Some chefs tell us that “marinade” is derived from the Italian word “marinare,” which means to soak or pickle in brine. The true origin of the word may be lost in history. Wherever the technique was created, marinades were used, traditionally, on lean, dry cuts of meat and had three primary functional ingredients: acid, oil or other liquid and aromatics. Acid was added to tenderize the meat by breaking down muscle fibers. Oil and other liquids were used to coat the meat so it remains moist during cooking. Aromatics, which were the heart of the marinade, created distinct flavor profiles or enhanced the primary protein.
Salt can be used to control purging of moisture, by modifying ionic strength in the solution. And, of course, salt increases water binding in meats by solubilizing proteins. Today's consumers are far more sodium-conscious than those of years past. Therefore, typical commercial marinades contain levels of sodium below 1%, compared to levels as high as 2% a decade ago. Of course, every chef knows that salt is a key flavor component. Caution must be exercised when reducing sodium levels lest the final flavor of a product be negatively impacted.