Application of ultraclave technology in the food industry

  1. Application of ultra-autoclave technology in meat processing

  (1) The sterilization effect of ultra-autoclave technology

  Meat is a very popular category of culinary food, whether it is red meat or white meat, meat is rich in nutrients. Ultra-high pressure technology is aimed at meat processing operations, mainly focusing on sterilization and tenderization.

  Ultra-high pressure sterilization technology is a relatively gentle means to improve food safety, which can be used to prevent secondary contamination of cooked meat products, such as: roast chicken, sausages, ham, tenderloin, fermented sausages, cured meat products and raw raw meat, etc. On the one hand, the means of sterilization is to destroy its physical structure and kill microorganisms, and Qiu Weifen et al. believe that the principle of sterilization is to affect DNA through pressure and other genetic material replication, which in turn affects a series of microbial physiological activities (inhibition of enzyme activity) ** death.

  Xiao Huazhi et al. found that ultra-high pressure technology can effectively eliminate Escherichia coli, Staphylococcus aureus and Bacillus subtilis in raw pork, which is 20 minutes under 600MPa pressure Sterilization effect during treatment**.

  Fu Yuying et al. also used pork as a carrier to prove that ultra-high pressure sterilization technology has an inhibitory effect on bacteria, and the results showed that gram-negative bacteria and yeast were at 400MPa When the pressure rises to 600 Mpa, Gram-positive bacteria will be deadly; In the case of spore-like bacteria, more pressure is used.

  However, Duan Xuchang et al. found that Gram-positive bacteria have a strong survival ability and a large number of residual bacteria after sterilization.

  In addition, Lerasle et al. believe that UHV sterilization technology can be used as an alternative to chemical preservatives, such as lactate added to food.

  (2) Other functions of ultra-autoclave technology

  In addition to sterilization applications, UHP technology can also be used to tenderize, change muscle gelability, and change the quality and color of meat. The study found that after pressure treatment, the bright red color of the meat weakened or enhanced, and the overall brightness brightened. The key substance that determines the color intensity of meat is myoglobin content, which changes color with changes in the ratio of myoglobin and oxymyoglobin. High pressure can improve flesh color, but it must be within a suitable range.

  Ma Hanjun et al. showed that the brightness L* value increased and the chromaticity a* value decreased with the increase of pressure. In terms of tenderness, * predates 1973 Macfarlane** proposed that beef will increase tenderness under high pressure.

  Chang Haijun proved through experiments that ultra-high pressure will cause the shear force of the bovine semi-tendon muscle to gradually decrease, and when the ultra-high pressure treatment time reaches 20 minutes, the tendering effect is ***.

  Bai Yanhong concluded that it was the same as the above, the difference was that her experimental raw materials were beef and mutton.

  2. The application of ultra-high pressure technology in fruit and vegetable products

  Ultra-high pressure technology has great advantages in the processing of fruit and vegetable products. At present, countries such as Japan and the United States have commercialized ultra-high pressure jam and juice products on the market. Xu Xiuju and others carried out 200~500 canned Hualai persimmons The results of ultra-high pressure treatment of MPa showed that the retention rate of vitamin C could reach more than 95%, which was much higher than that of conventional thermal processing food processing technology.

  At present, the tomato juice sold on the market is lost due to heat treatment, and Zhao Bin et al. treated tomato juice at the level of 400 MPa15 min, its vitamin C retention rate is about 93.6%, and lycopene retention rate is about 95.4%.

  Zeng Qingmei et al. studied the effects of different levels of ultra-high pressure on the oxidative activity of pear juice polyphenols, and the results showed that with the increase of pressure, the oxidative activity of pear juice polyphenols increased first and then decreased, when the pressure was 500 MPa, the oxidative activity of polyphenols decreased to 73%.

  Rodrigo et al. found that the lipooxidase in potatoes also increases first and then decreases with the increase of pressure, which can be found at 500 pressure MPa is completely inactive, and the inactivation of lip oxidase will inhibit the oxidation of fat during food processing and storage, and reduce the formation of undesirable flavors.

