WO2019085736A1 - Food vacuum freeze-drying and sterilization method and device - Google Patents
Food vacuum freeze-drying and sterilization method and device Download PDFInfo
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- WO2019085736A1 WO2019085736A1 PCT/CN2018/110355 CN2018110355W WO2019085736A1 WO 2019085736 A1 WO2019085736 A1 WO 2019085736A1 CN 2018110355 W CN2018110355 W CN 2018110355W WO 2019085736 A1 WO2019085736 A1 WO 2019085736A1
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- steam
- drying
- food
- water
- drying chamber
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- 235000013305 food Nutrition 0.000 title claims abstract description 100
- 230000001954 sterilising effect Effects 0.000 title claims abstract description 86
- 238000004659 sterilization and disinfection Methods 0.000 title claims abstract description 62
- 238000000034 method Methods 0.000 title claims abstract description 50
- 238000009777 vacuum freeze-drying Methods 0.000 title claims abstract description 34
- 238000001035 drying Methods 0.000 claims abstract description 99
- 238000010438 heat treatment Methods 0.000 claims abstract description 54
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 17
- 238000009928 pasteurization Methods 0.000 claims abstract description 15
- 238000004108 freeze drying Methods 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 141
- 239000000463 material Substances 0.000 claims description 54
- 230000001105 regulatory effect Effects 0.000 claims description 16
- 239000011148 porous material Substances 0.000 claims description 13
- 239000003507 refrigerant Substances 0.000 claims description 13
- 238000001816 cooling Methods 0.000 claims description 10
- 239000000498 cooling water Substances 0.000 claims description 10
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 8
- 238000007710 freezing Methods 0.000 claims description 7
- 230000008014 freezing Effects 0.000 claims description 7
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 6
- 230000003471 anti-radiation Effects 0.000 claims description 5
- 230000005496 eutectics Effects 0.000 claims description 4
- 239000002775 capsule Substances 0.000 claims 1
- 235000013611 frozen food Nutrition 0.000 abstract 3
- 238000000859 sublimation Methods 0.000 description 9
- 230000008022 sublimation Effects 0.000 description 9
- 230000000694 effects Effects 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 4
- 244000052616 bacterial pathogen Species 0.000 description 4
- 238000005265 energy consumption Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 238000004321 preservation Methods 0.000 description 3
- 238000005057 refrigeration Methods 0.000 description 3
- 238000010025 steaming Methods 0.000 description 3
- 241000194032 Enterococcus faecalis Species 0.000 description 2
- 241000588724 Escherichia coli Species 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 2
- 241000607142 Salmonella Species 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 229940032049 enterococcus faecalis Drugs 0.000 description 2
- 238000011081 inoculation Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 244000005700 microbiome Species 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 241000283690 Bos taurus Species 0.000 description 1
- 208000019331 Foodborne disease Diseases 0.000 description 1
- 241000186781 Listeria Species 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 238000012792 lyophilization process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 235000013324 preserved food Nutrition 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 239000008213 purified water Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000010257 thawing Methods 0.000 description 1
- 238000002061 vacuum sublimation Methods 0.000 description 1
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- 239000002699 waste material Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
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- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
- A23L3/40—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by drying or kilning; Subsequent reconstitution
- A23L3/44—Freeze-drying
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
- A23L3/001—Details of apparatus, e.g. for transport, for loading or unloading manipulation, pressure feed valves
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
- A23L3/16—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by heating loose unpacked materials
- A23L3/165—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by heating loose unpacked materials in solid state
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23V—INDEXING SCHEME RELATING TO FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES AND LACTIC OR PROPIONIC ACID BACTERIA USED IN FOODSTUFFS OR FOOD PREPARATION
- A23V2002/00—Food compositions, function of food ingredients or processes for food or foodstuffs
Definitions
- the invention relates to a food processing method, in particular to a method for vacuum freeze drying and sterilization of food.
- the invention also relates to a food vacuum freeze drying and sterilizing apparatus for treating food products by the method.
- Vacuum freeze-drying is a method of freezing the aqueous material below the eutectic point temperature, causing the water to become ice, and then sublimating the ice to water vapor at a suitable temperature and vacuum. Out, thereby obtaining the technology of the dried product.
- the moisture content in the food is low, generally not more than 5%, which inhibits the growth and reproduction of microorganisms and is beneficial for long-term preservation.
- pathogenic bacteria such as Salmonella, Listeria, and Escherichia coli can survive for a long period of time after vacuum freeze-drying, and can be propagated in large quantities, such as after contact with water.
- food-borne diseases caused by pathogenic bacteria of low-moisture foods have frequently occurred, and sterilization treatment before entering circulation has become a necessary condition for the production of many freeze-dried foods.
- the sterilized object generally refers to the equipment in the drying chamber, not the material to be lyophilized.
- the sterilized object generally refers to the equipment in the drying chamber, not the material to be lyophilized.
- Such as the patent CN200610031825.5 “freeze drying unit and its use of the same solution defrosting, cleaning, sterilization process", CN201210120209.2 “a method and device for online sterilization of freeze dryer", CN201420509624.1 “A freeze dryer sterilization system” and CN201520839764.X "an efficient sterilization and sterilization device for freeze dryers”.
- freeze-dried foods have low moisture content, and ordinary heating is not only difficult to remove pathogenic bacteria with strong heat resistance under low water activity, such as Salmonella and Escherichia coli, and too high heating temperature can easily cause the shape of the product. And color changes and destruction of nutrients.
- Patent CN201621458519.5 "A freeze-drying device for food drying and sterilization” first performs microwave sterilization operation on the material, and then performs freezing and cooling. Microwave sterilization uses the heat generated by microwaves to kill microorganisms. On the one hand, there is uneven sterilization. In addition, the local temperature of the materials may be too high to affect the quality, and there is still the possibility of food contamination during the subsequent freezing and drying process.
- Patent CN200710134872.7 A method for the preservation of lyophilized food by nano-silver coating film combined with microwave proposes that the food raw material is immersed in nano-silver aqueous solution, then freeze-dried, and then enters the microwave sterilization link; patent CN200710134405" A combined sterilization method for the preservation of freeze-dried foods by ozone, ultraviolet and nano silver coating film” lyophilizes the raw materials after coating treatment, and the finished product is sterilized by ozone in the sealed pocket, and then controlled by ultraviolet sterilization auxiliary sterilization method. Microbial content. Although the method achieves a certain bactericidal effect, the food contains nano silver, which is difficult to be widely accepted.
- the lyophilized food is sterilized by a high-pressure steam sterilizer, and although a better sterilization effect can be achieved, there is a problem that the water content increases after the food is sterilized, and the high-temperature and high-pressure steam affects the quality of the food.
- the sterilization method of the existing freeze-dried food generally adopts independent sterilization equipment and processes, and has the problems of poor sterilization effect, cumbersome process, complicated equipment, large occupied space, large energy consumption, and high labor cost.
- the food vacuum freeze-drying and sterilizing equipment of the invention can realize the lyophilization and sterilization process in one time in the same set of equipment, saves equipment investment, has short running time, saves energy, reduces operation steps and reduces labor cost.
- an aspect of the invention provides a method for vacuum freeze drying and sterilization of food, comprising:
- Pretreating the material freezing the material to be treated to below the eutectic point temperature and then feeding it into the drying chamber;
- the material is evacuated in the drying chamber, and the material absorbs heat under vacuum to sublimate the ice in the material into water vapor and escape from the material and desublimate;
- the drying chamber is filled with negative pressure saturated steam, the steam is condensed on the surface of the material and the internal pores, the temperature of the material rises to the desired pasteurization temperature, and the pasteurization temperature is maintained. Stop charging the negative pressure saturated steam after a period of time;
- the water vapor in the drying chamber is captured to reduce the pressure in the drying chamber, and the condensed water on the surface of the material and the internal pores evaporates, and the material is cooled;
- the pressure in the drying chamber is 13 to 130 Pa.
- the pasteurization temperature is 60 to 90 °C.
- the time during which the pasteurization temperature is maintained is from 10 to 90 min.
- the pressure of the negative pressure saturated steam corresponds to a temperature of saturated water that is 0 to 10 ° C higher than the pasteurization temperature.
- the steam trapping pressure is from 100 to 3000 Pa.
- a food vacuum freeze-drying and sterilizing apparatus comprising a drying compartment connected by a pipe, a heating device, a vacuum steaming device, and a vacuum trapping device, wherein the heating device and the negative steaming device a steam pressure device coupled to provide thermal energy for generating a vacuum-saturated steam, the vacuum steam device being coupled to the drying chamber for steam sterilization of a material contained in the drying chamber, the vacuum trapping device
- a drying chamber connection is used to trap water vapor in the drying chamber to reduce the pressure in the drying chamber.
- the drying chamber comprises a cylinder
- the cylinder body is internally provided with a heating plate assembly
- the heating plate assembly has a water inlet port and a water outlet port connected to the heating device through a pipe, the cylinder body
- An inlet port connected to the negative pressure steam device and an exhaust port connected to the vacuum trap are provided;
- the cylinder is further provided with an inlet air valve connected to the inlet port.
- a control device is further included, and the cylinder is internally provided with a temperature sensor and a vacuum pressure sensor respectively connected to the control device for collecting data.
- the outer surface of the cylinder is fixedly connected with a uniformly distributed heat exchange tube, and the water inlet and the water outlet of the heat exchange tube are respectively connected to the steam generating device through a pipeline;
- a counter-radiation panel is disposed inside, and a plurality of thermal insulation pads are disposed between the anti-radiation panel and the cylinder.
- the heat insulating mat has a thickness of 3 to 10 mm.
- the heating device comprises a soda water heat exchanger
- the inlet of the steam inlet side of the steam-water heat exchanger is connected to a high-pressure steam source through a first steam regulating valve, and the outlet passes through a first one-way valve and a hydrophobic a valve connection
- an outlet of one side of the output water of the steam-water heat exchanger is connected to the water inlet port of the heating plate assembly, and an inlet of one side of the input water of the steam-water heat exchanger is sequentially connected to a circulating water pump through the pipeline, Cooling water side of the heat exchanger and the water outlet port of the heating plate assembly
- a bypass valve is connected between the inlet and the outlet of the hot water side of the cooling heat exchanger through a bypass line
- the cooling A cooling water pump is connected to the inlet of the heat exchanger on the cooling water side.
- the negative pressure steam device comprises a steam generator, and the hot water outlet of the steam generator is connected in sequence to a hot water pump and a water inlet port of the heat exchange tube on the surface of the cylinder; the steam a hot water inlet of the generator is connected to the water outlet port of the heat exchange tube; the steam generator is provided with an automatic water supply valve connected to a water inlet pipe; a steam tube heater is arranged inside the steam generator The inlet of the coil heater is connected to a high pressure steam source through a second steam regulating valve, and the outlet of the coil heater is connected to a steam trap through a second one-way valve; the steam outlet on the upper part of the steam generator A first negative pressure steam valve is connected to the port; the temperature sensor for measuring the water temperature is disposed in the steam generator chamber, and the temperature sensor is connected to the control device.
