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AS WELL as adding flavour, marinades are supposed to tenderise meat before it is cooked and make it more juicy. There is plausible scientific theory and evidence to back up these claims, but when I tested some marinades, they weren’t all successful.

Salt is common to most marinades, in the main to improve flavour. But it affects texture too, dissolving some muscle proteins. Once salt has diffused into the meat, it draws moisture in from the marinade and ensures less moisture is lost during cooking.

Some marinades include acids such as citrus juice. Acids cause muscle proteins to unravel, which can soften meat. As they change shape, more parts of the proteins interact with water molecules, which may help the meat retain moisture. But if meat spends too long in a marinade that is too acidic, the unravelled proteins bond tightly and squeeze out moisture, becoming tough.

Yogurt, widely used in parts of Asia, and buttermilk, popular in the US, are weakly acidic. But the calcium they contain , increasing the activity of enzymes within the muscle that break down proteins.

In Chinese cooking, it is common to use baking soda, or sodium bicarbonate, to tenderise meat before stir-frying. There have been studies , but the mechanisms aren’t well understood.

Red wine can also have a tenderising effect on meat, partly because it is acidic, but research suggests , too. These polyphenol compounds, found in grape skins and responsible for the astringency of red wine, may react with proteins on the surface of the meat to form sticky substances that prevent juices from being squeezed out.

Some fruits, such as papaya and kiwi, contain enzymes that digest proteins, and these have also been used as .

So which is the most effective? To find out, I marinated beef cubes for 6 hours in six marinades: a salt solution, sodium bicarbonate solution, lime juice, red wine, yogurt and minced kiwi, all containing the same amount of salt. Then I put the beef on skewers and grilled the cubes for the same length of time.

Lime juice, red wine and baking soda all failed, yielding meat that was tougher and drier than the salt solution. The kiwi softened the meat, but the resulting texture was mushy and unpleasant. Only the yogurt marinade improved the meat texture so it was juicy and tender.

It turns out these marinades are more powerful than I expected, and perhaps they would have worked better if the meat had been marinated for less time.

For a reliably tenderising effect and delicious flavour, you can’t go wrong with an Indian tandoori-style marinade of yogurt, ginger, garlic, salt and any spices you like.

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