JPH047662B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a new method for purifying honey using a selective separation membrane. [Prior Art] There are many types of honey, and their components can be roughly divided into water-insoluble components and water-soluble components. In addition to proteins and beeswax, water-insoluble components include particulate contaminants such as pollen, wood chips, and leaf fragments, as well as various fungi, which have a size of several mm to 0.1 μm. On the other hand, water-soluble components include low-molecular substances such as water-soluble high-molecular proteins, sugars, minerals, organic acids, amino acids, and pigments. As described above, raw honey as a raw material contains many components, so when raw honey is used as a raw material for processing, it has disadvantages such as poor acid resistance and fruit juice resistance.
For example, when diluting honey with water, such as in soft drinks, water-insoluble proteins in crude honey precipitate to form a scum-like substance. Further, when fruit juice or the like containing pectin or other polymeric substances is mixed, similar sludge-like substances are generated. Therefore, crude honey cannot be used as a raw material for processing, and today honey that has been purified in various ways is currently used.
Honey purification mainly consists of two steps: decolorization and filtration, and deionization.The decolorization and filtration processes include activated carbon treatment, press filtration using diatomaceous earth as a filter medium, and deionization.
In the deionization step, treatment is performed using an ion exchange resin. There are various combinations of refining process sequences, but basically, crude honey, which is often crystallized, is first heated and dissolved, and then diluted with water. Next, activated carbon is added to this aqueous solution to adsorb impurities, followed by filtration with a press filter using diatomaceous earth, the resulting filtrate is subjected to ion exchange treatment, and finally concentrated to an appropriate concentration. However, the purification methods described above still have some unresolved problems. The first is that the water-insoluble proteins, beeswax, and bacteria contained in the raw materials are not completely removed. Water-insoluble proteins cause the formation of sludge when honey is used for drinking water, so currently they are removed by press filtration using activated carbon and diatomaceous earth, but it is possible to remove them in just one treatment. There isn't. Therefore, depending on the type of crude honey, it cannot be removed unless this process is repeated or a phosphate-based protein coagulant is added. Beeswax has a relatively low melting point, so it dissolves at high temperatures but precipitates at room temperature. Even when treated in the same way as water-insoluble proteins, it often cannot be removed because it has a low molecular weight. The current situation is that there are many. In addition, crude honey contains aerobic viable bacteria, aerobic heat-resistant viable bacteria, anaerobic viable bacteria, and anaerobic heat-resistant viable bacteria, among which these have recently become a problem as a cause of potulinosis in infants. Clostridium potulinum belongs to anaerobic fungi. Since these bacteria are usually present in crude honey with sizes ranging from submicrons to several tens of microns, they cannot be completely removed by press filtration using activated carbon or diatomaceous earth. Therefore, microscopic bacteria remain in honey after refining. The second problem is the waste cake produced from the refining process. The current refining process uses press filtration using activated carbon and diatomaceous earth as filter media, so for example, when refining 10 tons of raw honey,
0.5 to 1.0 tons of a mixture of activated carbon and diatomaceous earth are produced as industrial waste, and their disposal has become a problem. The third problem is the odor generated from the refining process site. In the conventional process, the tank is opened during the process, which causes the strong smell of raw honey to spread not only in the work room but throughout the factory, causing discomfort. Fourth, since refined honey is treated with activated carbon and ion exchange, even the pigments and aromatic components unique to honey are removed. One possible way to solve these problems is to use selective separation membranes, which have been put into practical use in various fields in recent years, although no attempt has been made to purify honey yet. In other words, if it becomes possible to remove water-insoluble proteins, beeswax, and bacteria using selective separation membranes such as reverse osmosis membranes, loose RO membranes, ultrafiltration membranes, and microfiltration membranes, it will be possible to remove water-insoluble proteins, beeswax, and bacteria. It is possible to omit the conventional activated carbon treatment and press filtration treatment, eliminate the problem of waste cake and odor in the refining process, and expect to obtain purified honey that is close to natural. However, with reverse osmosis membranes and loose RO membranes, the pore size of the membranes that separate solutes is too small, so it is obvious that even sugar, an essential component of honey, is removed. In addition, in contrast to reverse osmosis membranes and loose RO membranes, microfiltration membranes have too large pores, so although sugar can pass through, water-insoluble proteins, beeswax, and even bacteria that need to be removed can also pass through. There is a risk that it will happen. On the other hand, ultrafiltration membranes are considered to have the most potential because the membrane pore size is located between the separation membranes listed above, but in any case, it is difficult to purify honey using these selective separation membranes. The current situation is that there have been no examples of this in the past, and even if an ultrafiltration membrane is used, it is necessary to select the optimal pore size of the membrane to be used, as well as the treatment method, treatment conditions, how to combine it with other processes, etc. Must be set appropriately. [Object of the Invention] As a result of research aimed at solving the above-mentioned problems in honey refining methods, the present invention has been developed to solve the problem of non-refined honey in crude honey by using a selective separation membrane with an appropriate membrane pore size. We obtained the knowledge that water-soluble impurities can be removed, and based on this knowledge, we conducted various studies and completed the present invention.The purpose of this invention is to remove proteins, beeswax, and Reliably removes bacteria and, on the other hand, produces high-grade purified honey that retains the pigments and aroma components unique to natural honey, while preventing the production of industrial waste (waste cake) and leakage of unpleasant odors during the refining process. The purpose of the present invention is to provide a method for refining honey that eliminates the [Structure of the Invention] That is, the present invention provides coarse honey with a maximum surface pore size of 0.1 μm.
