ResolvableOwl
Notorious Lyear
MCT: All lauric oils contain MC fatty acids (C6:0…C10:0) to some degree (a few % of each). Palm kernel oil and coconut oil are the most economical sources, and manufacturers choose whatever is cheaper (and what to do with the “waste” lauric/myristic and long-chain fatty acids). To make MCT oil, a lot of fancy transesterification is going on, to concentrate the MC fatty acids with satisfactory yield; in the end it is somewhat “synthetical” regardless of the origin of the fatty acids. If manufacturers mix CO and PKO, the three FAs of one single MCT triglyceride molecule will probably originate from photosynthesis of both Elaeis guineensis and Cocos nucifera. (If the blend is 1:1, it's a fun little mathematical exercise to calculate that the chance, for any triglyceride, to source from both plants, is 87.5%).
Fractionated Coconut: the MCT-rich fraction of coconut oil. You might know the drops that sweat out of unrefined coconut oil when stored around room temperature for an extended time? It's just this liquid, just made by industrial-scale purification (like splitting palm oil into olein and stearin). Its MCT percentage (and, consequently, the saponification value) is very much dependent on how far the purification went, anywhere between “dirty” natural separation, and highly refined grades that are chemically indistinguishable from transesterified MCT. You won't easily know.
It is unfortunate that vendors really don't care about this distinction, and appear to wildly mix them up, depending on if they want it to appear a “high purity chemical” or a “natural ingredient” (serving very different markets that worship very different “red flags”, sigh). Saponification value critically depends on the precise fatty acid composition, and I'm actually surprised how close the different values are (0.232, 0.237, 0.2321, 0.237 [from my notes; they removed that value sometime in the last year]; theoretical values: tri-C12:0=0.188, tri-C10:0=0.216, tri-C8:0=0.255, tri-C6:0=0.310). However, additions are probably so small that these differences don't matter anyway, with the limited value of MCT oils (whatever variety) as soapmaking oils in mind (not even talking about price).
I have used MCT oil once as a solvent/carrier oil for grated orange zest, added to HP soap after cooking. Colour and scent carried over well, and the high excess fats didn't leave the skin greasy or inhibit lather as badly as long-chain superfats would.
Fractionated Coconut: the MCT-rich fraction of coconut oil. You might know the drops that sweat out of unrefined coconut oil when stored around room temperature for an extended time? It's just this liquid, just made by industrial-scale purification (like splitting palm oil into olein and stearin). Its MCT percentage (and, consequently, the saponification value) is very much dependent on how far the purification went, anywhere between “dirty” natural separation, and highly refined grades that are chemically indistinguishable from transesterified MCT. You won't easily know.
It is unfortunate that vendors really don't care about this distinction, and appear to wildly mix them up, depending on if they want it to appear a “high purity chemical” or a “natural ingredient” (serving very different markets that worship very different “red flags”, sigh). Saponification value critically depends on the precise fatty acid composition, and I'm actually surprised how close the different values are (0.232, 0.237, 0.2321, 0.237 [from my notes; they removed that value sometime in the last year]; theoretical values: tri-C12:0=0.188, tri-C10:0=0.216, tri-C8:0=0.255, tri-C6:0=0.310). However, additions are probably so small that these differences don't matter anyway, with the limited value of MCT oils (whatever variety) as soapmaking oils in mind (not even talking about price).
I have used MCT oil once as a solvent/carrier oil for grated orange zest, added to HP soap after cooking. Colour and scent carried over well, and the high excess fats didn't leave the skin greasy or inhibit lather as badly as long-chain superfats would.