JPH0571457B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a coffee beverage packed in a heat-shrinkable container. [Prior Art] Generally, coffee drinks are packaged in cans and sold as canned coffee drinks. This type of canned coffee beverage is manufactured by putting the coffee beverage into a can, sealing it, and placing it in a pressure and heat sterilization pot (retort pot), which then heats and pressurizes the coffee beverage inside the container to sterilize it. has been done. In this case, the sealed can always contains a small amount of air, which expands due to pressure heating by the pressure heating pot, causing the internal pressure of the can to increase significantly, and in some cases, the can resulting in rupture. In order to prevent such a can bursting phenomenon, the pressure inside the pressurized heating sterilization pot is maintained higher than the internal pressure of the container to prevent the can from bursting. Recently, attempts to use plastic containers in this field have been attracting attention. Plastic containers have a high degree of freedom in molding, so they can be easily formed into desired shapes and are inexpensive. However, when plastic containers are placed in a pressurized and heated sterilizer and subjected to pressurized and heated sterilization, their pressure resistance is very weak, so they may deform or burst. Furthermore, even if a constant differential pressure retort method (sterilization is carried out with the internal pressure of the retort pot being the same as the container internal pressure or with a constant pressure difference at all times) is adopted, in which pressurization of the air-containing plastic container is used for heat sterilization, The container shrinks due to heat,
Because the initial shape cannot be maintained, when plastic molded products are used as containers for coffee beverages, the coffee beverage alone is sterilized by pressure and heat, and then poured into the plastic container and sealed. There is. However, even with this method, bacteria adhering to the plastic container itself are sealed together with the coffee beverage, and these bacteria multiply during storage, leading to spoilage of the coffee beverage. Therefore, such coffee beverages packaged in plastic containers are only used for short-term storage under refrigerated distribution. In order to overcome these drawbacks, it has been considered to sterilize the plastic container itself under heat and pressure, but in this case, heat shrinkage of the container itself still occurs, which poses a considerable practical difficulty. [Problems to be Solved by the Invention] On the other hand, when a beverage such as coffee is placed in a cup-shaped container made of a laminated material of polyethylene and aluminum foil, and the container is sealed, the container is heated under pressure for the purpose of retort sterilization. In addition, a technique has been proposed in which a sealing lid is used as the lid of the cup-shaped container, which bends vertically due to the pressure difference between the inside and outside of the container to absorb the pressure difference (Japanese Utility Model Publication No. 59-765). This technology prevents the container itself from deforming by allowing the seal lid to flex and deform up and down in response to changes in pressure to absorb pressure differences, but the sterilization temperature is approximately 80 to 100 degrees Celsius. However, if retort sterilization is performed at temperatures exceeding 100°C, deformation of the container body itself cannot be prevented even if a sealing lid is used. In addition, according to this technology, the sealing lid expands upward or is recessed downward, which creates a negative impression on consumers (as if the lid has been pushed up due to decomposition). may give a bad impression). This invention was made in view of these circumstances, and provides a coffee beverage packaged in a heat-shrinkable container that does not deform due to heat during heat-pressure sterilization and can withstand heat-pressure sterilization at high temperatures. The purpose is to provide a manufacturing method for. [Means for Solving the Problems] In order to achieve the above object, the method for producing a coffee beverage in a heat-shrinkable container of the present invention includes placing a coffee beverage in a container, sealing the container, and heating the container in a pressurized heating pot. A method for producing a coffee beverage in a heat-shrinkable container that is sterilized by pressure, in which the container is made of heat-shrinkable synthetic resin, and the pressure during the sterilization by heat and pressure is set to the following (A)-(B). It is configured to be set to a certain pressure. (A): Pressure inside a non-heat-shrinkable container when coffee beverage is filled into the non-heat-shrinkable container and heated and pressurized. (B): Pressure of (a)-(A) below. (a): Pressure inside a heat-shrinkable synthetic resin container when coffee beverage is filled into the heat-shrinkable synthetic resin container and heated and pressurized (a) (A): Above pressure (A) [Function] This invention During sterilization in the pressure heating sterilization oven, the pressure is set to A- as described above.
Since the pressure is set to B, even if a container made of a heat-shrinkable material such as polyethylene or polypropylene is used, the container itself will not be deformed under heat and pressure and will maintain its initial shape. This means that at temperatures above 100℃,
The same applies to the case of pressure and heat sterilization. Therefore, not only is there no deterioration in the long-term shelf life of the coffee beverage, but there is also no deterioration in the appearance of the lid, such as vertical bending or expansion. This will be explained with reference to the drawings. In the drawings, A is a pressure curve inside a heat-shrinkable container when pressurized and heat sterilized using a heat-shrinkable container, and B is a non-heat-shrinkable container when a heat-shrinkable container such as a metal can is used. The pressure curve C is the pressure curve according to the present invention. In addition, pressure curve A is based on the pressure inside the heat-shrinkable container and the pressure inside the pressurized heat sterilization pot, which is the same pressure, because if the pressure inside the heat-shrinkable container is actually measured directly, it will burst and become impossible to measure. Measurements are made to prevent the container from bursting. Therefore, the pressure curve A means the pressure curve inside the pressure heat sterilization pot that is controlled to be the same pressure as the pressure inside the heat shrink container when performing pressure heat sterilization using a heat shrink container. do. Normally, when a non-heat-shrinkable container such as a metal can is used, as shown in curve B, as the pressure inside the pressure and heat sterilization pot increases, the internal pressure of the container also rises, and the pressure and heat sterilization occurs. When the internal pressure in the pot decreases, the internal pressure in the container also decreases. However, when using a container made of heat-shrinkable synthetic resin, even if the pressure inside the pot decreases, the curve A
As shown on the right side of the figure, the internal pressure of the container remains unchanged. This is because although the container heat-shrinks and its internal volume becomes smaller, the amount of coffee beverage and air inside the container remains unchanged.As a result, the remaining air inside the container expands, causing the container itself to bulge and become deformed. do. If it is cooled rapidly, it will dent in places and become even more deformed. Therefore, as a result of repeated research focusing on the internal pressure of the container, the inventors found that the pressure inside the container (curve B) when using a non-heat shrinkable container during pressurized heat sterilization