- the vacuum trap comprises a trap, one side of the trap is provided with an opening connected to the exhaust valve of the drying chamber, and the other side is passed through an evacuation valve and a vacuum pump Connected to the trap; a trap consisting of a plurality of sets of metal coils or metal plates is placed in the chamber of the trap, a refrigerant is circulated inside the trap, and an inlet of the trap passes through a refrigerant valve A refrigeration device is connected; a cavity is provided in the cavity of the trap for connecting a second negative pressure steam valve of the negative pressure steam device; and a lower portion of the trap is further provided with a drain valve.
- the trap is disposed inside or outside the cylinder. .
- the food vacuum freeze-drying and sterilization method and apparatus of the present invention have the following advantages:
- the general food vacuum freeze-drying mainly includes a process of food quick-freezing-pre-vacuum-sublimation drying-de-vacuum, etc.
- the invention increases the process of vacuum-steam sterilization after the sublimation of the food is finished, and pasteurization is performed.
- the negative pressure saturated steam corresponding to the temperature temporarily enhances the water activity of the dried food, and utilizes the characteristics of strong steam penetration and latent heat to quickly and efficiently kill the pathogenic bacteria. Sterilization is carried out after the sublimation drying process, the moisture inside the food no longer migrates, the structure of the food is stable, the negative pressure steam does not damage the internal structure of the food, and the sterilization process ensures that the quality of the food does not decrease to the greatest extent.
- the drying chamber is connected with the trap, and the water vapor is trapped by the low temperature ice layer on the surface of the cold trap, so that the pressure in the drying chamber is rapidly decreased, and when the pressure drops below the food temperature.
- the condensed water added to the surface of the food and the internal pores evaporates while the temperature of the food drops.
- the rapid evaporation of condensed water in food and the rapid cooling of food ensure proper storage conditions of food after sterilization.
- the steam trapping process of the present invention does not require the activation of the vacuum pump, thereby avoiding the adverse effects of moisture on the vacuum pump lubricating oil and also saving the energy consumption of the vacuum pump.
- the present invention utilizes the sterilized steam to remove a portion of the ice layer on the surface of the cold trap during the steam trapping process, thereby reducing the energy consumption required for cold trap deicing.
- This integrated energy utilization of the present invention can save about 35% of energy consumption compared to the independent cold trap de-icing process and the energy consumed by the steam sterilization process.
- the negative pressure steam generating device used in the present invention not only provides a negative pressure steam source for sterilization, but also the circulation of the hot water on the heat exchange tube of the drying tank body wall realizes temperature control of the drying chamber cylinder body. Avoid condensation of steam on the wall of the cylinder, and negative pressure steam can also quickly defrost the chiller trap.
- the food vacuum freeze-drying and sterilizing device of the invention not only saves equipment investment, but also has short running time. It also saves energy, reduces operating links, and reduces labor costs.
- Figure 1 is a schematic view showing the structure of a food vacuum freeze drying and sterilizing apparatus of the present invention
- Figure 2 is a partial enlarged view of a portion I of Figure 1.
- the food vacuum freeze drying and sterilization method of the present invention may, in some embodiments, include the following steps:
- Step 1) pretreating the material, and freezing the material to be processed to below the eutectic point temperature, and then feeding the material into the drying chamber;
- Step 2) the material is evacuated in the drying chamber, and the material absorbs heat under vacuum to make the ice in the material sublimate into water vapor and escape from the material and desublimate;
- Step 3 After the material reaches the required degree of dryness, the drying chamber is filled with negative pressure saturated steam, the steam is condensed on the surface of the material and the internal pores, and the temperature of the material rises to the desired pasteurization temperature, and is maintained at the bar. The sterilization temperature is stopped for a period of time and then the negative pressure saturated steam is stopped;
- Step 4 collecting water vapor in the drying chamber to reduce the pressure in the drying chamber, and the condensed water on the surface of the material and the internal pores evaporates, and the material is cooled;
- Step 5 after the pressure in the cabin drops to the required steam trapping pressure, the air is filled, the vacuum state in the drying chamber is released, and the freeze-drying and sterilization process is ended.
- FIG. 1 is a schematic structural view of a food vacuum freeze-drying and sterilizing apparatus according to an embodiment of the present invention
- FIG. 2 is a partial enlarged view of a portion I of FIG.
- the apparatus of the present invention comprises a drying compartment 1, a heating device 2, a vacuum steaming device 3 and a vacuum trapping device 4 connected by a pipe (not labeled in Fig. 1), wherein the heating device 2 and the device
- the negative pressure steam device 3 is connected to provide thermal energy for generating negative pressure saturated steam, and the negative pressure steam device 3 is connected to the drying chamber 1 for steam sterilization of the contents of the drying chamber 1
- a steam trap 4 is connected to the drying chamber 1 for trapping water vapor in the drying chamber 1 to lower the pressure in the drying chamber 1.
- the drying chamber 1 comprises a cylinder 11; the cylinder 11 is internally provided with a heating plate assembly 12, comprising two sets of symmetrically arranged heating plate sets (not shown in FIG. 1), two sets of heating plates
- the water inlet port and the water outlet port are respectively combined and connected to the heating device 2 through a pipe;
- the cylinder 11 of the drying chamber is internally provided with a temperature sensor 13 and a vacuum pressure sensor 14, and the sensors are connected to the control device.
- the drying chamber body 11 has an inlet port, and the inlet port is connected to the negative pressure steam device 3 through a pipeline; the drying chamber body 11 has an exhaust port, and the exhaust port passes through the exhaust valve 16 and the pipeline and the vacuum
- the collecting device 4 is connected; the drying chamber body 11 has an inlet air port, and the inlet air port is connected with an inlet air valve 15 through the pipeline; the outer surface of the drying chamber body 11 is fixedly connected by welding to have a uniform and orderly distribution.
- the heat exchange tube 17, the water inlet port and the water outlet port of the heat exchange tube 1 are connected to the negative pressure steam device 3 through a pipeline.
- the interior of the drying chamber body 11 is provided with a counter-radiation plate 18, and a plurality of insulating pads 19 are disposed between the anti-radiation plate 18 and the sterilization chamber cylinder 11.
- the thickness of the insulating pad 19 is 5 mm, and the end of the anti-radiation plate 18 The portion is fixed to the sterilization chamber cylinder 11 by bolts and nuts.
- the heating device 2 includes a soda water heat exchanger 25; the inlet of the steam side of the soda water heat exchanger 25 is connected to the high temperature and high pressure steam generated by the boiler through the first steam regulating valve 26, and the outlet passes through the first
- the check valve 27 is connected to the steam trap 28; the outlet of the water side of the steam-water heat exchanger 25 is connected to the water inlet port of the heating plate assembly 12 through a pipeline, and the inlet of the water side of the steam-water heat exchanger 25 is connected to the circulating water pump through the pipeline in turn.
- the water outlet port of the hot water side of the heat exchanger 22 and the hot plate assembly 12; the inlet and outlet of the hot water side of the cooling heat exchanger 22 are connected to the bypass valve 23 through the bypass line; the cooling heat exchanger 22 A cooling water pump 21 is connected to the inlet of the cooling water side.
- the negative pressure steam device 3 includes a steam generator 32; the hot water outlet of the steam generator 32 sequentially connects the hot water pump 31 and the water inlet port of the heat exchange tube 17; the heat of the steam generator 32 The water inlet is connected to the water outlet port of the heat exchange tube 17; the steam generator 32 is provided with an automatic water supply valve 37 connected to the purified water pipe (not shown in FIG.
- the steam generator 32 is internally provided with a coil heater 33, the disk
- the inlet of the tube heater 33 is connected to the high temperature and high pressure steam through a line and a steam regulating valve 36, and the outlet is connected to the line between the heating system check valve 27 and the steam trap 28 through the check valve 34; the upper portion of the steam generator 32
- a first negative pressure steam valve 38 is connected to the steam outlet port; a temperature sensor 35 for measuring the water temperature is provided inside the steam generator 32.
- the vacuum trap 4 includes a trap 41 having a side opening having an opening connected to the exhaust valve (16) of the drying chamber; the other side is connected to the exhaust valve 43 through The vacuum pump 44 is connected; the trap 41 is provided with a cold trap 42 composed of a plurality of sets of metal coils or metal plates.
- the inside of the metal tube or the metal plate of the cold trap 42 is circulated with a refrigerant, and the refrigerant inlet of the cold trap 42
- the refrigerant valve 45 is connected to the refrigeration device;
- the trap 41 has a second negative pressure steam valve 39 connected to the negative pressure steam device; and a drain valve 46 is disposed at the lower portion of the trap 41.
- Pre-vacuum The circulating water pump starts, the water circulation in the heating plate assembly; the refrigerant valve of the cold trap is opened, and the cold trap is cooled; the vacuum pump, the vacuum valve and the exhaust valve are opened, and the pressure in the drying chamber is lowered.
- the pressure in the drying chamber is preferably controlled to be 13 to 130 Pa.
- the first steam regulating valve automatically adjusts the water temperature of the heating plate according to the heat required for sublimation of the material in the process.
- the water temperature of the heating plate needs to drop rapidly, close the steam regulating valve and turn on the cooling water pump.
- the material reaches the desired degree of drying, the temperature of the heating plate and the material are both close to the set drying temperature, the drying process is finished, the material maintains the original shape but the inside forms a porous structure. Close the exhaust valve, vacuum valve, vacuum pump and refrigerant valve to stop vacuuming and refrigerant supply.
- Sterilization preparation the second steam regulating valve and the hot water pump on the negative pressure steam device are turned on, and the coil heater transfers the heat of the steam to the water in the negative pressure steam generator, so that the water temperature rises above the required
- the sterilization temperature is 0 to 5 ° C and maintained at this temperature, and the temperature of the wall surface of the drying cylinder body also rises; the water temperature of the heating plate group is set to the required sterilization temperature, and the temperature of the heating plate rises.
- the first negative pressure steam valve is opened, the saturated steam in the negative pressure steam generator enters the cavity of the drying chamber, and condenses on the surface of the lower temperature food and inside the pores, and the heat released by the steam condensation process makes The temperature of the food rapidly rises to the required sterilization temperature, and then the opening or start-stop state of the first negative pressure steam valve is adjusted, so that the food temperature is maintained at the sterilization temperature for a period of time, that is, the required sterilization time is reached (30 min). After that, close the first negative pressure steam valve and shut down the hot water pump.
