a PH of 7.0 or higher can be used, but in order to maintain the adsorption properties necessary as a membrane for edible oil regeneration, the PH should be 7.0 or less. preferable. However, the pH during treatment with alkaline substances
Even if the pH is 7.0 or higher, it can be lowered to 7.0 or lower by washing with water and, if necessary, neutralizing with diluted hydrochloric acid. However, it should be avoided to significantly change the adsorbent components by treatment with strong alkalinity, and the pH at the time of modification should be 7 or less, preferably 4 to 6.
It is. The pulp used in the present invention is not particularly limited as long as it is made of natural or synthetic fibers and is heat resistant and safe in terms of food hygiene.
High purity and tough vegetable fibers such as cotton, linen, rayon, etc. are preferred. The fiber length and fiber diameter are preferably long and thin and hydrophilic. The pulp used in the present invention is not limited to a single pulp, and two or more types can be used in combination. The composition of the regeneration membrane in the present invention is pulp 5-95
Parts by weight and adsorbent can be arbitrarily selected within the range of 95 to 5 parts by weight, depending on the type of pulp and adsorbent, but compositions consisting of 20 to 40 parts by weight of pulp and 80 to 60 parts by weight of adsorbent are It is more preferable because it is easy to handle and has good regeneration efficiency. The regeneration membrane of the present invention is not limited to a membrane consisting of only a single homogeneous mixed layer of pulp and modified adsorbent, but may also have a multilayered membrane structure, with layers having different composition ratios of pulp and adsorbent. It is possible. For example, the upper layer may consist of only pulp, the middle layer may contain a larger amount of adsorbent, and the lower layer may contain three layers of pulp. Also, the same 3
Among the layers, the upper and lower layers contain a large amount of pulp, and the middle layer contains only the adsorbent. Alternatively, a thin paper layer is provided as the bottom layer, and one layer of pulp and adsorbent is added on top of that.
Providing a layer or two layers will also help protect the adsorbent contained in the membrane during transportation and use. The size of the regeneration membrane is arbitrary, but for general household use, a membrane with a size of 100 to 150 m/mφ is preferable from the viewpoint of handling. The thickness of the membrane needs to be increased as the area increases from the viewpoint of regeneration efficiency and strength.
The thickness usually ranges from 0.1 to 5.0 m/m. The shape of the regenerating membrane is not limited to a flat sheet, but may be shaped into a cup with a large mouth that uses the membrane as a vessel wall and allows easy pouring of oil from a tempura pot. For example, when manufacturing membranes for recycling, conical shapes,
Conical shapes such as ellipses and pyramids, or inverted shapes such as pleated conical shapes, cup-shaped inverted truncated conical shapes with a bottom, and other arbitrary shapes. Alternatively, the side edges of two or more flat membranes may be aligned and joined with flexible non-porous tape to form a cup. It can also be formatted into In particular, a cup made by joining two fan-shaped sheets on both sides and at the bottom is preferable because it is foldable and can be recycled by putting a large amount of oil inside. The temperature of the edible oil refined using the regeneration membrane of the present invention varies somewhat depending on the characteristics of the adsorbent and the type of oil, but in the case of edible oil, as long as it does not decompose and deteriorate at that temperature, a higher temperature is better for regeneration efficiency. preferred and generally
A temperature of 80-160°C is optimal. Normally, the temperature of frying oil for tempura is around 180℃, so the temperature drops when it is poured from the pan onto the recycling membrane, and it falls within this temperature range. It is preferable to pour it on top. Also, when regenerating a long time after cooking, it is better to keep the oil temperature above 60℃, as this will reduce the viscosity of the oil and speed up the overspeed.
It is also preferred because adsorption purification is often carried out. When refining edible oil using the present invention, a holder for the regenerating membrane is not necessarily required depending on its shape, but for example, a cup-shaped holder may be placed on the top of the regenerated oil receiver (storage container). If a holder is installed and a cup-shaped regeneration membrane is fixed therein, there is no need to transfer the regenerated oil to another container, and handling becomes easy. In addition, it is possible to improve adsorption efficiency, overspeed, etc. by keeping the temperature of unregenerated oil above a certain temperature by installing a heating device in the retainer itself, or by placing the retainer itself in a vacuum bottle and holding it. be. When edible oil is recycled using the recycling membrane according to the present invention, there is of course no clay odor, but there is also less blackening of the membrane, less bubbles from the membrane caused by the recycled hot oil, and less overtime. It has characteristics such as shortening. The present invention will be explained below with reference to examples, but is not limited to the examples. Example 1 500 g of activated clay (manufactured by Mizusawa Chemical Co., Ltd., powder) and purified water 3 were placed in a 10-piece beaker and heated and stirred at 100° C. for 5 minutes. Next, 100 ml, 200 ml, 400 ml, 600 ml of 1/10N sodium bicarbonate (NaHCO ₃ ) was added to the above activated clay aqueous solution cooled to RT (room temperature) while stirring.
800 ml was added to each sample and the pH of each sample was measured. Furthermore, in order to remove water from the above substance, it was filtered using large paper (manufactured by Toyo Paper Co., Ltd.), and then dried in a dryer (120°C) for 3 hours to completely remove water. In a mixer (capacity 1.5), 10 g of natural pulp (manufactured by Toyo Paper) and the above activated clay 60 treated with 1/10 normal sodium bicarbonate (NaHCO ₃ ) were added.
g and 1200 g of purified water were added and mixed for 5 minutes. Next, a perforated mold for cup molding (upper diameter 120mm, 110mm)
〓, height 110 mm, pore diameter 1 mm〓) was installed in a suction tank, and the outside of the multi-hole mold was vacuumed using a suction pump, and the above mixture was suctioned into the mold and dehydrated, forming an inverted truncated conical shape. A cup was formed. Furthermore, the wet cup (still adsorbed to the porous mold) was dried in a dryer at 110°C for 30 minutes to remove moisture, cooled to room temperature, taken out from the porous mold, and made into an edible cup with a film thickness of 1.5 mm. A recycled cup for oil was obtained. Oil in which tempura is fried in a molded recycled cup (tempura oil; vegetables, fish, and meat are fried three times each)
Regeneration was carried out by pouring 800 g into a cup at 160°C. Table 1 shows the light transmittance and odor of the raw oil, sample oil for recycling (degraded oil), and recycled oil. Example 2 1/10 normal sodium carbonate (Na ₂ CO ₃ ) was used as the alkaline substance, and a mixed paper of natural pulp (manufactured by Toyo Paper Co., Ltd.) and rayon pulp (manufactured by Toyo Boseki Co., Ltd.) was used as the oil filtration paper. The same frying oil regeneration as in Example 1 was carried out. The reproduction results are shown in Table 1. Example 3 The same frying oil was regenerated as in Example 1 except that 1/10N sodium hydroxide (NaOH) was used as the alkaline substance. The reproduction results are shown in Table 1. Example 4 The same frying oil was regenerated as in Example 1 except that 2/10N potassium hydroxide (KOH) was used as the alkaline substance. The reproduction results are shown in Table 1. Example 5 Potassium carbonate (K ₂ CO ₃ ) as an alkaline substance
The frying oil was regenerated in the same manner as in Example 1, except that the same method as in Example 1 was used. The reproduction results are shown in Table 1. Comparative Example 1 Activated clay (manufactured by Mizusawa Chemical, powder) was added to 800 g of the same tempura frying oil as in Example 1 that had been cooled to 150°C.
60g was added and mixed for 10 minutes using a stirrer. Next, a glass funnel was set with roll paper (Toyo Roll Paper large size) and the above mixture was passed through it to obtain recycled oil. The reproduction results are shown in Table 1. Comparative Example 2 500g of activated clay (Mizusawa Chemical powder) was placed in a 10-piece beaker, and the mixture was heated and stirred at 100°C for 5 minutes. Next, the activated clay (aqueous liquid) cooled to RT (room temperature) with stirring was filtered through Ro paper (Toyo paper large format), and then dried in a dryer (120°C) for 3 hours to remove moisture. Except that the oil was completely removed, cups were formed using the same method as in Example 1, and the oil used for frying tempura was recycled in the same manner as in Example 1. The reproduction results are shown in Table 1.