filtration treatment by a cross-flow filtration method using a selective separation membrane with a rejection rate of less than m or a rejection rate of dextran T-500 of 75% or more and a rejection rate of dextran T-10 of 70% or less,
The present invention also provides a honey purification method characterized in that an ion exchange treatment is further performed after the filtration treatment as required depending on the purpose, and a purified honey characterized in that bacteria, proteins, etc. are removed by this method. Crude honey in the present invention is obtained by collecting sweet liquids such as nectar and honeydew from plants, changing them by adding substances produced by the honey itself such as secreted enzymes, and storing the honey in honeycombs for ripening. It's called natural honey. The material for the selective separation membrane used in the present invention is preferably one with excellent heat resistance, chemical resistance, etc., but is not particularly limited. Regarding the shape, it may be a flat membrane, a hollow fiber membrane, or a tubular membrane, but a hollow fiber membrane is suitable because it has a large membrane area per module and can perform cross-flow filtration. The properties of a selective separation membrane depend on the maximum pore size of its surface. The surface referred to in the present invention refers to the surface of a thin, dense layer on the surface of the membrane that prevents the permeation of solutes or suspended particles.Actually, it refers to the surface that comes into contact with the raw honey solution to be filtered. be. The pores on the surface are generally not circular or oval, but often have a complex shape, but the maximum pore diameter in this invention is the length of the longest part of the complex shape observed by electron microscopy. It is. However, if the pore size becomes smaller, it cannot be measured by electron microscopy, so it is expressed by the rejection rate of a standard substance (usually dextran) that defines the molecular weight. The selective separation membrane used in the present invention has a maximum pore diameter of less than 0.1 μm or a rejection rate of 75% for dextran T-500 (average molecular weight 500,000).
% or more and the lower limit is preferably a range in which the inhibition rate of Dextran T-10 (average molecular weight 10,000) is 70% or less. The inhibition rate of dextran T-500 is 75%.
This corresponds to the maximum pore diameter of 0.1 μm as measured by electron microscopy; if the pore diameter is larger than this, beeswax and bacteria, which are impurities in honey, cannot be sufficiently removed. In addition, depending on the membrane, the inside of the membrane may begin to be clogged with solutes, resulting in a rapid decrease in filtration rate and, in addition, poor cleaning recovery performance, making the membrane impractical. On the other hand, the membrane's pore size of 70% in rejection of dextran T-10 is a range in which the pore size cannot be measured by electron microscopy, and if the pore size is smaller than this, it will also inhibit sugars, which are the main components of honey. As a result, the object of the present invention cannot be achieved. The filtration step using the selective separation membrane in the present invention is as follows:
Although it can be introduced at any point in the various honey purification steps, it is preferable to carry out the filtration step immediately after dissolving and diluting the crude honey as a raw material. The filtrate at this point is easy to filter because the impurities in honey, such as water-insoluble proteins, beeswax, and bacteria, remain in their natural state, and after filtration, conventional steps can be followed. If you want to increase the degree of purification, such as by reducing coloring, you can use ion exchange treatment, which is included in the conventional process.If you want to retain the pigments and aroma components unique to natural honey, you can use ion exchange treatment. Instead, the vacuum concentration step should be started immediately. The raw material, raw honey, usually has a concentration of about 80 brix, which is difficult to process due to its high viscosity, so in the conventional refining process, it is diluted twice by adding the same amount of water to reach a concentration of 40 brix. In the method of the present invention, the concentration of the filtration stock solution varies depending on the filtration temperature, but the filtration temperature must be kept below 70°C in relation to the melting point of beeswax, and is preferably 0 to 70°C, preferably 50°C. A temperature of ~60°C is desirable. In this temperature range, the concentration is 30~
65 brix is suitable, and the filtration temperature is 0℃.
