Micrographs were obtained by scanning electron microscopy with dispersive energy system coupled (SEM-EDS) using Zeiss equipment (EVO/MA 15 Wave α-Max, Zeiss, Jena, Germany). Lyophilized samples were overlaid with gold, and a potential difference of 20 KV was employed. Micrographs were obtained at magnifi cations of 100×, 500×, 1,000×, and 4,000×. Fourier transform infr ared spectra (FTIR) were obtained using a Perkin Elmer spectro- photometer (Spectrometer Frontier, Perkin Elmer, Waltham, MA). The KBr disc method was employed (1% sample and 99% KBr), and the samples were analyzed in the region of 4,000 to 400 cm-1, with a resolution of 2 cm-1 and 16 accumulated scans. The samples were submitt ed to thermogravimetric (TG) and differential scanning calo- rimetry (DSC) analyses on a thermal analyzer (SDT Q600, TA Instruments, New Castle, DE). The TG and DSC analyses were performed in a synthetic air atmosphere at 25–600°C, using a fl ow rate of 50 mL/min and a heating rate of 10 °C/min. The content of carbohydrat es, ash (mineral residue), crude fi ber, lipids, crude protein, and moisture was determined. The analyses were performed following protocols described by the National Animal Reference Laboratory (17). An aqueous suspension cont aining 2% mucilage was prepared, and the pH was measured using a pH meter (Q400AS, Quimis, Diadema, Brazil) previously calibrated with buffer solutions with pH 4.0 and pH 7.0. EVALUATION OF MUCILAGE EXT RACTION YIELD The extraction yield was d etermined as a function of the lyophilized mucilage content obtained in relation to the wet rhizome content submitted to extraction. A rhizome weighing 3.192 kg was peeled and crushed, and the mucilage was extracted and sub- jected to the lyophilization process. The yield was calculated by the difference in mass between lyophilized mucilage content and the total wet mass of the rhizome. EVALUATION OF EMULSIFYING POTENTIAL AND EMULSIFICATION STABILITY OF MUCILAGE The emulsifying capacity ( EC) was determined according to the method described by Wang and Kinsella (18), with some modifi cations. A quantity of 0.5 g of lyophilized sample was suspended in 25 mL of water and agitated on a mechanical stirrer (TE 139, Tecnal, Diadema, Brazil) at medium speed (550 rpm) for 30 s. After this time, soybean oil was added at a fl ow rate of 10 mL/min under constant stirring at 550 rpm. The phase inversion point was recorded when there was an increase in the electrical resistance of the emulsion measured by a digital clamp meter (FT266C Clamp Meter, Profi eld, Ciudad del Este, Paraguay). The EC was calculated as the amount of emulsifi ed oil (g) per gram of protein in the sample, according to equation 1. The measurements were performed in triplicate. Amount of emulsified oil( EC= Amount of protein in the sample( ) g) g (1) The emulsifying activ ity (E A) of the sample was evaluated following the methodology proposed by Yasumatsu et al. (19), with some modifi cations. Seven grams of lyophilized TARO MUCILAGE IN COSMETIC FORMULATIONS 281

mucilage was suspended in 100 mL water and 100 mL soybean oil, and homogenized at 8,000 rpm in an extract dispenser (Q252-28, Quimis) for 1 min. The mixture was then separated into four tubes of 50 mL, each containing 30 mL of emulsion and immediately centrifuged at 4,000 rpm for 5 min. The EA was calculated by the ratio between the volume of the emulsifi ed layer and the total volume in the tube, according to equation 2: Volume of the emulsified layer(mL) EA = ×100 Total volume in the tube(mL) (2) To evaluate the emuls ion sta bility, an emulsion was prepared according to the procedure described earlier, heated in a water bath at 80°C for 30 min, and cooled in tap water for 15 min. The emulsion was then centrifuged for 5 min at 4,000 rpm in a centrifuge (Sorvall ST16R, ThermoFisher Scientifi c). The emulsion stability (ES) was calculated as the ratio between the volume of the remaining emulsifi ed layer and the total volume in the tube, according to equation 3. Volume of the remaining emulsified layer(mL) ES= ×100 Total volume in the tube(mL) (3) DEVELOPMENT OF COSMETIC FOR MUL ATIONS Four cosmetic formulations wer e developed using the ingredients described in Table 1. A volume of 1,000 mL of each cream formulation was prepared by heating the ingredients of the oil phase (Phase A: 90 g) and the aqueous phase (Phase B: 3 g in F1 and F3 1 g in F2 and 5 g in F4 dispersed in approximately 800 mL of water) separately, to a tempera- ture of 75° ± 5°C. Phase B was poured into Phase A under constant stirring (600 rpm) to avoid blistering using a mechanical stirrer (TE 139). Stirring was continued until the emulsion temperature reached 40°C and then added to Phase C (Phase C: 10 g of the solid Table I Cosmetic formulations Ingredients Concentration (% w/w) # F1 F2 F3 F4 Phase A: oily Glyceryl monostearate 3 3 3 3 Cetearyl alcohol 3 3 3 3 Helianthus annuus seed oil 1 1 1 1 Cocos nucifera oil 2 2 2 2 Phase B: watery TM - 0.1* 0.3* 0.5* Xanthan gum 0.3 - - - Distilled water q.s. q.s. q.s. q.s. Phase C Sodium benzoate 0.5 0.5 0.5 0.5 Caprilyl glycol 0.5 0.5 0.5 0.5 Distilled water q.s. q.s. q.s. q.s. # F1: control formulation using 0.3% xanthan gum, *F2: formulation using 0.1% mucilage, *F3: 0.3% mucilage, and *F4: 0.5% mucilage, q.s.: quantum satis/quantum suffi cit. JOURNAL OF COSMETIC SCIENCE 282