INFLUENCE OF PACKAGING ON COSMETIC EMULSION DURING STORAGE 251 L* values of samples stored in the cold as compared with that of fresh cosmetic cream was observed, whereas lightness of samples stored at room temperature decreased. The value of a* and b* was not signifi cantly changed in the case of samples stored in refrigerated conditions. For samples stored at room temperature for 4 mo, a* value slightly shifted to redness. It was especially visible for G samples (a* changed from -2.73 to -1.98). A slight increase in b* values was also observed for all samples in all packagings (cream became more yellow) with an exception of SAN samples. Taking into account the values of ΔE*ab, no visual changes in color of all samples stored in the cold for 2 mo were detected (ΔE*ab from 0.05 to 0.16). After 4 mo of storage, the color difference between fresh and stored samples could be defi ned as unnoticeable (for Al/PP Ac/PP, and G) or slightly noticeable (PP and SAN). For samples stored at room temperature, the color difference between fresh and stored sample was slightly noticeable (ΔE*ab from 0.86 to 1.19 for 2-mo storage, and from 1.02 to 1.46 for 4-mo storage). The Figure 2. FT-NIR spectra and their fi rst derivatives (inside) of fresh cream (F) and other samples stored at room temperature for (A) 2 mo and (B) 4 mo.

JOURNAL OF COSMETIC SCIENCE 252 Figure 3. PCA of the FT-NIR spectra of cream samples stored for 2 and 4 mo in different packagings (A) in the cold and (B) at room temperature: F, fresh samples Al/PP_2 and Al/PP_4, samples stored in alumnium jars with polypropylene thermos for 2 and 4 mo, respectively Ac/PP_2 and Ac/PP_4, samples stored in acrylic jars with polypropylene thermos for 2 and 4 mo, respectively G_2 and G_4, samples stored in glass jars for 2 and 4 mo, respectively PP_2 and PP_4, samples stored in propylene jars for 2 and 4 mo, respectively and SAN_2 and SAN_4, samples stored in SAN jars for 2 and 4 mo, respectively.