Potato starch dextrinization

Starches like ordinary baking flour and potato starch dextrin work to control insect pests by gumming up the leaf surfaces, trapping and holding the critters until they die. Flour is an old-fashioned pest control, but dextrin is the object of recent attention by researchers looking for new and safe insecticides. Dextrin is actually a sticky sugar extracted from potato starch. 

Protection Offered You can use potato starch dextrin to control aphids, spider mites, thrips, and whiteflies. It also controls powdery mildew on cucumbers. Other uses will likely be recommended once a commercial product reaches the market. Flour is a good control for larger pests like imported cabbage-worms and loopers on cabbage family crops. 

Paleine or Paleina. Dynamites patented by Langfrey in Engl in 1878 contg nitrated straw ( fulmi-paille ). One of the formulations could [G 35.0, Nitrostriv/ 18.6, ssltpstsr 32.5, sulfur 4.6, and potato starch 9.3%. Part of the sulfur could be replaced with hardwood charcoal, and dextrin could be substituted for the starch... 

The first report in the literature of the isolation of a substance recognizable as a cyclodextrin was that of Villiers which appeared in 1891. From digests of Bacillus amylobacter on potato starch, Villiers obtained a small amount (3 g per 1000 g of starch) of a crystalline material, which he named cellulosine because of its resemblance in some respects to cellulose. The foundations of cyclodextrin chemistry were laid down, however, in the period 1903-1911 by Schardinger, and, in fact, some of the older literature frequently refers to the cyclodextrins as Schardinger dextrins. 

The best dextrins, derived from good potato starch, exhibit a shining reflection, those which appear opaque being usually obtained from wheat or maize starch. 

Starch pastes irradiated with 130,000 V, 15 mA X-rays lost their viscosity, and there was concurrent decrease of iodine-binding ability and pH. Other properties measured after such treatment point to dextrinization and oxidation of starch.78-79 Other results of such irradiation is the cleavage of phosphoric acid esters from glucose units of potato starch. This effect is observed at 50,000 V and 8 mA as well as at 150,000 V and 12 mA. The effect of X-ray irradiation is similar in this respect to irradiation with 7-rays, whereas neither sonication with ultrasound nor exposure to UV light evoke such effects.5 Starch irradiated by X-rays, contains free radicals, and thus the presence of free radicals in starch provides evidence of previous irradiation. 

FIG. 21.—Quantities (Q) [mg/mL] of water-soluble dextrins as a function of water content (W) in potato starch (o, irradiation under oxygen , irradiation under nitrogen) (from Ref. 101). 

The effect of microwave radiation on maize, potato, and cassava starch (all either air-dried, in slurry, or pregelatinized) has been studied by Muzimbaranda and Tomasik.295a Starch readily dextrinized under such treatment. The sensitivity to microwaves increased in the order com > cassava >> potato starch. Micro-wave radiation also allowed facile cross-linking of starch with formaldehyde. The reaction took place for 5-15 min. and did not require any catalyst. Extended periods of reaction led to dextrins. In the presence of hydrogen peroxide, starch could be cross-linked with acetylene.2953... 

In a similar use of a-amylase, Parrish and Whelan249 treated potato starch with crystalline human salivary a-amylase and obtained a phosphorylated maltotetraose that had previously been reported by Postemak250 and that was the smallest phospho-dextrin formed. They determined its structure to be 63-phosphomaItotetraose, similar in structure to the smallest a-limit dextrin, 63-a- D-glucopyranosylmaltotriose, formed by this enzyme and porcine pancreatic a-amylase. 

Large quantities of starch are consumed as a component of adhesives for paper and paperboard, especially in the production of corrugated board. Dextrins, derived from com or potato starch, are used as adhesives for laminated products and as gums for envelope construction and sealing. 

Sealing tape has 35 to 90 pounds per ream of kraft paper as a substrate, whereas, reinforced sealing tape is based on a bonded laminate of kraft paper, reinforcing fibers, and kraft paper. The adhesives applied to these substrates may be thin-boiling, waxy starches alone, or blended with a soluble dextrin (5). More recently, blends of a soluble dextrin with oxidized potato or a hydrox-ypropyl ether of an oxidized potato starch are being used (9). Also, the acetate or succinate of an oxidized waxy starch may be used (15) as well as specially produced waxy starch acrylamide graft copolymer products (16). 

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