Retro gradation, starch

As mentioned previously, one problem encountered in starch-based adhesives is retro-gradation. Colloid stabilizers such as soaps and sodium chloride are used to retard this tendency. Borax, sodium hydroxide, and several common plasticizers also perform this... 

V.J. Morris, Starch Gelation and Retro gradation. Trends Food Sci. Tech., 1, 2,1990. 

Kim JO, Kim WS, Shin MS. A comparative of rice starch and a-amylase study on retro-gradation gels by DSC, X-ray methods. Starch 1997 49 (2) 71-75. 

Nonionic surfactants and emulsifiers are compounds whose molecules have both aqueous (polar) and alkane (nonpolar) compatible sectors. Their molecules have regions that are sufficiently similar to become part of either system, with the other sectors sufficiently dissimilar to interrupt continuation of that system. For example, when added to a crystallizing fat, some nonionic surfactants may orient themselves to become part of the crystal, and will prevent further replication thus limiting crystal size. Likewise, some will react wth gelatinized starch in aqueous systems and prevent its recrystallization (retro-gradation). Further, surfactants may orient around discrete droplets to stabilize water in oil (W/O) or oil in water (O/W) emulsions. When this occurs, the compatible end becomes associated with the discrete droplet, leaving the other end turned outward to associate with the compatible continuous phase. 

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