Murumuru butter: SAP value and fatty acids
Murumuru butter has a saponification value of 235 mg KOH/g. One gram needs 0.168 g of sodium hydroxide (NaOH) for bar soap or 0.235 g of potassium hydroxide (KOH) for liquid soap to turn fully into soap, before any superfat.
Key numbers
- SAP, NaOH
- 0.167527 g per g oil
- SAP, KOH
- 0.235 g per g oil
- Saponification value
- 235 mg KOH/g
- Iodine value
- 10.3
- INS
- 225
- INCI name
- Astrocaryum Murumuru Seed Butter
Example: 100 g of Murumuru butter with no superfat needs 16.8 g of 100% NaOH, or 23.5 g of 100% KOH. A 5% superfat uses 5% less.
In soap
Its main fatty acids in our cited profile are lauric (51.6%) and myristic (25.8%). The eight fatty acids used in soap-quality scores make up 95.1% of the profile.
On its own it scores 86 for hardness, 77 for cleansing and 9 for conditioning, with a saturated : unsaturated split of 86 : 9.
Lauric/myristic-rich palm-kernel-type butter, so it needs coconut-like amounts of lye. A measured supplier batch came in at 237.7, close to this value. Published sources for this oil differ by more than 3%, so checking your supplier's certificate of analysis matters more than usual.
Fatty-acid profile
| Fatty acid | % of fatty acids | Counts toward |
|---|---|---|
| lauric | 51.6% | hardness, cleansing, bubbly lather |
| myristic | 25.8% | hardness, cleansing, bubbly lather |
| palmitic | 6% | hardness, creamy lather |
| stearic | 2.9% | hardness, creamy lather |
| ricinoleic | 0% | conditioning, bubbly and creamy lather |
| oleic | 5.7% | conditioning |
| linoleic | 3% | conditioning |
| linolenic | 0.1% | conditioning |
Basis: Mambrin & Barrera-Arellano 1997 Grasas y Aceites Tabla VI: crude murumuru kernel fat (Astrocaryum murumuru), GLC.
Soap-quality scores (this oil alone)
| Hardness | 86 |
|---|---|
| Cleansing | 77 |
| Conditioning | 9 |
| Bubbly lather | 77 |
| Creamy lather | 9 |
| Iodine | 10 |
| INS | 225 |
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: 235 mg KOH/g (A measured lot COA (237.7) and theoretical values from two independent profiles (233.6-240.8) bracket the previous 235, which also matches Skinchakra (230-240) and The Soapery (234). FNWL's 245-260 is above every profile-based value. Value unchanged.), from Saponification Chart, From Nature With Love (soap/cosmetic supplier). Printed value: 245 - 260 mg KOH/g.
Published values we checked:
- 245 - 260 mg KOH/g — From Nature With Love (soap/cosmetic supplier)
- 234 mg KOH/g — The Soapery (UK soap supplier)
- 230-240 mg KOH/gr mg KOH/g — Skinchakra (EU supplier)
- Spec 220-250; result 237.70 mg KOH/g mg KOH/g — MakingCosmetics Inc. (US supplier; 'all data are as per our supplier')
- 205.1 ± 4.70 (Table 1, Murumuru) mg KOH/g — MDPI (open access, peer-reviewed)
Fatty acids and iodine: Mambrin M.C., Barrera-Arellano D. (1997) Caracterización de aceites de frutos de palmeras de la región amazónica del Brasil. Grasas y Aceites 48(3):154-158. doi:10.3989/gya.1997.v48.i3.783, CSIC (peer-reviewed, open access). Also checked: MDPI (open access, PMC9502718) (FA table, 'Murumuru fat' row (citing Serra et al. 2019 Food Res Int)); MDPI (open access, PMC9268242) (Table 3, MUK column (review of Pereira 2019, Serra 2019, Mambrin 1997)); MDPI (open access, PMC10295824) (Table 2, Murumuru column).
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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