Learning objectives
To describe to the student the chemical composition of foods and the chemical reactions and transformations occurring upon technological processes, heat treatments and shelf-life.
Prerequisites
Bases of inorganic, organic, analytical chemistry and biochemistry.
Course unit content
Principal and secondary components of foods. Water in food, free and bound, water activity (aw). Drinking and mineral waters. Carbohydrates, classification and properties. Monosaccharides, disaccharides, polisaccharides, starch and fibre. Lipids, classification of fatty acids: structure and occurrence in food. Sterols and phospholipids. Proteins and amino acids. Organoleptic properties of food, colour, taste and aroma. Food vitamins and minerals. Chemical degradation of food components during processing and shelf-life. Maillard and Strecker reactions. Composition of main foods: milk and dairy products. Protein foods: cheese, egg, meat, fish. Lipid foods: oils and fats. Foods rich of glucides: sucrose, flours, bread, pasta. Foods rich of fiber: fruits and vegetables. Fermented foods: wine, beer, vinegar, yogurt. Tonic foods: coffee, tea, cacao. Functional and nutraceutical substances in foods. Molecular markers of food quality. Control of contaminants for food safety.
Full programme
Definition of food, nutritional characteristics, tables of percentage composition, Kieldahl proteins, Soxhlet and lipids. Soluble carbohydrates, starch, fibre. Secondary components, mineral salts, vitamins. Potable water quality, technical treatments. Mineral waters. Simple and complex carbohydrates, structure, reactivity and functional properties. Soluble and raw dietary fibre. Main industrial carbohydrates, production of sucrose, invert sugar, glucose, fructose and lactose. Starch hydrolysis and dextrines. Reactions of sugars with acids, bases and heat, thermal formation of HMF, lactulose, furosine. Maillard reaction, sugars fermentation. Nitrogen substances of food, origin, structure and properties. Natural free and protein amino acids, protein structure, thermal degradation, racemization, deamination, decarboxylation and formation of isopeptydes. Strecker reaction, xenobiotics formation. Enzymes of food industrial interest, enzyme kinetic: Km, Vmax. Hydrophilic and lipophilic acidity, hydroxy-acids and fatty acids. Simple and complex lipids, triacylglycerols, insaponifiables. Isomerisation and oxidation processes of fatty acids and sterols, reaction with oxygen and ozone. Molecular markers of lipid oxidation. Antioxidants. Substances responsible of colour, aroma, taste and consistence of food.
Characteristics of the main food products: cow milk, composition and thermal conditioning, butter, cheese, yogurt, milk serum by-products. High protein foods fresh and transformed, eggs, meat and ham, fish. High lipid foods: table sugar, rice, cereal meal, bread and pasta. Fibre rich foods: main classes of fruits and vegetables. Special foods: aromatic herbs, spices, fungi. Tonic beverages: coffee, tea, chocolate. Fermented foods: wine, vinegar, beer. Food preservation techniques by heating, freezing and chemical additives. Classification of food aromas. Environmental, industrial and packaging contamination of food. Notice on dietary supplements, OGM food, dietetic, functional, nutraceutical foods.
Bibliography
P. Cappelli, V. Vannucchi "Chimica degli alimenti-Conservazione e trasformazioni" Ed. Zanichelli (Bologna, 2004); P. Cabras, A. Martelli, "Chimica degli alimenti“, Ed. Piccin (Padova, 2004); H.D. Belitz - W. Grosch – P- Schieberle, “Food Chemistry”, Springer-Verlag Ed. (Berlin, Germany, 2005); O. R. Fennema, “Food Chemistry”, CRC Press Ed. (New York, USA);
Assessment methods and criteria
Written and/or oral examination.
