Hardened palm kernel oil

Hard Fats. These are substances like lard or hard vegetable fats such as hardened palm kernel oil (HPKO) or blended hard vegetable fats. These are normally weighed out and mixed into the system,... 

Lipase splits fatty acids from glycerol to produce free fatty acids, for example, butyric acid. If the original fat is butterfat then at low levels this produces a buttery or creamy flavour. As the free fatty acid content is increased, this strengthens the flavour to cheesy . Normally in toffees free butyric acid is not a problem at any practical level, possibly because of losses during cooking. Other free fatty acids have different flavours. Laurie acid, which is found in nuts, tastes of soap. This is not too surprising as soap often contains sodium laurate. Laurie fat sources, such as hardened palm kernel oil, are often used as a substitute for butter another potential source is nuts, which are sometimes combined with toffee. In any of these cases, lipolytic activity can shorten the shelf life of the product or render it totally unacceptable. 

The situation was not always as it is now. The original vegetable fat used in toffees was hardened palm kernel oil (HPKO). This material does have the advantage of being cheap but, unfortunately, it is a lauric fat and tends to reduce the shelf life because of soapy rancidity. 

Timms (21) has heat of fusion to 17.7-22.3 kcal/kg for milkfat, 24-31 kcal/kg for fully hardened milkfat, 26-29 kcal/kg for cocoa butter in the p polymorph, 22.6 kcal/kg for refined, bleached, and deodorized (RBD) palm oil, 29.7 kcal/kg for RBD palm kernel oil, 26.0 kcal/kg for RBD coconut oil, 31.6 kcal/kg for fully hardened palm kernel oil, and 31.2 kcal/kg for fully hardened coconut oil. The heat of fusion is an empirical physical property dependent on the thermal history or tempering of the oil. 

A/G No. 3a Antiverm (25%) 17% hardened palm kernel oil, 26% diethylphthalate, 20% magensium carbonate, 12% beeswax... 

For CBE manufacture, fractionation is preferred to hardening by hydrogenation, which causes melting behaviour unsuitable for bar chocolate. Hydrogenation is however used to produce CBR and CBS from palm or palm kernel oil and rapeseed oil. Fats containing a substantial proportion of lauric acid (lauric fats) which are not compatible with cocoa butter are used in CBS and CBR. 

Other Sources The most commonly used oils and fats in soap making around the world are tallow, palm oil, and their stearines and the two lauric oils, coconut and pahn kernel oil. However, over the years local shortages in these oils and fats have led to a plethora of alternative oils/fats being used as nonlauric and lauric oil substitutes. For instance until the 1990s, India relied on blends of local oils such as linseed, rice bran, and castor which with appropriate hardening, dehydroxylation, etc., could produce a nonlauric blend that mimicked the process and in use behavior of palm oil. Similarly in South America partially hardened soya bean oil has been used as a partial replacement for tallow. Other oils/fats occasionally used as nonlauric replacements include lard (pig fat) and a number of soft oils such as sunflower and groundnut oil. Alternatives to the common lauric oils are extremely limited but include rosin and a range of synthetic surfactants (18). 

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