Food Science Glossary

A quick-reference glossary of food science terms used across this site. Each definition links to the full article where the concept is explained in depth.

Acid: A compound that donates hydrogen ions in solution. Acids have a pH below 7. In cooking, acids like vinegar, lemon juice, and buttermilk affect browning, texture, and flavor. See: Acids and Bases in Cooking

Acrylamide: A chemical compound that forms during the Maillard reaction in starchy foods cooked at high temperatures. French fries and potato chips are the main dietary sources. Research on its health effects is ongoing. See: The Maillard Reaction

Advanced Glycation End Products (AGEs): Compounds formed when proteins or fats combine with sugars in a process called glycation. They form in the body (during normal metabolism) and in food during high-heat cooking. Elevated AGEs in tissue are linked to aging and chronic disease. See: Advanced Glycation End Products

Amino Acid: The building block of protein. There are 20 standard amino acids. Nine are essential, meaning your body can’t make them and they must come from food. Amino acids also play a key role in the Maillard reaction. See: The Maillard Reaction

Antinutrients: Compounds in plant foods that interfere with the absorption of nutrients. Common examples include phytates (in grains and legumes), oxalates (in spinach), and lectins (in beans). Many are reduced or eliminated by cooking. See: Antinutrients Explained

Artificial Sweeteners: Non-nutritive or low-calorie sugar substitutes including aspartame, sucralose, saccharin, and stevia-derived compounds. They provide sweetness without the caloric load of sugar. Their effects on metabolism, gut bacteria, and appetite are an active area of research. See: Artificial Sweeteners

Bioavailability: The fraction of a nutrient that’s actually absorbed and used by the body. Eating a nutrient doesn’t guarantee absorbing it. Cooking method, food pairing, and individual factors all affect it. See: Bioavailability Explained

Botulism: A rare but serious illness caused by the toxin of Clostridium botulinum bacteria. The toxin can form in improperly canned or preserved low-acid foods. Proper canning temperatures and times are designed to eliminate this risk. See: Canning Science

Caramelization: The browning of sugar through heat, without amino acids involved. Different from the Maillard reaction. Caramelization happens at higher temperatures (roughly 320–370°F depending on the sugar) and produces sweet, buttery, caramel-like flavors. See: Caramelization vs. Maillard

Carrageenan: A seaweed-derived polysaccharide used as a thickener and stabilizer in dairy products, infant formula, and processed foods. Approved by the FDA and considered safe at food-use levels, though some consumer controversy exists. See: Carrageenan

Cholesterol: A waxy lipid found in cell membranes and used to make hormones, bile acids, and vitamin D. Your liver produces most of it. Dietary cholesterol has less impact on blood cholesterol than was once believed. Saturated fat has a stronger effect. See: Cholesterol Science

Citric Acid: A weak organic acid found naturally in citrus fruits and used widely as a food additive for flavor, preservation, and pH control. It’s produced commercially by fermenting carbohydrates with Aspergillus niger mold. See: Citric Acid

Cross-Contamination: The transfer of harmful bacteria or allergens from one surface, food, or tool to another. A leading cause of foodborne illness. Separate cutting boards for raw meat and produce, and proper handwashing, are the main controls. See: Cross-Contamination

Denaturation: The unfolding of a protein’s three-dimensional structure due to heat, acid, or mechanical action. Cooking an egg is denaturation in action. The protein unfolds and re-bonds in new configurations, changing texture and digestibility. See: Protein Denaturation

Emulsification: The process of dispersing one liquid into another that doesn’t normally mix. Oil and water don’t mix on their own, but with an emulsifier (like lecithin in egg yolk), tiny droplets of one can stay suspended in the other. Mayonnaise is a classic example. See: Emulsions Explained

Fermentation: A metabolic process in which microorganisms (bacteria, yeast, or molds) convert sugars into acids, gases, or alcohols. Used to make yogurt, bread, kimchi, beer, wine, cheese, and many other foods. See: Fermentation Basics

Fiber (Dietary): Non-digestible carbohydrates found in plant foods. Divided broadly into soluble fiber (which forms a gel in water and slows digestion) and insoluble fiber (which adds bulk and speeds transit). Gut bacteria ferment much of the soluble fiber into short-chain fatty acids. See: Fiber Types

Food Dyes (FD&C): Synthetic color additives approved by the FDA for use in food. Common examples include Red 40, Yellow 5, and Blue 1. They’re some of the most studied food additives in the regulatory system. Concerns about hyperactivity in children have been studied but results are mixed. See: Food Dyes

Food Irradiation: A food safety technology that exposes food to ionizing radiation to kill pathogens, reduce spoilage organisms, or inhibit sprouting. Approved and regulated by the FDA. Does not make food radioactive. See: Food Irradiation

Gelatinization: What happens when starch granules absorb water and heat, causing them to swell and thicken a liquid. The main mechanism behind sauces, gravies, and porridges thickening when heated. See: How Starch Thickens

Gluten: A protein network formed when glutenin and gliadin proteins in wheat flour are hydrated and worked. Gives bread its structure and chew. Problematic for people with celiac disease or non-celiac gluten sensitivity. See: Gluten Development

Glycemic Index (GI): A measure of how quickly a food raises blood sugar compared to pure glucose (GI of 100). Low-GI foods digest more slowly and produce a more gradual blood sugar response. Context matters more than the number alone. See: Glycemic Index Explained

