Artificial sweeteners: Provide sweet taste without calories (not metabolized or metabolized differently).

Saccharin: Ortho-sulfobenzoic acid imide. 550x sweeter than sugar. First artificial sweetener (1879). Excreted unchanged — zero calories. Slight bitter aftertaste.

Aspartame: Dipeptide methyl ester of aspartic acid and phenylalanine. 200x sweeter. Has calories but used in tiny amounts. WARNING on labels: contains phenylalanine (dangerous for phenylketonuria patients). Unstable at high temperatures — cannot be used in cooking.

Sucralose: Made from sucrose by replacing 3 -OH groups with Cl. 600x sweeter. Heat-stable (can cook with it). Not metabolized.

Alitame: 2000x sweeter. High potency means tiny amounts needed — difficult to control sweetness level.

Food preservatives: Sodium benzoate (C6H5COONa, E211 — prevents yeast/mold growth in acidic foods), potassium metabisulfite (K2S2O5 — antioxidant in wines, dried fruits), sodium sorbate. Antioxidants: BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene) — prevent fat/oil rancidity by scavenging free radicals.