May 23, 2005 ISSUE #161
A popular orange-flavored soft drink in Australia is labeled Peel Juice. Much like Sunny Delight in the States, it is a sweet, non-carbonated drink with cloud added for appearance.
Adding water to fresh orange peel is the first step in making Peel Juice. Once the sugars in the peel are diffused into the water, the mass is pressed to separate the liquid. This step is repeated three times (three stage washing) until the Brix of the peel is reduced to below 1o Bx.
Converting this bitter liquid into a soft drink requires only a few steps. First, enzymes are used to break down the pectin. Next, resins are used to de-bitter the liquid. Finally, the liquid is concentrated in an evaporator in order to facilitate transportation and storage. Subsequently it is blended and packaged into a range of consumer products.
Specialty resins are supplied by Bucher Unipektin through their Citrus Division in Chittaway Bay in Australia.
The press cake (washed peel solids) from the final pressing is sold as fresh animal feed. The sheep love it.
An interesting variation of this technology has been pursued in Sicily. Several citrus plants on the island produce pectin peel. More than one of these is experimenting with peel juice made from their used wash water.
Pectin peel is the raw material that companies like CP Kelco and Danisco use to produce pectin, the food ingredient. Pectin peel is produced by washing the sugars from the peel. This is done by diffusing the sugars out of the peel in counterflow wash systems.
A major problem faced by pectin peel producers is the disposal of the used wash water, as this water contains the sugar from the peel. Large amounts of solids are involved: by weight, the amount of sugar approaches the weight of pectin peel being produced. In the last fifteen years all of the pectin peel plants in the United States have shut down, at least partly because of this environmental problem. Thus, the Italian technology for converting the used wash water into a by-product may someday become widespread.
Vincent screw presses are an important part of these processing systems.