Based on this pressure, the pressure α (pressure of curve A - pressure of curve B) corresponding to the increase in container internal pressure due to heat contraction of the heat-shrinkable synthetic resin container is subtracted from this pressure. The present invention was achieved by finding that when the pressure inside the pot is set (curve C), the internal pressure of the heat-shrinkable synthetic resin container decreases after the sterilization is completed, thereby preventing the container from deforming. Note that the above curves A and B can be determined in advance through preliminary experiments. Next, this invention will be explained in detail. The coffee beverage in a heat-shrinkable container of this invention is
A coffee beverage, a heat-shrinkable synthetic resin container for sealing the coffee beverage, and a pressurized heat sterilization pot are used. The coffee beverages mentioned above are not particularly limited, and include various beverages containing coffee as an active ingredient. Typical examples include black coffee, milk coffee, and spiced coffee. The heat-shrinkable synthetic resin container is not particularly limited, and may be made of various plastic materials, and its shape may be arbitrary. usually,
It consists of a cup-shaped container and a lid that seals the opening. Typical constituent materials for the container include polyethylene, nylon, polycarbonate, polyvinylidene chloride, polyethylene, and the like. These may be used alone or
Alternatively, a combination of several or more of them may be used as a composite material. Typical examples of such composite materials include nylon and polypropylene, polycarbonate and polypropylene, polyolefin and saponified ethylene-vinyl acetate copolymer and polyolefin, polypropylene polyvinylidene chloride and polypropylene, polyethylene and polyvinylidene chloride and polyethylene, polypropylene and ethylene- Examples include saponified vinyl acetate copolymer and polypropylene, polyethylene and saponified ethylene-vinyl acetate copolymer and polyethylene. Among these, a three-layer structure composite of polypropylene, a saponified ethylene-vinyl acetate copolymer, and polypropylene is highly airtight and provides good results in terms of long-term storage. However, high-barrier type composites using the above saponified ethylene-vinyl acetate copolymer in the center layer have high heat shrinkability;
Care must be taken when performing pressure and heat sterilization. In addition, a high barrier type composite material using polyvinylidene chloride instead of the saponified ethylene-vinyl acetate copolymer has high heat shrinkage as well, so please be careful when setting the pressure and heat sterilization conditions. It takes. In this invention, for example, the cup-shaped container body of a heat-shrinkable synthetic resin container as described above is filled with a coffee beverage, a lid made of the same material is attached to the opening of the container, and the joint between the two is heated. After sealing using a known sealing method such as a seal, heat and pressure sterilization is performed in a heating and pressurizing pot. For example, this is placed in a pressure-heating sterilization pot such as a steam-type retort machine that can control pressure, and sterilized by pressure and heat at 115°C for about 15 minutes. In this case, the pressure inside the pot at the time of pressure and heat sterilization is determined by calculating the pressure difference α from curve A and curve B obtained in a preliminary experiment, and converting the pressure difference α into the pressure difference α from curve B.
This is done by setting the pressure at a reduced pressure. in this case,
Since the pressure difference α etc. change over time, the pressure within the pot is adjusted accordingly. In this case, it is not necessary to maintain the pressure difference α from the initial stage of sterilization to the final stage of sterilization (at the right end of curve A, α becomes abnormally high, so it cannot be maintained), and If the pressure difference α is maintained for most of the time including the maximum pressure, the heat-shrinkable synthetic resin container will be prevented from deforming. The thus obtained coffee beverage packaged in a heat-shrinkable container has been sterilized by pressure heating and has an extremely long shelf life, and the heat-shrinkable container itself is not deformed due to heat shrinkage. Because of this, the original beautiful shape has been preserved. [Effects of the Invention] As described above, in the method for producing a coffee beverage in a heat-shrinkable container of the present invention, the pressure in the sterilization pot is set to (A)-(B) during heat-pressure sterilization. Even if a container made of a heat-shrinkable material such as polyethylene or polypropylene is used, the container is filled with coffee beverage, sealed, and sterilized by heating and pressure at a temperature exceeding 100°C, the container body does not deform at all. Therefore, unlike the proposed method, the coffee beverage can be sterilized without causing the lid to bulge upward or dent downward, resulting in an unsightly appearance. Next, examples will be described together with comparative examples. [Preparation] First, the following coffee beverage was prepared as a coffee beverage to be filled into a container. That is, commercially available regular coffee (city roast) for iced coffee is ground with a known coffee mill, 100 g of this ground coffee is drip-extracted by a known method to make 100 g of coffee extract, and this coffee extract is used. Granulated sugar and water were added to this to create a coffee beverage with a composition of 50% extract, 8% granulated sugar, and 42% water. In addition, as a container for filling this coffee beverage, a blow molded bottle container (plastic container) with an internal volume of 500 ml made of a three-layer composite of polypropylene, saponified ethylene-vinyl acetate copolymer (EVAL), and polypropylene, and a 500 ml internal volume blow-molded bottle container (plastic container). A metal can was prepared. Using a coffee beverage and container as described above,
A packaged coffee beverage was produced in the following manner. Example 1 480 g of the coffee beverage obtained as described above was placed in a blow-molded cup-shaped bottle with an internal volume of 500 ml.
ml at room temperature, put a lid on the opening of the bottle,
The joint was sealed by heat sealing. The lid in this case was a laminate seal lid made of polyester, aluminum, and polypropylene. Next, this sealed body was placed in a pressure-controllable steam retort machine, and retort sterilized at 115°C for 27 minutes to produce a product. In this case, pressurized heat sterilization is performed by determining curves A and B shown in the drawing in advance by testing,
The pressure difference α was measured, a curve C was created based on it, and the pressure inside the pot was adjusted according to this curve C. Comparative Example 1 Pressurized heat sterilization was performed using a constant differential pressure retort method (a method in which sterilization is performed with the pressure inside the retort pot always being higher than the internal pressure of the container by a constant pressure), and the product was produced in the same manner as in Example 1 except for the following. was manufactured. A metal can was used to measure the pressure change inside the container in order to prevent internal pressure from being impossible to measure due to heat shrinkage deformation, and a plastic container was used for the sensory evaluation of container deformation as in the example.

