Watermelon seed oil: SAP value and fatty acids
Watermelon seed oil has a saponification value of 196.44 mg KOH/g. One gram needs 0.140 g of sodium hydroxide (NaOH) for bar soap or 0.196 g of potassium hydroxide (KOH) for liquid soap to turn fully into soap, before any superfat.
Key numbers
- SAP, NaOH
- 0.140039 g per g oil
- SAP, KOH
- 0.19644 g per g oil
- Saponification value
- 196.44 mg KOH/g
- INCI name
- Citrullus Lanatus Seed Oil
Example: 100 g of Watermelon seed oil with no superfat needs 14.0 g of 100% NaOH, or 19.6 g of 100% KOH. A 5% superfat uses 5% less.
In soap
Its main fatty acids in our cited profile are linoleic (49.5%) and oleic (21.2%). The eight fatty acids used in soap-quality scores make up 98.4% of the profile.
On its own it scores 28 for hardness, 0 for cleansing and 71 for conditioning, with a saturated : unsaturated split of 28 : 71.
Published values vary widely with variety and extraction; check your COA.
Fatty-acid profile
| Fatty acid | % of fatty acids | Counts toward |
|---|---|---|
| lauric | 0% | hardness, cleansing, bubbly lather |
| myristic | 0% | hardness, cleansing, bubbly lather |
| palmitic | 15.2% | hardness, creamy lather |
| stearic | 12.5% | hardness, creamy lather |
| ricinoleic | 0% | conditioning, bubbly and creamy lather |
| oleic | 21.2% | conditioning |
| linoleic | 49.5% | conditioning |
| linolenic | 0% | conditioning |
Basis: Mean of four Pakistani watermelon varieties, Raziq et al. 2012 Table 5 (only C16:0, C18:0, C18:1, C18:2 reported; others recorded as 0).
Soap-quality scores (this oil alone)
| Hardness | 28 |
|---|---|
| Cleansing | 0 |
| Conditioning | 71 |
| Bubbly lather | 0 |
| Creamy lather | 28 |
Each score adds up certain fatty acids, the way Soap Ledger scores a whole recipe. They are for comparing recipes; they don't predict how a bar will feel, and they say nothing about safety or skin.
Sources
SAP value: 196.44 mg KOH/g (Median of sources' mgKoh_mid (no Codex/pharmacopoeia standard found)), from Raziq S., Anwar F., Mahmood Z., Shahid S.A., Nadeem R. (2012) Characterization of seed oils from different varieties of watermelon [Citrullus lanatus (Thunb.)] from Pakistan. Grasas y Aceites 63(4):365-372. doi:10.3989/gya.022212, CSIC (peer-reviewed, open access). Printed value: 190.20–205.57 (four varieties) mg KOH/g.
Published values we checked:
- 190 - 200 mg KOH/g — From Nature With Love (soap/cosmetic supplier)
- 190.20–205.57 (four varieties) mg KOH/g — CSIC (peer-reviewed, open access)
Fatty acids: Raziq S., Anwar F., Mahmood Z., Shahid S.A., Nadeem R. (2012) Characterization of seed oils from different varieties of watermelon [Citrullus lanatus (Thunb.)] from Pakistan. Grasas y Aceites 63(4):365–372. doi:10.3989/gya.022212, CSIC (open access, peer-reviewed). Also checked: MDPI (open access, peer-reviewed) (Introduction (cites literature)).
NaOH and KOH values are converted from mg KOH/g with the molar masses 39.997 and 56.106 and rounded to 6 decimals, exactly as in the Soap Ledger app. Real oils vary by origin, grade and lot: check your supplier's certificate of analysis. Verify every weight before you make this, and follow lye safety. Not a safety or compliance certification.
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