214 JOURNAL OF COSMETIC SCIENCE EFFECT OF MINERAL, SUNFLOWER AND COCONUT OIL ON PREVENTION OF HAIR DAMAGE Aarti S. Rele Marico Industries Ltd, Mumbai, India SYNOPSIS Previously published results showed that coconut oil application to hair prevents hair damage. Using the same methodology, the properties of mineral and sunflower oil on hair were studied. Taguchi Design of Experimentation was used to include all the variables and factors such as hair types, treatments, oils and to reduce experimentation, cost and effort without impacting the results. Among three oils, coconut oil was the only oil found to reduce the protein loss remarkably. (both as a pre/post-wash). This difference in results could be because of composition of each of these oils. Coconut oil, being a tri- glyceride of lauric acid has a high affinity for hair proteins, additionally low molecular weight and straight linear chain, enhances its penetration into the hair shaft. Mineral oil, being a hydro-carbon and sunflower oil, being a tri- glyceride of linoleic acid with a bulky structure (presence of double bonds), do not penetrate the hair. INTRODUCTION Morphologically, a fully formed hair fiber contains three and sometimes four different units or structures, i.e. cuticle, cortex, medulla and intercellular cement. Because of extensive cross-linking, cuticle cells tend to be brittle and therefore, are susceptible to damage by grooming procedures, especially wet combing (1). The loss of cuticle cells by gradual chipping impairs the cosmetic qualities of hair such as smoothness and shine. Grooming methods involving abrasive procedures are known to damage hair and its appearance. Historically, coconut oil has been used as a hair dressing in the developing countries in the tropical regions of the globe where coconut is cultivated extensively. Prolonged use of coconut oil has been known to lead to healthy looking long hair, suggesting that it may prevent damage to the cuticle in grooming procedures involving abrasion. However, in modem times, the trend is more towards usage of non-sticky oils such as mineral oil or less greasy oils such as sunflower oil in hair oil formulations. This investigation is aimed at comparing the effects of these two oils along with that of coconut oil in preventing hair damage. Although, several methods involving scanning electron microscopy (SEM), measurement of combing forces and tensile mechanical properties have been used earlier to characterize hair damage, we have used protein loss and water uptake methods for this purpose. Furthermore, these methods have been extended to study the beneficial effects of these oils on in preventing chemical, thermal and UV damage. Efficacy of these methods has been established in an earlier paper from this laboratory (3). MATERIALS AND METHODS MATERIALS Samples of straight, curly, wavy and perm hair of Indian origin, 25cm in length were used in this work. For each of the treatment per hair type, 25 hair tresses were used. The reagents for protein estimation were obtained from Sigma Chemicals Co. of St. Louis, MO. The other reagents such as buffers, salts, etc were of analytical grade. Whereas the oil samples were the way they are available commercially. SAMPLE PREPARATION Hair tresses of 34-0.5 g were prepared for this investigation. They were standardized. Both Undamaged and damaged hair tresses were used. The damaging treatments were Bleaching, UV and boiling water treatment. These hair tresses were treated both before (pre) and after (post) these treatments with coconut/mineral/sunflower oil. The entire study involved a large no. of variables such as oils, hair types, oiling sequence, etc. resulting in quite complex study. In order to simplify the complexity of the experiment without compromising on the quality of results, a statistical tool termed as Taguchi Design Of Experimentation was used.

2002 ANNUAL SCIENTIFIC MEETING 215 METHODS The tresses were wetted under running tap water (28øC), were washed with a 20% solution of Sodium laureth (3 moles of EO) sulfate (SLES) and thereafter rinsed with water. After this treatment the tresses were subjected to the following investigations. COMBING DAMAGE - The protein loss method of Sandhu and Robbins (2) was used. WATER RETENTION INDEX (WRI) - The method for determination of water retention index specified in the earlier publication (3) was used, HALF - HEAD TEST - Half-head test as mentioned in the earlier publication (3) was used. The outcome of all above experiments was analyzed statistically using parametric test termed as t-test.. RESULTS AND DISCUSSION PROTEIN LOSS The data in Fig 1 - 4 clearly show that the performance of coconut oil in reducing protein loss was better than those of mineral and sunflower oils. The difference between coconut and mineral oil is probably due to the difference in their ability to penetrate the hair (4). The smaller effect of sunflower oil may be due to the presence of unsaturation in the molecule. The same effect was seen in Half-head test in Salon as seen in figure (9). The entire data was analysed statistically (t-test) which clearly indicates that damaged as well as undamaged hair benefit from application of coconut oil whereas in case of sunflower oil and mineral oil, there was no effect. WATER RETENTION INDEX From the data of water retention index as seen in fig (5), it is evident that coconut oil reduces the WRI of undamaged hair to the tune of 44% whereas there was no effect case of mineral oil and sunflower oil. The ability of coconut oil to penetrate hair (4) supports this observation. The data for the bleached, Heat and UV damaged hair are shown in figures (6 - 8 resp.). The entire data was analysed statistically (t-test) which clearly indicates that for damaged samples, WRI is much higher than that for the undamaged hair. However, these damaged samples show a reduction in the WRI only when coconut oil was used for treatment. CONCLUSIONS This study has firmly established the superiority of protective effect of coconut oil on hair damage in grooming processes as well as damaging processes as compared to mineral oil and sunflower oil. The penetrative ability of coconut oil into hair cuticle and cortex seems to be responsible for this effect. Thus coconut oil really acts as a hair damage protectant whereas mineral oil and sunflower oil do not exhibit this property. ACKNOWLEDGEMENT The author would like to thank Mr R.B. Mohile, Head - Technology, R & D, Nature-Care Division, Marico Industries Ltd. for giving an opportunity to work on this project and Dr Yash Kamath, Director - Research, T.R.I., Princeton, U.S.A. for his valuable guidance in writing this paper. REFERENCES (1) M. L. Garcia and J. Diaz, J. Soc. Cosmet. Chem., 27, 379 - 398 (1976) (2) S.S. Sandhu and C. Robbins, J. Soc. Cosrnet. Chem., 44, 163 -175 (1993) (3) Aarti Rele, R.B.Mohile, J. Cosmet. Sci., 50, 327-339 (1999) (4) S.B. Ruetsch, Y. K. Kamath, Aarti S. Rele and R. B. Mohile, J. Cosmet. Sci., 52, 169-184 (2001) (5) J.A. Swift and A. C. Brown, J. Soc. Cosmet. Chem., 23, 695-702 (1972) (6) J.A. Swift, International J. Cosmetic Science, 13, 143 (1991) (7) S. B. Ruetsch and H. D. Weigmaun, J. Cosmet. Chern., 47, 13-26 (1996)