RBD coconut oil
Mike Foale
In response to the inquiry of Ben, Perth, Australia here are some notes about RBD processing taken from The Australasian Handbook of Edible Oils. RBD oil is suitable for food uses but less attractive than VCO. It is also less expensive.
When oil is extracted from ordinary sun dried or hot-air-dried copra, as distinct from the high quality “white” copra that is carefully dried and stored to avoid any contamination or activity of micro-organisms and pests, this “industrial oil” needs to be upgraded by three processes, Refining, Bleaching to remove the brown colour, and Deodorising.
Refining: First step is “degumming” to remove phosphatides using water and phosphoric acid. This is followed by
Alkali refining – traditional method of treating with sodium hydroxide which neutralizes the FFA. Centrifuging to remove the soap that is generated by the reaction of alkali and free fatty acids..
New technology for “physical refining “ involves pretreatment with bleaching earth followed by high temperature processing under vacuum to remove the ffa. This method generates less loss that the alkali method.
Bleaching: Acid activated earth (based on bentonite and montmorillonite) is dispersed in the oil, at 105C under vacuum to remove water. Citric acid is used as a chelating agent mixed with the earth. Bleached oils have a characteristic odour that must be removed before the fat can be described as edible.
Deodorising: Steam distillation of volatile compounds under vacuum, operating at 250C for 15 minutes, under 3mm mercury. Cool as soon as possible and sparge with nitrogen to remove dissolved air. Addition of 50 ppm of citric acid during cooling acts as an effective chelator of metals and as an antioxidant.
Details of the Handbook are available from Dr Laurence Eyres at eyr...@gmail.com and from www.foodsworks.co.nz/oilsfats/
Mike Foale
Hugh Harries
The handbook URL had an extra "s" and should be:
http://www.foodworks.co.nz/oilsfats
Following the "Library" link reveals an useful sounding document
entitled "Are You Moving Towards Sustainable Palm Products? - article
by Geoff Webster, Foodinc." but it is all about African oil palm and
makes no mention of coconut. It has a link to "Green Palm
Sustainability" - and that also ignores coconut.
Should coconut stakeholders be concerned? Should they ignore oil palm,
or follow their example?
Another option might be to establish an international centre for palms
- like rice, potato, maize an wheat have already - but for ALL palm
genera and on-line, a virtual reality institute . . .
Dream on!
Hugh