Food Science Vocabulary in English — 20 Essential Terms

Emulsification is the process of combining two immiscible liquids — most commonly oil and water — into a stable, uniform mixture by using an emulsifying agent. Emulsifiers work because they have a molecule with one end that is attracted to water (hydrophilic) and one end attracted to oil (hydrophobic), allowing them to sit at the boundary between the two liquids and prevent separation. In food production, emulsification is fundamental to products such as mayonnaise, salad dressings, ice cream, and many baked goods. Without it, these products would separate into oily and watery layers within minutes of being made.

Pasteurisation and sterilisation are both heat treatments designed to make food safer, but they differ in the temperatures used, the duration, and the outcome. Pasteurisation uses relatively moderate temperatures — typically between 63°C and 90°C — for a set time, which destroys most pathogenic microorganisms while preserving the nutritional quality and flavour of the food. However, it does not eliminate all microorganisms, so pasteurised products still require refrigeration and have a limited shelf life. Sterilisation, by contrast, uses much higher temperatures, often above 121°C, to destroy virtually all microbial life, including heat-resistant spores. Sterilised products, such as canned goods or UHT milk, can be stored at room temperature for months or years, but the intense heat can alter flavour and reduce some heat-sensitive vitamins.

The Maillard reaction is a chemical reaction between amino acids and reducing sugars that produces hundreds of flavour, aroma, and colour compounds when food is subjected to heat. It is responsible for the appetising brown colour and complex flavour of roasted coffee, toasted bread, grilled meat, and baked biscuits. Caramelisation, by contrast, involves only the thermal breakdown of sugars themselves — no amino acids are required — and occurs at higher temperatures. Both processes produce browning, but the Maillard reaction is far more complex, generating a greater variety of flavour compounds. The easiest way to remember the difference is that the Maillard reaction requires protein as well as sugar, whereas caramelisation needs only sugar.

The pH level is a scale from 0 to 14 that indicates how acidic or alkaline a substance is. A pH of 7 is neutral (pure water), values below 7 are acidic, and values above 7 are alkaline. In food science, pH is critically important for several reasons. First, many pathogenic bacteria such as Clostridium botulinum cannot grow at low pH values, so acidic foods (below pH 4.6) are considered inherently safe from this particular risk. Second, pH affects the activity of enzymes that cause browning or spoilage in fruit and vegetables. Third, it controls the behaviour of proteins: for example, the texture of cheese and yoghurt depends on precise pH values during fermentation. Finally, pH affects the stability of colours and flavours, so manufacturers monitor it carefully throughout production.

HACCP stands for Hazard Analysis and Critical Control Points. It is a preventive, science-based food safety management system that systematically identifies biological, chemical, and physical hazards at every stage of food production and processing, then establishes control measures and monitoring procedures to ensure those hazards are eliminated or reduced to safe levels. HACCP is not merely a best practice — in the European Union, the United States, Canada, and many other countries, it is a legal requirement for all food businesses that produce, process, or handle food commercially. Even small businesses such as catering companies, bakeries, and farm shops are required to implement some form of HACCP-based food safety management. The system typically produces written records that inspectors can review to verify that safety procedures have been followed.

Viscosity and texture are related but distinct concepts in food science. Viscosity is a physical property of liquids and semi-liquids that describes their resistance to flow. A high-viscosity fluid such as honey flows slowly and thickly, while a low-viscosity fluid such as water flows freely. Texture is a broader sensory concept that describes the overall physical feel of a food in the mouth and during handling, including properties such as hardness, crunchiness, chewiness, creaminess, and stickiness. Viscosity is a component of texture for liquid and semi-liquid foods, but texture also encompasses solid and semi-solid properties that cannot be described by viscosity alone. Food scientists measure viscosity objectively with instruments called viscometers or rheometers, while texture is evaluated through both instrumental methods and human sensory panels.

Bioavailability refers to the proportion of a nutrient or bioactive compound from a food that is actually digested, absorbed, and used by the body, as opposed to the total amount present in the food. The same nutrient can have very different bioavailability depending on where it comes from and how the food has been processed. The food matrix — the complex physical and chemical structure of a food including all the interactions between its components — plays a major role in determining bioavailability. For example, the beta-carotene in a raw carrot is enclosed within intact plant cell walls, making it relatively difficult to absorb. However, cooking or pureeing the carrot breaks down the cell walls, releases the beta-carotene, and dramatically increases its bioavailability. Consuming fat alongside the carrot increases it further, because beta-carotene is a fat-soluble compound.

Fermentation is a metabolic process in which microorganisms such as bacteria, yeasts, or moulds convert carbohydrates — primarily sugars — into other compounds such as organic acids, ethanol, or carbon dioxide, typically under conditions where oxygen is absent or limited. In food production, fermentation serves multiple purposes: it preserves food by lowering pH or producing alcohol, it creates distinctive flavours and aromas, it improves digestibility, and it can increase the bioavailability of nutrients. Familiar fermented foods include yoghurt and cheese (lactic acid bacteria), bread and beer (yeast), wine (yeast), kimchi and sauerkraut (lactic acid bacteria), soy sauce and miso (moulds and bacteria), and vinegar (acetic acid bacteria). Fermented foods are also associated with potential probiotic benefits, because some contain live microorganisms that may support gut health.

Denaturation is an irreversible change in the three-dimensional structure of a protein caused by exposure to heat, acid, alcohol, or mechanical force. Under normal conditions, proteins fold into precise shapes held together by weak bonds, and this shape determines their function. When a protein denatures, these bonds break and the protein unfolds or re-folds into a different shape, losing its original biological activity. In food science, denaturation is extremely important because it changes the physical properties of food. When egg white is heated, the transparent liquid proteins denature and coagulate into a white solid. When meat is cooked, muscle proteins denature and the texture changes from soft and raw to firm and cooked. When milk is acidified during cheese-making, casein proteins denature and aggregate to form curds. Understanding denaturation allows food technologists to control the texture and appearance of food products with precision.

Sensory evaluation is a scientific discipline that measures, analyses, and interprets the responses of trained or consumer panellists to the sensory properties of food and beverages using the five senses — sight, smell, taste, touch, and hearing. In the food industry, it is used throughout product development and quality control. During new product development, sensory panels assess prototype formulations to identify which recipe best meets consumer expectations. During reformulation (for example, when reducing sugar or salt), sensory evaluation checks whether the change is detectable. During shelf-life studies, panels monitor how flavour, colour, and texture change over time. Consumer acceptance testing helps manufacturers predict how products will perform in the marketplace before launch. Sensory evaluation may use trained expert panels for objective analytical testing or untrained consumer panels for preference and acceptance testing, depending on the question being investigated.