Molecular Trasformations and neo-formations compounds in processed food
Learning outcomes of the course unit
To describe to the student the chemical composition of foods and the chemical reactions and transformations occurring upon technological processes and heat treatments (cooking).
Course contents summary
Introduction. What is Food Chemistry? Principal and secondary components of foods.
Water: water structure. Interactions of water with food components and matrices. Bound water, water activity (aw).
Carbohydrates. Classification and properties. Monosaccharides. Oligosaccharides. Polisaccharides. Starch.
Lipids. Classification. Fatty acids: structure and occurrence. Essential fatty acids. Triglycerides. Melting and cristallization. Sterols. Polar lipids.
Proteins. Amino acids. Protein structure. Essential amino acids and nutritional quality of proteins. Denaturation. Technological properties of proteins.
Organoleptic aspects. Taste and aroma of foods.
Milk and dairy products. Milk: definition and physico-chemical properties. Composition: proteins (caseins and serum proteins), casein micelles, lactose, lipids, enzymes. Main technological treatment of milk. Milk types. Heat induced reactions (Maillard reaction). Fermented milks. Yoghurt. Milk cream. Butter. Condensed milk and milk powders. Derivde products: caseinates, serum proteins, lactose. Ice cream. Milk analyses.
Cheese. Definition. Clogging process. Cheese ageing: proteolysis.
Eggs. Structure, physical properties and composition. Proteins of albumen and yolk. Lipids. Colorants. Egg products.
Meat. Definition. Skeletal muscle structure. Meat composition: proteins (actin, myosin). Meat color: myoglobin. Collagen. Carbohydrates: glycogen. Post-mortem changes in muscle: rigor mortis, tendering, defects. Hydration capacity. Heat induced transformations (denaturation, gelling, Maillard reaction, Strecker reaction). Main preserving methods. Cured meat products. Meat flavor. Meat analyses.
Fish. Classification. Composition: proteins and other nitrose components. Carbohydrates and lipids. Volatile substances. Preservation and transformation.
Oils and fats. Animal and vegetal fats and oils. Olive and seed oils. Rancidity: oxydation of unsaturated fatty acids. Characteristics of fats and oils. Virgin and refined oils. Hydrogenated fats. Interesterification. Emulsions: margarine, mayonnaise. Fat analyses.
Cereals and baked products. Chemical composition. Proteins: Osborne fractions. Wheat proteins: gluten formation. Enzymes. Starch: structure and properties. Non-starch polysaccharides. Lipids. Milling: flour and semola. Bread making: chemical, physical and coking tests for flour quality. Improvers. Chemistry of gluten formation. Starch gelling and retrogradation. Dough formation and gluten matrix. Cooking: chemical modifications and aroma formation. Pasta. Other cereals (maize, barley, rice, oat).
Legumes. Chemical composition. Inhibitors of proteases and amylases. Biologically active substances: glycosides, saponins, phyitoestrogens. Soy and groundnuts: derived products. Texturalization of vegetal proteins.
Vegetables. Chemical composition. Proteins and carbohydrates. Vitamins. Color: chlorophyll, carotenoids and betacyanins. Derived products.
Fruits. Chemical composition. Proteins, carbohydrates, lipids. Vitamins and antioxidant compounds. Poliphenols. Fruit color. Fruit aroma. Fruit preservation and derived products.
Sugar and sugar products. Honey.
Alcoholic beverages. Wine, beer.
Coffea, tea, chocolate.
Spices, vinegar, salt.
Additives: Classification. Chemical properties of food additives (presrvatives, antioxidants, emulsifyiers, ecc.).
Undesirables. Toxicological aspects. Classes of undesirable components in foods. Phytotoxins. Toxins in animal products. Mycotoxins. Bacterial toxins. Allergens. Toxic residues from agriculture. Heavy metals. Toxic substances from thermal treatments. Toxic compounds from packaging. Environmental pollutants.
Texts and bibliography
T. P. Coultate, “La Chimica degli Alimenti”, 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); P. Cappelli, V. Vannucchi "Chimica degli alimenti-Conservazione e trasformazioni" Ed. Zanichelli (Bologna, 2004)
Assessment methods and criteria
Written and oral examination.