CN104013069B - A kind of high-power electron beam controls the processing method of the microorganism of dehydration spice in conjunction with heated-air drying - Google Patents

Abstract

The invention relates to a method for processing microorganisms of dehydrated spices controlled by high-energy electron beam combined with hot air drying, which belongs to the technical field of deep processing of agricultural products. The process of the invention: the fresh spices are selected, cleaned and drained, irradiated by high-energy electron beams, and then dried by hot air at normal pressure in stages after the irradiation. Advantages of the present invention: the irradiation of high-energy electron beams on fresh spices can directly kill some microorganisms in raw materials and reduce the number of microorganisms, and secondly, the penetration of high-energy electron beams will cause deformation, shrinkage or rupture of cell structures in fresh spices. , the interstitial fluid in the cells is more likely to seep or lose, and the content of free water increases, which is conducive to the outward diffusion of water during drying and improves the drying efficiency; the segmented hot air drying is to evaporate the raw material water to obtain dried products, and the second is due to the microorganisms. Irradiation effect, the physiological functions of microorganisms in spices are damaged to varying degrees, and it is difficult to repair during drying. Low-dose irradiation can effectively kill microorganisms in spices and improve the efficiency of hot air drying.

Description

A processing method of high-energy electron beam combined with hot air drying to control microorganisms of dehydrated spices

technical field

The invention relates to a method for processing microorganisms of dehydrated spices controlled by high-energy electron beam combined with hot air drying. The invention belongs to the technical field of deep processing of agricultural products and relates to the drying, storage and processing of agricultural products.

Background technique

Edible spices have a long history and are commonly used food ingredients in daily life. They occupy an extremely important position and are also indispensable raw materials in the modern food processing industry. Spices are susceptible to microbial contamination during raw material harvesting, processing and storage, which directly affects their quality and hygienic safety. In order to control microorganisms in spices, traditional sterilization methods usually include high-temperature sterilization, adding preservatives, chemical fumigation, etc., but these methods basically have defects such as long sterilization time, incomplete sterilization, high energy consumption, or environmental pollution. And often can affect the original local flavor and nutritional labeling of spices.

Irradiation is one of the ideal cold sterilization technologies, with remarkable sterilization effect, wide sterilization range, non-toxic, no residue, green environmental protection and low energy consumption. Electron accelerator sterilization technology is the application of high-energy electron beams generated by electron accelerators. High-energy electron beams can effectively kill various microorganisms and pests. At present, they have been widely used in sterilization of medical and sanitary products and food sterilization. Compared with ⁶⁰ Co irradiation technology, the biggest advantage of electron accelerator irradiation is that the irradiation electron beam is concentrated and oriented, the energy is fully utilized, the irradiation efficiency is high, the dose distribution is uniform, and no radioactive waste is produced. As the price of cobalt sources and the cost of waste source treatment continue to rise, electron accelerator irradiation is showing its economic advantages. Electron accelerator irradiation technology is one of the high-tech fields that has attracted much attention in the world.

In my country, the most commonly used drying method for dehydrated spices is hot air drying. The advantages of hot air drying are less investment in equipment, simple operation, and no need for complicated maintenance techniques. However, due to the lack of effective pretreatment methods for raw materials, conventional hot air drying produces The number of microorganisms in dehydrated spices is large, and the quality and safety are low. There are many studies and reports on the sterilization of dehydrated spices. Yan Weiqiang (2013) studied the D ₁₀ value of microorganisms in spices irradiated by high-energy electron accelerators. The D ₁₀ values under the electron accelerator are 2.87, 1.36, 2.16 respectively, and the D ₁₀ values of mold and yeast are 2.90, 1.59 and 2.77 respectively. To control the number of microorganisms in dehydrated spices within a safe range, the electron beam irradiation The dose should not be lower than 6.0kGy. A method of irradiation sterilization of dehydrated vegetables (public number: CN201110190459.9), the main method is to control the irradiation dose of 4-10kGy according to the different initial bacteria content of dehydrated vegetables through ⁶⁰ Co gamma-rays; Chinese Academy of Agricultural Sciences, Beijing A method for irradiating pathogenic bacteria in fresh cooked dumplings from the Institute of Animal Husbandry and Veterinary Medicine (publication number: CN200610152521.4). Cobalt source irradiation can be stored at low temperature for 21 days; these patents are the most conventional way of irradiation processing at present, that is, the final product is irradiated and sterilized, which is very different from the present invention. Wang Jun of Zhejiang University et al. used ⁶⁰ Co γ-rays to irradiate carrots for pretreatment, and studied the effects of irradiation dose, drying temperature, and slice thickness on drying and temperature characteristics; The method for the extraction rate of total flavonoids (authorization number: CN101961357B), the invention mainly uses irradiation decomposition to improve the extraction rate of total flavonoids in spices. Existing radiation research and patents are more about sterilization, fresh-keeping and quarantine. The radiation source is basically ⁶⁰ Co gamma-rays. There are generally single technologies, high radiation doses, and long radiation time. The characteristics are: Long irradiation time will cause different degrees of deterioration in the final quality of the product. The present invention uses high-energy electron beam irradiation technology combined with segmental hot air drying to process dehydrated spices, which is completely different from existing patents in terms of method, processing object and purpose. and research.

