What is the impact of new food processing technologies on food nutrition?

Impact of microwave technology on food nutrition

In food processing, microwave processing technology is widely used, and common microwave technologies include microwave heating and drying, microwave sterilization, microwave baking and so on.

Microwave technology can affect the molecular density and molecular structure of food, which in turn affects the taste and impact of food. Microwave technology also affects the stability of fat. The treatment of cow’s milk by microwave technology does not show significant changes in fat content, but the diameter of the fat globules is reduced by the effect of decomposition. Smaller fat globules increase the surface area of the overall fat, which in turn increases the specific gravity, leading to reduced buoyancy and affecting fat separation. Microwave heating technology increases the amount of phospholipid loss, and proteins and carbohydrates can combine with phospholipids to form complexes.

It can be seen that in the processing of oil and fat food, should be reasonable application of microwave processing technology, the heating time is strictly controlled, generally controlled within 15min, the nutrient content of the food will be reduced with the prolongation of microwave heating time.

In the heating treatment of soybean food, the content of oleic acid and fatty acids will increase, improving the flavor and texture of food. Under the action of weaker microwaves, small molecules such as glucose will gradually melt, and under the action of stronger microwaves, Melad reaction, pasteurization, coking, etc. may occur, resulting in changes in molecular structure. Treating starch with microwave heating treatment technology affects the moisture in the starch, which in turn destroys the hydrogen bonds in the starch.

Compared with traditional food processing treatment, microwave technology can save more time, reduce the impact on vitamins, achieve the purpose of protecting vitamins, and enhance the nutritional value of the treated food. In the chicken, pork and other animal liver contains a lot of vitamin B. Microwave technology can protect the vitamin B in the food to a certain extent, to avoid excessive loss of nutrients in the food. Vegetable oil contains a large amount of vitamin E. Treating vegetable oil with microwave technology will consume a large amount of vitamin E, but will not affect the total amount of unsaturated oil.

Vitamin C is one of the very important elements in human life activities, and the vitamin has strong reducing properties. When food is conventionally processed, the vitamin C content is reduced considerably and the food also loses a lot of water. Compared with the traditional heating means, the loss of vitamin C after microwave heating treatment is lower. Vitamin C has a strong heat sensitivity, in order to avoid excessive loss of vitamin C in food, when using microwave treatment of food should be a reasonable choice of containers, avoid the use of metal utensils with good thermal conductivity, as far as possible to retain the vitamin C in the food, preserving the original nutrition of the food.

Non-heating Sterilization Technology

Influence on food nutrition

2.1 Influence of biological antiseptic sterilization technology on food nutritional quality
The nutritional quality of food will be directly affected by biological antiseptic sterilization technology. Biological antiseptic sterilization technology, mainly through the influence of biological metabolites to achieve the purpose of inhibiting the growth and reproduction of microorganisms, and kill microorganisms. The raw materials used more often in the preparation of microbial preservatives are natural agricultural products.

After a long period of accumulated research experience, it can be seen that many biological preservatives are microbial metabolism produced by some antimicrobial substances, which will have an effect on the cell membrane and inhibit the growth of microorganisms. These biological preservatives will not affect human health, heat treatment can gradually decompose these substances, and will not affect the human digestive flora.

The nutritional value of the food and its components are not affected by natamycin during the biopreservative sterilization process. For example, in the sterilization treatment of loquat fruit can be processed using lactic acid streptococcus lactis, the technology can reduce the rate of weight loss and total acid content of food, to avoid excessive impact on food nutrition. The shelf life of food after biological antiseptic sterilization treatment has been effectively extended, antiseptic sterilization treatment can also avoid excessive loss of food nutrients [1].

2.2 Impact of pulsed intense light sterilization technology on food nutritional quality
In the sterilization process, microorganisms on the surface of transparent liquids or solids will be killed under the stimulation of pulse flash. Pulse light sterilization technology will have a greater impact on the proteins and nucleic acids in food, food proteins will be deformed under the influence of pulse light, if the irradiation time is longer, it will also gradually destroy the organic molecules in the food, which will have an impact on the food that is richer in fat content.

In addition, the use of pulsed light sterilization technology in milk sterilization needs to be strictly controlled time, should try to shorten the sterilization time, in order to ensure that the sterilization effect at the same time, to avoid the impact on the fat and protein in milk.

