People have been using starch for centuries, from cementing strips of papyrus in ancient Egypt to preventing ink penetration in ancient China. In the 1500s, starch was introduced to England and France for use in laundry and fashion. By the 1930s, scientists developed many starch products. Starches from plants like wheat, potato, rice, maize, and more are important sources of carbohydrates in human diets. Food processors prefer starches with better qualities, so they use modifications to improve their properties for specific uses.
| Types | Properties | Applications |
| Pregelatinization | Cold-water dispersibility | Useful in instant convenience foods |
| Partial acid or enzymatic hydrolysis | Reduced molecular weight polymers, exhibit reduced viscosity, increased retrogradation, and setback | Useful in confectionery, batters, and food coatings |
| Oxidation/bleaching | Low viscosity, high clarity, and low-temperature stability | Used in batters and breading for coating various foodstuffs, in confectionery as binders and film formers, in dairy as texturizers |
| Pyroconversion (dextrinization) | Low to high solubility depending on conversion, low viscosity, high reducing sugar content | Used as coating materials for various foods, good film-forming ability, and as fat replacers in bakery and dairy products |
| Etherification | Improved clarity of starch paste, greater viscosity, reduced syneresis, and freeze-thaw stability | Used in wide range of food applications such as gravies, dips, sauces, fruit pie fillings, and puddings |
| Esterification | Lower gelatinization temperature and retrogradation, lower tendency to form gels, and higher paste clarity | Used in refrigerated and frozen foods, as emulsion stabilizers and for encapsulation |
| Cross-linking | Higher stability of granules toward swelling, high temperature, high shear, and acidic conditions Stability | Used as viscosifiers and texturizers in soups, sauces, gravies, bakery, and dairy products |
| Dual modification | Stability against acid, thermal, and mechanical degradation and delayed retrogradation during storage | Used in canned foods, refrigerated and frozen foods, salad dressings, puddings, and gravies |
| Grafting | Better biodegradability and thermal stability, higher hydrodynamic radius, and hydrodynamic volume | Used for filmmaking, during delivery, water-absorbing materials, and textile |
Starch can be modified in different ways, including using enzymes, physical methods, or chemicals. Enzymes are used to break down or extend starch, creating maltodextrin, modified starches, or syrups. Physical modification can include heat treatments or non-thermal processes. Chemical modification involves changing the starch through methods like etherification or cross-linking. Scientists can study the changes in starch through tests like microscopy, DSC, and RVA/dynamic rheometer. There is growing interest in the nutritional value of starch, and it is categorized based on its effect on blood sugar levels. Some modified starches have been shown to have lower glycemic loads, providing health benefits.
| Modification | Types | Preparation |
| Enzymatic | Degradation | Food-grade enzymes such as amyloglucosidase, pullulanase, α-amylase, β-amylase, and isomerase are used to produce syrup, cyclodextrin, and debranched starch |
| Enzymatic | Chain extension | β-amylase are used to retard retrogradation Amylosucrase are used to extend certain length α-glucan chain |
| Physical | Hydrothermal | Heat-moisture treatment is heating starch at a temperature above its gelatinization point with insufficient moisture Annealing is heating starch slurry at a temperature below its gelatinization point for prolonged periods of time |
| Physical | Pregelatinization | Pregels/instant/cold-water swelling starches are prepared using drum drying/spray cooking/ extrusion/solvent-based processing |
| Physical | Nonthermal | Radiation (gamma, electron beam, and ultraviolet irradiation) induces free radicals and changes starch molecular fragments resulting in reduction of viscosity and high water solubility Sonication is applied sounds at 20-100 kHz to homogenize, emulsify, mix, extract, dry, and disrupt starch High-pressure processing is used to gelatinize starch at pressure above 400 MPa but maintains its granular morphology |
| Chemical | Conversion | Pyroconversion (dextrinization) and pyrodextrin is prepared by dry roasting acidified starch Partial acid hydrolysis by hydrochloric acid or ortho-phosphoric acid or sulfuric acid Alkali treatment with sodium hydroxide or potassium hydroxide Oxidation/bleaching treatment with peracetic acid and/or hydrogen peroxide, sodium hypochlorite or sodium chlorite, sulfur dioxide, potassium permanganate, or ammonium persulfate |
| Chemical | Substitution | Hydroxypropyl starch-Esterification with propylene oxide Starch acetate-Esterification with acetic anhydride or vinyl acetate Acetylated distarch adipate-Esterification with acetic anhydride and adipic anhydride Starch sodium octenylsuccinate-Esterification by octenylsuccinic anhydride |
| Chemical | Cross-linking | Monostarch phosphate-Esterification with ortho-phosphoric acid, sodium or potassium ortho-phosphate, or sodium tripolyphosphate Distarch phosphate-Esterification with sodium trimetaphosphate or phosphorus oxychloride Phosphated distarch phosphate-Combination of treatments for monostarch phosphate and distarch phosphate |
| Chemical | Duel modification | Acetylated distarch phosphate-Esterification by sodium trimetaphosphate or phosphorus oxychloride combined with esterification by acetic anhydride or vinyl acetate Hydroxypropyl distarch phosphatedEsterification by sodium trimetaphosphate or phosphorus oxychloride combined with etherification by propylene oxide |