Research Progress of Food Packaging Contaminants (2)

4 Alkylphenols

Alkylphenols are widely used as plastic plasticizers, industrial detergents, agrochemical emulsifiers, finishing agents for the textile industry, and the like, and include: nonylphenols (NP), octylphenols , octylphenol, styrenes, polyvinyl chloride, 4-ethylphenol, o-cresol, phenol, 4-octylphenol, 4-nonylphenol, 2,3,4-tris Chlorophenol, 2,4-dichlorophenol.

In 1938 it was discovered that alkyl phenols have estrogenic activity. It has been reported that taking 4 mg of nonylphenol per kilogram of body weight and 24 hours can damage DNA structure and inhibit uterine peroxidase activity. Alkylphenol as a representative of endocrine disruptors has become a hotspot in environmental toxicology studies. Its toxicity is related to the structure of alkylphenols: tri-branch alkyl>di-branched alkyl>straight chain, para-position>meta> Orthosteric, but also the most difficult to biodegradation. Moreover, the degree of DNA damage has a certain relationship with the chemical structure. Addition of other groups in the phenol ring can increase the mutagenic activity, and with the increase in the number of chlorine atoms in the phenol ring, the mutagenic activity is also enhanced, with the phenol As the number of carbon atoms increases, the mutagenic activity increases.

5 Factors affecting food migration

The main factors influencing the migration of endocrine disruptors from packaging materials to foods are: plasticizer concentration, storage time, storage temperature, food fat content and contact area in packaging materials.

For example, the migration of DEHA in PVC wrappers increased with increasing fat content, storage time, and temperature in pork and beef. DEHA only stays 2cm away from the meat surface in fresh meat, and double-layered PVC wrappers in 5 °C The amount of migration after 3 days of storage was greater than that of single-layer packages. However, after the pork was first wrapped in a single layer of PVC for 2 days and then wrapped in another PVC for 1 day, DEHA had the smallest amount of migration.

DEHA in food packaging plastics is related to the time of exposure to cheese foods, the fat content and moisture content of the food, and the integrity of the cheese. Under the condition of refrigerating at 5±0.5°C, the equilibrium time of DEHA migration to Edam was 100 h, while that of Kefalotyri cheese was 150 h, 240 h did not reach equilibrium when migrating to Roquefort cheese, and refrigerated for 240 h. The DEHA content of the above products was: 222.5 mg/kg (12.2 mg/dm2), 345.4 mg/kg (18.9 mg/dm2), and 133.9 mg/kg (7.3 mg/dm2) in the plastic packaging of the three types of cheese. The DEHA content was reduced by 24.3, 37.8 and 14.6%, respectively. The migration volume obtained in this study has exceeded the EU's maximum migration requirement (10 mg/dm2 or 60 mg/kg). Furthermore, the DEHA is distributed on the contact surface of the cheese and does not exceed the depth of 3.6 mm from the contact surface.

And other ways will also affect the migration, for example, in the beverage water using g-ray instead of conventional heat sterilization, found that with the increase of irradiation intensity, the migration speed of DEHP to the water increased significantly; shake the bottle will increase the migration of DEHP; The freshly made croquette is immediately hot-packed with plastic film, or placed for 5-30 minutes before packaging. The former is 3.5 to 14 times the amount of contaminant migration; the bottled water is almost not detected at the time of bottling. By DMP, DEP, BBP, and DEHP, but after storage in polyethylene bottles for 10 weeks, the total endocrine disruptor content reached 0.681 mg/L (but it did not cause any health risk); even under low temperature storage conditions, there were Contaminants can migrate into foods, especially those with low molecular weight, such as BBP.

6 Degradation

Domestic research has used photodegradation methods to remove bisphenol A from water; Singaporean scholars have established a laboratory-scale microfiltration-reverse osmosis water treatment system to remove bisphenol A in water, but it has not yet reached the industrialized large-scale application. degree.

Algae and microorganisms can be degraded. The degradation rate of DMP by Chlorella 5 d was 66.8%. Fungi cutinase can degrade BBP in frying and oily food packaging films. The degradation rate is 60% after 7.5 h, and the BMP content in the product is 1/107 of esterase degradation products, while BMP oxidizes damaged cells.
An enzyme in cucumber, tomato, and red pepper can degrade DINA, DEHA, di-2-ethylhexyl sebacate, bis-2-ethylhexyl sebacate, and di-2-ethylhexyl twelve Acid esters. The molecular weight of the enzyme is 25 000-45 000 Da. As the maturity of the vegetables and the number of carbons in the plasticizer component increase, the degradation power gradually decreases.

Human food ingredients are those that have already been contaminated (plants, animals, fungi, etc.). Although it has been reported that most of the plants or animals in the body have not yet exceeded this standard, they can safely eat them, but these data are based on the content of raw materials. That's it. As I know, these raw materials still need to be processed before they enter the human body. Then, in a variety of processing processes, such as heating, high pressure, frying, stir-fry and so on, what happens to these compounds? Is it free from the food matrix? Will it react with food components to produce non-toxic or more toxic products? With regard to this process, there is currently no data available and almost no relevant basic data can be found. Research in this field is still a blind spot. In other words, the true content of these contaminants in food before eating is still a problem worth studying.

Source: Print Market Network