- Inoculation and quick freezing Take several pieces of the raw materials after pre-treatment such as washing and dicing, and inoculate Enterococcus faecalis (ATCC 8459), the inoculation quantity is 8 ⁇ 10 7 cfu/g; then the raw materials are frozen in the frozen storage. After filling to -25 ° C, it is placed in the drying chamber 1 .
- the circulating water pump 31 is started to heat the water in the heating plate; the refrigerant valve 45 of the vacuum trap 4 is opened, the cold trap 42 is cooled; the vacuum pump 44, the vacuum valve 43 and the exhaust valve 16 are opened, and the drying chamber is opened. The pressure in the chamber drops.
- the first steam regulating valve 26 automatically adjusts the opening degree according to the heat required for sublimation of the material in the process to adjust the water temperature of the heating plate.
- the first steam regulating valve 26 is closed and the cooling water pump 21 is turned on.
- the material reaches the desired degree of drying, the temperature of the heating plate and the material are both close to the set drying temperature of 40 ° C, the drying process is finished, the material maintains the original shape but the inside forms a porous structure.
- the exhaust valve 16, the vacuum valve 43, the vacuum pump 44, and the refrigerant valve 45 are closed, and the vacuuming and refrigerant supply are stopped.
- Sterilization preparation The second steam regulating valve 36 and the hot water pump 31 on the negative pressure steam device are turned on, and the coil heater 33 transfers the heat of the steam to the water in the negative pressure steam generator 32, so that the water temperature rises to At 80 ° C and maintained at this temperature, the temperature of the wall surface of the dried casing body 11 also rises; the water temperature of the heating plate group 12 is set to a desired sterilization temperature of 75 ° C, and the temperature of the heating plate rises.
- the first negative pressure steam valve 38 is opened, the saturated steam in the negative pressure steam generator 32 enters the cavity of the drying chamber, and condenses on the surface of the lower temperature food and inside the pores, and is released by the steam condensation process.
- the heat causes the temperature of the food to rise rapidly to the desired sterilization temperature, and then adjusts the opening or the start-stop state of the first negative pressure steam valve to maintain the food temperature at the sterilization temperature for 30 minutes, and then closes the first negative pressure steam valve 38. , shut down the hot water pump 31.
- the above materials are freeze-dried and sterilized by the method of vacuum freeze-drying and sterilization of the food provided by the embodiments of the present invention, the water content of the raw materials is reduced from 72% to 4%, and the number of implanted Enterococcus faecalis is reduced. 5 logarithmic units, and the sterilization process ensures maximum quality of the food.
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- Health & Medical Sciences (AREA)
- Nutrition Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Drying Of Solid Materials (AREA)
- Freezing, Cooling And Drying Of Foods (AREA)
Abstract
A food vacuum freeze-drying and sterilization method and device. The method comprises the following steps: put frozen food in a drying chamber, and enabling the frozen food to absorb heat energy under a vacuum state, so that ice in the frozen food sublimates to form steam, and the obtained steam escapes and condenses on the surface of a cold trap; when the food reaches a desired drying degree, inflate negative-pressure saturated steam, so that the temperature of the food reaches a desired pasteurization temperature, and enable the heated food to be kept at the temperature for a period of time; trapping steam in the drying chamber by using a low-temperature ice layer on the surface of the cold trap, so as to reduce the pressure in the drying chamber, evaporate moisture condensed from the food, and reduce the temperature of the food; and remove the vacuum state, and take out the food. The device comprises a drying chamber, a heating device, a negative-pressure steam device, and a vacuum steam-trapping device. By means of the method and the device, freeze-drying and pasteurization treatment can be carried on food, and the quality of the food is kept.
Description
本发明涉及一种食品加工方法,特别是一种用于食品真空冷冻干燥及灭菌的方法。本发明还涉及采用该方法对食品进行处理的食品真空冷冻干燥及灭菌设备。The invention relates to a food processing method, in particular to a method for vacuum freeze drying and sterilization of food. The invention also relates to a food vacuum freeze drying and sterilizing apparatus for treating food products by the method.
真空冷冻干燥,简称冻干,是一种将含水物料冻结到共晶点温度以下,使其中的水变成冰,然后在适当的温度和真空度下,使冰升华为水蒸气从物料中逸出,从而获得干燥制品的技术。冻干后食品中的水分含量低,一般不超过5%,抑制了微生物的生长及繁殖,有利于长期保存。但许多致病性细菌如沙门氏菌、李斯特菌和大肠杆菌等可以在真空冷冻干燥后长期存活,并在合适的场合,如接触水后,可以大量繁殖。近年来因为低水分食品的致病性细菌引起的食源性疾病频发,在进入流通之前的灭菌处理已成为许多冻干食品生产的必要条件。Vacuum freeze-drying, referred to as lyophilization, is a method of freezing the aqueous material below the eutectic point temperature, causing the water to become ice, and then sublimating the ice to water vapor at a suitable temperature and vacuum. Out, thereby obtaining the technology of the dried product. After lyophilization, the moisture content in the food is low, generally not more than 5%, which inhibits the growth and reproduction of microorganisms and is beneficial for long-term preservation. However, many pathogenic bacteria such as Salmonella, Listeria, and Escherichia coli can survive for a long period of time after vacuum freeze-drying, and can be propagated in large quantities, such as after contact with water. In recent years, food-borne diseases caused by pathogenic bacteria of low-moisture foods have frequently occurred, and sterilization treatment before entering circulation has become a necessary condition for the production of many freeze-dried foods.
现有的带有在位灭菌功能的冻干机,灭菌的对象一般指的是干燥舱内的设备,而非要冻干的物料。如专利CN200610031825.5“冷冻干燥机组及其用同一种溶液除霜、清洗、灭菌的工艺”,CN201210120209.2“一种用于冻干机在线灭菌的方法及其装置”,CN201420509624.1“一种冻干机灭菌系统”和CN201520839764.X“一种用于冻干机的高效消毒灭菌装置”。In the existing lyophilizer with in-situ sterilization function, the sterilized object generally refers to the equipment in the drying chamber, not the material to be lyophilized. Such as the patent CN200610031825.5 "freeze drying unit and its use of the same solution defrosting, cleaning, sterilization process", CN201210120209.2 "a method and device for online sterilization of freeze dryer", CN201420509624.1 "A freeze dryer sterilization system" and CN201520839764.X "an efficient sterilization and sterilization device for freeze dryers".
对冻干食品的灭菌,采用的方法及存在的问题有:For the sterilization of freeze-dried foods, the methods used and the problems are:
在物料干燥后,采用干热的办法进行灭菌,如微波加热、热风加热或辐射加热。但冻干食品水分含量低,普通加热不仅难于去除在低水活度下具有很强耐热性的致病性细菌,如沙门氏菌和大肠杆菌等,同时过高的加热温度还易造成产品的形状及颜色的改变及营养成分的破坏。After the material is dried, it is sterilized by dry heat, such as microwave heating, hot air heating or radiant heating. However, freeze-dried foods have low moisture content, and ordinary heating is not only difficult to remove pathogenic bacteria with strong heat resistance under low water activity, such as Salmonella and Escherichia coli, and too high heating temperature can easily cause the shape of the product. And color changes and destruction of nutrients.
专利CN201621458519.5“一种食品干燥灭菌用冻干装置”对物料先进行微波灭菌操作,之后再进行冷冻降温。因微波灭菌是利用微波产生的热来 杀灭微生物,一方面存在杀菌不均匀,另外可能导致物料局部温度过高而影响品质,且后续的冻结及干燥过程中仍然有产生食品污染的可能。Patent CN201621458519.5 "A freeze-drying device for food drying and sterilization" first performs microwave sterilization operation on the material, and then performs freezing and cooling. Microwave sterilization uses the heat generated by microwaves to kill microorganisms. On the one hand, there is uneven sterilization. In addition, the local temperature of the materials may be too high to affect the quality, and there is still the possibility of food contamination during the subsequent freezing and drying process.
专利CN200710134872.7“一种纳米银涂膜与微波联用对冻干食品保质杀菌的方法”提出将食品原料放在纳米银水溶液中浸泡后进行冷冻干燥,之后再进入微波杀菌环节;专利CN200710134405“一种臭氧、紫外和纳米银涂膜对冻干食品保质的联合杀菌方法”将涂膜处理后的原料进行冻干处理加工,成品在封口袋臭氧杀菌,之后采用紫外照射的辅助杀菌方法来控制微生物含量。所述方法虽然达到了一定的杀菌效果,但食品中含有纳米银,很难被广泛接受。Patent CN200710134872.7 "A method for the preservation of lyophilized food by nano-silver coating film combined with microwave" proposes that the food raw material is immersed in nano-silver aqueous solution, then freeze-dried, and then enters the microwave sterilization link; patent CN200710134405" A combined sterilization method for the preservation of freeze-dried foods by ozone, ultraviolet and nano silver coating film" lyophilizes the raw materials after coating treatment, and the finished product is sterilized by ozone in the sealed pocket, and then controlled by ultraviolet sterilization auxiliary sterilization method. Microbial content. Although the method achieves a certain bactericidal effect, the food contains nano silver, which is difficult to be widely accepted.
另外,将冻干后的食品放到高压蒸汽灭菌器灭菌,虽然能达到较好的灭菌效果但存在食品灭菌后含水量增加、高温高压蒸汽影响食品品质等问题。而且现有冻干食品的灭菌方法一般采用独立的灭菌设备及过程,存在灭菌效果不佳、过程繁琐、设备复杂、占用空间大、能源消耗大、用工费用高等问题。In addition, the lyophilized food is sterilized by a high-pressure steam sterilizer, and although a better sterilization effect can be achieved, there is a problem that the water content increases after the food is sterilized, and the high-temperature and high-pressure steam affects the quality of the food. Moreover, the sterilization method of the existing freeze-dried food generally adopts independent sterilization equipment and processes, and has the problems of poor sterilization effect, cumbersome process, complicated equipment, large occupied space, large energy consumption, and high labor cost.
发明内容Summary of the invention
鉴于现有技术存在上述问题,本发明的目的在于提供用于食品真空冷冻干燥及灭菌的方法和设备。在本发明的食品真空冷冻干燥及灭菌的设备能够实现冻干及灭菌过程在同一套设备中一次完成,设备投资省,运行时间短,还节约能源,减少操作环节,降低人工成本。In view of the above problems in the prior art, it is an object of the present invention to provide a method and apparatus for food vacuum freeze drying and sterilization. The food vacuum freeze-drying and sterilizing equipment of the invention can realize the lyophilization and sterilization process in one time in the same set of equipment, saves equipment investment, has short running time, saves energy, reduces operation steps and reduces labor cost.
