ResolvableOwl
Notorious Lyear
Just found this paper that discusses several antioxidants (ROE, tocopherol/vitamin E, ascorbyl palmitate, and citric acid, as well as combinations thereof). For sure also a great starting point for further research into the academic literature around slowing down rancidity.
They, however, look only on sunflower oil as-is (not soap). Hence, their results aren't directly applicable on soap. One has to keep that in mind when comparing with other (conflicting) information (like Kevin Dunn, who found the combination ROE+citrate to be not a good antioxidant).
https://www.sciencedirect.com/science/article/abs/pii/S0308814600001618
DOI 10.1016/S0308-8146(00)00161-8
PDF: http://www2.nkust.edu.tw/~ikuojm/file3/ref16.pdf
Tocopherol once again caused some weird pro-oxidation issues. The landslide winners in this study are ROE + citric acid, and ROE + ascorbyl palmitate. In a hindsight, it appears surprising that ascorbyl palmitate plays no role for soapmaking, although it's easy to obtain, and doesn't come with the stigma of being one of the anthropocenic designer chemicals (BHT, EDTA and the likes).
They, however, look only on sunflower oil as-is (not soap). Hence, their results aren't directly applicable on soap. One has to keep that in mind when comparing with other (conflicting) information (like Kevin Dunn, who found the combination ROE+citrate to be not a good antioxidant).
https://www.sciencedirect.com/science/article/abs/pii/S0308814600001618
DOI 10.1016/S0308-8146(00)00161-8
PDF: http://www2.nkust.edu.tw/~ikuojm/file3/ref16.pdf
Tocopherol once again caused some weird pro-oxidation issues. The landslide winners in this study are ROE + citric acid, and ROE + ascorbyl palmitate. In a hindsight, it appears surprising that ascorbyl palmitate plays no role for soapmaking, although it's easy to obtain, and doesn't come with the stigma of being one of the anthropocenic designer chemicals (BHT, EDTA and the likes).
