HAIR DAMAGE PREVENTION BY COCONUT OIL 329 solution of sodium laureth (3 moles of EO) sulfate (SLES). One milliliter of the solution was applied per tress and the tresses were worked between fingers to produce a lather. Following this, they were extensively rinsed to remove all the SLES residues. After this treatment the tresses were subjected to the following investigations. Combing damage. The protein-loss method of Sandhu and Robbins (3) was used in the following manner: Each of the wet tresses was combed with a fine-toothed nylon comb (20-22 teeth/inch) 50 times, rather vigorously, along the entire length of the tress on both sides. After every five strokes the comb was dipped in 50 ml of water contained in a beaker to dislodge the debris. The entire tress was dipped in water after every ten strokes to collect the damaged and dislodged cuticle cells. The water suspension was tested for protein content using the Lowry method. This method involves the formation of a copper-protein complex in alkaline solution that in turn reacts with phosphomolybdic-phosphotungstate reagent (Folin-Ciocaltaeu phenol re- agent) to yield an intense blue-colored solution, which is analyzed spectrophotometri- cally. Water-retention index (WRI). The SLES-washed tress was weighed and then soaked in a 0.01% solution of polysorbate 80 for 30 min. Following this procedure, the tress was centrifuged to remove capillary water and then weighed. In the next step, the dry weight of the hair was determined by drying the tress in a vacuum oven at 50øC for 90 min and then weighing it again. The water retention index (WRI) is given by: WRI = (Wwe t - Wdry) 100/Wdry Evaluation of cosmetic attributes. These evaluations were made on normal untreated and bleached hair, with and without coconut oil. For each treatment three tresses were treated with 0.2 ml of coconut oil and the other three were used as untreated controls. The attributes evaluated in this study were ease of combing (wet and dry), smoothness, bounce, setting, luster, and flyaway. All the attributes were rated on a scale of 1-5 (1 is poor and 5 is excellent). Three judges did the ranking. Half-head tests. Each half-head test involved 20 clients, each with normal and bleached hair. The hair was parted in the middle, and half the head was treated with coconut oil and the other half was left without treatment. Then the hair was washed with warm water (28øC, 200 ppm hardness) using 20% SLES and rinsed well to remove any residue. To avoid inherent differences in damage from left to right side, application of the treatment was randomized. Panelists with an odd number were treated on the left side, while those with an even number were treated on the right side. After shampooing and rinsing, the hair was combed with a fine-toothed comb (separate comb for each side). After each of the ten combing strokes, both the hair and the comb were dipped in 200 ml of water to recover broken cuticle debris. A total of 100 strokes (50 on each side) was applied. The suspension with cuticle debris was used for protein estimation. The entire study was carried out according to a completely randomized block design approach, and the outcome of these experiments was analyzed statistically (taking into account the mean standard deviation of the number of replicates) for the significance of the treatment effects within the confidence limits.

330 JOURNAL OF COSMETIC SCIENCE RESULTS AND DISCUSSION PROTEIN LOSS This is the most important measurement relevant to hair damage. It is well known that wet combing is accompanied by the breaking of the surface cuticle cell because of its brittleness. Histologically, the major component of the cuticle cell consists of the exocuticle and the endocuticle as shown in Figure 1. The exocuticle, being highly cross-linked, is not swollen by water. The endocuticle and the cell membrane complex, on the other hand, are less crosslinked and are more vulnerable to damage. This leads to the lifting of the surface cuticle via bending. Such cuticle cells can be broken in the process of combing or teasing. The protein loss observed in these measurements results mostly from the cuticular region. Because of the short time involved in the combing and brief immersion of the comb tress in water, it is unlikely that proteins from the bulk of the fiber are involved in this measurement. The data for protein-loss measurement for undamaged hair are shown in Figure 2. Forc• Crack Swollen endocuticle Figure 1. Schematic diagram of the possible mechanism ofchipping of surface cuticle cells in wet combing.