为实现上述目的,本发明一个方面提供了一种食品真空冷冻干燥及灭菌的方法,包括:In order to achieve the above object, an aspect of the invention provides a method for vacuum freeze drying and sterilization of food, comprising:
预处理物料,将需要处理的物料冻结到其共晶点温度以下后送入干燥舱内;Pretreating the material, freezing the material to be treated to below the eutectic point temperature and then feeding it into the drying chamber;
使物料在干燥舱内被抽真空,在真空状态下使物料吸收热量以使物料内的冰升华为水蒸气并从物料中逸出并凝华;The material is evacuated in the drying chamber, and the material absorbs heat under vacuum to sublimate the ice in the material into water vapor and escape from the material and desublimate;
待物料达到所需的干燥程度后,向干燥舱内充入负压饱和蒸汽,蒸汽在物料表面及内部孔隙凝结,物料温度上升到所需的巴氏灭菌温度,维持在巴氏灭菌温度一段时间后停止充入负压饱和蒸汽;After the material reaches the required degree of dryness, the drying chamber is filled with negative pressure saturated steam, the steam is condensed on the surface of the material and the internal pores, the temperature of the material rises to the desired pasteurization temperature, and the pasteurization temperature is maintained. Stop charging the negative pressure saturated steam after a period of time;
捕集干燥舱内的水蒸气以使干燥舱内压力下降,物料表面及内部孔隙的凝结水分蒸发,物料降温;The water vapor in the drying chamber is captured to reduce the pressure in the drying chamber, and the condensed water on the surface of the material and the internal pores evaporates, and the material is cooled;
待舱内压力下降到所需的捕汽压力后,充入空气,解除干燥舱内的真空状态,结束冻干及灭菌过程。After the pressure in the cabin drops to the required steam trapping pressure, the air is filled, the vacuum state in the drying chamber is released, and the freeze-drying and sterilization process is ended.
作为优选,其中物料在干燥舱内被抽真空后,干燥舱内压力为13~130Pa。Preferably, after the material is evacuated in the drying chamber, the pressure in the drying chamber is 13 to 130 Pa.
作为优选,其中所述巴氏灭菌温度为60~90℃。Preferably, the pasteurization temperature is 60 to 90 °C.
作为优选,其中维持巴氏灭菌温度的时间为10~90min。Preferably, the time during which the pasteurization temperature is maintained is from 10 to 90 min.
作为优选,其中所述负压饱和蒸汽的压力对应的饱和水的温度比所述巴氏灭菌温度高0~10℃。Preferably, wherein the pressure of the negative pressure saturated steam corresponds to a temperature of saturated water that is 0 to 10 ° C higher than the pasteurization temperature.
作为优选,其中所述捕汽压力为100~3000Pa。Preferably, the steam trapping pressure is from 100 to 3000 Pa.
本发明的另一方面提供了一种食品真空冷冻干燥及灭菌设备,包括通过管道连接的干燥舱、加热装置、负压蒸汽装置和真空捕汽装置,其中,所述加热装置与所述负压蒸汽装置连接以提供生成负压饱和蒸汽的热能,所述负压蒸汽装置与所述干燥舱连接以对所述干燥舱内容置的物料进行蒸汽灭菌,所述真空捕汽装置与所述干燥舱连接用于捕集所述干燥舱内的水蒸气以使所述干燥舱内压力下降。Another aspect of the present invention provides a food vacuum freeze-drying and sterilizing apparatus comprising a drying compartment connected by a pipe, a heating device, a vacuum steaming device, and a vacuum trapping device, wherein the heating device and the negative steaming device a steam pressure device coupled to provide thermal energy for generating a vacuum-saturated steam, the vacuum steam device being coupled to the drying chamber for steam sterilization of a material contained in the drying chamber, the vacuum trapping device A drying chamber connection is used to trap water vapor in the drying chamber to reduce the pressure in the drying chamber.
作为优选,所述干燥舱包括一筒体,所述筒体内部装有加热板组件,所述加热板组件具有通过管道与所述加热装置连接的进水端口和出水端口,所述筒体上设有与负压蒸汽装置相接的进汽端口,以及与所述真空捕集装置相连的排汽端口;所述筒体上还设有与所述进空气端口连接的进空气阀。Preferably, the drying chamber comprises a cylinder, the cylinder body is internally provided with a heating plate assembly, and the heating plate assembly has a water inlet port and a water outlet port connected to the heating device through a pipe, the cylinder body An inlet port connected to the negative pressure steam device and an exhaust port connected to the vacuum trap are provided; the cylinder is further provided with an inlet air valve connected to the inlet port.
作为优选,还包括一控制装置,所述筒体内部设有分别与所述控制装置连接以采集数据的温度传感器和真空压力传感器。Preferably, a control device is further included, and the cylinder is internally provided with a temperature sensor and a vacuum pressure sensor respectively connected to the control device for collecting data.
作为优选,所述筒体的外表面上固定连接有均匀分布的换热管,所述换热管的进水口和出水口分别通过管路与所述蒸汽发生装置相接;所述筒体的内部设有反辐射板,所述反辐射板与所述筒体之间设有若干隔热垫。Preferably, the outer surface of the cylinder is fixedly connected with a uniformly distributed heat exchange tube, and the water inlet and the water outlet of the heat exchange tube are respectively connected to the steam generating device through a pipeline; A counter-radiation panel is disposed inside, and a plurality of thermal insulation pads are disposed between the anti-radiation panel and the cylinder.
作为优选,所述隔热垫的厚度为3~10mm。Preferably, the heat insulating mat has a thickness of 3 to 10 mm.
作为优选,所述加热装置包括汽水换热器,所述汽水换热器的输入蒸汽一侧的进口通过一第一蒸汽调节阀连接一高压蒸汽源,出口经过一第一单向阀与一疏水阀连接;汽水换热器的输出水的一侧的出口连接所述加热板组件的进水端口,所述汽水换热器的输入水的一侧的进口通过管路依次连接一循环水泵、一冷却换热器的热水侧和所述加热板组件的所述出水端口;所述冷却换热器的热水侧的进口和出口之间通过旁通管路连接有一旁通阀;所述冷却换热器的冷却水侧的进口连接有一冷却水泵。Preferably, the heating device comprises a soda water heat exchanger, the inlet of the steam inlet side of the steam-water heat exchanger is connected to a high-pressure steam source through a first steam regulating valve, and the outlet passes through a first one-way valve and a hydrophobic a valve connection; an outlet of one side of the output water of the steam-water heat exchanger is connected to the water inlet port of the heating plate assembly, and an inlet of one side of the input water of the steam-water heat exchanger is sequentially connected to a circulating water pump through the pipeline, Cooling water side of the heat exchanger and the water outlet port of the heating plate assembly; a bypass valve is connected between the inlet and the outlet of the hot water side of the cooling heat exchanger through a bypass line; the cooling A cooling water pump is connected to the inlet of the heat exchanger on the cooling water side.
作为优选,所述的负压蒸汽装置包括一蒸汽发生器,所述蒸汽发生器的热水出口依次连接一热水泵和所述筒体表面的所述换热管的进水端口;所述蒸汽发生器的热水进口连接所述换热管的出水端口;所述蒸汽发生器上设有与一进水管道相连的一自动补水阀;所述蒸汽发生器内部放置有一盘管加热器,所述盘管加热器的进口通过一第二蒸汽调节阀连接至高压蒸汽源,所述盘管加热器的出口通过一第二单向阀与一疏水阀连接;所述蒸汽发生器上部的出汽端口上连接有第一负压蒸汽阀;用于测量水温的所述温度传感器设置于所述蒸汽发生器腔体内,所述温度传感器与所述控制装置相连。Preferably, the negative pressure steam device comprises a steam generator, and the hot water outlet of the steam generator is connected in sequence to a hot water pump and a water inlet port of the heat exchange tube on the surface of the cylinder; the steam a hot water inlet of the generator is connected to the water outlet port of the heat exchange tube; the steam generator is provided with an automatic water supply valve connected to a water inlet pipe; a steam tube heater is arranged inside the steam generator The inlet of the coil heater is connected to a high pressure steam source through a second steam regulating valve, and the outlet of the coil heater is connected to a steam trap through a second one-way valve; the steam outlet on the upper part of the steam generator A first negative pressure steam valve is connected to the port; the temperature sensor for measuring the water temperature is disposed in the steam generator chamber, and the temperature sensor is connected to the control device.
作为优选,所述真空捕汽装置包括一捕集器,所述捕集器的一侧设有与所述干燥舱的排气阀相连的开孔,其另一侧通过一抽空阀与一真空泵连通;所述捕集器的腔内放置有由多组金属盘管或金属板组成的一冷阱,所述冷阱的内部流通有制冷剂,所述冷阱的进口通过一制冷剂阀与一制冷装置相连;所述捕集器的腔内设有开孔用于连接所述负压蒸汽装置的一第二负压蒸汽阀;所述捕集器的下部还设置有排水阀。Preferably, the vacuum trap comprises a trap, one side of the trap is provided with an opening connected to the exhaust valve of the drying chamber, and the other side is passed through an evacuation valve and a vacuum pump Connected to the trap; a trap consisting of a plurality of sets of metal coils or metal plates is placed in the chamber of the trap, a refrigerant is circulated inside the trap, and an inlet of the trap passes through a refrigerant valve A refrigeration device is connected; a cavity is provided in the cavity of the trap for connecting a second negative pressure steam valve of the negative pressure steam device; and a lower portion of the trap is further provided with a drain valve.
作为优选,所述捕集器设置于所述筒体的内部或外部。。Preferably, the trap is disposed inside or outside the cylinder. .
与现有技术相比较,本发明的食品真空冷冻干燥及灭菌方法和设备,具有如下的优点:Compared with the prior art, the food vacuum freeze-drying and sterilization method and apparatus of the present invention have the following advantages:
其一,普通的食品真空冷冻干燥主要包括食品速冻-预抽真空-升华干燥-解除真空等过程,本发明在食品升华干燥结束后增加了负压饱和蒸汽灭菌的过程,利用巴氏灭菌温度对应的负压饱和蒸汽,暂时提升干燥食品的水活度,并利用蒸汽穿透性强、潜热大的特点,快速高效地灭杀致病菌。灭菌在升华干燥过程结束后进行,食品内部的水分不再迁移,食品的组织结构稳定,负压蒸汽不会破坏食品内部结构,灭菌过程最大程度地保证食品的品质不下降。First, the general food vacuum freeze-drying mainly includes a process of food quick-freezing-pre-vacuum-sublimation drying-de-vacuum, etc. The invention increases the process of vacuum-steam sterilization after the sublimation of the food is finished, and pasteurization is performed. The negative pressure saturated steam corresponding to the temperature temporarily enhances the water activity of the dried food, and utilizes the characteristics of strong steam penetration and latent heat to quickly and efficiently kill the pathogenic bacteria. Sterilization is carried out after the sublimation drying process, the moisture inside the food no longer migrates, the structure of the food is stable, the negative pressure steam does not damage the internal structure of the food, and the sterilization process ensures that the quality of the food does not decrease to the greatest extent.