[Table] Comparative Example 2 Pressure heat sterilization using a steam retort pot was canceled, and 480 ml of coffee beverage was heated to 85°C in a water bath, immediately filled into the plastic container, and sealed with a heat seal to produce a product. This is based on the conventional hot pack method. Thirty coffee beverages in heat-shrinkable containers obtained in each of the above Examples and Comparative Examples were used, and 10 of each were used as samples for container deformation and storage stability tests. The results are as follows. (Sensory evaluation of container deformation) Using 10 general panels, Examples and Comparative Examples 1 and 2 obtained as described above were designated as Samples A, B, and C, respectively.
The state of appearance deformation was sensory evaluated using Sietshue's paired comparison method. The results are shown in Table 2, and it can be seen that the appearance deformation of Sample A, which is an example product, is 5% significantly different from Comparative Example 1 and 1% significantly superior to Comparative Example 2. .

[Table] (Storability test) Sample A (Example product), B (Comparative example 1 product), C
(Comparative Example 2 products) were placed in an atmosphere of 40℃,
After 7 days, 14 days, and 35 days, the samples were taken out and tested for the following items. (1) Sensory evaluation A panel of 7 coffee experts evaluated the taste of the contents using a frozen product as a standard by assigning a 5-level rating. The results are shown in Table 3.

