Recent Developments in Starch Modification by Organic Acids: A Review

Abstract

Treatment or processing of starch with organic acids (citric, stearic, succinic, and malic acids) can be used to obtain starch properties like low retrogradation, desirable viscosity, shear resistance, and high resistant starch. Esterification, cross linking, and hydrolysis of starch may occur after modification with organic acids (citric, succinic acid, malic acid) whereas a complex between starch and stearic acid may be formed on use of stearic acid. The conditions of reactions namely duration, starch acid concentration ratio, and temperature may influence physicochemical and structural properties of starch. Citric acid, succinic acid, stearic acid, and malic acid are regarded as "GRAS" and thus the starch citrate, starch succinate, starch stearate, and starch maleate are widely used in manufacturing of starch films, blends, nanoparticles, fat replacer, viscosity enhancer, and many other products. This review paper discusses the reaction conditions of organic acid modification of starches along with their influence on physicochemical and structural characteristics.

Improving water resistance property of starch straw by synergistic effects of chemical crosslinking, physical barrier, and surface modifications

“…In this process, hydrophilic groups are reduced, and hydrophobic ester bonds are obtained. The unreacted citric acid residue has been proven to be nutritionally harmless 52,55 . Similarly, boric acid, as a safe, non‐toxic, and environmentally friendly cross‐linking agent, has multiple hydrogen bond generation sites.…”

“…In order to improve the mechanical properties and reduce the moisture sensitivity of starch-based materials, various acids (citric, boric, malic, succinic acid), especially those with smaller molecular weight and water soluble behavior have been widely used to modify starch (hydroxyl groups of starch) through esterification or acetylation. [52][53][54][55] Citric acid is a natural ternary carboxylic acid, which is cheap, has a high reaction efficiency, and can stabilize polysaccharide materials. Under the action of heat or catalyst, the multi-carboxyl group contained in citric acid forms a stable covalent intermolecular ester bond with the hydroxyl group of starch, connecting multiple starch molecules.…”

“…The unreacted citric acid residue has been proven to be nutritionally harmless. 52,55 Similarly, boric acid, as a safe, non-toxic, and environmentally friendly crosslinking agent, has multiple hydrogen bond generation sites. Crosslinking with starch can effectively reduce the humidity sensitivity of starch materials and improve their water and thermal stability.…”

“…Crosslinking with starch can effectively reduce the humidity sensitivity of starch materials and improve their water and thermal stability. 52,53 Furfural contains a highly reactive carbonyl group and conjugated double bond. 29,56 Zhang et al reported the cross-linking of starch and furfural for the preparation of a starch-furfural resin with higher mechanical properties and water resistance.…”

Preparation of high‐performance poly(butylene adipate‐co‐terephthalate)/thermoplastic starch compounds with epoxidized soybean oil as compatibilizer

“…When organic acids are used for compatibilization, the unreacted organic acids accelerate the degradation of PBAT, so other methods of PBAT/TPS compatibilization have been explored. 21 Zhang et al 22 modified starch with polyurethane prepolymer. The isocyanate group in the polyurethane prepolymer reacts with the hydroxyl group in starch and grafts onto the surface of the starch.…”