EFFECT OF COCONUT OIL ON HAIR DAMAGE 185 Table V Analysis of Variance Data for Treatment Effects for Water Retention Index Source Degrees of Sum of Mean F-Value at 95% Hair type variance freedom squares square confidence level Undamaged Oil type MO (straight, curly) Undamaged Oil type MO (wavy, permed) Undamaged Oil type CNO (straight, wavy) Undamaged Oil type SFO (curly, perreed) Boiled Oil type MO (straight, curly) Boiled Oil type MO (wavy, permed) Boiled Oil type SFO (straight, wavy) Boiled Oil type CNO (curly permed) Bleached Oil type MO (straight, curly) Bleached Oil type MO (wavy perreed) Bleached Oil type SFO (wavy, straight) Bleached Oil type CNO (curly, permed) UV-Treated Oil type MO (wavy, permed) UV-Treated Oil type MO (curly, straight) UV-Treated Oil type SFO (wavy, straight) UV-Treated Oil type CNO (curly, permed) Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error Between treatments Experimental error 2 29.2 14.6 6.2 2 4.7 2.4 2 19.1 9.6 2.4 2 7.8 3.9 2 93.6 46.8 31.2 2 2.9 1.5 2 83.0 41.5 6.3 2 13.1 6.6 2 35.5 17.8 7.4 2 5.3 2.7 2 19.1 9.6 2.4 2 7.8 3.9 2 20.4 10.2 4.8 2 4.2 2.1 2 33.7 16.9 21.1 2 1.7 0.8 2 4.2 2.1 0.9 2 4.5 2.3 2 15.3 7.6 12.4 2 12.3 6.2 2 40.0 20.0 4.2 2 9.5 4.8 2 40.0 20.0 22.2 2 1.8 0.9 2 17.4 8.7 2.1 2 8.2 4.1 2 23.4 11.7 8.3 2 2.8 1.4 2 12.4 6.2 4.4 2 2.8 1.4 2 41.6 20.8 26.0 2 1.6 0.8 F theoretical for (2.2) degrees of freedom at 95% confidence level = 19.0. RESULTS AND DISCUSSION PROTEIN LOSS The process of cuticle chipping that results from abrasion of hair against objects such as grooming devices or even other hair is a major factor in hair damage. The proteins that constitute the cuticle cells are lost during wet combing. It is well known that wet

186 JOURNAL OF COSMETIC SCIENCE % WATER RETENTION INDEX 12 15.3 •' t14.1 COCONUT OIL •'-•.. •:. . i SUNFLOWER OIL 5.• 14.9 14 5 13.8 • :::: ß .•_,?..'..• ,• . i I I COCONUT OIL ,}•{•' SUNFLOWER Oil PRE-WASH TYPES OF OILS POST-WASH ltll WITHOUT [3WITH Figure 6. Comparison of water retention index for undamaged hair. 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. The exocuticle, being highly cross-linked is not swollen by water. The endocuticle and the cell membrane complex, on the other hand, are less cross-linked and are more vulnerable to swelling 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 combed 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 and differently damaged hair are shown in Figures 1-4. The bars on the left refer to tests where oil was used as a pre-wash conditioner, whereas those on the right are for the tests involving post-wash treatments where oil was applied after drying the hair. The data in Figures 1-4 clearly show that the performance of coconut oil in reducing protein loss was better than that of mineral and sunflower oils. Coconut oil performed better as a pre-wash rather than a post-wash conditioner. This shows the importance of lubrication vs reduction in the swelling of the cuticle cells that leads to their breaking in wet combing. The difference between