What You Need to Know
The batter undergoes lactic acid fermentation, producing CO₂ and lowering pH to ~4.5–5.0, which leavens the dough and imparts a slight sourness. During frying, Maillard browning between reducing sugars and amino acids generates melanoidins, while starch gelatinizes to form a crisp exterior and chewy interior. The syrup, boiled to 110–120 °C, becomes viscous enough to coat the porous fried rings.
The Science
Primary Reaction
Fermentation (lactic acid fermentation) and Maillard browning during frying