Membrane separation technology

The technology mainly uses the principle of osmosis to deal with food, a certain or a certain type of material in the mixture will be separated under the permeation effect of the membrane body. The current common membrane body is mainly semi-permeable membrane, nano membrane, ultrafiltration membrane and so on. On both sides of the membrane, the pressure difference or potential difference is large, which prompts the molecules to flow from the high pressure or high potential region to the low pressure or low potential region, so as to realize the effective separation of the mixture.

Membrane separation technology has been widely used in many aspects, such as common water treatment, industrial separation, food fermentation and so on, by virtue of the advantages of low energy consumption, no pollution, simple operation and so on. Currently ultrafiltration, microfiltration, reverse osmosis, dialysis and electrodialysis are common membrane separation technology. In the food industry, membrane separation technology is widely used in fruit and vegetable juice clarification.

Studies have shown that membrane separation technology can play a good effect in removing pectin, soluble cellulose, protein ketones and other macromolecules in fruit and vegetable juice [2]. In the process of continuous development, the clarification of fruit and vegetable juice will be more and more widely used membrane separation technology, and the technology will not affect the vitamins, minerals and other small molecules in fruit and vegetable juice.

Zeng Fankun and others once reported that the vitamins in fruit and vegetable juices treated with ultrafiltration technology can pass through the membrane better, with a transmission rate of more than 86%, and the mineral elements also have a high transmission rate, in which the average values of the transmission rates of potassium, calcium, magnesium and phosphorus are more than 99%, 85% and 90%, respectively, and the average rate of transmission after ultrafiltration is more than 99% [3].

In addition, the membrane separation technology can also play a good role in the treatment of harmful bacteria in liquid food. Because the membrane separation technology used in the membrane are molecular level, microbial diameter is large, can not pass through the membrane, and then can realize the separation of microorganisms. In milk sterilization, drinking water sterilization and other treatments can make full use of membrane separation technology for microbial filtration.

However, membrane technology also has some shortcomings, such as small molecular diameter is easy to block the membrane body, which increases the separation pressure, and even membrane rupture. Another example is that this technology requires more investment, which makes it impossible to be effectively promoted.

Ultra-high pressure technology

Ultra-high pressure technology is in the liquid medium into the food, and then the use of hydrostatic pressure or ultra-high pressure for pressurized treatment, inactivation of food enzymes, proteins and other macromolecular substances, currently in the field of food sterilization has a relatively wide range of applications.

Ultra-high-pressure sterilization technology can kill most of the microorganisms at lower temperatures, even if the killing of spores and mold spores, the actual action of the temperature and time is much lower than the traditional ultra-high-temperature sterilization technology, the principle of physical pressurization for small molecules, such as vitamins, minerals, amino acids, small molecules of sugar, pigments and organic acids aroma components, etc., without the slightest impact on the composition of food and fiber structure of the impact is also limited, can greatly retain the food and the structure of the food. Limited, can greatly retain the original flavor, color, crispness and toughness of food. Therefore, the use of high-pressure treatment of a wide range of food, both liquid food and solid food, fresh food in the eggs, meat, fruit, milk and natural fruit juices, etc.; fermented foods in the pickles, jams, beer, etc. can be processed using high-pressure technology [4-5].

Conclusion

At the same time as the national standard of living continues to improve, the food nutrition, taste, safety and other aspects of the higher requirements, the food processing industry is also facing more challenges. In food processing, many new technologies are beginning to be popularized and applied to make food processing more professional and safe. In food processing, operators need to fully analyze the food characteristics and processing requirements, according to the actual needs of reasonable choice of processing technology, reduce the impact of processing technology on food nutrition, so as to ensure food quality and safety.
References:
[1] Guo Yanting, Huang Xue, Chen Man, et al. Application of ultra-micro pulverization technology in food processing[J]. Journal of Zhongkai Agricultural Engineering College, 2017, 30(3):60-64.
[2] Zhang MY, Liu YQ. Membrane separation technology and its application in food industry[J]. Modern Food, 2018(2):136-138.
[3] Zeng Fankun, Hu Xiufang, Wu Yongxian. Effect of ultrafiltration on the quality of several fruit and vegetable juices[J]. Food and Fermentation Industry, 1999(2):33-36.
[4] Ren Tingting. Practice of ultrahigh pressure technology in fermented food processing technology[J]. Modern Food, 2017(6):12-13, 16.
[5] Wang B, Long Xiu. Application of new freezing and concentration equipment in the teaching of food processing technology[J]. Guangdong vocational and technical education and research, 2017(1):92-95.