其二,本发明食品在蒸汽巴氏灭菌后,干燥舱与捕集器连接,利用冷阱表面的低温冰层捕集水蒸气,使干燥舱压力迅速下降,当压力下降到低于食品温度对应的饱和压力时,食品表面及内部孔隙中增加的凝结水蒸发,同时食品温度下降。食品中的凝结水快速蒸发及食品快速降温保证了食品在灭菌后合适的储存条件。Secondly, after the steam pasteurization of the food of the invention, the drying chamber is connected with the trap, and the water vapor is trapped by the low temperature ice layer on the surface of the cold trap, so that the pressure in the drying chamber is rapidly decreased, and when the pressure drops below the food temperature. At the corresponding saturation pressure, the condensed water added to the surface of the food and the internal pores evaporates while the temperature of the food drops. The rapid evaporation of condensed water in food and the rapid cooling of food ensure proper storage conditions of food after sterilization.
其三,本发明的蒸汽捕集过程无需启动真空泵,避免了水分对真空泵润滑油的不利影响,也节省了真空泵的能耗。Third, the steam trapping process of the present invention does not require the activation of the vacuum pump, thereby avoiding the adverse effects of moisture on the vacuum pump lubricating oil and also saving the energy consumption of the vacuum pump.
其四,本发明在蒸汽捕集过程中利用灭菌后的蒸汽去除冷阱表面的部分冰层,减少了冷阱除冰所需的能源消耗。与相互独立的冷阱除冰过程及蒸汽灭菌过程所耗能源相比,本发明的这种能量综合利用可节省约35%的能源消耗。Fourth, the present invention utilizes the sterilized steam to remove a portion of the ice layer on the surface of the cold trap during the steam trapping process, thereby reducing the energy consumption required for cold trap deicing. This integrated energy utilization of the present invention can save about 35% of energy consumption compared to the independent cold trap de-icing process and the energy consumed by the steam sterilization process.
其五,本发明中利用的负压蒸汽发生装置,不仅提供灭菌所用的负压蒸汽源,热水在干燥舱筒体壁面换热管上的循环实现了对干燥舱筒体的温度控制,避免蒸汽在筒体壁面的凝结,负压蒸汽还可以对冻干机冷阱进行快速除霜。Fifth, the negative pressure steam generating device used in the present invention not only provides a negative pressure steam source for sterilization, but also the circulation of the hot water on the heat exchange tube of the drying tank body wall realizes temperature control of the drying chamber cylinder body. Avoid condensation of steam on the wall of the cylinder, and negative pressure steam can also quickly defrost the chiller trap.
其六,与将食品在冻干设备中冻干之后再移到灭菌设备中进行灭菌的系统设备相比,本发明的食品真空冷冻干燥及灭菌设备不仅设备投资省,运行时间短,还节约能源,减少操作环节,降低人工成本。Sixth, compared with the system equipment for sterilizing the food in the lyophilization device and then moving to the sterilization device for sterilization, the food vacuum freeze-drying and sterilizing device of the invention not only saves equipment investment, but also has short running time. It also saves energy, reduces operating links, and reduces labor costs.
图1为本发明的用于食品真空冷冻干燥及灭菌设备的结构示意图;Figure 1 is a schematic view showing the structure of a food vacuum freeze drying and sterilizing apparatus of the present invention;
图2为图1中I部分的局部放大图。Figure 2 is a partial enlarged view of a portion I of Figure 1.
主要附图标记:Main reference mark:
1、干燥舱;2、加热装置;3、负压蒸汽装置;4、真空捕汽装置;11、筒体;12、加热板组件;13、温度传感器;14、压力传感器;15、进空气阀;16、排汽阀;17、换热管;18、反辐射板;19、隔热垫;21、冷却水泵;22、冷却换热器;23、旁通阀;24、循环水泵;25、汽水换热器;26、第一蒸汽调节阀;27、第一单向阀;28、疏水阀;31、热水泵;32、负压蒸汽发生器;33、盘管加热器;34、第二单向阀;35、温度传感器;36、第二蒸汽调节阀;37、自动进水阀;38、第一负压蒸汽阀;39、第二负压蒸汽阀;41、捕集器;42、冷阱;43、抽真空阀;44、真空泵;45、制冷供液阀;46、排水阀。1. Drying cabin; 2. Heating device; 3. Negative pressure steam device; 4. Vacuum steam catching device; 11. Cylinder; 12, heating plate assembly; 13. Temperature sensor; 14. Pressure sensor; ; 16, steam exhaust valve; 17, heat exchange tube; 18, anti-radiation board; 19, insulation pad; 21, cooling water pump; 22, cooling heat exchanger; 23, bypass valve; 24, circulating water pump; Soda water heat exchanger; 26, first steam regulating valve; 27, first check valve; 28, steam trap; 31, hot water pump; 32, negative pressure steam generator; 33, coil heater; One-way valve; 35, temperature sensor; 36, second steam regulating valve; 37, automatic water inlet valve; 38, first negative pressure steam valve; 39, second negative pressure steam valve; 41, trap; Cold trap; 43, vacuum valve; 44, vacuum pump; 45, refrigeration liquid supply valve; 46, drain valve.
以下结合附图对本发明的结构做进一步详细的说明。The structure of the present invention will be further described in detail below with reference to the accompanying drawings.
在传统的食品的冻干工艺中,对食品的冻干和灭菌是独立的两个环节进行,即食品在冻干设备中冻干之后再移到灭菌设备中进行灭菌。与之不同的是,本发明的食品真空冷冻干燥及灭菌方法,在一些实施方式中,可以包括以下步骤:In the traditional lyophilization process of food, lyophilization and sterilization of food are carried out in two separate steps, that is, the food is lyophilized in a lyophilization device and then moved to a sterilizing device for sterilization. In contrast, the food vacuum freeze drying and sterilization method of the present invention may, in some embodiments, include the following steps:
步骤1),预处理物料,将需要处理的物料冻结到其共晶点温度以下后送入干燥舱内;Step 1), pretreating the material, and freezing the material to be processed to below the eutectic point temperature, and then feeding the material into the drying chamber;
步骤2),使物料在干燥舱内被抽真空,在真空状态下使物料吸收热量以使物料内的冰升华为水蒸气并从物料中逸出并凝华;Step 2), the material is evacuated in the drying chamber, and the material absorbs heat under vacuum to make the ice in the material sublimate into water vapor and escape from the material and desublimate;
步骤3),待物料达到所需的干燥程度后,向干燥舱内充入负压饱和蒸汽,蒸汽在物料表面及内部孔隙凝结,物料温度上升到所需的巴氏灭菌温度,维持在巴氏灭菌温度一段时间后停止充入负压饱和蒸汽;Step 3) After the material reaches the required degree of dryness, the drying chamber is filled with negative pressure saturated steam, the steam is condensed on the surface of the material and the internal pores, and the temperature of the material rises to the desired pasteurization temperature, and is maintained at the bar. The sterilization temperature is stopped for a period of time and then the negative pressure saturated steam is stopped;
步骤4),捕集干燥舱内的水蒸气以使干燥舱内压力下降,物料表面及内部孔隙的凝结水分蒸发,物料降温;Step 4), collecting water vapor in the drying chamber to reduce the pressure in the drying chamber, and the condensed water on the surface of the material and the internal pores evaporates, and the material is cooled;
步骤5),待舱内压力下降到所需的捕汽压力后,充入空气,解除干燥舱内的真空状态,结束冻干及灭菌过程。Step 5), after the pressure in the cabin drops to the required steam trapping pressure, the air is filled, the vacuum state in the drying chamber is released, and the freeze-drying and sterilization process is ended.
图1所示为本发明一种实施方式的食品真空冷冻干燥及灭菌设备的结构示意图,图2为图1中I部分的局部放大图。1 is a schematic structural view of a food vacuum freeze-drying and sterilizing apparatus according to an embodiment of the present invention, and FIG. 2 is a partial enlarged view of a portion I of FIG.
如图1所示,本发明的设备包括通过管道(图1未标注)连接的干燥舱1、加热装置2、负压蒸汽装置3和真空捕汽装置4,其中,所述加热装置2与所述负压蒸汽装置3连接以提供生成负压饱和蒸汽的热能,所述负压蒸汽装置3与所述干燥舱1连接以对所述干燥舱1内容置的物料进行蒸汽灭菌,所述真空捕汽装置4与所述干燥舱1连接用于捕集所述干燥舱1内的水蒸气以使所述干燥舱1内压力下降。As shown in Fig. 1, the apparatus of the present invention comprises a drying compartment 1, a heating device 2, a vacuum steaming device 3 and a vacuum trapping device 4 connected by a pipe (not labeled in Fig. 1), wherein the heating device 2 and the device The negative pressure steam device 3 is connected to provide thermal energy for generating negative pressure saturated steam, and the negative pressure steam device 3 is connected to the drying chamber 1 for steam sterilization of the contents of the drying chamber 1 A steam trap 4 is connected to the drying chamber 1 for trapping water vapor in the drying chamber 1 to lower the pressure in the drying chamber 1.
进一步地,如图1所示,干燥舱1包括筒体11;筒体11内部装有加热板组件12,包括两组对称设置的加热板组(图1未示出),两组加热板组的进水端口与出水端口分别合并后通过管道与加热装置2连接;干燥舱的筒体11内部设有温度传感器13和真空压力传感器14,上述传感器均与控制装置相连。干燥舱筒体11上有进汽端口,进汽端口通过管路与负压蒸汽装置3相接;干燥舱筒体11上有排汽端口,排汽端口通过排汽阀16和管路与真空捕集装置4相连;干燥舱筒体11上有进空气端口,进空气端口通过管路连接有进空气阀15;干燥舱筒体11的外表面上通过焊接方式固定连接有均匀有序分布的换热管17,换热管1的进水端口和出水端口通过管路与负压蒸汽装置3相接。干燥舱筒体11的内部设有反辐射板18,反辐射板18与灭菌室筒体11之间设有若干隔热垫19,隔热垫19的厚度为5mm,反辐射板18的端部通过螺栓与螺母固定在灭菌室筒体11上。Further, as shown in FIG. 1, the drying chamber 1 comprises a cylinder 11; the cylinder 11 is internally provided with a heating plate assembly 12, comprising two sets of symmetrically arranged heating plate sets (not shown in FIG. 1), two sets of heating plates The water inlet port and the water outlet port are respectively combined and connected to the heating device 2 through a pipe; the cylinder 11 of the drying chamber is internally provided with a temperature sensor 13 and a vacuum pressure sensor 14, and the sensors are connected to the control device. The drying chamber body 11 has an inlet port, and the inlet port is connected to the negative pressure steam device 3 through a pipeline; the drying chamber body 11 has an exhaust port, and the exhaust port passes through the exhaust valve 16 and the pipeline and the vacuum The collecting device 4 is connected; the drying chamber body 11 has an inlet air port, and the inlet air port is connected with an inlet air valve 15 through the pipeline; the outer surface of the drying chamber body 11 is fixedly connected by welding to have a uniform and orderly distribution. The heat exchange tube 17, the water inlet port and the water outlet port of the heat exchange tube 1 are connected to the negative pressure steam device 3 through a pipeline. The interior of the drying chamber body 11 is provided with a counter-radiation plate 18, and a plurality of insulating pads 19 are disposed between the anti-radiation plate 18 and the sterilization chamber cylinder 11. The thickness of the insulating pad 19 is 5 mm, and the end of the anti-radiation plate 18 The portion is fixed to the sterilization chamber cylinder 11 by bolts and nuts.
