INFLUENCE OF PACKAGING ON COSMETIC EMULSION DURING STORAGE 247 overall changes in cosmetic emulsions stored in various packagings and for making the best choice of packaging protecting the original quality of cosmetic products during long-term storage. MATERIALS AND METHODS MATERIALS Moisturizing body creams with shea butter and cocoa, packed in opaque plastic contain- ers, were purchased from a local cosmetic store. They were from the same production batch to be sure that repacked samples will be uniform at the beginning of storage. The cosmetic emulsion was repacked into fi ve different cosmetic containers (30 ml) and stored in a refrigerator (4°–6°C) and at room temperature (22°–25°C) for 2 and 4 mo with natural access of light. Five samples were analyzed for each type of container. The characteristics of the cream containers, including aluminum jar with polypropylene thermos (Al/PP), transparent acrylic jar with polypropylene thermos (Ac/PP), glass (G) jar, polypropylene (PP) white jar, and transparent styrene acrylonitrile (SAN) jar, are presented in Table I. METHODS FOURIER TRANSFORM NEAR-INFRARED (FT-NIR) ANALYSIS The FT-NIR spectra of the cosmetic cream samples were measured using the MPA (multipurpose analyzer) FT-NIR spectrometer (Bruker Optik, GmbH, Ettlingen, Ger- many) with an integrating sphere for measuring solids and pastes in diffuse refl ection mode. A sample rotator (diameter 45 mm) assuring high reproducibility for heteroge- neous samples was applied. The FT-NIR spectra were measured in the range of 12,500– 4,000 cm-1. The spectral data of each sample were acquired 32 times with resolution of 16 cm-1 and collected using the OPUS software ver. 7.0 (Bruker Optik, GmbH, Ettlingen, Germany). COLOR MEASUREMENTS The color of the cosmetic cream samples was determined in the CIE 1976 L*a*b* color space. L* describes the lightness, a* indicates the intensity of the red (in the positive range) and the green color (in the negative range), and b* value indicates the intensity of yellow or blue color in the positive or negative range, respectively. All color functions were calculated for illuminant D65 and the 2° angle observer using the tristimulus values obtained using Minolta Chroma Meter CR200 (Konica Minolta, Tokyo, Japan) offering 8-mm-diameter measuring area and wide-area illumination/0° viewing geometry (d/0°). The cream samples were placed in granular-materials attachment CR-A50 (Konica Minolta) covered with a quartz plate. For each packaging, fi ve measurements were per- formed. Total color difference (ΔE*ab) between the values corresponding to the stored (s) and fresh (f) samples was calculated using the following equation: * * 2 * 2 * 2 1/2 * * * * * * * * =[( ) +( ) +( ) ] , where = – = – and = – % % % % % % %b* ab s f s f s f E L a b L L L a a a b b .

JOURNAL OF COSMETIC SCIENCE 248 According to Cserhalmi et al. (20), ΔE*ab values of 0–0.05 indicate unnoticeable difference, 0.5–1.5 indicate slightly noticeable difference, 1.5–3.0 indicate noticeable difference, 3.0–6.0 indicate well-visible difference, and values higher than 6.0 indicate great difference. DATA ANALYSIS PCA with cross-validation of spectral data was carried out on the FT-NIR spectra (12,500–4,000 cm-1) of cosmetic samples. Full cross-validation was also applied to all of the PLS1 regressions. Multiplicative scatter correction (MSC) was used to compensate for multiplicative and/or additive scatter effects in the spectral data. First derivative pro- cessing of spectral data was carried out with the Savitzky–Golay procedure, which used a second polynomial order with a 15-point segment (smoothing points). The regression Table I Characteristics of Cream Containers Symbol Type Packaging material Al/PP Round jar with thermos Aluminum jar, polypropylene white thermos and spacer, nut with a protective insert Ac/PP Round jar with thermos Transparent acrylic jar, polypropylene thermos and spacer, nut with a protective insert G Round jar Glass jar, nut with a protective insert, without spacer PP Round jar with thermos Polypropylene white jar, polypropylene white spacer SAN Round jar Transparent SAN jar, ABS nut with an expanded PE washer