In Brazil , Colocasia esculenta, popularly known as taro, is cultivated mainly in the South- Central regions, and the cultivars are classifi ed as domesticated or wild depending on the calcium oxalate content present. The rose variety also named rose or pork yam is classifi ed as wild and is used in swine feed (4,5), although still little exploited commercially. Taro is one of the oldest crops in the world used as food, and it has the potential to produce reasonable yields under conditions where most crops would fail, and this makes it a food security crop (6). The cultivation of this crop is generally carried out by small farmers and has great importance for the livelihood of many subsistence farmers in some developing countries, playing relevant economic and nutritional roles (3,6). The mucil age contained in the rhizomes of the plant could be investigated for technological applications as an emulsifying hydrocolloid. Mucilages are hydrocolloids found in vegetables as products of plant metabolism and are molecules derived from the polymerization of mono- saccharides which often have uronic acids in their constitution. These hydrocolloids form viscous masses or gels in the presence of water, and may have an amorphous (7–9) or semicrys- talline structure (10). In this context, they act as thickeners, binders, suspending agents, emulsifi ers, gelling agents, and stabilizers (11), presenting unique rheological properties (2,12). Some mucilages have been used as excipients in the production of cosmetics, pharma- ceuticals, foods, textiles, paints, and stationery, replacing the synthetic excipients and emulsi- fi ers (8,13). They are biocompatible, biodegradable, nontoxic, less expensive than synthetic products, and available in nature. It is important to highlight the recent trend and interest in relation to the use of herbal products and the replacement of synthetic additives by natural products (14,15). In previous research, sensory aspects in the use of Colocasia esculenta mucilage as an emulsifying agent in cosmetic emulsions were studied, and the results showed a potential use in cosmetic emulsions with good acceptance by consumers (16). Now, with a focus on chemical and physicochemical aspects, the pink variety Colocasia escu- lenta (L.) Schott mucilage was extracted and characterized by different analytical techniques. In addition, this hydrocolloid was studied for the fi rst time as an ingredient for cosmetic formulations, and its properties have been compared with a commercial biopolymer. MATERIAL AND METHODS MUCILAGE EXTRACTION The mucil age of the rose variety Colocasia esculenta (TM) was extracted from the rhizome of the plant. The rhizomes were washed, weighed, and peeled, and a portion of 300 g was mixed with 100 mL water and triturated in an industrial blender for 3 min. The crushed biomass was fi ltered through polyester cloth, frozen and dehydrated by lyophilization (LIO- TOP L108, Liobras, Brazil), and then stored in polyethylene pots in a desiccator until use. MUCILAGE CHARACTERIZATION X-ray dif fraction analysis (XRD) was performed using a Rigaku diffractometer (Minifl ex 600, Rigaku, Japan) with a copper radiation source (CuKα: 1.5418 Å), 40 kV voltage, 15 mA and readings performed in the range of 3–60° (2θ), step width of 0.02° (2θ), and scanning speed of 2° per minute. JOURNAL OF COSMETIC SCIENCE 280

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