Soapnuts and Science
Soapnut is a berry.. So it is natural…but how does it clean? We have burried our selves in the Bodleian Library of Oxford to investigate. Here is your short literature review.
Almost all the articles we reviewed acknowledge the cleaning properties of soapnuts and explain how they work, supported peer-reviewed research. Pušić et al. (2011) for example, do a great job at summarizing what other authors say, they find that “good washing performance of soapnut shells evaluated through primary effect was obtained… Beneficial multiple washing performance of natural saponins have been confirmed through less ash content as well as low level of mechanical damage. Total washing performance of soapnut shells provides many benefits for consumer from technological and ecological point of view.” (ibid. p.30).
Some articles provided an in-depth explanation on how they tested the soapnuts to prove their cleaning properties. For instance Noochuay et al (2014) “used water to extract substances from hulls of soapnut fruits to remove waxes in cotton scouring process. CMC [Critical Micellar Concentration] value from soapnut fruits were found to be 6 mg/ml with surface tension of 54.67 mN/m and can be used as wetting agent when the temperature is lower than 70 °C. The results exhibited that [soapnuts] can be used to remove waxes in cotton scouring process. At the 40% of substance powder by fabric weight, the cotton fabric absorbed water in 5 seconds” (ibid. p.768). In addition, one can notice that authors such as Jagannadha and Lakshmi (2012) or Meena et al (2012) suggest that “besides the famous benefit of keeping the hair long and healthy and also useful in the treatment of lice and dandruff. It is an excellent herb for skin problems like eczema and psoriasis. Soapnut powder is a very good antibacterial and antifungal agent” (ibid, p.420).
Finally, an exciting piece of research comes from Loretta Ieng Tak Lou (2017). In her article “The Material Culture of Green Living in Hong Kong”, the author does a great summary of what soapnuts (soapberries) are, what they are used for and how they are used:
“Cuttle fish bone, camellia seed powder and soapberries are some of the environmentally friendly cleaning products common to Hong Kong households. Before the popularization of personal and household cleaning products, people used camellia seed powder (cha zi fen) and soapberries (wu huanzi) to create their own multipurpose cleansing solution. Both contain natural saponins, chemical compounds that form in a way similar to dish soap.
Like camellia seed powder, the natural saponins in soapberries can be easily converted into a useful household cleaning solution. Simply soak 30 pieces of soapberries in 750 millimeters of water for an hour. Bring the soapberries to boil and remove the soapberries from the soapy water. Let it cool and keep the solution in an airtight container. The solution will stay fresh for four weeks. The used soapberries can be reused until they do not produce any bubbles anymore” ( Lou, 2017, p.72)
Taking a critical look, and having analysed all the literature, we must say that there is so much to learn a from natural and millenia-old solutions from all the different corners around the world! Luckily, Europe seems to be taking an eco-friendly route and hopefully we will see more and more people using natural and proven solutions for their daily routines. Laundry is something that everyone does (we hope!), and it has never been easier to be eco-friendly and start the change from one’s own household! Our peer-reviewed expert conclusion is the following: Soapnuts rock!
Hari Jagannadha Rao, G., Lakshmi, P. (2012) International Journal of Pharmacy and Technology, 4 (3), pp. 2201-2214.
Kruschwitz, A., Augsburg, A., & Stamminger, R. (2013). How Effective are Alternative Ways of Laundry Washing?. Tenside Surfactants Detergents, 50(4), 263-269.
Lou, L. I. T. (2017). The Material Culture of Green Living in Hong Kong. Anthropology Now, 9(1), 70-79.
Meena, V. N., Rajakohila, M., Syndia, L. A. M., Prasad, P. N., & Ariharan, V. N. (2012). Multifacetious uses of Soapnut Tree–A mini review. Res. J. Pharm. Biol. Chem. Sci, 3, 420-424.
Noochuay, A., Sae-Bae, P., Kumphai, P., & Suangtho, S. (2014). Scouring Cotton Fabric by Water-Extracted Substance from Soap Nut Fruits and Licorice. In Applied Mechanics and Materials(Vol. 535, pp. 768-771). Trans Tech Publications.
Pušić, T., Grgić, K., Dekanić, T., & Soljačić, I. (2011). Washing performance of soap nut shells. Tekstil: časopis za tekstilnu tehnologiju i konfekciju, 60(1), 30-35.
Rao, G. H. J., & Lakshmi, P. (2012). Sapindus trifoliatus: A review. IJPT, 4(3), 2201-2204.