Hydrophilic describes molecules — or parts of molecules, or surfaces — that are attracted to water and dissolve or mix readily in it: from the Greek for “water-loving.” Sugars, salts, and the charged heads of emulsifier molecules are hydrophilic, while fats and oils are hydrophobic (“water-fearing”). The interplay drives food structure: proteins fold with hydrophilic groups outward toward water; emulsifiers bridge the two worlds, their hydrophilic heads in water and hydrophobic tails in oil, stabilising mayonnaise and ice cream. Starch’s hydrophilic hydroxyl groups explain why flour drinks up water in doughs. Formulators balance hydrophilic and lipophilic character — the HLB scale — to build stable emulsions.