A process for wet processing coconuts was adapted from the Krauss-Maffei process for removal of oil from peanuts. The husked coconuts are steamed in autoclave at a pressure of 3 kg/cm2 for 10 min to facilitate removal of the kernel from the shell. The nuts are then opened, the kernels pried out and fed into a cutter. The disintegrated material is further comminuted by passing through a roller mill with closely set rollers, then fed into a screw press to squeeze out the “coconutmilk”. The milk is separated into an oil phase and a water phase by centrifuge. The oil phase is heated to 195oF, centrifuged and filtered to get good quality oil. The water phase is heated to 210oF in a flow heater to coagulate the proteins which are separated by centrifuge and dried. The whey is concentrated under vacuum to a syrup-like product called “coconut honey”. A pilot plant with a capacity of 5,000 coconuts per day is in operation at the Central Food Technological Research Institute, Mysore.
Since freezing of plant tissue causes rupture of cell walls, a study was made of the effect of freezing and thawing coconut endosperm on the extraction of the oil. In some instances freezing resulted in a lower percentage of oil extraction. The average percentages of oil extraction of unfrozen coconut ranged from 73.05 to 50.00, and those of the frozen samples ranged from 69.36 to 47.91.
Temperature, rate of freezing, and alternate freezing and thawing, didn’t effect the percentages of extraction of oil. In general, at the same temperature, longer freezing seemed to reduce the percentage of oil extraction. The probable reasons for this are protein denaturation, curdling, of “cream”, and evaporation of water.