Pineapple juice is produced at canneries from pineapple meat that cannot be used for higher value products such as slices, chunks, tidbits, and crushed. The juice is concentrated from 12º natural Brix to as high as 60º in order to reduce shipping volume and tonnage. Typically Cook TASTE evaporators (vertical tube, falling film, multiple effect) are used for this purpose.

Last year Vincent ran screw press tests at a long established pineapple cannery. The principal sources of juice were (a) eradicator meat that is scraped off the skin in the Ginaca machines, (b) the core (central fibrous portion of the fruit), and (c) strip slices that are cut from the top and bottom of the plug of meat that is being sliced. These various juice components were all directed to a Rietz RD-18 Disintegrator.

To produce beverage juice, the shredded material is first pumped to a bank of three FMC finishers. The juice from the FMC’s goes to four Brown finishers. The pulp from the FMC’s and Brown’s goes to a Jones screw press for a third pressing. The juice from these three sources is combined, filtered and concentrated.

Cake from the Jones press is directed to the area of the plant where mill (as opposed to beverage) juice is extracted. This cake is mixed with skin material and pressed one more time before the cake is sold as silage (animal feed).

Alternatively, pineapple juice can be produced from the whole pineapple. This month we visited five small plants in Costa Rica and Panama that do this. They start with a Brown International machine known as the Pine-O-Mat. The first step in its operation is to split the fruit in half, along the core. Then all of the juicy pulp is scraped from the inside of each half. The outer skins are directed from the Pine-O-Mat into a Vincent 12″ or 16″ screw press, while the pulp is pumped to a series of finishing machines or a centrifuge. Press liquor from the screw press goes to finishers and, maybe, an evaporator.

Operation of the Pine-O-Mat is interesting. It has two large drums, one with a grating surface and one with a feeder surface. While being scoured, the pineapple is pressed against a screen/grid plate. The pressure and preset gap of the grid plate can be adjusted for different diameters of pineapple. The idea is to scrape off the pulp and juice, down to the eyes. The eyes are pulled back to the skin as the pineapple half is compressed between the rolls. This allows the grate to operate at high juice yields, without adding the bitterness from the eyes into the juice.

The Pine-O-Mat juice yield is about 50% of the weight of topped pineapples and can go as high as 55% with over-ripe fruit. Combined canning and juice lines can yield up to 75% by weight of the pineapple.