natural polymers and previously reported by Mishra et al. (10) in mucilagen of fen-Greek. This crystallographic profi le is mainly due to the presence of starch in the sample. The in- tensity of diffraction with principal peaks at 15, 17, 18, and 23° (2θ) characterizes this starch as type A (20), because of the presence of amylopectin with a lower chain length (21). Scanning electron microscopy. Scanning electron m icroscopy of the mucilage of Colocasia esculenta (L.) Schott revealed an ir- regular surface area containing structures with asymmetric edges resembling broken ceramic pieces (Figure 2A and B). The presence of starch granules in circular and irregular shapes de- posited on the TM surface (Figure 2C and D) also was observed, similarly to that described by Andrade et al. (9) in the mucilage from Colocasia esculenta. The starch present in the mucilage does not interfere in its emulsifying power, but the starch may be interesting for the develop- ment of cosmetic emulsions, since it is responsible for the velvety effect and softness in creams. The EDS analysis indicated the presence of carbon and oxygen, as already expected for this type of sample, as well as magnesium, phosphorus, chlorine, and potassium (Table 2). The major minerals described in the literature for Colocasia esculenta were Mg, P, and K in different proportions, and some authors correlate these variations to the soil in which the plant was cultivated, genetics, and species variations (13,22). Thermal analysis. The sample presented three exot hermic events (Fi gure 3). The fi rst event occurred be- tween 29 and 100° C and was attributed to the loss of adsorbed material and water in the Figure 1. X-ray diffraction for the mucilage of Colocasia esculenta (L) Schott. JOURNAL OF COSMETIC SCIENCE 284

polymer structure (23). The second mass loss event started at 225° C, being attributed to the degradation of the organic matter, with a maximum peak at 254° C. The last event occurred at 369° C, being attributed to the fi nal degradation of the sample (carboniza- tion) (24). The total mass loss was 91.14%, and the fi nal mineral residue was 8.86%, close to that found in the ash analysis, possibly referring to the oxides containing potas- sium, magnesium, or phosphorus, as observed in the DES analysis. At temperatures of 254°–423° C, the mass loss is due to depolymerization of the hydro- colloid, and the exothermic peak occurs because there is structural disorganization and consequent release of energy, similar to that presented by Andrade (24). FTIR analysis. The infrared spectrum (Figure 4) of the TM sample showed a broadband at 3,365 cm-1 region, corresponding to the axial deformation of hydroxyl groups (OH-), characteristic of polysaccharides, and found also by Goh et al. (25) in the mucilage of chia (Salvia his- panica L.). The bands found in the region of 2,930 cm-1 are attributed to the axial defor- mation of the C–H bond, and represent the –CH and aromatic group of sugars in polysaccharides (25). At 1,642 cm-1 region, the band corresponds to the C = O stretch of the Figure 2. Scanning electron microscopy for TM. Amplitudes of 100 × (A), 500 × (B), 1,000 × (C), and 4,000 × (D). Table II. Yield values, proximal composition, mineral composition, emulsifying capacity, emulsifying activity and emulsion stability for MC Proximal composition (g/100g) Total carbohydrate 62.47 Proteins 21.19 Lipids 0.65 Raw fi ber 0.46 Mineral residue (ash) 8.5 Moisture 6.73 Yield in mucilage 8.83 Mineral content and oxygen (%) Carbon 39.52 Phosphor 2.03 Oxygen 46.84 Chlorine 0.76 Magnesium 0.30 Potassium 11.4 Physico-chemical parameters Emulsifying activity (%) 55 Stability of the emulsion (%) 80 Emulsifying capacity (g soybean oil/g protein) 1,172.72 pH 5.91 TARO MUCILAGE IN COSMETIC FORMULATIONS 285