A fundamental imporatance of carbohydrates in food science and technology

A fundamental imporatance of carbohydrates in food science and technology for B.Sc and M.Sc food tech students.

1. Carbohydrates: Sugars, Starches, Fibres & Modified Starches Dr.Aashwini.T Assistant Professor FPE, TDU. 15/10/2025

2. Introduction • Carbohydrates = major macronutrients in foods • Provide energy (4 kcal/g) • Structural and functional roles • Categories: Sugars, Starches, Fibres , Modified Starches

3. Sugars – Simple Carbohydrates • Monosaccharides: Glucose, Fructose, Galactose • Disaccharides: Sucrose, Lactose, Maltose • Properties: sweetness, solubility, browning reactions • Role: flavor, preservation, texture

4. Starches – Complex Carbohydrates • Plant storage polysaccharide (amylose & amylopectin) • Properties: gelatinization, retrogradation, viscosity • Applications: thickening, gelling, texture modification Gelatinization is the process of converting starch into a gelatinous form, typically by heating it with water Starch retrogradation is the recrystallization of starch molecules after they have been cooked and cooled, causing cooked foods like bread to become stale and hard over time

5. Fibres – Non-digestible Carbohydrates • Soluble fibres : pectin, gums, β-glucans • Insoluble fibres : cellulose, hemicellulose, lignin • Roles: bowel health, reduce cholesterol, regulate blood sugar • Food functionality: water-holding capacity

6. Modified Starches • Chemically, physically, or enzymatically altered starches • Types: cross-linked, pregelatinized, acid-modified • Applications: improve stability, freeze–thaw resistance, control viscosity Acid-modified starch is a starch treated with acids to partially hydrolyze its molecules, which reduces its viscosity and gelatinization temperature while improving its stability Applications Food industry:  Used as a thickener, stabilizer, or emulsifier in products like confectionery and baked goods.  Paper industry:  Used for surface sizing and coating, improving paper strength and printability.  Textile industry:  Used for warp sizing, strengthening yarns for weaving.  Other applications:  Pharmaceuticals and cosmetic formulations. 

7. Functional Roles in Foods • Sugars: sweetness, preservation, fermentation substrate • Starches: thickener, stabilizer, texture enhancer • Fibres : bulking agent, water retention • Modified starches: tailor-made processing needs

8. Examples in Food Products • Sugars → soft drinks, candies, jams • Starches → sauces, puddings, baked goods • Fibres → whole grains, fruits, vegetables • Modified starches → instant soups, frozen foods, dressings

9. Summary • Carbohydrates = energy, structure, and functionality • Sugars → quick energy, sweetness • Starches → energy storage, processing functions • Fibres → health benefits, texture • Modified starches → improved processing & stability

10. Additional information

11. Carbohydrates: sugars, starches, fibres, modified starches

12. Chemical structure of Glucose

13. Disaccharides

14. Hydration of disaccharides involves the interaction of water molecules with disaccharides, leading to two main processes: solvation (dissolving) and hydrolysis (breaking down)

15. Polysaccharides are major classes of biomolecules. They are long chains of carbohydrate molecules, composed of several smaller monosaccharides. These complex bio-macromolecules functions as an important source of energy in animal cell and form a structural component of a plant cell. It can be a homopolysaccharide or a heteropolysaccharide depending upon the type of the monosaccharides. Polysaccharides can be a straight chain of monosaccharides known as linear polysaccharides, or it can be branched known as a branched polysaccharide.

16. Characteristics Of Polysaccharides Polysaccharides have the following properties: They are not sweet in taste. Many are insoluble in water. They are hydrophobic in nature. They do not form crystals on desiccation. They are high molecular weight carbohydrates. Inside the cells, they are compact and osmotically inactive. They consist of hydrogen, carbon, and oxygen. The hydrogen to oxygen ratio being 2:1.

17. Functions Of Polysaccharides The polysaccharides serve as a structural organization in animals and plants. Other functions of polysaccharides include: They store energy in organisms. Due to the presence of multiple hydrogen bonds, the water cannot invade the molecules making them hydrophobic. They allow for changes in the concentration gradient which influences the uptake of nutrients and water by the cells. Many polysaccharides become covalently bonded with lipids and proteins to form glycolipids and glycoproteins. These glycolipids and glycoproteins are used to send messages or signals between and within the cells. They provide support to the cells. The cell wall of plants is made up of polysaccharide cellulose, which provides support to the cell wall of the plant. In insects and fungi, chitin plays an important role in providing support to the extracellular matrix around the cells.

18. References • Fennema, O.R. Food Chemistry • Belitz & Grosch. Food Chemistry • Fellows, P. Food Processing Technology