Marinating is a culinary term that refers to soaking an item of food in a combination of ingredients known as a marinade. This technique is generally used to add flavor to food, as well as to tenderize the texture of meat, poultry, and seafood, which is why many marinade recipes call for an acidic ingredient. Acid, such as in citrus juice or wine, tenderizes food by breaking down the tough protein fibers. While meat and poultry can generally withstand acidic marinade ingredients for longer periods of time, seafood tends to be more delicate and the acid may actually start to tighten up the protein fibers and make it tougher. When choosing a seafood marinade, limiting the amount of acid and only marinating it for a short time can help add flavor and tenderness without making it tough or chewy.
The majority of marinade recipes tend to have acidic ingredients in them for flavor purposes, as well as for tenderizing, so avoiding acid altogether could result in a bland final seafood dish. When selecting a seafood marinade that contains an acidic ingredient, counteracting it with a higher amount of a non-acid liquid, like vegetable or olive oil, can help ensure the seafood soaks up the flavor of the acidic ingredient without toughening up the protein fibers. For seafood, it is often recommended to use a marinade that is one part acid to four parts non-acidic liquid.
Other marinade ingredients that have been found to help tenderize are dairy products. When selecting a seafood marinade with a dairy base, buttermilk or plain yogurt tend to be commonly used options for tenderizing without overpowering the seafood flavor. Although the dairy products may be slightly acidic, they are typically less prone than more acidic ingredients to toughening seafood. They may be more preferable to beginner cooks who do not wish to risk the texture of the seafood by accidentally exposing it to too much acid.
Prior to marinating seafood, additional flavoring agents may be mixed into the marinade. Common ingredients include fresh or dried herbs, spices, or garlic. Once the remaining ingredients are chosen, they may be whisked into the seafood marinade base. The marinade may be poured over raw seafood in a dish and then covered, or combined with the seafood in a resealable bag. To prevent foodborne bacteria, it is usually advised to only marinate seafood in the refrigerator and not at room temperature, and to discard the raw marinade before cooking the seafood.