Love Me Tender and Marinate Me

I’m Curious

Marinating meat is first, to instill flavor into meat and then, often known to tenderize the meat and collagen via acid or enzymes. But does connective tissue in tough cuts of meat actually breakdown with acid? Do enzymes increase tenderness? How do acids and enzymes in marinades can tenderize meat? How do different marinades compare as tenderizers? I’m curious.

Experiment

I decided to open up the test kitchen <that sounds fancy, for my personal kitchen counter and refrigerator> to really test the impact of acids and enzymes on proteins. Off to the Asian market I went, for uniformly fine sliced pieces of beef chuck (containing meat, collagen and fat). This is the same beef slices used for hot pot or shabu shabu, so I figured with 1/8″ slices, I could visually see the difference of marinades, feel the impact of the marinades, if any and observe any textural changes when eating.

One slice of beef chuck was saved as a control and the remaining slices separated into 8 different containers and mixed with 1/4 cup of respective “marinade.” Approximate pH readings were scooped off Google. Note: beef has a pH of 5.4 to 5.7.

Lids were snapped onto the meat slice containers and stacked into a fridge for 28 hours.

After my visual observations, I placed the meat onto a parchment laid baking sheet (in the same order as the marinade photos) and baked in an oven at 350F for 10 minutes.

Observed Visual and Textural Outcomes after Marination

Conclusions

• Generally, the more acidic the marinade, the more tender the meat
• Fresh pineapple dissolved the meat, even though its not very acidic – something else is happening there
• On the acidic marinades, the meat is tender, but the bubbly clear bits (connective tissue) were also tender
• Did the white wine marinade cook the beef slice? I think yes!
• Pickle juice is starting to look like the perfect marinade in my book – the acid tenderizes and the brine is pre-made. <Now if I could only find some ice cream….>

Food Learnings

There are 2 different marinades that breakdown meat and connective tissue, acid and enzymes. Plus a few interesting comments (per Discover Magazine)

• Acidic marinades work by denaturing the proteins (unravels the protein coils) and interrupts the structure of collagen. Collagen is part of the connective tissue that is tough and chewy when it has not yet converted into gelatin.
• Enzymes breakdown amino acids (and meat apparently is mainly composed of amino acids). Thus, with enzymatic action, meats will become more tender. Certain fruits contain enzymes that are well known as tenderizers: pineapple (bromelain), papaya (papain), figs (ficin), mangos (amylase)
• Marinades with alcohol will dissolve fat since meat fat is soluble in alcohol. <Hmm! So… marinating in beer and wine will melt fat, eh?>
• Dairy is slightly acidic (think buttermilk and yogurt) and contain the enzyme, lactase

America’s Test Kitchen: Science of Good Cooking says that acidic marinades can often make meat mushy or tough and dry if the electrical charges of the meat meets the isoelectric point. This is typically around pH 5.2. When the positive and negative protein molecules balance to the isoelectric point, the proteins get cozy and start squeezing together, which then squeezes out moisture. Thus, if protein sits in marinade for too long and the pH of the meat drops to the isoelectric point, the meat becomes tough and dry. I think the beef slice marinated in white wine hit the isoelectric point or the acid chemically cooked the beef in my experiment.

Tips to Tenderize Meat with an Acidic or Enzymatic Marinade

Meat is protein (amino acids) and connective tissue (elastin fibers and collagen). When cooking, the protein fibers will coil or tighten up. Elastin fibers can be manually separated (see further below) and the collagen will convert to gelatin with enough time and heat. (Without the collagen heating up, the collagen will remain tough and chewy.) Meat gelatin is the same substance as what you think of Grandma’s soft and jiggly strawberry jello dessert. Gelatin gives the smooth silky mouthfeel. Cooking meat that is high in connective tissue (often the harder working muscles like shanks (legs) or shoulder like brisket or pork shoulders) to >180F to ensure the conversion of collagen to gelatin will change a chewy cut to a tender cut.

Add moisture when cooking. Dry meat inevitably be chewy, so moist cooking environments like steaming, braising or steaming will keep the meat fibers from drying out.

I recommend marinating for several hours to overnight (4 to 12 hours). My experiment was the far extreme and I’m never organized enough to want to marinate longer than one day or 28 hours in this case.

Reducing the concentration of acid by using oil or other liquids and reducing the marination time will prevent chemically cooking or reaching the isoelectric point of the meat.

Use a closed freezer bag for marinating to maximize surface area of marinade. Bags are also great, as it allows for the air to be squeezed out or removed, again, to increase surface area and requiring less marinade. <Did I mention I am also thrifty?>

Marinating only impacts the surface of the meat. To encourage the tenderizing impact of a marinade, marinades can be injected (especially into larger tough cuts, like beef brisket or pork shoulder.

Marinate in the refrigerator, you still want all your food, food safe!