Anotace:
Phthalic acid esters are plasticizers, they can migrate freely from plastic to their surroundings. They have negative health effects. European legislation sets specific migration limits for phthalic acid esters. In our study, we deal with two esters of phthalic acid, dibutylphtalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP). It was studied the effect of storage of four types of yoghurt on the concentration of phthalic acid esters. Yoghurts contained 1% chia flour, 5% chia flour, 1% bamboo fiber and 5% bamboo fiber. Yoghurts were stored in plastic cups, which contained both examined phthalic acid esters. Esters of phthalic acid were determined after 1 week of storage then after 2 weeks of storage and in the original raw material. Furthermore, the pH of the yoghurt was determined. The pH values were correlated with phthalate concentrations: the correlation coefficient for DBP with a pH of -0.0265 and for DEHP with a pH of 0.3075. Mean concentrations of DEHP decreased over time, while DBP decreased for yoghurt with 1% chia flour, while in other cases they increased. The mean DBP concentrations in yoghurt were higher than the average concentrations of DEHP. Comparing the mean sample values with t-test for dependent samples for yoghurt of the same type, when comparing the DBP or DEHP concentration in week 1 with the DBP or DEHP concentration at week 2, the mean values were consistent. It can be noted that there was no increase in DEHP concentrations from cups to yoghurts, which was probably due to a lower concentration in cups than the DBP concentration. DBP concentrations increased in 3 of the 4 types of yoghurt. The determined pH in yoghurts did not differ significantly. Apparently a greater effect on the migration of phthalic acid esters will have in our case a different yoghurt consistency than pH. It would be appropriate to examine the effect of food density on the migration of phthalic acid esters. Likewise, it would be appropriate to examine the effect of pH but in the same food with different pH on the migration of phthalic acid esters.