Potatoes grading

The production capacity of Rodenburg Polymer is about 8,000 tonnes per year (2003) and 40,000 tonnes per year has been announced (2005). PLA is made here from potatoes. Grades for injection are commercially available and allow the injection of objects presenting thin walls (0.5 mm). Another application is for the release of fertiliser rods. 

The development of a by-production system could further minimize the cost of such plant-derived products. For example, potatoes are the raw material for the production of technical grade starch. During this process, soluble proteins are separated by heat treatment and sold as animal fodder. Recombinant proteins could be produced in transgenic potato tubers as a by-product of starch extraction, and this would be useful for proteins produced in large amounts with a low commercial impact, like structural fiber proteins. 

By 2006, the U.S. had 77 ethanol plants producing more than 3 billion gallons of ethanol per year. Canada produced an additional 60 million gallons. Corn was the feedstock in 62 of the 77 U.S. plants. Other feedstocks included seed corn, corn and barley, corn and beverage waste, brewery waste, cheese whey, corn and milo, corn and wheat starch, potato waste and various sugars. The U.S. had 11 additional plants under construction and 55 proposed. West Central Soy processes soybeans to a food grade oil. Alcohol and a catalyst are then used to produce biodiesel fuel and glycerin. 

Gould, W. A. (1999d). Appendix 2 USA Standards for Grades of Potatoes for Processing. In W. A. Gould (Ed.), Potato Production, Processing and Technology (pp. 189-198). CTT Publications, Inc, Timonium, Maryland, USA. 

Bioethanol production by yeasts is widely used for biodegradation of potato. However, yeasts cannot ferment starch directly, and a two-step enzymatic reaction to glucose is necessary. Different potato wastes such as industrial residues, low-grade potatoes, and spoiled potatoes can be used for acetone/ethanol production (Nimcevic et al., 1998). They used whole potato media... 

Eight potatoes of uniform size ( 50-mm square-mesh grading)... 

A third major field of developments will be in co-products. These streams will be treated as product streams rather than as waste streams. Much attention will be paid to product specification and GMP-like production. Also the recovery of better (more suited to specific applications) co-products will be investigated. Examples of this might include the recovery of asparagine, citric acid, low-potassium deproteinized concentrated potato juice, potassium nitrate, food-grade fiber and food-grade protein. 

Anionic starches are obtained by reaction with phosphoric acid and alkali metal phosphates or by derivatization with carboxymethyl groups.30,31 This modification is primarily used to introduce amphoteric properties into cationic com starch for application on the wet end of the paper machine. Anionic starches with carboxymethyl substitution are used as thickeners in coating colors or as binders in coatings for specialty paper grades. Oxidized starches are inherently anionic but without thickening action. Potato starch already carries sufficient natural anionic charge to provide amphoteric properties after cationization.32... 

In general, starch triacetates are soluble in acetic acid and, except perhaps for potato starch triacetate, are soluble in chloroform, 1,1,2-tri-chloroethane, tetrachloroethane, and other halogenated hydrocarbons. High grade starch triacetates do not appear to be soluble in ethyl acetate or alcohol, while some controversy exists as to the extent of their solubility in pyridine and acetone. Waxy com starch triacetate, perhaps due to its smaller molecular weight, is readily soluble in a wide variety of organic solvents. 

Moisture content all starches are hyjp-oscopic and rapidly absorb atmospheric moisture. Approximate equilibrium moisture content values at 50% relative humidity are 11% for com starch 18% for potato starch 14% for rice starch and 13% for wheat starch. Between 30% and 80% relative humidity, corn starch is the least hygroscopic starch and potato starch is the most hygroscopic. Commercially available grades of corn starch usually contain 10-14% water. See also Figures 2 and 3. 

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