Oxidized Hydroxypropyl Starch

Propylene Chlorohydrin Determine the residual propylene chlorohydrin in hydroxypropyl starch, hydroxypropyl starch phosphate, and oxidized hydroxypropyl starch as directed under Propylene Chlorohydrin, Appendix X. 

PPO PPOX PPT PS a-PS polylphenylene oxide) polylpropylene oxide) hydroxypropyl starch polystyrene atactic-polystyrene... 

Derivatization Etherification Hydroxypropyl starch - Esterification with propylene oxide... 

Hydroxypropylated starch 1440 E1440 Propylene oxide <10% (or 25%e) Propylene chlorohydrin <1 mg/kg... 

Properties of rice starches are changed by chemical modification in the same way as the properties of other starches (see Chapter 18). Starches prepared via the alkali method have been modified to provide additional pH and shear stability. In general, hypochlorite-oxidized rice starch has a lower gelatinization temperature and lower maximum paste viscosity producing a softer, clearer gel. Hydroxypropylated rice starches have lower gelatinization temperatures, whereas crosslinked rice starch has an increased gelatinization temperature, increased shear resistance and acid stability. 

Hydroxypropyl starch is produced industrially from natural starch, using propylene oxide as the modifying reagent in the presence of alkali, adding hydroxypropyl (CH(OH)CH2CH3) groups at the OH positions by an ether linkage. 

Hydroxyethylation of starch, which is obtained from starch and ethylene oxide. This compound has been utilized in papermaking for sizing and coating, in textile manufacturing, and as a blood plasma extender. Hydroxypropylated starch has also practical applications. 

The reaction of starch with propylene oxide in alkali forms 0-(2-hydroxypropyl)starch.892,930-938 A granular derivative can be prepared by impregnating starch with acetic acid prior to its alkali treatment with and reaction propylene oxide.939 Etherification at 0-3 and 0-2 occurs at approximately the same rate, and the reaction at 0-6 is slightly less favorable.933 However, etherification at 0-2 has priority.940... 

Borax has frequently been used in conjunction with such reagents as (3-chloro-2-hydroxypropyl)trimethylammonium salts,1853 epichlorohydrin or formaldehyde,1401185318541855 melamine-formaldehyde resins,1856 (carboxymethyl) starch, oxidized (carboxymethyl)starch, (carboxymethyl)starch-acrylamide copolymer,1857 and oxidized starch.1858 Boric acid was also used jointly with formaldehyde,1859 and starch dialdehyde has been crosslinked with boric acid.526... 

Myristamine oxide Octoxynol-50 foam builder, cleansers Hydroxypropyl starch phosphate Linoleamidopropyl betaine foam builder, coal dust suppression lsodeceth-11 foam builder, coatings... 

The starch content of a natural product or of a man-made product may be required. The latter products might contain modified starches, and a limited number are permitted for food purposes acetate, adipate, succinate, oxidized, hydroxypropyl. For nonfood applications cationic and carboxymethyl starches are in common use. Polarimetric methods, when applied to such modified starches, reveal that calcium chloride dissolution is better than the Ewers method. Even with cross-bonded starches, which are difficult to solubilize, complete dissolution is achieved within 30 min with calcium chloride solution. Recovery, based on a universal optical rotation of 203°, is over 95%. While this application of the method needs further verification, several laboratories in an ISO work group report similar findings. 

Electroneutral starch ethers, i.e., hydroxyethyl starch (HES) and hydroxypropyl starch (HPS) are manufactured in analogy to the corresponding cellulose ethers by reaction of alkalinized starch with ethylene oxide or propylene oxide (Figure 4A.40). 

The two main types of hydroxyalkyl ethers industrially produced are hy-droxyethyl starch and hydroxypropyl starch. These compounds are synthesized by reaction of ethylene oxide or propylene oxide respectively with starch under alkaline conditions (134). 

Hydroxypropyl starch By reacting starch with propylene oxide in the presence of alkali Binder, Disintegrant... 

For these and a variety of special non-food purposes esters with higher fatty acids, succinic, adipic and citric acids and carbamates (reaction products with urea), have also been prepared. Examples of starch ethers are 2-hydroxyethyl and 2-hydroxypropyl starches prepared by reaction of starch with oxirane (ethylene oxide) and methyloxirane (propylene-l,2-oxide). The reaction occurs preferentially at the secondary hydroxyl groups at C-2, with less on the C-3 and C-6 hydroxyl groups. The most common products are those shown in Figure 4.15. The degree of substitution tends to be <0.2. According to the reaction conditions, polyoxaalkyl starches ... 

The chemical substitution of hydroxyl groups with functional groups yields modified starches with unique functionalities and uses. Acetylated and hydroxypropylated starches are produced after treatment with anhydrous acetic and propylene oxide under an alkaline pH, respectively. After the reaction, the slurry is neutralized, filtered, and dried. These derivatized starches are less prone to retrogradation, produce weaker and clearer gels, and have improved water-holding capacity (Mauro et al. 2003, Thomas and Atwell 1999). 

Starch, 2-hydroxypropyl ether. See Hydroxypropyl starch Starch, oxidized... 

Figure 10.6 Effects of hydroxypropylation on the granule morphology of potato starches, (a) Potato starch granules after hydroxypropylation (at 10% propylene oxide concentration), (b) Effect of increased concentration of propylene oxide (15%) on the starch granule structure (source Kaur et al., 2004).

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