Why does lemon juice prevent browning?
Show answer & explanation
Answer: Acid lowers pH stopping enzymes
Coats fruit blocking oxygen — Wrong. Liquid can reduce oxygen contact, but the primary mechanism is chemical—citric acid lowers pH, denaturing polyphenol oxidase enzyme.
Acid lowers pH stopping enzymes ✓ — Correct! Enzymatic browning (apples, avocados) requires polyphenol oxidase enzyme to work at specific pH (~6-7). Lemon juice is acidic (pH ~2), which lowers the fruit's pH below the enzyme's best range, denaturing it and stopping oxidation. The enzyme can't function in acidic conditions!
Sugar content preserves fruit — Wrong. Lemon juice has minimal sugar. The anti-browning effect comes from citric acid denaturing the enzyme that causes oxidation.
More Food & Nutrition questions
- Parmigiano Reggiano is made with milk, salt, and rennet only, so why can older pieces taste more savory or spicy without extra seasoning?
- Why does a Parmigiano Reggiano wheel wait until at least 12 months for the official selection mark instead of being fully approved when it is molded?
- How can Parmigiano Reggiano keep developing flavor after its starter bacteria have done their early acid-making job?
- A young Parmigiano Reggiano can taste milky, while older wheels lean nutty, spicy, or broth-like; what pushes the flavor away from plain dairy?
- Why does aging Parmigiano Reggiano from 12 months to 36 months not matter much for removing lactose?
- Why can older Parmigiano Reggiano turn crumblier and grainier instead of simply becoming a harder block?