OCTOBER 15, 2015
Pectin is a food ingredient which has a great many food and commercial applications. It gives firmness to products we consume on a daily basis: jelly, yogurt, ice cream, gravy, salad dressing and many, many others. Its characteristics include good palatability, and it blends without affecting the flavor of the base material.
Commercial markets include pharmaceutical gel caps, paints, toothpaste and shampoos,
Pectin can be made from apples and sugar beets, plus other minor crops. However, most pectin comes from citrus peel. The preferred peel is from limes (mostly Mexican and Persian), closely followed by lemons. Citrus pectin comes 56% from lemons, 30% from limes, and 13% from orange peel. Pectin sells for around $15 a kilo – there are many different grades. 55,000 tons a year are sold, plus more in other forms. The market is up to a billion dollars per year.
The citrus peel from which pectin is extracted is purchased from citrus processors. These are primarily in Argentina and Mexico, although it is also produced in Brazil, Peru, Spain, Italy, and even Bolivia. After extracting the juice, these processors wash the peel to remove oil and dissolved sugars, dry it gently, and then bale it for transport to the facilities which produce the pectin.
The major pectin producers are CP Kelco, DuPont, Cargill, Yantai Andre Pectin, and Herbstreith & Fox. CP Kelco has three plants, in Denmark, Germany, and Brazil. DuPont has plants in Mexico and Europe. Cargill's plants are in Germany, France, and, added very recently, Italy. Andre Pectin has their plant in China, and Herbstreith and Fox operates in Germany. This link gives a listing of these firms: http://www.ippa.info/members_of_ippa.htm
Pectin is extracted from the washed and dried citrus peel by first using acid to dissolve the pectin. The spent peel is then removed, and the remaining solution is treated with alcohol. The alcohol causes the pectin to precipitate. The pectin thus formed is dried and sold in powder from.
There are three applications for Vincent's screw presses in the production of pectin.
SPENT PECTIN PEEL
After the acid treatment there is a residual product, spent pectin peel. This waste material has some value as an animal feed. The material is very hard to dewater, so it is sold with high moisture content. CP Kelco has done the best marketing by assigning a trade name, Braspulpa, to their material.
Over the years Vincent has done development work in Sicily, seeking to dewater spent pectin peel in a screw press. It was found that a dosing with hydrated lime and cellulose (ground wood) fiber allowed a significant amount of water to be removed. Unfortunately, the water removed would have overloaded the wastewater treatment plant, so it became one more technical success but commercial failure.
INTERMEDIATE ALCOHOL PRECIPITATION
The alcohol precipitation step involves alcohol washing. This is done in a two stage counterflow wash, first with 60% alcohol and then 80% alcohol. A screw press, vapor-tight of course, is used between the two wash stages. This is a "soft squeeze" application.
FINAL ALCOHOL SEPARATION
Squeezing out the alcohol ahead of the pectin dryer is a "hard squeeze" application which requires a great more torque capability in the screw press.
When presses are supplied for these applications in Europe, they are designed and built to meet the ATEX explosion-proof standards. These are ATEX Certified presses. In other countries, where certification is not required, a less expensive unit, meeting the same standards, is supplied.