Marinades are mixtures that change the flavor, surface texture, and juiciness of foods such as meat, poultry, fish, tofu, and vegetables. They usually contain acid, oil, salt, sugar, herbs, spices, and aroma compounds. Food scientists study marinades because small changes in chemistry can affect tenderness, browning, safety, and taste.
Understanding how ingredients interact helps students design marinades that are flavorful without damaging the food.
Key Facts
- A typical marinade contains acid + oil + salt + flavor compounds.
- Diffusion moves dissolved molecules from high concentration in the marinade to lower concentration near the food surface.
- Diffusion rate increases when pieces are smaller, surfaces are cut, or temperature is warmer, but food safety limits how warm marinating can be.
- Salt can help proteins hold water by changing protein structure and improving moisture retention.
- Acids such as vinegar, lemon juice, or yogurt can denature surface proteins, but too much acid for too long can make the outside mushy.
- Maillard browning is promoted by amino acids + reducing sugars + heat, which helps create roasted flavors during cooking.
Vocabulary
- Marinade
- A seasoned liquid mixture used to add flavor and sometimes change the texture of food before cooking.
- Diffusion
- The movement of particles from an area of higher concentration to an area of lower concentration.
- Denaturation
- A change in the shape of a protein caused by acid, heat, salt, or enzymes.
- Osmosis
- The movement of water across a membrane or tissue from a region of lower solute concentration to higher solute concentration.
- Maillard reaction
- A browning reaction between amino acids and reducing sugars that creates many roasted, savory flavor compounds.
Common Mistakes to Avoid
- Using too much acid for too long, because strong acid can denature the surface proteins so much that the food becomes mushy instead of tender.
- Assuming marinade penetrates deeply into large cuts, because most flavor molecules mainly affect the surface and only small ions such as salt move inward more easily.
- Marinating at room temperature for a long time, because bacteria can multiply quickly in the temperature danger zone and make food unsafe.
- Pouring used raw-meat marinade onto cooked food, because the liquid may contain harmful microbes unless it is boiled thoroughly first.
Practice Questions
- 1 A student makes 240 mL of marinade using 60 mL vinegar, 120 mL oil, and 60 mL soy sauce. What percent of the marinade is vinegar?
- 2 A marinade recipe uses 2 g of salt for every 100 mL of liquid. How many grams of salt are needed for 350 mL of marinade?
- 3 Two chicken pieces are marinated for the same time: one whole thick piece and one thin piece with shallow cuts on the surface. Explain which piece will likely have stronger marinade flavor and why.