[Table] In Table 3, + indicates that the taste is superior to the standard product, and - indicates that the taste is inferior. (2) Microbial test Samples A, B, and C were stored in an atmosphere at 37°C, and taken out after 7, 14, and 35 days, 1 ml of each sample was cultured using the standard agar culture method (37°C, 48 hours).
In addition to measuring the number of viable bacteria per sample, each 5 samples were subjected to a heat shock at 100℃ for 10 minutes, and 1 ml of the sample was heated using a modified method.
Anaerobic culture (55°C, 48 hours) was performed in TGC medium, and the presence or absence of growth of heat-resistant spore bacteria was determined. The results are shown in Tables 4 and 5.

【table】

[Table] As is clear from Tables 4 and 5, sample A (example product) showed no general viable bacteria count or heat-resistant spore bacteria, indicating that it has excellent long-term storage stability. I can see it. (3) Measurement of brownness Samples A, B, and C were stored immediately after production and in an atmosphere of 40°C for 7, 14, and 35 days, and then the brownness was measured using a colorimeter manufactured by Nippon Denshoku Kogyo Co., Ltd. It was determined by measuring the transmitted color L value. The smaller the transmitted color L value is, the greater the degree of browning is. In addition, in the measurement, the coffee was diluted to have a solid content of 1%. The results are shown in Table 6.

[Table] From Table 6, sample A (example product) has almost the same degree of browning as sample B produced by the conventional retort method, and the Maillard reaction progresses well during heat sterilization, resulting in a change in color and It can be seen that the fragrance is in a suitable state, and in this state, the browning does not progress much over time, and storage is good (as can be seen from the small difference in L value between day 0 and after 35 days). I understand that. As mentioned above, Sample A (example product) has almost no deformation of the container and also showed good results in the storage test, indicating that it is superior to products produced by the conventional retort method and hot pack method. Recognize.

[Brief explanation of the drawing]

The drawing is a pressure curve diagram for explaining the pressure during pressurized heat sterilization of the present invention. A...Pressure curve inside the container when a heat-shrinkable container is used. B...Pressure curve inside the container when a heat-shrinkable container is used. C...Pressure curve in the present invention.

Claims (1)

[Scope of Claims] 1. A method for producing a coffee beverage in a heat-shrinkable container, in which a coffee beverage is placed in a container, sealed, and sterilized by heating and pressure in a pressure-heating pot, the container being made of heat-shrinkable synthetic material. 1. A method for producing a coffee beverage in a heat-shrinkable container, which is made of resin and is carried out by setting the pressure during the heat-pressure sterilization to the following pressures (A) to (B). (A): Pressure inside a non-heat-shrinkable container when coffee beverage is filled into the non-heat-shrinkable container and heated and pressurized. (B): Pressure of (a)-(A) below. (a): Pressure inside a heat-shrinkable synthetic resin container when coffee beverage is filled into the heat-shrinkable synthetic resin container and heated and pressurized (a) (A): Above pressure (A)