Marinades add wonderful flavour to fish and meat, especially when they are enhanced by adding herbs and spices. But used incorrectly they can actually toughen the meat instead of tenderising it. 

MARINADE 101

Marinades come in the form of liquids, pastes and rubs. In liquid form they are mostly either acidic (made with citrus, wine or vinegar) and enzymatic (made with ingredients such as papaya or pineapple).

According to Shirley Corriher, a biochemist and author of CookWise: The Hows and Whys of Successful Cooking, both types work primarily on the surface of the food, but lead to different results.

Highly acidic marinades can actually toughen food while enzymatic marinades can turn the surface of the food to mush. For true tenderising, the most effective marinades are those containing dairy products.

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USING AN ACIDIC MARINADE

Sometimes mildly acidic marinades can add wonderful flavour to fish and meat, especially if you enhance the mixture with fresh herbs, spices, or liquid like Worcestershire sauce.

The key is to use the correct strength acid for the food you're marinating. For shrimp Shirley uses a low-acid marinade of one part mild acid to four parts oil to avoid turning the fish rubbery.

As a rule of thumb, use two tablespoons each of vinegar and caper juice and one cup of oil.

A fairly tough cut of meat like flank steak can survive a more acidic marinade since the marinade only penetrates a fraction of an inch and as such it won't toughen the meat.

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ENZYMATIC MARINADES

Raw pineapple, figs, papaya, honeydew melon, ginger, and kiwi all contain protein enzymes that break down muscle the connective tissue, but they sometimes work so well that they turn the touch meat muscle into mush.

The longer the meat marinates, the greater the breakdown of proteins and the mushier the texture.

BUT THE CRACKLING IS SUPERB

Shirley tells the delightful story of a certain Dr. Nicholas Kurti, a famous Oxford physicist, who tried tenderising a pork roast by injecting half with pineapple juice, leaving the other half untouched. Noted chef Michel Roux was to judge, on television, which side was better.

After cooking, the half treated with pineapple was total mush and looked like a pile of stuffing. Not surprisingly, Chef Roux preferred the untreated half but when trying to say something nice about the mushy half and noticing its crisp skin, announced, "But the crackling is superb!"

Dr. Kurti used the comment as the title for his book on his experiments with tenderising enzymes, published way back in 1988.  

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DAIRY IS BEST FOR TENDERISING

Shirley believes dairy products are the only marinades that truly tenderise. Hunters have long marinated tough game in milk, Indian recipes use yogurt marinades for lamb and tough goat meat, and cooks from the American south soak chicken in buttermilk before frying.

Buttermilk and yogurt are only mildly acidic, so they don't toughen the way strongly acidic marinades do. It's not quite clear how the tenderising occurs, but it seems that calcium in dairy products activates enzymes in meat that break down proteins, a process similar to the way that aging tenderises meat.

She loves making fish fingers by briefly immersing strips of fish fillets in buttermilk, seasoned with cayenne, dusting them with seasoned flour, and then frying them.

Food with a tighter texture, such as chicken or lamb, can tolerate several hours in a dairy-based marinade, even one that's mildly acidic.

QUICK TIPS

• The smaller the meat cut, the shorter the marinating time
• If you're using a rub as a marinade, cover the meat in plastic wrap and place in the refrigerator
• Always marinate in a ceramic dish - acids react to metal

OUR FAVOURITE MARINATED RECIPES

Grilled calamari in a coconut-curry marinade.  This marinade is lovely and light with fragrant flavours that are a little sweet and zesty at the same time, making it perfect for calamari. 

Portuguese-style steak rolls in a chilli, garlic and red wine marinade. Don’t be fooled by the simplicity of this marinade, sometime less is more! The ingredients are simple but the perfect combination for steak.

Marinated roast prawns in white wine and garlic. Prawns and other shellfish like mussels and clams love white wine and garlic; the flavours always find their way into the nooks and crannies of the seafood for that wonderful burst of flavour.

Crispy five-spice duck breasts with teriyaki sauce. Chinese five spice was made for meats like duck; the flavours really seep into the fat beautifully. This marinade is wonderfully thick and sticky, perfect for finger licking

Miso-marinated barbeque Hawaiian chicken Fresh pineapple, miso paste and ginger add fab flavour to this recipe that takes charred chicken to new heights. America meets Asia for a unique flavour combination that will blow your taste buds away and is definitely worth a try.

Marinated butterflied leg of lamb with sweet potatoes and garlic-coriander pesto. In this showstopper meal the lamb is marinated in a tikka-yoghurt marinade for one hour then done over the coals. 

READY-MADE MARINADES WE LOVE

Woolworths has a super range of marinades. We especially like the limited edition Moroccan marinade that's a warmly spiced, fruity marinade with cumin, coriander and apricot jam. Great for chicken.

The sticky soy, honey and ginger marinade is great on pork chops and the olive oil, rosemary and garlic marinade with brings veg to life.

Visit the Woolworths Pantry for more ideas on cooking like a chef.