INFLUENCE OF PACKAGING ON COSMETIC EMULSION DURING STORAGE 249 relationships were evaluated using the coeffi cient of determination (R2). The data analysis was carried out using Unscrambler 7.0 (CAMO, Oslo, Norway) software. Differences between the color parameters of the fresh and stored samples were evaluated by using the least signifi cant difference (LSD) test at α = 0.05. RESULTS AND DISCUSSION In the present study, the infl uence of packaging on cosmetic creams stored in different conditions was monitored by FT-NIR spectroscopy and L*a*b* color measurements. Average FT-NIR spectra of fresh samples and samples stored at refrigerated conditions for 2 and 4 mo and their fi rst derivatives are presented in Figures 1 and 2. No visible changes were observed in the FT-NIR spectra without data processing for samples stored in different packagings both in the cold (Figure 1A) and at room temperature for 2 mo (Figure 2A). Some differences were observed between the fi rst derivative of the FT-NIR spectra of samples stored for 2 mo at refrigerated conditions in SAN jars as compared with other samples (Figure 1A). After 4 mo, a decrease in the intensity of bands at about 7,170 and 5,310 cm-1 was observed for all samples as compared with samples of fresh cream (Figures 1B and 2B). It is especially visible for samples stored at room temperature in glass jars (Figure 2B). These bands could be associated with the content of water. A strong water absorption band exists at about 1,450 nm (6,900 cm-1 OH vibration of water) and at 1,940 nm (5,155 cm-1 a combination band involving OH stretching and OH deformation) (14). In contrast to other packagings used in the present study, glass jar had packaging without thermos or an additional spacer between the nut and the content of the jar. This could be the reason for the most visible changes in the content of water in the samples stored in this packaging. PCA was performed on FT-NIR spectra to visualize the changes in cream samples during storage. The PCA results of the FT-NIR spectra of cosmetic emulsions stored in the cold and at room temperature for 2 and 4 mo are presented in Figure 3. The effect of time on cream samples stored in Al/PP, Ac/PP, G, PP, and SAN jars was observed separate groups were formed by fresh samples (F) and samples stored for 2 and 4 mo. The fi rst two principal components (PC1 and PC2) described 98% of the total data variance of samples stored both in the refrigerated conditions and at room temperature (Figure 3). The fi rst principal component PC1 that explained 94% (samples stored in the cold) and 92% (samples stored at room temperature) of the total data variance was linked to the time of storage. It differentiated samples stored for 4 mo from fresh samples (F) and those stored for 2 mo. The PC2 explained 4% and 6% of the total data variance of samples stored in the cold and at room temperature, respectively. It was related to the variability due to the type of samples (fresh and stored samples). It was found that the changes in samples stored in the cold for 2 mo were similar for all applied packaging materials as compared with fresh samples (F), although samples in SAN jars formed a separate group (Figure 3A). After 4 mo, a separate group was formed by samples stored in glass (G) jars. For samples stored at room temperature, the infl uence of packaging materials on cosmetic emulsions was observed just after 2 mo of storage (Figure 3B). The smallest changes in the FT-NIR spectrum of a cream as compared with the fresh one (F) were observed for samples stored in Al/PP. The changes for other packaging

JOURNAL OF COSMETIC SCIENCE 250 materials were similar. Four-month storage resulted in the formation of four groups: Al/ PP plus PP, SAN, Ac, and G. As it was observed after direct analysis of the FT-NIR spec- tra, the differences between fresh cream and samples stored at room temperature in glass jars were the most clear. It cannot be excluded that the most visible effect of glass on overall changes in cream samples as compared with fresh samples is due to different structure and properties of glass from those of polymer materials used as packagings in the present study they formed one group. Moreover, glass jars were packaging without additional thermos or a protecting spacer. Storage of cosmetics in different packagings may infl uence the color of products. Therefore, in the present study, color parameters of stored samples were also measured. The results of L*a*b* color measurements and total color differences (ΔE*ab) of stored samples as compared with the fresh ones are presented in Tables II and III. A slight increase in Figure 1. FT-NIR spectra and their fi rst derivatives (inside) of fresh cream (F) and other samples stored in refrigerated conditions for (A) 2 mo and (B) 4 mo.