再进一步地,如图1所示,加热装置2包括汽水换热器25;汽水换热器25的蒸汽一侧的进口经过第一蒸汽调节阀26连接锅炉产生的高温高压蒸汽,出口经过第一单向阀27与疏水阀28连接;汽水换热器25的水侧的出口通过管路连接加热板组件12的进水端口,汽水换热器25的水侧的进口通过管路依次连接循环水泵23、冷却换热器22热水侧和加热板组件12的出水端口;冷却换热器22热水侧的进口和出口之间通过旁通管路连接有旁通阀23;冷却换热器22的冷却水侧的进口连接有冷却水泵21。Further, as shown in FIG. 1, the heating device 2 includes a soda water heat exchanger 25; the inlet of the steam side of the soda water heat exchanger 25 is connected to the high temperature and high pressure steam generated by the boiler through the first steam regulating valve 26, and the outlet passes through the first The check valve 27 is connected to the steam trap 28; the outlet of the water side of the steam-water heat exchanger 25 is connected to the water inlet port of the heating plate assembly 12 through a pipeline, and the inlet of the water side of the steam-water heat exchanger 25 is connected to the circulating water pump through the pipeline in turn. 23. The water outlet port of the hot water side of the heat exchanger 22 and the hot plate assembly 12; the inlet and outlet of the hot water side of the cooling heat exchanger 22 are connected to the bypass valve 23 through the bypass line; the cooling heat exchanger 22 A cooling water pump 21 is connected to the inlet of the cooling water side.
再进一步地,如图1所示,负压蒸汽装置3包括蒸汽发生器32;蒸汽发生器32的热水出口依次连接热水泵31和换热管17的进水端口;蒸汽发生器32的热水进口连接换热管17的出水端口;蒸汽发生器32上带有自动补水阀37与纯净水管道(图1中未示出)相连;蒸汽发生器32内部放置有盘管加热器33,盘管加热器33的进口通过管路和蒸汽调节阀36与高温高压蒸汽相连,出口通过单向阀34后连接到加热系统单向阀27和疏水阀28之间的管路上;蒸汽发生器32上部的出汽端口上连接有第一负压蒸汽阀38;蒸汽发生器32内部设有测量水温的温度传感器35。Further, as shown in FIG. 1, the negative pressure steam device 3 includes a steam generator 32; the hot water outlet of the steam generator 32 sequentially connects the hot water pump 31 and the water inlet port of the heat exchange tube 17; the heat of the steam generator 32 The water inlet is connected to the water outlet port of the heat exchange tube 17; the steam generator 32 is provided with an automatic water supply valve 37 connected to the purified water pipe (not shown in FIG. 1); the steam generator 32 is internally provided with a coil heater 33, the disk The inlet of the tube heater 33 is connected to the high temperature and high pressure steam through a line and a steam regulating valve 36, and the outlet is connected to the line between the heating system check valve 27 and the steam trap 28 through the check valve 34; the upper portion of the steam generator 32 A first negative pressure steam valve 38 is connected to the steam outlet port; a temperature sensor 35 for measuring the water temperature is provided inside the steam generator 32.
再进一步地,如图1所示,真空捕汽装置4包括捕集器41,捕集器41的侧面有开孔与干燥舱的排汽阀(16)相连;另一侧通过抽空阀43与真空泵44连通;捕集器41腔内放置有由多组金属盘管或金属板组成的冷阱42,冷阱42的金属管或金属板的内部流通有制冷剂,冷阱42的制冷剂进口通过制冷剂阀45与制冷装置相连;捕集器41腔内有开孔连接负压蒸汽装置的第二负压蒸汽阀39;捕集器41下部布置有排水阀46。Still further, as shown in FIG. 1, the vacuum trap 4 includes a trap 41 having a side opening having an opening connected to the exhaust valve (16) of the drying chamber; the other side is connected to the exhaust valve 43 through The vacuum pump 44 is connected; the trap 41 is provided with a cold trap 42 composed of a plurality of sets of metal coils or metal plates. The inside of the metal tube or the metal plate of the cold trap 42 is circulated with a refrigerant, and the refrigerant inlet of the cold trap 42 The refrigerant valve 45 is connected to the refrigeration device; the trap 41 has a second negative pressure steam valve 39 connected to the negative pressure steam device; and a drain valve 46 is disposed at the lower portion of the trap 41.
另外,本发明上述实施方式所提供的再进一步地,可根据实际情况选择合适设备实现。但优选采用本发明一并提出的食品真空冷冻干燥及灭菌设备实现,其具体工作流程可以参照如下执行:In addition, the above-described embodiments of the present invention further provide that a suitable device can be selected according to actual conditions. However, it is preferred to implement the food vacuum freeze drying and sterilizing device proposed by the present invention, and the specific work flow can be carried out as follows:
a)经过前处理及速冻后的食品及其承载物进入干燥舱内。a) The pre-treated and quick-frozen food and its carrier enter the drying chamber.
b)预抽真空:循环水泵启动,加热板组件内的水循环;冷阱的制冷剂阀开启,冷阱制冷;真空泵、抽真空阀和排汽阀开启,干燥舱腔内压力下降。在这一步骤中,物料在干燥舱内被抽真空后,干燥舱内压力优选地控制为13~130Pa。b) Pre-vacuum: The circulating water pump starts, the water circulation in the heating plate assembly; the refrigerant valve of the cold trap is opened, and the cold trap is cooled; the vacuum pump, the vacuum valve and the exhaust valve are opened, and the pressure in the drying chamber is lowered. In this step, after the material is evacuated in the drying chamber, the pressure in the drying chamber is preferably controlled to be 13 to 130 Pa.
c)升华干燥:干燥舱腔内压力达到工作压力(13~130Pa)后,蒸汽调节阀开启,汽水换热器将蒸汽热量传递给另一侧的水,循环水泵的运行使加 热板组的温度升高,加热板通过辐射将热量传递给食品,食品吸热后其中的水分逐渐升华。物料升华出的水蒸气通过排汽阀进入捕集器内,在温度较低的冷阱表面凝华。c) Sublimation drying: After the pressure in the drying chamber reaches the working pressure (13-130Pa), the steam regulating valve is opened, the steam-water heat exchanger transfers the heat of the steam to the water on the other side, and the operation of the circulating water pump makes the temperature of the heating plate group When it is raised, the heating plate transfers heat to the food through radiation, and the moisture in the food gradually sublimates after the heat is absorbed. The water vapor sublimated from the material enters the trap through the exhaust valve and condenses on the surface of the cold trap with a lower temperature.
升华干燥过程中,第一蒸汽调节阀根据过程中物料升华所需热量自动调节加热板的水温。当加热板水温需要迅速下降时则关闭蒸汽调节阀并开启冷却水泵。当物料达到所需的干燥程度时,加热板和物料的温度均接近于设定的干燥温度,干燥过程结束,物料维持原有形状但内部形成多孔结构。关闭排汽阀、抽真空阀、真空泵和制冷剂阀,停止抽真空和制冷剂供液。During the sublimation drying process, the first steam regulating valve automatically adjusts the water temperature of the heating plate according to the heat required for sublimation of the material in the process. When the water temperature of the heating plate needs to drop rapidly, close the steam regulating valve and turn on the cooling water pump. When the material reaches the desired degree of drying, the temperature of the heating plate and the material are both close to the set drying temperature, the drying process is finished, the material maintains the original shape but the inside forms a porous structure. Close the exhaust valve, vacuum valve, vacuum pump and refrigerant valve to stop vacuuming and refrigerant supply.
d)灭菌准备:负压蒸汽装置上的第二蒸汽调节阀和热水泵开启,盘管加热器将蒸汽热量传递给负压蒸汽发生器内的水,使水温升高到高于所需的灭菌温度0~5℃并维持在该温度,同时干燥舱筒体壁面的温度也上升;将加热板组的水温设定为所需的灭菌温度,加热板温度上升。d) Sterilization preparation: the second steam regulating valve and the hot water pump on the negative pressure steam device are turned on, and the coil heater transfers the heat of the steam to the water in the negative pressure steam generator, so that the water temperature rises above the required The sterilization temperature is 0 to 5 ° C and maintained at this temperature, and the temperature of the wall surface of the drying cylinder body also rises; the water temperature of the heating plate group is set to the required sterilization temperature, and the temperature of the heating plate rises.
e)蒸汽灭菌:第一负压蒸汽阀开启,负压蒸汽发生器内的饱和蒸汽进入干燥舱的腔内,并在温度较低的食品表面及孔隙内部凝结,蒸汽凝结过程释放的热量使食品温度迅速上升到所需的灭菌温度,之后调节第一负压蒸汽阀的开度或启停状态,使食品温度维持在该灭菌温度一段时间,即达到所需的灭菌时间(30min)后,关闭第一负压蒸汽阀,关停热水泵。e) Steam sterilization: the first negative pressure steam valve is opened, the saturated steam in the negative pressure steam generator enters the cavity of the drying chamber, and condenses on the surface of the lower temperature food and inside the pores, and the heat released by the steam condensation process makes The temperature of the food rapidly rises to the required sterilization temperature, and then the opening or start-stop state of the first negative pressure steam valve is adjusted, so that the food temperature is maintained at the sterilization temperature for a period of time, that is, the required sterilization time is reached (30 min). After that, close the first negative pressure steam valve and shut down the hot water pump.