Contents of the invention

The purpose of the present invention is to provide a low-dose, high-energy electron beam irradiation treatment combined with segmented normal-pressure hot air drying of spices, which can kill and control the number of microorganisms in dehydrated spice products to a safe range. At present, regarding the radiation sterilization of spice microorganisms, fresh spices are usually dried and then subjected to high-dose radiation sterilization treatment, and the radiation dose of products is generally high. The invention uses high-energy electron beam irradiation technology combined with hot air drying to realize the control of microorganisms in dehydrated spices, and its advantages are: the irradiation effect of high-energy electron beams on fresh spice raw materials can directly kill some microorganisms in the raw materials and reduce the risk of microorganisms. The second is that the penetration of high-energy electron beams will cause deformation, shrinkage or rupture of the cell structure in fresh spices, and the interstitial fluid in the cells is more likely to seep or lose, and the content of free water increases, which is conducive to the outward diffusion of moisture during drying. Improve the efficiency of hot air drying; segmented hot air drying is to evaporate the moisture of raw materials to obtain dried products, and the second is the irradiation effect of high-energy electron beams on microorganisms. The physiological functions of microorganisms in spices are damaged to varying degrees. In a dry environment, these microorganisms with damaged physiological functions are difficult to repair. During the drying process, as the temperature increases and the moisture decreases, the purpose of effectively killing the microorganisms in the spices after pre-irradiation treatment is achieved. Through high-energy electron beam irradiation combined with hot air drying technology, low-dose irradiation can kill microorganisms in spices and improve the efficiency of hot air drying.

The technical scheme of the present invention: a high-energy electron beam combined with hot air drying to control the microbial processing method of dehydrated spices, through the use of high-energy electron accelerator electron beam irradiation technology and segmented normal pressure hot air drying technology to kill microorganisms in the product, Control the final microbial count of dehydrated spices and improve the efficiency of subsequent hot air drying of spices. The main process of the present invention is as follows: fresh spice raw materials are subjected to high-energy electron beam irradiation treatment after the sundries are selected, cleaned and drained, and after irradiation, the spices are subjected to segmental hot air drying with different process parameters, and then processed by high-energy electron beam irradiation. Drying with hot air realizes the control of microorganisms in dehydrated spices.

1. Pretreatment of raw materials: Remove foreign matter and obviously rotten raw materials from fresh spices, wash with tap water and drain;

2. High-energy electron beam treatment: 1) The drained spices are evenly placed on metal trays. According to the specific gravity of different spice varieties, the thickness of raw materials in the tray is controlled at 5-8cm; 2) High-energy electron accelerator processing technical parameters: electron The output energy of the beam is 5-10MeV, the distance between the high-energy electron beam scanner and the product is 400-520mm, the scanning frequency is 200-420pps, the scanning width is 600mm, and the transmission speed of the tray under the scanner beam is 5.0-6.2m/min. Electron beam irradiation dose is controlled at 2-3kGy;

3. Segmented atmospheric pressure hot air drying: 1) The first heating drying stage: drying temperature 80-100 ℃, drying time 1-1.5h; 2) The second constant speed drying stage: drying temperature 70-80 ℃, drying time 3-5h; 3) The third decelerating drying stage: the drying temperature is 60-70°C, the drying time is 3-5h, and finally dried until the moisture content of the dehydrated spices is below 8%.