【table】

[Table] The light transmittance in the table is measured at 450 m using a self-recording spectrophotometer manufactured by Hitachi, Ltd., with the sample and blank (distilled water) placed in a 10 x 10 x 30 mm quartz cell.
It is the transmittance of light with a wavelength of μ. In addition, human senses are often more sensitive to the odors in Examples and Comparative Examples of the present invention than in chemical measurements (for example, it is said that there is a correlation between oxidation, POV, and radical carbonyl value). There are many different types of odors, especially
Since sensory testing is on the same level as practical issues, we selected 20 taste judges through rigorous taste tests, and conducted a three-point discrimination test method (○△x method) in a constant temperature and humidity sensory testing room. The odor (flavor) of oil was evaluated. In the table, ○ indicates an odor similar to that of raw oil, × indicates a strong clay odor, and △ indicates an odor with some residual clay odor. Other properties such as oxidation value (AV), peroxide value (POV), and foaming were also measured, and when the cup of the present invention was used, it showed better results than commercially available oil filters. In addition, when tempura was fried using oil recycled according to the present invention, in all of Examples 1 to 6, new oil (raw oil) was used.
The odor, color, taste, etc. were about the same as those fried. Example 6 Calcium hydroxide (Ca
(OH) ₂ ) was used to treat activated clay in the same manner as in Example 1. Calcium hydroxide (Ca(OH) ₂ ) was obtained by stirring 30 g of calcium hydroxide in 8 portions of distilled water in 10 beakers at room temperature for about 10 minutes, and then using the supernatant. Pour 10g of natural pulp (manufactured by Toyo Paper), 60g of the above white clay, and 1200g of purified water into a mixer (1.5).
Mixed for a minute. Next, a perforated mold for sheet molding (vertical
300 mm wide, 600 mm wide, and pore diameter 1 mm) was placed in a suction tank, and the bottom of the porous mold was sucked and adsorbed using a suction pump to dehydrate the above mixture, and a sheet was molded.
Furthermore, the wet sheet (still adsorbed to the porous mold) was left in a dryer (110°C) for 30 minutes to remove moisture, cooled to room temperature, and removed from the porous mold. The frying oil was recycled in the same manner as in Example 1, except that the sheet was cut into 150 mm pieces and placed in a container with a flange using a silicone rubber gasket. The reproduction results are shown in Table 1.

Claims (1)

[Scope of Claims] 1. Activated clay in which the pH of an aqueous dispersion treated with 5 to 95 parts by weight of pulp and an alkaline aqueous solution is 7.0 or less.
An edible oil regenerating membrane comprising one or more layers comprising 95 to 5 parts by weight. 2. Claim 1, characterized in that multiple pulp layers with different adsorbent mixing ratios are laminated.
Membrane for edible oil regeneration as described in section. 3. The edible oil regenerating membrane according to claim 1, wherein the membrane is formed or shaped into a cup shape.