How to Mess Up Enzymes

Reader Hermes asks, since I mentioned that heat treating is only the “most popular” way to denature (wreck) browning enzymes in fruit, what other methods are there? A great question I’d be happy to answer, Hermes.

Acids do a great job of stopping browning enzymes from going to work on phenols. Depending on how strong they are they can slow down the the functioning of an enzyme, stop it from functioning altogether, or denature (gank) it. Ascorbic acid (lemon juice) and acetic acid (vinegar) are popular for this purpose.

Antioxidants inhibit browning by reacting with — and thereby using up — the oxygen that browning enzymes need to function. Ascorbic acid happens to be an antioxidant as well as just an acid, which is why a small dose of it on, say, a cut pear does a very nice job of maintaining its color and texture. As I mentioned earlier, immersing the fruit in water or wine works as well, since that deprives enzymes of oxygen as well.

And then of course there’s good ol’ sulphur dioxide, which bonds to the phenols and prevents browning enzymes from interacting with them. The application of sulphur dioxide is known as “sulfuring” and it’s a process that’s gotten a bad rap in recent years, though the ancient Egyptians and Chinese employed it for millennia and never complained. There’s just no pleasing some people.

2 thoughts on “How to Mess Up Enzymes”

  1. Since the post definitely needs to be more awkward, I would be one of those people who complain. I perceive (and I may be wrong as this is only a small sample, ie me) that sulfur dioxide, well, after consuming it you may not want to be locked in a small car with me. I initially thought, oh, it could just be that I am consuming dried fruit. But then I realized a substantial difference after I ate regular raisins versus golden raisins. The golden ones were sprayed with sulfur dioxide. Maybe I’m crazy, but now I am cautious when eating trail mix or dried fruit. I mean, someone could be hiking right behind me!

    1. The ancient papyri are strangely silent on the subject of flatulence, Derek. Then again I’m no expert here, the Egyptians might have designed a hieroglyphic to depict the condition and I’m simply not aware of it. Perhaps when they exposed dates and figs to sulphur dioxide gas they inadvertently exposed themselves to, well, another sort of gas. But we’ll likely never know for sure. A very thought-provoking comment though…thanks!

      – Joe

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