1 Foundations of Food Chemistry
Explore how food composition, structure, and processing shape food properties, sensory qualities, preservation, and safety.
and chemistry
applies physical, biological, and engineering principles to understand foods, how they change, and how to process and preserve them. focuses on food components and the reactions and interactions that affect quality, safety, and usefulness.
Together, these perspectives connect the composition and structure of food with its behavior during preparation, processing, storage, and use.
Food structure and properties
A food is more than a list of ingredients: it is a in which water, , , fats, minerals, and other compounds interact. Their composition and arrangement help determine firmness, thickness, crispness, color, flavor, and shelf life.
Foods can be solutions, gels, foams, or mixtures of particles and droplets. Milk, for example, is an of fat droplets dispersed in a water-based phase.
Two kinds of properties are especially useful for describing foods:
are observable or measurable characteristics, such as texture, viscosity (resistance to flow), density, and melting or freezing behavior.
relate to composition and reactions, including acidity measured as , oxidation, and changes caused by heat, enzymes, or microorganisms.
and
include sugars, starches, and many fibers. Sugars contribute sweetness and can promote browning during heating. Starch absorbs water and thickens mixtures; during cooking, starch granules swell and gelatinize, as in a thickened sauce.
are chains of amino acids. Heat, acid, or mechanical action can cause to , changing their ability to bind together or hold water. These changes help explain why egg white sets when heated and why mixing can alter dough structure.
Fats, emulsions, and water
Fats and oils, also called lipids, do not mix readily with water. They add richness and carry some aromas. When fat is finely dispersed in water, it can form an ; emulsifiers help keep the droplets from separating.
Oxygen, light, and heat can promote lipid oxidation, which may produce stale or rancid flavors.
Water dissolves many ingredients, moves heat and dissolved substances, and supports reactions. Total water content is not the same as , written : describes how available water is for reactions and microbial growth. Salting or sugaring can reduce by binding water.
Processing, preservation, and safety
Processing changes food properties to make foods easier to use, more consistent, or longer-lasting. Different processing approaches have different effects:
Heating can cook ingredients and reduce microorganisms.
Cooling slows many reactions and microbial growth.
Drying removes water.
Fermentation uses microorganisms to produce characteristic acids, flavors, or textures.
Acidity and are among the factors that influence whether particular microorganisms can grow. No single factor guarantees safety in every food. Safe production depends on controlling hazards across ingredients, processing, storage, and use. systems organize this work by identifying hazards and controlling important steps in a process.
Sensory qualities
People judge foods through appearance, aroma, taste, and texture; temperature and sound also contribute. Sensory qualities emerge from food composition and structure: bubbles make some foods light, fat droplets can create creaminess, and pigments and browning reactions influence color.
Food scientists measure these properties and use to understand how changes in ingredients or processing affect what people perceive.
How food properties connect
Food composition, structure, and processing together determine physical and chemical behavior. , , fats, and water each contribute distinctive functions, while their interactions shape texture, flavor, stability, and safety. Understanding these relationships helps explain food preparation, preservation, and quality.