f)蒸汽捕集:开启排汽阀,干燥舱腔内的蒸汽进入捕集器,并在低温的冷阱冰霜层的表面凝结,干燥舱腔内的压力下降,压力下降到低于食品温度对应的饱和压力时,食品表面及孔隙内部的凝结水蒸发,食品温度下降。在蒸汽捕集过程中,同时调低加热板的水温设定值至25~40℃,加热板温度下降。f) Steam trapping: the steam exhaust valve is opened, the steam in the drying chamber enters the trap, and condenses on the surface of the low temperature cold trap frost layer, the pressure in the drying chamber drops, and the pressure drops below the food temperature. At the saturation pressure, the condensed water on the surface of the food and inside the pores evaporates and the temperature of the food drops. During the steam trapping process, the water temperature setting of the heating plate is simultaneously lowered to 25 to 40 ° C, and the temperature of the heating plate is lowered.
g)解除真空:当干燥舱内的压力下降到所需的捕汽压力(100~3000Pa)时,蒸汽捕集过程结束。食品温度下降,食品表面及孔隙内部的凝结水全部蒸发。关闭排汽阀后开启进空气阀,解除干燥舱真空状态。同时开启第二负压蒸汽阀,对冷阱表面未融化的冰层进行化霜,直至冷阱表面冰层全部融化,关闭第二负压蒸汽阀。g) De-vacuum: When the pressure in the drying chamber drops to the required steam trapping pressure (100-3000 Pa), the steam trapping process ends. As the temperature of the food drops, the condensate on the surface of the food and inside the pores evaporates. After closing the exhaust valve, open the inlet air valve to release the vacuum condition of the drying chamber. At the same time, the second negative pressure steam valve is opened to defrost the unmelted ice layer on the surface of the cold trap until the ice layer on the surface of the cold trap is completely melted, and the second negative pressure steam valve is closed.
h)干燥舱真空状态解除后,取出食品及其承载物,对食品进入后处理及包装。开启排汽阀和排水阀,排出捕集器内的水。h) After the vacuum condition of the drying chamber is released, the food and its load are taken out, and the food is processed and packaged. Open the exhaust valve and drain valve to drain the water from the trap.
实施例1Example 1
下面以原料含水量为72%的牛脏的冻干及灭菌过程为例对上述实施方式的工作流程描述如下:The following is a description of the workflow of the above embodiment by taking the lyophilization and sterilization process of bovine waste with a water content of 72% as follows:
a)接种及速冻:将经过清洗及切块等前处理后的原料中取数块接种粪肠球菌(ATCC 8459),接种数量为8×10
7cfu/g;再将原料在冻结库中速冻到-25℃后装入干燥舱内1内。
a) Inoculation and quick freezing: Take several pieces of the raw materials after pre-treatment such as washing and dicing, and inoculate Enterococcus faecalis (ATCC 8459), the inoculation quantity is 8×10 7 cfu/g; then the raw materials are frozen in the frozen storage. After filling to -25 ° C, it is placed in the drying chamber 1 .
b)预抽真空:循环水泵31启动,加热板内的水循环;真空捕汽装置4的制冷剂阀45开启,冷阱42制冷;真空泵44、抽真空阀43和排汽阀16开启,干燥舱腔内压力下降。b) pre-vacuum: the circulating water pump 31 is started to heat the water in the heating plate; the refrigerant valve 45 of the vacuum trap 4 is opened, the cold trap 42 is cooled; the vacuum pump 44, the vacuum valve 43 and the exhaust valve 16 are opened, and the drying chamber is opened. The pressure in the chamber drops.
c)升华干燥:干燥舱腔内压力达到工作压力70Pa后,第一蒸汽调节阀26开启,汽水换热器25将蒸汽热量传递给另一侧的水,循环水泵31的运行使加热板组12的温度升高,加热板通过辐射将热量传递给食品,食品吸热后其中的水份逐渐升华。物料升华出的水蒸气通过排汽阀16进入捕集器41内,在温度较低的冷阱42表面凝华。升华干燥过程中,加热板的水温按运行时间设置为多个温度区间,其中最高水温控制在120℃,冷阱温度控制在-40℃。c) sublimation drying: after the pressure in the drying chamber reaches the working pressure of 70 Pa, the first steam regulating valve 26 is opened, the soda heat exchanger 25 transfers the heat of the steam to the water on the other side, and the operation of the circulating water pump 31 causes the heating plate group 12 to The temperature rises, the heating plate transfers heat to the food through radiation, and the moisture in the food gradually sublimates after the food absorbs heat. The water vapor sublimated from the material enters the trap 41 through the exhaust valve 16, and is desublimed on the surface of the cold trap 42 having a lower temperature. During the sublimation drying process, the water temperature of the heating plate is set to a plurality of temperature intervals according to the running time, wherein the highest water temperature is controlled at 120 ° C and the cold trap temperature is controlled at -40 ° C.
升华干燥过程中,第一蒸汽调节阀26根据过程中物料升华所需热量自动调整开度以调节加热板的水温。当加热板水温需要迅速下降时则关闭第一蒸汽调节阀26并开启冷却水泵21。当物料达到所需的干燥程度时,加热板和物料的温度均接近于设定的干燥温度40℃,干燥过程结束,物料维持原有形状但内部形成多孔结构。关闭排汽阀16、抽真空阀43、真空泵44和制冷剂阀45,停止抽真空和制冷剂供液。During the sublimation drying process, the first steam regulating valve 26 automatically adjusts the opening degree according to the heat required for sublimation of the material in the process to adjust the water temperature of the heating plate. When the water temperature of the heating plate needs to rapidly drop, the first steam regulating valve 26 is closed and the cooling water pump 21 is turned on. When the material reaches the desired degree of drying, the temperature of the heating plate and the material are both close to the set drying temperature of 40 ° C, the drying process is finished, the material maintains the original shape but the inside forms a porous structure. The exhaust valve 16, the vacuum valve 43, the vacuum pump 44, and the refrigerant valve 45 are closed, and the vacuuming and refrigerant supply are stopped.
d)灭菌准备:负压蒸汽装置上的第二蒸汽调节阀36和热水泵31开启,盘管加热器33将蒸汽热量传递给负压蒸汽发生器32内的水,使水温升高到80℃并维持在该温度,同时干燥舱筒体11壁面的温度也上升;将加热板组12的水温设定为所需的灭菌温度75℃,加热板温度上升。d) Sterilization preparation: The second steam regulating valve 36 and the hot water pump 31 on the negative pressure steam device are turned on, and the coil heater 33 transfers the heat of the steam to the water in the negative pressure steam generator 32, so that the water temperature rises to At 80 ° C and maintained at this temperature, the temperature of the wall surface of the dried casing body 11 also rises; the water temperature of the heating plate group 12 is set to a desired sterilization temperature of 75 ° C, and the temperature of the heating plate rises.
e)蒸汽灭菌:第一负压蒸汽阀38开启,负压蒸汽发生器32内的饱和蒸汽进入干燥舱的腔内,并在温度较低的食品表面及孔隙内部凝结,蒸汽凝结过程释放的热量使食品温度迅速上升到所需的灭菌温度,之后调节第一负压蒸汽阀的开度或启停状态,使食品温度维持在该灭菌温度30min后,关闭第一负压蒸汽阀38,关停热水泵31。e) steam sterilization: the first negative pressure steam valve 38 is opened, the saturated steam in the negative pressure steam generator 32 enters the cavity of the drying chamber, and condenses on the surface of the lower temperature food and inside the pores, and is released by the steam condensation process. The heat causes the temperature of the food to rise rapidly to the desired sterilization temperature, and then adjusts the opening or the start-stop state of the first negative pressure steam valve to maintain the food temperature at the sterilization temperature for 30 minutes, and then closes the first negative pressure steam valve 38. , shut down the hot water pump 31.
f)蒸汽捕集:开启排汽阀16,干燥舱腔内的蒸汽进入捕集器,并在低温的冷阱表面凝结,干燥舱腔内的压力下降,同时食品表面及孔隙内部的凝 结水蒸发,食品温度下降。在此过程中,调低加热板的水温设定值至40℃,加热板温度下降。f) Steam trapping: the exhaust valve 16 is opened, the steam in the drying chamber enters the trap, and condenses on the surface of the cold trap, the pressure in the drying chamber drops, and the condensate on the surface of the food and inside the pore evaporates. The food temperature has dropped. During this process, the water temperature setting of the heating plate is lowered to 40 ° C, and the temperature of the heating plate is lowered.
g)解除真空:当干燥舱内的压力下降到1500Pa时,蒸汽捕集过程结束。食品温度下降至45℃,食品表面及孔隙内部的凝结水全部蒸发。关闭排汽阀16后开启进空气阀15,解除干燥舱真空状态。同时开启第二负压蒸汽阀39,对冷阱表面未融化的冰层进行化霜,直至冷阱表面冰层全部融化,关闭第二负压蒸汽阀39。g) De-vacuum: When the pressure in the drying chamber drops to 1500 Pa, the steam trapping process ends. The temperature of the food dropped to 45 ° C, and the condensed water on the surface of the food and inside the pores all evaporated. After the exhaust valve 16 is closed, the inlet air valve 15 is opened to release the vacuum state of the drying chamber. At the same time, the second negative pressure steam valve 39 is opened to defrost the ice layer which is not melted on the surface of the cold trap until the ice layer on the surface of the cold trap is completely melted, and the second negative pressure steam valve 39 is closed.
h)干燥舱真空状态解除后,取出食品及其承载物,对食品进入后处理及包装。开启排汽阀16和排水阀46,排出捕集器内的水。h) After the vacuum condition of the drying chamber is released, the food and its load are taken out, and the food is processed and packaged. The exhaust valve 16 and the drain valve 46 are opened to discharge the water in the trap.
经过检测,通过本发明实施例提供的食品真空冷冻干燥及灭菌方法对上述物料进行冻干和灭菌,原料的含水量由72%减少至4%,植入的粪肠球菌的数量减少了5个对数单位,且灭菌过程最大程度地保证食品的品质不下降。After testing, the above materials are freeze-dried and sterilized by the method of vacuum freeze-drying and sterilization of the food provided by the embodiments of the present invention, the water content of the raw materials is reduced from 72% to 4%, and the number of implanted Enterococcus faecalis is reduced. 5 logarithmic units, and the sterilization process ensures maximum quality of the food.
当然,以上所述是本发明的优选实施方式,应当指出,对于本技术领域的普通技术人员来说,在不脱离本发明原理的前提下,还可以做出若干改进和润饰,这些改进和润饰也视为本发明的保护范围。The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make several improvements and retouchings without departing from the principles of the present invention. It is also considered to be the scope of protection of the present invention.