  It is generally believed that the degradation of chlorophyll is the root cause of its color degradation during the processing of vegetables. He Yiwen et al. systematically studied the chlorophyll retention rate in kiwifruit juice under different holding pressures, times and temperatures, and the results showed that the retention of chlorophyll was positively correlated with the retention of chlorophyll at 350 At MPa and above, the retention rate of chlorophyll can reach more than 76%, which may be related to the enzymatic reaction that inactivates the color change.

  Liu et al. compared the advantages and disadvantages of ultra-high pressure (600 MPa/10 min) and high-temperature short-term sterilization (110 °C/8.6 s) in carrot juice processing,2 The total amount of carotene under ultra-high pressure treatment was higher than that of high-temperature short-term sterilization, which was better than high-temperature short-term sterilization in terms of total phenol retention and weakening of browning.

  The impact of ultra-high pressure technology on the shelf life of fruit and vegetable products is the focus of attention of fruit and vegetable processing enterprises, mainly focusing on the microbiological safety and storage time of products.

  Jiang Bin et al. studied the effects of ultra-high pressure treatment on freshly squeezed apple juice and freshly squeezed carrot juice, which could be stored at 4 °C after 15 min of high-pressure 400 MPa treatment7 Sky; After 400 MPa and 45 min ultra-high pressure treatment, the storage characteristics of freshly squeezed carrot juice were poor, and it could be stored at 4 °C*3 Sky. This may be related to the pH of the two, apple juice has a pH of 3.79 and carrot juice has a pH of 6.59, indicating that ultra-high pressure technology has a greater advantage in acidic fruit and vegetable products.

  3. Application of ultra-autoclave technology in aquatic products

  (1) The sterilization effect of ultra-autoclave technology on aquatic products

  Extending the shelf life of aquatic products is a necessary basis for expanding sales, and the application of ultra-high pressure technology in aquatic products also provides more possibilities for the development of this industry. OHSHIMA* has long applied ultra-autoclave technology to aquatic products, and he treats tuna with a parameter of 450 MPa, 15 min, but it did not meet the commercial sterility standard after treatment, so storage and transportation still had to be refrigerated.

  Karim et al. used this technique to process herring (400MPa, 15 min, 7°C) and extended the shelf life by 13 days.

  Erkan et al. treated red bonito (300 MPa, 5 min, 4°C) and extended the shelf life by 3 days.

  Ojagh et al. Treatment Salmon (300 MPa, 10 min) The shelf life was extended by 13 days at 7°C with gelatin lignin film. According to a large number of data, when the ultra-high pressure pressure reaches 300MPa and above, most microorganisms in aquatic products at room temperature will be dead. In contrast, it is at 300 MPa Below, the time is less than 3 minutes, and it basically has no effect on microorganisms.

  (2) The application of ultra-autoclave technology to the shelling of aquatic products

  Compared with traditional operation methods, it effectively improves work efficiency, improves production rate, reduces working time, and saves labor, which is one of the most popular shelling methods at present, and is also a technology suitable for industrial and efficient shelling. After ultra-high pressure treatment, the tertiary structure of shellfish is changed, and its adhesin is denatured, which directly detaches the shell meat and other shell meat.

  Wang Min used this technology to process mussels (300MPa, 2min), the mussels were completely shelled, and the shellfish meat was intact, and the quality was **; When the conditions changed (400MPa, 5min), it was found that the texture characteristics of shellfish meat changed significantly, and the chewiness, elasticity and hardness were improved.

  Jia Ying et al. concluded from the experiment that shrimp were shelled at 350-400MPa for 8 minutes The effect is **, compared with the traditional shelling technology, the delay time and production rate are ****, and the frightening color after treatment is bright, the color is tender white, and the water holding effect is good. It can be seen that ultra-high pressure technology has great development prospects in the application of aquatic products.

  Although there are still some shortcomings in the practical application of ultra-autoclave preservation technology, its advantages in food processing are still irreplaceable by other technologies. With the further deepening of the development, research and application of ultra-high voltage technology, its cost will continue to decrease, the problem of continuous production will be gradually solved, and its application in the food industry will be more **.