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Tea polyphenol (Teapolyphenol, TP), with strong reducibility, can effectively scavenge free radicals, which contains natural fresh-keeping ingredients, can be used for food preservation, can inhibit the occurrence of putrefaction during food storage, prolong the storage period, and can be used as a good natural food preservative. In addition, it also has the effect of removing reactive oxygen species, chelating cations, combining oxidase; at the same time, it has the effect of antibacterial sterilization, which can effectively protect various nutrients of food, and has good application and broad development prospects in the food industry and other industries.
<h1 class="pgc-h-arrow-right" data-track="7" > the preservation mechanism of tea polyphenols in food</h1>
<h1 class="pgc-h-arrow-right" data-track="69">01</h1>
<h1 class="pgc-h-arrow-right" data-track="70" > antioxidant properties of tea polyphenols</h1>
Tea polyphenols have antioxidant properties and can prolong the storage time of food. At present, the preservation mechanism of tea polyphenols in food has not been uniformly concluded, and it is summarized as follows through a large number of literature consultations:
(1) The inhibition of tea polyphenols on oxidase directly inactivates the enzyme, the essence of the enzyme is protein, and the content of oxidase in the body decreases through complexation;
(2) Tea polyphenols hinder the production pathway of oxidase, which can inhibit the production of oxidase at the molecular level such as transcription and translation, affecting its activity;
(3) The vast majority of transition metal ions in the body are isolated electrons, which are free electrons, which can catalyze the formation of free radicals. Tea polyphenols can provide isolated electron binding of electrons to transition metals, which reduces the activity of free radicals in the body;
(4) Tea polyphenols will bind with free radicals to form a relatively stable phenolic oxygen free radical state, and the free radical content will decrease to prevent damage to the body;
(5) Tea polyphenols can not only directly scavenge free radicals, but also activate the body's own antioxidant mechanism, so as to achieve the effect of scavenging free radicals.
<h1 class="pgc-h-arrow-right" data-track="71">02</h1>
<h1 class="pgc-h-arrow-right" data-track="72" > the bacteriostatic properties of tea polyphenols</h1>
(1) Tea polyphenols can coagulate bacterial proteins, thereby inhibiting the growth of bacteria; at this time, the oxidation rate of oils and fats is minimized, which can effectively scavenge free radicals. Interferes with the metabolism of microorganisms and delays the decay and deterioration of food.
(2) Tea polyphenols combine with genetic factors in bacteria to break the membrane structure, and then gradually dissolve the complete pseudomonas cell wall, so as to achieve the purpose of bacteriostaticism.
<h1 class="pgc-h-arrow-right" data-track="73" > the preservation of tea polyphenols in food</h1>
Because of its excellent antioxidant capacity, broad-spectrum sterilization properties and its high safety, tea polyphenols have been widely used in the preservation of many high-fat foods. Relevant studies have shown that the compound use of tea polyphenols with other preservatives can not only enhance the bacteriostatic spectrum of tea polyphenols, play the role of preservatives, but also reduce their cost and use, and enhance the preservation effect.
<h1 class="pgc-h-arrow-right" data-track="74">1 tea polyphenols for the preservation of pork products</h1>
When animals are slaughtered, fresh meat and carcasses are contaminated with microorganisms, and fresh meat quickly deteriorates. Due to the high safety and nutritional value of cooled meat, it has become a meat consumption trend. The enzymes in meat, the role of microorganisms and the decomposition of proteins in meat, and the oxidation of fat are the main reasons that affect the storage period of meat products, and also affect the quality and edible value of meat, restricting the development of the meat industry. Yang Xinlei et al. studied the effect of tea polyphenols with different mass fractions on the preservation of cooled pork under low temperature storage. The results show that the tea polyphenol treatment can slow down the growth rate of microorganisms in the cooled meat, significantly control the oxidation of lipids, delay the increase of TVB-N, maintain its good edible quality for a long period of time, and prolong its shelf life. Han Xinfeng et al. studied the effect of tea polyphenols on the quality change of refrigerated meat products, and the results showed that tea polyphenols can effectively inhibit microbial growth and reproduction and scavenging free radicals. It can be seen that tea polyphenols have a good antioxidant and bacteriostatic effect on meat products, which can slow down the growth rate of amines and prolong the shelf life of cooled meat products. Within a certain concentration range, the higher the volume fraction of tea polyphenols in the preservation liquid, the greater the inhibition effect on microorganisms in refrigerated meat products, which can be well applied to the preservation of meat products.
<h1 class="pgc-h-arrow-right" data-track="75" >2 tea polyphenols for fish preservation</h1>
Fish products are rich in nutrients, microorganisms are easy to breed, resulting in spoilage and deterioration; secondly, fish products contain unsaturated fatty acids, which are easily destroyed under light and heat conditions, and gradually generate aldehydes and ketones, resulting in qualitative change of fish products. Li Haiyan et al. used tea polyphenols for the processing of grilled catfish to study their effects on fat oxidation. Ju Jian et al. used fresh sea bass as raw materials to study the effects of different concentrations of tea polyphenols on TBA, TVB-N and other indicators in the refrigeration process of sea bass. The results show that tea polyphenols not only play a good role in preserving catfish and perch, but also play a good role in the preservation of grass carp. Ouyang Tao et al. measured the changes of grass carp in the refrigeration process, treated the fresh grass carp, and soaked them in 5 tea polyphenol solutions of different concentrations. The results showed that soaking could significantly reduce the TVB-N content, slow down the rate of sensory quality decline, and inhibit the reproduction of microorganisms. The above studies have shown that tea polyphenols have a good preservation effect on fish products and delay the spoilage of fish. Fish products are easy to spoil, frozen storage method is easy to denature protein, modified atmosphere storage is not easy to store and transport. The application of tea polyphenols as natural preservatives to fish products shows strong freshness preservation ability.
<h1 class="pgc-h-arrow-right" data-track="76" >3 tea polyphenol compound preservatives for the preservation of surimi products</h1>
Surimi products are favored by consumers because of their rich nutritional content and low price advantages. However, surimi products have high moisture and rich nutrients, and are very susceptible to microbial contamination and spoilage, which seriously restricts the development of the surimi industry. In addition, at present, surimi products mainly rely on cold chain (-18 °C) transportation, long-term freezing greatly reduces the elasticity of fish balls and other sensory qualities, and increases the transportation cost, energy consumption is larger. Therefore, the combination of biotechnology and cold chain transportation is an important link in promoting the development of the surimi industry. Bi Haidan et al. studied the effect of tea polyphenols and whey protein addition on the preservation effect of refrigerated surimi, and studied the effects of tea polyphenols and whey protein on the oxidation and quality of refrigerated surimi by measuring the changes of total thiol content, TBA, POV, TVB-N, moisture content and gel strength by using grass carp surimi as the experimental raw material. The results show that the addition of tea polyphenols can significantly inhibit the oxidation of proteins and fats, and the preservatives of tea polyphenols and whey protein are applied to the production of surimi products in synergistically, which is more conducive to improving the preservation effect of surimi products.
<h1 class="pgc-h-arrow-right" data-track="77" >4 tea polyphenol compound preservatives for the preservation of fruits and vegetables</h1>
(Angen team excerpted from Guan Zhenxin et al.: Research progress on the application of tea polyphenols in food preservation)
The Angen team, more than 20 agricultural experts in various fields, provide mature soil restoration integration programs, ecological remediation integration solutions, pesticide residue solutions and ecological agriculture socialization services.