Claims (15)
- 食品真空冷冻干燥及灭菌方法,其特征在于,包括:A food vacuum freeze drying and sterilization method, characterized in that it comprises:预处理物料,将需要处理的物料冻结到其共晶点温度以下后送入干燥舱内;Pretreating the material, freezing the material to be treated to below the eutectic point temperature and then feeding it into the drying chamber;使物料在干燥舱内被抽真空,在真空状态下使物料吸收热量以使物料内的冰升华为水蒸气并从物料中逸出并凝华;The material is evacuated in the drying chamber, and the material absorbs heat under vacuum to sublimate the ice in the material into water vapor and escape from the material and desublimate;待物料达到所需的干燥程度后,向干燥舱内充入负压饱和蒸汽,蒸汽在物料表面及内部孔隙凝结,物料温度上升到所需的巴氏灭菌温度,维持在巴氏灭菌温度一段时间后停止充入负压饱和蒸汽;After the material reaches the required degree of dryness, the drying chamber is filled with negative pressure saturated steam, the steam is condensed on the surface of the material and the internal pores, the temperature of the material rises to the desired pasteurization temperature, and the pasteurization temperature is maintained. Stop charging the negative pressure saturated steam after a period of time;捕集干燥舱内的水蒸气以使干燥舱内压力下降,物料表面及内部孔隙的凝结水分蒸发,物料降温;The water vapor in the drying chamber is captured to reduce the pressure in the drying chamber, and the condensed water on the surface of the material and the internal pores evaporates, and the material is cooled;待舱内压力下降到所需的捕汽压力后,充入空气,解除干燥舱内的真空状态,结束冻干及灭菌过程。After the pressure in the cabin drops to the required steam trapping pressure, the air is filled, the vacuum state in the drying chamber is released, and the freeze-drying and sterilization process is ended.
- 如权利要求1所述的食品真空冷冻干燥及灭菌方法,其特征在于,其中物料在干燥舱内被抽真空后,干燥舱内压力为13~130Pa。The food vacuum freeze-drying and sterilizing method according to claim 1, wherein the pressure in the drying chamber is 13 to 130 Pa after the material is evacuated in the drying chamber.
- 如权利要求1所述的食品真空冷冻干燥及灭菌方法,其特征在于,其中所述巴氏灭菌温度为60~90℃。The food vacuum freeze-drying and sterilizing method according to claim 1, wherein the pasteurization temperature is 60 to 90 °C.
- 如权利要求1所述的食品真空冷冻干燥及灭菌方法,其特征在于,其中维持巴氏灭菌温度的时间为10~90min。The food vacuum freeze-drying and sterilizing method according to claim 1, wherein the pasteurization temperature is maintained for 10 to 90 minutes.
- 如权利要求1所述的食品真空冷冻干燥及灭菌方法,其特征在于,其中所述负压饱和蒸汽的压力对应的饱和水的温度比所述巴氏灭菌温度高0~10℃。The food vacuum freeze-drying and sterilizing method according to claim 1, wherein the pressure of the negative pressure saturated steam corresponds to a temperature of saturated water that is 0 to 10 ° C higher than the pasteurization temperature.
- 如权利要求1所述的食品真空冷冻干燥及灭菌方法,其特征在于,其中所述捕汽压力为100~3000Pa。The food vacuum freeze-drying and sterilizing method according to claim 1, wherein the steam trapping pressure is 100 to 3000 Pa.
- 食品真空冷冻干燥及灭菌设备,其特征在于,包括通过管道连接的干燥舱、加热装置、负压蒸汽装置和真空捕汽装置,其中,所述加热装置与所述负压蒸汽装置连接以提供生成负压饱和蒸汽的热能,所述负压蒸汽装置与所述干燥舱连接以对所述干燥舱内容置的物料进行蒸汽灭菌,所述真空捕汽装置与所述干燥舱连接用于捕集所述干燥舱内的水蒸气以使所述干燥舱内压力下降。a food vacuum freeze-drying and sterilizing apparatus, comprising: a drying chamber connected by a pipe, a heating device, a vacuum steam device, and a vacuum steam catching device, wherein the heating device is connected to the negative pressure steam device to provide Generating heat energy of the negative pressure saturated steam, the negative pressure steam device is connected to the drying chamber to steam sterilize the contents of the drying chamber, and the vacuum trap is connected to the drying chamber for catching The water vapor in the drying chamber is collected to reduce the pressure in the drying chamber.
- 如权利要求7所述的食品真空冷冻干燥及灭菌设备,其特征在于,所述干燥舱包括一筒体,所述筒体内部装有加热板组件,所述加热板组件具有 通过管道与所述加热装置连接的进水端口和出水端口,所述筒体上设有与负压蒸汽装置相接的进汽端口,以及与所述真空捕集装置相连的排汽端口;所述筒体上还设有与所述进空气端口连接的进空气阀。A food vacuum freeze-drying and sterilizing apparatus according to claim 7, wherein said drying chamber comprises a cylinder, and said cylinder body is internally provided with a heating plate assembly, said heating plate assembly having a pipe and a pipe a water inlet port and a water outlet port connected to the heating device, the cylinder body is provided with an inlet port connected to the vacuum steam device, and an exhaust port connected to the vacuum trap device; There is also an inlet air valve connected to the inlet air port.
- 如权利要求8所述的食品真空冷冻干燥及灭菌设备,其特征在于,所述食品真空冷冻干燥及灭菌设备还包括一控制装置,所述筒体内部设有分别与所述控制装置连接以采集数据的温度传感器和真空压力传感器。The food vacuum freeze-drying and sterilizing apparatus according to claim 8, wherein the food vacuum freeze-drying and sterilizing apparatus further comprises a control device, wherein the cylinder is internally provided with a connection with the control device A temperature sensor and a vacuum pressure sensor for collecting data.
- 如权利要求8所述的食品真空冷冻干燥及灭菌设备,其特征在于,所述筒体的外表面上固定连接有均匀分布的换热管,所述换热管的进水口和出水口分别通过管路与所述蒸汽发生装置相接。The food vacuum freeze-drying and sterilizing apparatus according to claim 8, wherein the outer surface of the cylinder is fixedly connected with a heat exchange tube uniformly distributed, and the water inlet and the water outlet of the heat exchange tube are respectively The steam generating device is connected to the pipeline.
- 如权利要求8所述的食品真空冷冻干燥及灭菌设备,其特征在于,所述筒体的内部设有反辐射板,所述反辐射板与所述筒体之间设有若干隔热垫。The food vacuum freeze-drying and sterilizing apparatus according to claim 8, wherein the inside of the cylinder body is provided with a counter-radiation plate, and the heat-insulating pad is arranged between the anti-radiation plate and the cylinder body. .
- 如权利要求8所述的食品真空冷冻干燥及灭菌设备,其特征在于,所述加热装置包括汽水换热器,所述汽水换热器的输入蒸汽一侧的进口通过蒸汽调节阀连接一高压蒸汽源,出口经过一第一单向阀与一疏水阀连接;汽水换热器的输出水的一侧的出口连接所述加热板组件的进水端口,所述汽水换热器的输入水的一侧的进口通过管路依次连接一循环水泵、一冷却换热器的热水侧和所述加热板组件的所述出水端口;所述冷却换热器的热水侧的进口和出口之间通过旁通管路连接有一旁通阀;所述冷却换热器的冷却水侧的进口连接有一冷却水泵。A food vacuum freeze-drying and sterilizing apparatus according to claim 8, wherein said heating means comprises a soda water heat exchanger, and an inlet of the steam inlet side of said steam-water heat exchanger is connected to a high pressure through a steam regulating valve a steam source, the outlet is connected to a steam trap through a first one-way valve; an outlet of one side of the output water of the steam-water heat exchanger is connected to the water inlet port of the heating plate assembly, and the input water of the steam-water heat exchanger The inlet of one side is connected to a circulating water pump, a hot water side of a cooling heat exchanger and the water outlet port of the heating plate assembly through a pipeline; between the inlet and the outlet of the hot water side of the cooling heat exchanger A bypass valve is connected through the bypass line; a cooling water pump is connected to the inlet of the cooling water side of the cooling heat exchanger.
- 如权利要求9所述的食品真空冷冻干燥及灭菌设备,其特征在于,所述的负压蒸汽装置包括一蒸汽发生器,所述蒸汽发生器的热水出口依次连接一热水泵和所述筒体表面的所述换热管的进水端口;所述蒸汽发生器的热水进口连接所述换热管的出水端口;所述蒸汽发生器上设有与一进水管道相连的一自动补水阀;所述蒸汽发生器内部放置有一盘管加热器,所述盘管加热器的进口通过一蒸汽调节阀连接至高压蒸汽源,所述盘管加热器的出口通过一第二单向阀与一疏水阀连接;用于测量水温的所述温度传感器设置于所述蒸汽发生器腔体内,所述温度传感器与所述控制装置相连。A food vacuum freeze-drying and sterilizing apparatus according to claim 9, wherein said negative pressure steam device comprises a steam generator, and said hot water outlet of said steam generator is connected to a heat pump and said a water inlet port of the heat exchange tube on the surface of the cylinder; a hot water inlet of the steam generator is connected to a water outlet port of the heat exchange tube; and the steam generator is provided with an automatic connection with a water inlet pipe a water supply valve; a coil heater is disposed inside the steam generator, the inlet of the coil heater is connected to a high pressure steam source through a steam regulating valve, and the outlet of the coil heater passes through a second check valve Connected to a trap; the temperature sensor for measuring the temperature of the water is disposed in the steam generator chamber, and the temperature sensor is coupled to the control device.
- 如权利要求7所述的食品真空冷冻干燥及灭菌设备,其特征在于,所述真空捕汽装置包括一捕集器,所述捕集器的一侧设有与所述干燥舱的排气阀相连的开孔,其另一侧通过一抽空阀与一真空泵连通;所述捕集器的腔 内放置有由多组金属盘管或金属板组成的一冷阱,所述冷阱的内部流通有制冷剂,所述冷阱的出口通过一制冷剂阀与一制冷装置相连;所述捕集器的腔内设有开孔用于连接所述负压蒸汽装置的一负压蒸汽阀;所述捕集器的下部还设置有排水阀。A food vacuum freeze-drying and sterilizing apparatus according to claim 7, wherein said vacuum trapping device comprises a trap, and one side of said trap is provided with exhaust gas from said drying chamber An open hole connected to the valve, the other side of which is in communication with a vacuum pump through an evacuation valve; a trap having a plurality of sets of metal coils or metal plates placed inside the chamber of the trap, the inside of the cold trap Circulating a refrigerant, the outlet of the cold trap is connected to a refrigerating device through a refrigerant valve; the chamber of the trap is provided with an opening for connecting a negative pressure steam valve of the negative pressure steam device; The lower portion of the trap is also provided with a drain valve.
- 如权利要求14所述食品真空冷冻干燥及灭菌设备,其特征在于,所述捕集器设置于所述干燥舱筒体的内部或外部。A food vacuum freeze-drying and sterilizing apparatus according to claim 14, wherein said trap is disposed inside or outside said drying capsule body.
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