Brazil Nut Oil
INCI Bertholletia Excelsa Seed Oil. CAS 356065-50-4, as CosIng gives it. Also: Bertholletia excelsa seed oil, Brazil nut kernel oil, Castanha-do-brasil oil, Para nut oil.
Published values
| Saponification value | 178.5–191.62 mg KOH/g (typical 191.62) |
| Used by the calculator | 191.6 mg KOH/g (typical) |
| SAP for NaOH | 0.1366 g/g |
| Iodine value | 85.8–95 g I₂/100 g |
| INS (SAP − IV) | 101 |
| Melting point | — |
| Unsaponifiable matter | — |
One soapmaking book prints 0.138 g NaOH per g, which agrees with ours to within 2 %. Two soapmaking books print 0.175 g NaOH per g for Brazil nut oil, a figure that belongs to a coconut-type oil and sits just below babassu in one of them. Brazil nut oil's fatty acids put it near 193 mg KOH/g, so we use 191.6 (0.137), the measured value that agrees with them; a third book's 0.138 is right.
A bar made of 100 % Brazil Nut Oil
Conventional qualities summed from the fatty-acid groups; a single-oil bar is a reference point, not a recipe.
How much lye
| Oil | NaOH | KOH |
|---|---|---|
| 500 g | 64.9 g(60.4–64.9) | 91.0 g(84.8–91.0) |
| 1 kg | 129.8 g(120.9–129.8) | 182.0 g(169.6–182.0) |
| 1 lb (454 g) | 58.9 g(54.8–58.9) | 82.6 g(76.9–82.6) |
| 2 lb (907 g) | 117.7 g(109.7–117.7) | 165.1 g(153.8–165.1) |
For this oil alone at 5 % superfat, with pure sodium hydroxide (NaOH) or pure potassium hydroxide (KOH); in brackets, across the published range of its saponification value. KOH is usually sold at 90 %: divide by 0.9. For a whole recipe, open the calculator.
Fatty-acid profile
Saturated : unsaturated 27 : 73
| Fatty acid | Published range, % | Used | |
|---|---|---|---|
| Lauric acid | C12:0 · saturated | 0.2–0.2423 (typical 0.2423) | 0.2 |
| Myristic acid | C14:0 · saturated | 0.2–0.215 (typical 0.215) | 0.2 |
| Palmitic acid | C16:0 · saturated | 13–14.2674 (typical 14.2674) | 14.3 |
| Palmitoleic acid | C16:1 | 0.2–0.2899 (typical 0.2899) | 0.3 |
| Stearic acid | C18:0 · saturated | 10.6132–11 (typical 10.6132) | 10.6 |
| Oleic acid | C18:1 | 38.5021–39.3 (typical 38.5021) | 38.5 |
| Linoleic acid | C18:2 | 31.2651–36.1 (typical 31.2651) | 31.3 |
| α-Linolenic acid | C18:3 n-3 | 0.155 | 0.2 |
| Arachidic acid | C20:0 · saturated | 0.3627 | 0.4 |
Where these numbers come from
Table 1: refractive index 1.466 at 25 C, relative density 0.911, acid value 2.14 +/- 0.05 mg KOH/g, peroxide 12.0 meq/kg, saponification value 178.5 +/- 0.05 mg KOH/g, pH 3.80; iodine value 95.0 is given in the text. Table 2: eleven-acid GC profile of B. excelsa oil (with comparison columns for pracaxi, buriti, passion fruit and peanut that are quoted from other work and are not used here). Open-access PDF read in full.
Saponification index 191.62 mg KOH/g and iodine index 85.8 g I2/100 g (Wijs) on ultrasound-extracted oil, with refractive index 1.460, density 0.9165, acidity 2.57 mg NaOH/g, peroxide 5.74 meq/kg, 68.72 % unsaturated fatty acids. Also cites iodine values of 97.8 (Queiroga Neto et al. 2009, pressed) and 93.5 (Araujo 2008) for comparison.
Table 2 'Participacao relativa de acidos graxos no oleo de Bertholletia excelsa' (crediting Chunhieng et al. 2004): lauric 0.2, myristic 0.2, palmitic 13.0, palmitoleic 0.2, stearic 11.0, oleic 39.3, linoleic 36.1, summing to 100. Widens the min/max here. No saponification or iodine value; the chapter notes the oil is semi-drying and goes rancid easily, and gives phytosterols at 140 mg/100 g.
The saponification range is two independent titrations on different Brazilian lots: 178.5 +/- 0.05 mg KOH/g in Muniz et al. 2015 (Pharmacognosy Magazine 11(41):147-151, DOI 10.4103/0973-1296.149730, AOCS methods plus Brazilian pharmacopoeial assays) and 191.62 mg KOH/g in Schons et al. 2017 (Interciencia 42(9):586-590, ultrasound-assisted hexane extraction). Muniz et al. additionally report 198.5 mg KOH/g from Ferreira et al. for a third lot; that document was not read here, so it is mentioned rather than used. The iodine range comes from the same two papers, 95.0 and 85.8 g I2/100 g. Schons et al. attribute their lower figure to unsaturations degraded by the ultrasound step and cite 97.8 and 93.5 from two pressing studies, so the upper end is the more representative one for a pressed oil. The fatty-acid profile takes typical from Muniz et al. Table 2, the fuller of the two at eleven acids by GC, with min/max widened to include the EMBRAPA Brazil-nut chapter's table (Nascimento and Carvalho, 'Plantas para o Futuro - Regiao Norte', MMA 2022, Table 2, after Chunhieng et al. 2004: lauric 0.2, myristic 0.2, palmitic 13.0, palmitoleic 0.2, stearic 11.0, oleic 39.3, linoleic 36.1). Undecylic acid (C11:0, 0.0943 %) and margaric acid (C17:0, 0.0766 %) are dropped as the database does not record it, but that is not why the profile is short: Muniz et al.'s eleven acids only account for about 96 % of the fat by their own arithmetic, since they report 25.55 % saturated and 70.19 % unsaturated. The profile here therefore sums to 95.9 % and the missing 4 % is unidentified in the source rather than lost in transcription. The published pair is internally a little loose. The recorded composition implies 193 mg KOH/g and 92 g I2/100 g by stoichiometry; the iodine values agree well, but the 178.5 end of the saponification range sits about 8 % below what the composition supports, and on the evidence it is Muniz et al.'s titration that looks low against their own chromatogram rather than the chromatogram that looks wrong. The calculator uses Schons et al.'s 191.62 as the typical value, within 1 % of the composition-derived figure (see below). For soap this behaves as a soft, linoleic-rich oil with an unusually large stearic fraction for a nut oil at 10-11 %, about the same as its palmitic, so it firms a bar more than its roughly 70 % unsaturation would suggest. It is also a fast-rancidity oil - the EMBRAPA chapter says flatly that it 'se rancifica facilmente' - and the peroxide values in both papers, 12.0 and 5.74 meq/kg, were measured on fresh unrefined oil, which is a poor starting point for a long cure. Unsaponifiable matter and melting point are published in none of the three documents read, so both are null. INCI name from CosIng. The typical is Schons et al.'s 191.62, the one titration that agrees with the composition (about 193 mg KOH/g). Muniz et al.'s 178.5 sits 7.6 % under their own chromatogram and stays as the minimum.
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