Cire de myrica

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Read this one differently from the other waxes in the dataset. Beeswax, candelilla and carnauba are wax esters, hydrocarbons and alcohols, which is why their records carry no fatty-acid profile; bayberry wax is a glycerolipid, so it saponifies like a fat and a normal profile describes it. Simpson and Ohlrogge (The Plant Cell, 2016, doi 10.1105/tpc.15.00900) analysed the surface wax of Myrica pensylvanica fruit and found it entirely saturated acylglycerol - triacylglycerol, diacylglycerol and monoacylglycerol in a molar ratio of about 30:62:8 - with acyl composition C16:0 above 75 %, C14:0 below 25 % and C18:0 under 1 %, and no unsaturated acid detected at all; the wax is 32 % of the fruit's dry weight and crystallises above 40 C. The mostly-diacylglycerol structure is worth holding on to, because it explains the saponification value: a pure tripalmitin would titrate at 208 mg KOH/g, a dipalmitin at about 197 and a monopalmitin at 170, and a 30:62:8 mixture on this acyl composition works out near 205 - the middle of the producer's band, not the 208-215 a reader would predict from 'mostly palmitic triglyceride'. The recorded values are the producer specification for Koster Keunen Bayberry Wax (their code 188): melting point 40-55 C by USP <741>, saponification value 188-225 mg KOH/g by USP <401>, colour light brown to olive green, INCI Myrica Cerifera (Bayberry) Fruit Wax, CAS 8038-77-5. No iodine value, acid value or composition is published with it, so iodineValue is null; on the Plant Cell composition a fully saturated glyceride should measure close to zero. Two things will catch a maker out. First, species. The INCI names Myrica cerifera, the eastern North American bayberry, while the same producer's own page calls the shrub native to Central and South America, which is the Andean wax laurel (Morella pubescens) traded under the same name; the profile recorded here was measured on a third species, M. pensylvanica, because that is the analysis available in an allowed document. No primary analysis of M. cerifera or M. pubescens fruit wax was found - older compilations describe bayberry wax as myristic-dominant (around 58 % C14:0) rather than palmitic-dominant, which is more likely a species split than a contradiction, but none of them is a document this dataset may cite. So treat the profile as indicative of the palmitic-type material and the saponification value, which is measured on whatever is actually in the drum, as the number to calculate with. Second, the width of that number: 188-225 is plus or minus 9 % about its own centre, three times the spread of a Codex oil. At 5-10 % of a recipe that is a fraction of a percent of the total lye and a normal superfat absorbs it; at 30 % with a 3 % superfat it does not.

Cette fiche fait partie de la base d’ingrédients ouverte (ODbL). Vous avez trouvé une erreur ou une meilleure source primaire ? Le jeu de données est sur GitHub ; les corrections accompagnées d’un lien vers un document sont bienvenues.