Beneficial effects of the present invention: Compared with the background technology, the present invention adopts high-energy electron beam irradiation and segmented normal-pressure hot air drying technology, and its outstanding feature is low-dose irradiation sterilization pretreatment of high-energy electron beam, combined with subsequent hot air Drying, its outstanding advantage is to greatly reduce the dose of electron beam irradiation sterilization, improve the efficiency of hot air drying of spices, can effectively overcome the odor and quality deterioration caused by irradiation of dehydrated spices, the product can maintain the unique flavor of spices, and can Long-term storage at room temperature. Its beneficial effect is embodied in the following aspects:

1. The irradiation dose is greatly reduced. The present invention firstly carries out pre-irradiation to the fresh spice raw materials. Because the water content in the fresh spice is high, the microorganisms are under the condition of high water content. The action of enzymes, enzymes and proteins is more effective. By destroying this active substance, it can kill microorganisms or inhibit their growth and reproduction. The D ₁₀ value of microorganisms in high-moisture raw materials is relatively low, so it can be achieved with a lower irradiation dose Effective sterilization effect. The radiation dose of the electron beam in the present invention is generally 2-3kGy, while the radiation dose of the dehydrated spices is usually 8-10kGy. In addition, electron beams can inhibit or passivate the activity of polyphenol oxidase in fresh spices, thereby reducing enzymatic browning of spices in the subsequent drying process and protecting the quality of the final dried product such as color.

2. The dose distribution of spices with high water content is uniform when irradiated by electron beams, and the dose unevenness is less than 1.1, while the traditional cobalt source radiation dose unevenness exceeds 2.0, and the uniformity of dose distribution will directly affect the quality of irradiated products and their Sterilization effect. The dose distribution diagram of fresh peppers treated with high-energy electron beams is shown in Figure 1. It can be seen from the figure that when the thickness of peppers does not exceed 6.5cm, the energy absorption and distribution of peppers on electron beams is basically uniform, so as to achieve uniform sterilization. Effect.

3. Improvement of drying efficiency. The present invention makes full use of the drying curve of spices, adopts corresponding drying parameters for different drying stages, thereby improving drying efficiency; in addition, electron beam irradiation will destroy the cell structure of spices, and the cell wall becomes thinner, More loose or broken, the water in the cells is easier to diffuse outward, and the amount of free water increases. At the same time, the high-energy electron beam will have a certain decomposition effect on the chemical bonds between the substances in the spices, and the tight or stable structure formed by water and other molecules will be produced. Splitting or loosening makes it easier for internal moisture to diffuse outward, thereby improving the efficiency of hot air drying and reducing energy consumption in production.

In general, the present invention utilizes high-energy electron beams combined with atmospheric pressure hot air drying to control the microorganisms of dehydrated spices, effectively reducing the radiation dose of the product, improving the efficiency of hot air drying, shortening the drying time, and reducing production energy consumption, thereby ensuring After drying, the quality of dehydrated spices is controlled, and the number of microorganisms in the final product is controlled so that it is within a safe range.

Description of drawings

Fig. 1 Dose distribution diagram of high-energy electron beam treatment of fresh pepper.

Detailed ways

Embodiment 1: the method for the production of dehydrated chili dried by high-energy electron beam combined with hot air drying

Pretreatment of fresh peppers, removal of inclusions and obvious rotten peppers in fresh raw materials, washing with tap water, removing foreign matter such as leaves attached to the surface, and then draining; put the peppers evenly in a metal tray, and spread the peppers on the tray The thickness is controlled to be no more than 8cm, followed by high-energy electron accelerator irradiation treatment. The irradiation technical parameters are the output energy of the electron beam 5MeV, the distance between the high-energy electron beam scanner and the product is 400mm, the scanning frequency is 420pps, and the scanning width is 600mm. The transmission speed of the tray under the scanner beam is 6.2m/min, and the electron beam irradiation dose is controlled at 2.0kGy. Peppers after electron beam irradiation were dried with hot air at atmospheric pressure in three stages. The parameters of the first drying stage were drying temperature of 85±5°C and drying time of 1.5h. The parameters of the second drying stage were drying temperature of 75±5°C and drying time of 3h. , the parameters of the third drying stage are drying temperature 65±5°C, drying time is about 5 hours, and finally dried until the moisture content of the dehydrated chili is below 8%. After testing the microorganisms in the dried dehydrated peppers, the total number of colonies is 480CFU·g ^-1 , mold and yeast are 36CFU·g ^-1 , coliforms are less than 3.0MPN·g ^-1 , and the moisture content is 7.2% (wet basis).

