Introduction to Food Chemistry

Introduction to Food Chemistry

• Food chemistry is the study of the chemical composition, properties, and reactions of food.
• It encompasses the basic structure of molecules (carbohydrates, proteins, lipids) to interactions during processing and storage.
• Understanding food chemistry is vital for new product development, improved food safety, and maintaining nutritional value.

Macronutrients

• Carbohydrates: Organic compounds (carbon, hydrogen, oxygen) crucial for energy.
  • Types: monosaccharides (simple sugars), disaccharides (double sugars), polysaccharides (complex carbohydrates).
  • Examples: starch (digestible), cellulose (indigestible).
• Proteins: Essential for building and repairing tissues.
  • Composed of amino acids linked by peptide bonds.
  • Structures (primary, secondary, tertiary, quaternary) dictate function.
  • Examples: enzymes, hormones, structural proteins.
• Lipids: Fats, oils, and waxes, for energy storage, insulation, and cell membranes.
  • Fats are solid, oils are liquid at room temperature.
  • Composed of fatty acids and glycerol.

Micronutrients

• Vitamins: Organic compounds needed in small amounts for metabolic processes.
  • Classified as water-soluble (e.g., vitamin C, B vitamins) or fat-soluble (e.g., vitamins A, D, E, K).
• Minerals: Inorganic elements essential for various bodily functions.
  • Examples: calcium, iron, sodium, potassium.

Food Reactions

• Maillard Reaction: Non-enzymatic browning reaction between amino acids and reducing sugars during heating, affecting color, flavor, and texture.
• Oxidation: Loss of electrons by a substance.
  • Fat oxidation causes rancidity (affecting flavor and safety).
  • Antioxidants prevent or delay oxidation.
• Hydrolysis: Chemical reaction using water to break larger molecules into smaller ones, like protein breakdown into amino acids during digestion.
• Denaturation: Change in a protein's three-dimensional shape due to heat, acids, or bases, affecting texture and function.

Food Preservation

• Methods extend food shelf life.
• Freezing: Stops microbial growth and enzyme activity.
• Refrigeration: Slows bacterial growth.
• Irradiation: Uses ionizing radiation to kill bacteria and pests.
• Preservatives: Chemicals (e.g., salt, sugar) inhibit microbial growth.

Food Additives

• Substances added to food to improve quality, safety, or appearance.
  • Includes colorings, flavorings, preservatives, and stabilizers.
  • Understanding additive effects is crucial for consumer health.

Sensory Properties of Food

• Sensory properties (flavor, aroma, texture, color) are influenced by chemical components.
• Sensory evaluation assesses food quality.

Food Processing

• Techniques alter food properties.
• Examples: cooking, freezing, canning, fermentation, drying.
• Affects chemical and physical properties, leading to changes in flavor, texture, and shelf life.

Food Safety

• Crucial aspect of food chemistry.
• Microbial contamination and foodborne illnesses are major concerns.
• Proper food handling and storage prevent illness.