Biorefinery platforms – Starch
Concept
- Starch serves the plants as a reserve food supply. It is manufactured from excess glucose produced during photosynthesis. It is found in maize, wheat, potato, rice, barley and many other plants.
- Starch is a complex polysaccharide made up of a large number of glucose units joined together by glycosidic bonds. The basic chemical formula of the starch molecule is (C6H10O5)n. It consists of two types of molecules: the linear amylose (20-25% by weight) and the branched amylopectin (75-80% by weight).
- Pure starch is a soft, white, tasteless and odourless powder that is insoluble in cold water or alcohol.
- The starch industry extracts and refines starches from seeds, roots and tubers, by wet grinding, washing, sieving and drying. After harvesting, feedstocks are cleaned and grinded into pulp. The starch slurry and juice are then separated. The juice is further processed to produce proteins and concentrated fruit juice. Starch slurry is refined and dried to produce native starch to be sent to granulate production. Concentrated fruit juice, proteins and pulp are obtained as co-products of the starch production process.
Applications
- Food and feed. The starch industry produces native starches, physically or chemically modified starches and sweeteners (maltodextrins, starch-based sugars and polyols) that can be used as ingredients in food, drinks and feed.
- Feedstock for the sugar platform.
- Plastics. Starch is a natural resource that allows to produce biodegradable plastic goods that can be readily manufactured on existing processing equipment with little or no modification. Starch plastics are blends of starch with one or more polymers (fossil or biobased polyesters). Plasticisers such as glycerine can be used to convert native starch into thermoplastic starch for improved mechanical properties.
- Pulp and paper. Starch is used in paper manufacturing to increase the strength of paper and is also used in the surface sizing of paper. It is used in the manufacture of corrugated paperboard, paper bags and boxes, gummed paper and tape.
- Textile. Large quantities of starch are used in the textile industry as warp sizing, which imparts strength to the thread during weaving.
- Pharmaceuticals and cosmetics. Starches make a variety of contributions in pharmaceutical, cosmetic, make up and healthcare products. For instance, binder and sugarless sweetener.
References