Unlocking Starch Potential: Exploring Modifications for Enhanced Properties
The structural modifications of starch can profoundly impact its final properties. Here, we delve into various types of alterations and their effects on starch characteristics.
Acetylation/Esterification:
- Acetylation disrupts starch granules, reducing crystallinity and gelatinization temperature.
- Acetylated Black and Pinto bean starches exhibit improved properties like reduced syneresis, lower glycemic index, and increased resistant starch levels.
- Acetylation of Musa AAB (poovan banana) starch reduces non-starch components, enhances B-type crystalline structure, and increases swelling capacity.
Surface Modification:
- Surface esterification using dodecenyl succinic anhydride strengthens cornstarch films, enhancing strength, rigidity, and flexibility.
- Hydroxypropylated starches, created by adding propylene oxide, result in films with higher elongation, water vapor permeability, and transparency.
Cross-linking:
- Cross-linking alters physical and thermal properties, slowing retrogradation and raising gelatinization temperature.
- Graft copolymerization of phenyl methacrylate onto potato starch creates amphiphilic copolymers with unique properties.
Oxidation:
- Oxidation with hypochlorite or hydrogen peroxide changes starch molecular structure, affecting gelation, viscosity, and retrogradation.
- Ozone treatment reduces solubility in sago and tapioca starches but increases it in oxidized cornstarch.
Acid Hydrolysis:
- Acid-thinning hydrolysis increases gelatinization temperature, retrogradation tendency, and solubility, while decreasing viscosity and average molecular weight.
Enzymatic Hydrolysis:
- Heat-stable α-amylase partially hydrolyzes starches, breaking down granules and reducing solid properties.
Understanding these modifications offers insights into tailoring starch for specific applications, from improved film properties to enhanced functional characteristics.