If the concentration is lower or exceeds 65 brix, the viscosity will increase, resulting in a slow filtration rate and poor workability, making it impractical. On the other hand, if the concentration is lower than 30 brix, the filtration rate is high and the work is easy, but more water must be removed in the vacuum concentration step after the purification step, resulting in higher costs. When the filtration temperature exceeds 70°C, the beeswax that has aggregated in the crude honey melts and can no longer be removed by the selective separation membrane having the specific membrane pore size range of the present invention.
Selective separation membranes that can be removed even when melted have smaller pore diameters, but they may also remove sugar components that are essential for honey, making them undesirable for honey refining. . Although the method of filtration is not necessarily limited, since the purpose of the present invention is to remove particulate components from honey, if the removed particulate components are deposited on the membrane surface, The filtration speed decreases and the filtration process cannot be continued for a long time. Therefore, it is desirable to use the so-called cross-flow filtration method, in which the filtration solution is flowed in a direction perpendicular to the permeation direction of the membrane, that is, in a direction parallel to the membrane surface, thereby removing the particulate components remaining on the membrane surface. carried away with him. Since the membrane surface can always be kept fresh, long-term filtration is possible. [Effects of the Invention] According to the present invention, problems in conventional honey refining methods can be solved: 1) removal of proteins, beeswax, and bacteria contained in raw honey; 2) waste produced as industrial waste; We are able to solve the problems of cake, 3) odor, and 4) retention of pigments and aroma components unique to natural honey, making it possible to supply honey for processing like never before, and for use in soft drinks. It can be used not only as a food, but also as a highly hygienic food and a nutritional food, making it extremely useful industrially. The present invention will be explained below with reference to Examples. Example 1 An aqueous honey solution was prepared by adding the same amount of water to Chinese buckwheat honey and diluting it by 1/2 to prepare a filtered stock solution. The selective separation membrane is a hollow fiber selective separation membrane (effective membrane area 785 cm ² , effective length 50 cm) manufactured by Pharmacia Fine Chemicals that has a rejection rate of 95% and 10% for dextran T-500 and T-10, respectively. using the stock solution 10
, filtration temperature 60℃, circulation capacity 60/h, inlet pressure
The stock solution was subjected to internal pressure filtration under conditions of 2.5 Kg/cm ² and outlet pressure of 1.0 Kg/cm ² to obtain purified honey. Comparative Example 1 Using the same filtration stock solution as in Example 1, activated carbon treatment and diatomaceous earth press filtration treatment were repeated twice, followed by ion exchange treatment, followed by vacuum concentration. Regarding the obtained purified honey and crude honey, the number of bacteria,
The absorbance at a wavelength of 400 to 750 nm was examined, and fruit juice resistance and general resistance tests were also conducted. The results are shown in Table 1, Table 2, and Figure 1. According to the method of the present invention, bacteria contained in crude honey were almost completely removed (Table 1) and In the conventional method, most of the pigment is removed, but in the method of the present invention, the absorbance at around 400 nm, which indicates brown color, is high (Figure 1), indicating that the pigment unique to natural honey remains. . From Table 2, it was found that the honey has excellent fruit juice resistance and general tolerance, and as a result, the honey can be used for various food processing purposes. It has become clear that it can be used in hot fruit juice drinks and carbonated drinks.

【table】

[Table] Salt resistance test × ○

Claims (1)

[Claims] 1. Crude honey with a surface maximum pore diameter of less than 0.1 μm or a dextran T-500 rejection rate of 75% or more,
A method for purifying honey, characterized in that the honey is filtered by a cross-flow filtration method using a selective separation membrane having a dextran T-10 rejection rate of 70% or less. 2. The method for refining honey according to claim 1, further comprising performing an ion exchange treatment after the filtration treatment. 3. The honey purification method according to claim 1 or 2, wherein the temperature during the filtration treatment is in the range of 0 to 70°C. 4. Sterilized honey characterized by having been purified by removing bacteria by the method according to claim 1. 5. Deproteinized honey, characterized in that it has been purified by removing proteins by the method according to claim 1.