Stabilizers Starch, films

Krogars, K., Heinamaki, J., Karjalainen, M., Niskanen, A., Leskela, M., and Yliruusi, J. Enhanced stability of rubbery amylose-rich maize starch films plasticized with a composition of sorbitol and glycerol, Int. J. Pharm., 251, 205, 2003. 

Further, Akter et al. (2012] observed that the differential thermal analysis showed two exothermic peaks for chitosan around 74 and 289°C, but starch-chitosan blend films displayed two strong exothermic peaks around 95 and 303°C. This confirmed that composite films are more stable than simply chitosan films. Therefore, it is clearly revealed that thermal stability of chitosan-reinforced starch-based films improved significantly compared to native chitosan or starch films. 

Fernandez-Cervera M, Karjalainen M, Airaksinen S, Rantanen J, Krogars K, Heinamaki J, Iraizoz-Colarte A, Yliruusi J [2004]. Physical stability and moisture sorption of aqueous chitosan-amylose starch films plasticized with polyols. EurJ Pharm Biopharm, 58,69-76. 

Uses Food emulsifier emulsion stabilizer and film-former in caramels retards starch crystallization in starch jellies inhibits oil separation in peanut butter in dehydrated potatoes antistatfor PP, PS useful in food pkg. 

Starch acetates may have low or high DS. The industrial importance of low DS acetates results from their abiUty to stabilize aqueous polymer sols. Low DS acetates inhibit association of amylose polymers and reduce the association of the longer outer chains of amylopectin. These properties are important in food appHcations. Highly derivatized starches (DS 2—3) are useful because of their solubiHty in organic solvents and abiHty to form films and fibers. 

Polymers. In combination with various metal salts, sorbitol is used as a stabilizer against heat and light in poly(vinyl chloride) (qv) resins and, with a phenohc antioxidant, as a stabilizer in uncured styrene—butadiene mbber (qv) compositions and in polyolefins (see Heat stabilizers Olefin POLYMERS Rubbercompounding). Heat-sealable films are prepared from a dispersion of sorbitol and starch in water (255). Incorporation of sorbitol in coUagen films gready restricts their permeabiUty to carbon dioxide (256). 

Low melt temperatures, e.g., 140-170°C for Ecoflex and Ecoflex /starch compounds, 165-190°C for Ecovio need to be achieved, which are beneficial for blown film stability and thermal stability. 

Because of the limited thermal stability of, e.g., Ecoflex /starch compounds, dead spots in the feed block adapter or the film die have to be avoided. As a consequence, reduction of the film width by closing the die with metal bars (deckling) is not recommended for Ecoflex /starch compounds. 

Starch is an abundant, inexpensive polysaccharide that is readily available from staple crops such as com or maize and is thus is mostly important as food. Industrially, starch is also widely used in papermaking, the production of adhesives or as additives in plastics. For a number of these applications, it is desirable to chemically modify the starch to increase its hydrophobicity. Starch modification can thus prevent retrodegradation improve gel texture, clarity and sheen improve film formation and stabilize emulsions [108], This may, for example, be achieved by partial acetylation, alkyl siliconation or esterification however, these methods typically require environmentally unfriendly stoichiometric reagents and produce waste. Catalytic modification, such as the palladium-catalyzed telomerization (Scheme 18), of starch may provide a green atom-efficient way for creating chemically modified starches. The physicochemical properties of thus modified starches are discussed by Bouquillon et al. [22]. 

Improved stability towards oxidation of spray dried flavor oils was achieved by using a combination of a high-maltose syrup, maltodextrin and a high molecular weight, film-forming polysaccharide, such as starch octenylsuccinate or gum ara-bic.200 201 Emulsification performance of maltodextrins is improved by treatment with octenylsuccinic anhydride and aluminum sulfate. 

Surimi is fish paste from deboned fish used to make simulated crab legs and other seafood. For preservation the paste is blended with cryoprotectants, such as sucrose, sorbitol and phosphates, and frozen. To make the final product, the frozen paste is thawed, blended with starch and extruded as a film onto a belt. The belt takes the film into an oven that heat-denatures the fish protein and cooks the starch. The film is then rolled to form striations, shaped, colored and cut. Depending on the required distribution, the product is frozen or refrigerated. Potato and tapioca starch were used in surimi products 400 years ago, since they provided a cohesive, elastic matrix consistent with seafood. Frozen distribution has made the use of highly-stabilized, moderately crosslinked tapioca starch popular, alone or with native tapioca starch. Modified waxy maize products are used, as is unmodified com starch, for increased cuttability. Kim188 reported that the gel strengthening ability of starch correlates with starch paste viscosity. 

The cooked pastes of ETHYLEX demonstrate excellent viscosity stability over prolonged periods of time and show little change in viscosity due to temperature fluctuations. Films produced from these pastes are clear, continuous and decidedly more flexible than those produced from other starch modifications. These characteristics, and others to be discussed later, strongly recommend the ETHYLEX Gums to widespread application in the paper, textile and adhesive industries. 

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