Embodiment 2: the method for the production of dehydrated black pepper of high-energy electron beam combined with hot air drying

Pretreatment of fresh black pepper, pick out the inclusions in the fresh black pepper raw materials, obviously rotten black pepper, wash with tap water, remove foreign matter such as leaves attached to its surface, and then drain; after pretreatment, the fresh black pepper is subjected to high-energy electronic Beam irradiation treatment, put the black pepper evenly into the metal tray, and the black pepper is laid in the tray to control the thickness of about 5cm; after that, the high-energy electron accelerator irradiation treatment is carried out. The irradiation technical parameters are that the output energy of the electron beam is 10MeV, and the high-energy electron The distance between the beam scanner and the product is 450mm, the scanning frequency is 200pps, and the scanning width is 600mm. The transmission speed of the raw material tray under the scanner beam is 5.0m/min, and the electron beam irradiation dose is controlled at 3.0kGy. The black pepper grains after electron beam irradiation were dried with hot air at atmospheric pressure in three stages. The parameters of the first drying stage were drying temperature 95±5°C and drying time 1 h. The parameters of the second drying stage were drying temperature 75±5°C and drying time was 4h, the parameters of the third drying stage are drying temperature 65±5℃, drying time about 4h, and finally drying until the moisture content of the dehydrated black peppercorns is below 8%. By detecting the microorganisms of dehydrated black peppercorns after drying, the total number of colonies is 370CFU·g ^-1 , mold and yeast are 12CFU·g ^-1 , coliforms are less than 3.0MPN·g ^-1 , and the moisture content is 6.3% (wet basis) .

Embodiment 3: the method for producing dehydrated Zanthoxylum bungeanum grains by high-energy electron beam combined with hot air drying

Pretreatment of fresh peppercorns, picking out the inclusions in the fresh peppercorns raw materials, washing them with tap water, removing foreign matter such as leaves attached to the surface, and then draining. After pretreatment, the fresh peppercorns are irradiated with high-energy electron beams, and the peppercorns are evenly placed in a metal tray. The thickness of the peppercorns laid in the tray does not exceed 7cm; The output energy of the beam is 8MeV, the distance between the high-energy electron beam scanner and the product is 520mm, the scanning frequency is 390pps, the scanning width is 600mm, the transmission speed of the tray under the scanner is 5.6m/min, and the electron beam irradiation dose is controlled at 2.5kGy . After electron beam irradiation, the Zanthoxylum bungeanum grains were dried in three stages of normal pressure hot air. The parameters of the first drying stage were drying temperature 90±5°C and drying time 1h. The parameters of the second drying stage were drying temperature 75±5°C and drying time 5h. , the parameters of the third drying stage are drying temperature 65±5°C, drying time about 3 hours, and finally drying until the moisture content of the dehydrated Zanthoxylum bungeanum is below 8%. By detecting the microorganisms of dehydrated peppercorns after drying, the total number of colonies is 420CFU·g ^-1 , mold and yeast are 23CFU·g ^-1 , coliforms are less than 3.0MPN·g ^-1 , and the moisture content is 6.5% (wet basis).

Claims (2)

1. high-power electron beam controls the processing method of microorganism for dehydration spice in conjunction with heated-air drying, it is characterized in that the main process processed is: fresh spice raw material is selected, clean, drain, high-energy electron beam irradiation, segmented convective airflow drying;

(1) pretreatment of raw material: reject foreign matter and the raw material that obviously rots in fresh spice raw material, drain with after running water cleaning;

(2) high-power electron beam process: the spice after draining, evenly put into metal tray, according to different spice kind proportion, be laid in pallet Raw THICKNESS CONTROL at 5-8cm, high-energy electron beam irradiation treatment technology parameter: the output energy of electron beam is 5-10MeV, the distance of high-energy electron beam scanning device and product is 400-520mm, scan frequency is 200-420pps, sweep length 600mm, pallet is 5.0-6.2m/min in scanner bundle underdrive speed, and electron beam irradiation dosage controls at 2-3kGy;

(3) segmented convective airflow drying: heated-air drying in three stages: the first drying stage: baking temperature 80-100 DEG C, drying time 1-1.5h; Second drying stage: baking temperature 70-80 DEG C, drying time 3-5h; 3rd drying stage: baking temperature 60-70 DEG C, drying time, 3-5h, was finally dried to wet basis moisture content less than 8% in dehydration spice.

2. high-power electron beam according to claim 1 controls the processing method of the microorganism of dehydration spice in conjunction with heated-air drying, it is characterized in that raw material is common fresh spice.