403 THE EFFECT OF VEGETABLE OIL COMPOSITION was defined as: R = BO/BA. R between the BO and the BA varied from 0:10 to 10:0. In total, seven different formulations were prepared and studied for each oil: 10:0, 8:2, 7:3, 5:5, 3:7, 2:8, and 0:10. All the oleogels were prepared by following the same protocol. First, the oleogelator and the oil were heated together at 85°C in a water bath under magnetic stirring. When the oleogelator was completely dissolved and the samples was limpid and homogenous by naked eyes, the sample was maintained for 5 min at 85°C. All the formulations were liquid and homogeneous at 85°C. After heating, the samples were allowed to cool down quiescently to room temperature without any stirring, resulting in an estimated cooling rate of around 5°C/min. Upon cooling to room temperature, they all formed oleogels, which sustained their own weight when inverted. Each oleogel formula was prepared in triplicate. All the measurements were performed after 24 h of storage at Table I Fatty Acid Chain Length Composition (%/w) and Degree of Unsaturation of each Carbon of the Oils. Fatty Acid Chain Length Composition (%w/w) Sunflower (%) Olive (%) Apricot (%) Camelina (%) Rapeseed (%) Myristic acid (C14:0) 0.19 — — — 0.05 Total C14 0.19 — — — 0.05 Palmitic acid (C16:0) 7.33 11.30 5.34 5.70 4.56 Palmitoleic acid (C16:1) — 1.00 0.86 — 0.21 Total C16 7.33 12.30 6.20 5.70 4.77 Margaric acid (C17:0) — — — — 0.07 Heptadecenoic acid (C17:1) — — — — 0.12 Total C17 — — — — 0.19 Stearic acid (C18:0) 3.81 3.40 1.08 2.70 1.78 Oleic acid (C18:1) 27.23 75.10 60.02 18.80 62.71 Linoleic acid (C18:2) 58.71 7.30 29.10 20.80 18.21 Linolenic acid (C18:3) 0.79 0.70 0.80 30.20 8.60% Total C18 90.54 86.50 91.00 72.50 91.30% Arachidic acid (C20:0) 0.28 0.40 — 1.30 0.64% Eicosenoic acid (C20:1) 0.23 0.30 — 13.00 1.35 Eicosanedienoic acid (C20:2) — — — — 0.57 Total C20 0.50 0.70 — 14.30 2.56 Behenic acid (C22:0) — 0.10 — — 0.38 Erucic acid (C22:1) 0.19 — — 2.30 0.43 Total C22 0.19 0.10 — 2.30 0.81 Lignoceric acid (C24:0) 7.33 0.10 — — 0.13 Nervonic acid (C24:1) — — — — 0.16 Total C24 7.33 0.10 — — 0.29

404 JOURNAL OF COSMETIC SCIENCE room temperature. The results of the oleogels based on sunflower oil previously published, have been added to this study in order to compare with the four new oils (27). DIFFERENTIAL INTERFERENCE CONTRAST (DIC) MICROSCOPY All the oleogels were analyzed by DIC Microscopy to study the shape and size of the crystals. An AxioImager M2 Microscope (ZEISS, Jena, Germany) connected to a Tri CCD APEX3200 3 × 3Mp Camera (JAI, Denmark) was used. A small amount of gel was placed on a glass microscope slide and covered with a coverslip. Samples were observed at room temperature, using a ×40 magnification and images were digitally captured and analyzed with Archimed software (v.11.3.1, Microvision). TEXTURE PROFILE ANALYSIS METHOD The hardness of the oleogels was determined by using the Texture Profile Analysis (TPA) method as described in the literature (18). A TA.XT Plus texture analyzer (Stable Micro Systems Ltd., Godalming, United Kingdom) was used. The measurements were analyzed with Exponent software (v.6.1.5.0, Stable Micro Systems Ltd. Godalming, United Kingdom). Immediately after preparation, molten gels were poured into a 30-mL (height: 40.00 mm, diameter: 53.00 mm) glass tub and cooled at room temperature and stored 24 h before measurements. The experiment was performed with a P/6 cylindrical stainless steel probe (height: 60.00 mm, diameter: 6.00 mm) with a 5 g trigger force. All the oleogels were pen- etrated once at 2 mm·s−1 for 10 mm with a pretest speed at 10 mm·s−1. For each sample, the maximum force was recorded and the average force was calculated for each R. The hardness was defined as the maximum force. OIL LOSS A centrifuge equipped with temperature control unit (SIGMA 3–30K, Osterode am Harz, Germany) was used to evaluate the ability of the oleogel to hold oil at 25°C. Five gram of an oleogel were placed in a 30-mL centrifuge tube. Before the measurement, the tube was placed in a water bath at 85°C under magnetic stirring until complete melting of the oleogel occurred in order to remove the thermal history. The sample was then main- tained for 5 min at 85°C. It was then weighed and stored for 24 h at room temperature to crystallize. All samples were centrifuged three successive times for 30 min at 14,000 rpm at 25°C. The excess liquid oil at the top was removed with a pipette just after each centrifugation step. The sample was weighed to measure the oil loss after three cycles of centrifugation. The percentage of oil loss was calculated by using the equation (1). w w w %oilloss = 100 beforecentrifugation after3cycles beforecentrifugation × - (3) where, w: sample weight. DIFFERENTIAL SCANNING CALORIMETRY (DSC) To determine the melting properties of oleogels, thermal analysis was performed with a DSC 822e (Mettler-Toledo, Viroflay, France). A 20-mL·min−1 flow of nitrogen was used