Gıda Matrisi ve Mikroplastik Etkileşiminin İncelenmesi

Abstract

Plastic production has multiplied over the last years and reached 57.9 million tonnes in Europe and 368 million tonnes in World in 2019. Plastic polymers are used in wide areas including packaging, agriculture, household etc. Among plastic particles, less than 5 mm are considerable as microplastic (MP). Nowadays, microplastic pollution has been found in the atmosphere, oceans, lakes, agricultural soils, and foods and beverage like mussels, canned fish, salt, packaged meats, and bottled water. Due to microplastics present in foods, they can be consumed via diet and this situation create a threat to human heath. As a result, microplastics cause inflammation, cytotoxicity, accumulation in organs, and induce reactive oxygen species have been observed. In biological solutions that contian proteins, some proteins in the soluttion cover the particle surface or a part of it and a structure called “protein corona” is formed. The resulting protein corona structure affects many properteies of the particle, including its toxicity. In this thesis, it is aimed to examine the interaction of polystyrene microplastic (PSMP) with real food environment and to investigate the changes in the corona structure of digestion. As a result of the studies, it was determined that there was no significant change in the hydrodynamic diameters of PSMPs interacted with fat and skim milk samples, but their ζ-potentials decreased. It has been observed that the protein corona structure dormed on the particle surface mostly contains α and β-casein fractions found in milk. In the second stage of the study, in-vitro digestion simulation was applied to PSMPs and PSMPs interacted with milk samples and the ffect of digestion on particle properties and corona structure was investigated. It was observed that the protein corona structure of PSMPs interacted with milk samples and exposed to digestion was thinned. It has also been observed that the particles bind enzymes in the digestive juices during digestion. It has been shown that PSMPs not interacted with milk form a corona structure during digestion and continue to increase until the end of digestion.

At the final stage of study, the toxic effect of PSMPs interacted and not interacted with milk on Caco-2 cell before and after digestion were investigated. As a result of cytotoxicity analysis, it was observed that the protein corona structure did not have an effect on cell viability. Although it was observed that particles with a corona structure reduced the formation of reactive oxygen species, this diffrence was not statistically significant.

At the end of this study, it has been shown that PSMPs form protein corona structure as a result of their interaction with real food environment. It has also been shown that this formed corona structure changes throughout the digestion simulation. PSMP samples did not affect cell viability on Caco-2 cells. However, it was determined that the formed corona strucutre and in-vitro digestion simulation had no effect on the cytotoxicity of the particles. In this thesis, fort he first time, the interaction of polystyrene microplastic, which is one of the microplastics that are increasingly polluted in the World and starting to be found in our food, with real food and the effects of this interaction on characteristics of the particles were investigated.