GRAS (Generally Recognized as Safe): A designation by the FDA indicating that a substance is considered safe by qualified experts for its intended use in food. Many common food additives hold GRAS status. See: MSG

Gut Microbiome: The community of trillions of microorganisms (mostly bacteria) living in your large intestine. They ferment fiber, train the immune system, produce certain vitamins, and influence gut-brain communication. Diet is one of the strongest factors shaping the microbiome. See: Your Gut Microbiome

High-Fructose Corn Syrup (HFCS): A sweetener made from corn starch by converting some glucose to fructose, producing a mixture of roughly 42–55% fructose. Used widely in processed foods and beverages. Its effects compared to table sugar (sucrose) is a debated area in nutrition science. See: High-Fructose Corn Syrup

Intermittent Fasting: An eating pattern that cycles between periods of eating and fasting. Common protocols include 16:8 (fast 16 hours, eat within an 8-hour window) and 5:2 (eat normally five days, restrict calories two days). Research shows effects on metabolic markers, though long-term evidence is still developing. See: Intermittent Fasting Science

Maillard Reaction: A chemical reaction between amino acids and reducing sugars that happens when food is heated above roughly 280°F (140°C). It creates hundreds of new flavor and aroma compounds and the characteristic brown color of seared meat, bread crust, and roasted coffee. See: The Maillard Reaction

Melanoidin: The large, dark brown polymer molecules produced in the final stages of the Maillard reaction. They’re responsible for the brown color of toasted bread, roasted coffee, and seared meat. See: The Maillard Reaction

MSG (Monosodium Glutamate): The sodium salt of glutamic acid, a common amino acid. Dissolves into sodium and glutamate ions that activate umami taste receptors. FDA-classified as Generally Recognized as Safe (GRAS). The “Chinese Restaurant Syndrome” concern was not supported by controlled research. See: MSG: The Science

Omega-3 Fatty Acids: Essential polyunsaturated fats that must come from diet. The key forms are ALA (from plants), and EPA and DHA (from marine sources). EPA and DHA have the strongest evidence for cardiovascular and anti-inflammatory benefits. Conversion from plant-based ALA is poor. See: Omega-3 vs Omega-6

Osmosis: The movement of water across a membrane from an area of lower solute concentration to higher. In food science, this is why salt draws moisture out of vegetables and meat, and how brining works. See: The Science of Salt

Pasteurization: A heat treatment that kills most pathogenic microorganisms in food without sterilizing it completely. Named after Louis Pasteur. Used in milk, juice, eggs, and many other products. See: Raw Milk

Pathogen: A microorganism capable of causing disease. Common foodborne pathogens include Salmonella, E. coli O157:H7, Listeria monocytogenes, Campylobacter, and Clostridium botulinum. See: Temperature Danger Zone

pH: A measure of how acidic or basic a solution is, on a scale from 0 (most acidic) to 14 (most basic). 7 is neutral. pH affects browning reactions, microbial safety, texture, and flavor in food. See: Acids and Bases in Cooking

Reducing Sugar: A sugar capable of acting as a reducing agent in a chemical reaction. Glucose and fructose are reducing sugars. They’re one of the two required ingredients for the Maillard reaction, along with amino acids. Sucrose is not a reducing sugar until it’s broken down. See: The Maillard Reaction

Short-Chain Fatty Acids (SCFAs): Compounds produced when gut bacteria ferment dietary fiber. The main ones are acetate, propionate, and butyrate. Butyrate is the primary fuel for colonocytes (colon lining cells) and plays a role in reducing inflammation. See: Your Gut Microbiome

Smoke Point: The temperature at which an oil starts to break down visibly and produce smoke. Different oils have different smoke points. Above this temperature, the oil degrades, producing off-flavors and potentially harmful compounds. See: Smoke Points Explained

Sodium Benzoate: A preservative used in acidic foods and beverages to inhibit mold and bacterial growth. Effective at low pH. A concern at high concentrations in combination with vitamin C (ascorbic acid), which can produce small amounts of benzene. See: Sodium Benzoate

Sodium Nitrite: A curing salt used in processed and cured meats (bacon, hot dogs, deli meats) to inhibit Clostridium botulinum, preserve color, and develop flavor. Linked to the formation of nitrosamines at high temperatures. Regulated with strict limits. See: Sodium Nitrite

Soy Lecithin: An emulsifier extracted from soybean oil processing. Found in chocolate, margarine, baked goods, and hundreds of other products. Generally considered safe. Contains trace soy protein but allergic reactions in people with soy allergy are rare. See: Soy Lecithin

Umami: The fifth basic taste, distinct from sweet, salty, bitter, and sour. Described as savory, meaty, or brothy. Triggered by glutamate (the same molecule in MSG) activating specific taste receptors. Found naturally in high concentrations in parmesan cheese, soy sauce, anchovies, and tomatoes. See: MSG: The Science

Water Activity (Aw): A measure of the availability of water in food for microbial growth and chemical reactions. Ranges from 0 to 1. Lower water activity means safer preservation. Jerky, honey, and hard candy have low water activity and don’t support bacterial growth. See: The Temperature Danger Zone

Xanthan Gum: A polysaccharide produced by fermenting glucose with Xanthomonas campestris bacteria. Used as a thickener and stabilizer in salad dressings, sauces, and gluten-free baked goods. FDA-classified as GRAS. See: Xanthan Gum