Beginning today, I will post a new entry every day about the controversial food additive, MSG. This series started out as a single essay, but I had so much fun learning about MSG that, before long, I had too much to say for just one post. Reading about food additives and our perception of tastes has certainly made eating a different experience for me. I hope you find the subject equally eye-opening! At the end of the series, I’ll put up a list of sources for further reading.
So without further ado, here marks the start of everything you have ever wanted to know about MSG —
PART I: What is Glutamate?/ The History of MSG
I learned my way around a kitchen by watching my mother cook. She taught me how to wash vegetables by soaking them in a tub and letting the dirt fall to the bottom. Different greens required different chopping techniques. The ends of green beans were to be snapped off, celery chopped at a diagonal, slices of lotus root (ǒu) steeped in water with a splash of vinegar, and the stems and leaves of leafy greens placed in separate piles so the firm stems could be placed in the wok first. Meats needed to be washed, butchered, and seasoned before cooking.
There was a whole other set of rules for when foods made it to the stove-top. Cook meat with ginger. Season starchy vegetables, like dōng guā (winter melon), nán guā (kabocha squash), and hú luó bo (carrots), at the beginning of cooking. Season leafy vegetables – bái cài (bok choy), jiè lán (Chinese broccoli), dà bái cài (napa cabbage) – at the end, so they don’t release too much water. But regardless of whether we were cooking meat, root, or leafy vegetable, I could always count on one thing – when the dish was just about finished, my mother would turn down the heat, and add a tiny spoonful of MSG for taste.
Of course, it was not until years later that I would learn that this was MSG. Instead, I knew this last ingredient as wèi jīng, which, in Chinese, literally means “flavor essence”. I knew MSG as the tiny spoonful of broken snowflakes that my mom would sprinkle on top of our food like fairy dust.
Naturally, I was surprised the first time someone told me that MSG was harmful. This was something that I had been eating every single day of my life, and nothing had happened to me, anyone in my family, or, as far as I knew, any of the billion-something MSG-consuming Asians in the world. Even wèi jīng’s English name – monosodium glutamate – seemed foreign. Monosodium glutamate sounded like a compound from my lab notebook for chemistry class. I couldn’t reconcile that with the small jar of crystals that my mom kept by the stove with all of her other spices and multiple varieties of soy sauce.
Still, I kept hearing about this so-called “Chinese restaurant syndrome”. I started seeing labels on food packages and signs proudly displayed in Chinese restaurants – “WE DON’T USE MSG”. As if trying to avoid some sort of contagion, everyone wanted to put as much distance as possible between themselves and MSG. I started to wonder if there was actually something to the claims of “monosodium glutamate symptom complex”. For the first time, I questioned what wèi jīng was, exactly.
Let’s start with the basic definition of MSG. Monosodium glutamate (molecular formula C5H8NNaO4) is a salt made from one positively-charged sodium ion and one negatively-charged glutamate ion. It is derived from glutamic acid, an amino acid that our bodies can synthesize naturally.
Glutamate plays an important role in various physiological processes. These include the citric acid, or Krebs, cycle; the urea cycle; drug detoxification; and the synthesis and transport of amino acids. In addition to facilitating processes like metabolism and protein synthesis, glutamate is the most abundant excitatory transmitter in the brain, and plays an important role in learning and memory. Though it is essential to have enough glutamate in one’s body, having too much of it can also be toxic.
Once you have glutamic acid, it’s not difficult to isolate monosodium glutamate. Breaking down glutamic acid through processes like cooking, fermentation, or ripening yields glutamate. Mix this with some table salt and water to stabilize the glutamate ion, and – voilà! - you have yourself some MSG.
Most commercial MSG production today uses bacterial fermentation, in a process similar to the ones we use in making beer, chocolate, sauerkraut, or yogurt. This involves culturing bacteria with a source of carbon (often foods containing sucrose, like beets or sugar cane), and ammonia as a source of nitrogen. As they ferment, the bacteria excrete glutamic acid into the culture broth – from which glutamate is then isolated and mixed with sodium. You end up with white, odorless crystals that are soluble in water and stable under conditions of food processing and cooking (contrary to some popular beliefs, MSG doesn’t decompose until 247°C, roughly the temperature at which corn oil begins to smoke).
Although glutamic acid was first identified in 1866 by German chemist Karl Heinrich Leopold Ritthausen, its flavor properties were not recognized until 1908, when a Japanese chemist named Kikunae Ikeda tried to isolate the unique taste of the seaweed in broths his wife would make for him. Specifically, Dr. Ikeda wanted to capture the essence of an edible kelp called kombu.
At the time, it was commonly believed that there were four primary tastes – sweet, bitter, salty, and sour. However, Ikeda believed that the flavor of kombu transcended these four categories – and that, in fact, this distinct taste was also present in “asparagus, tomatoes, cheese, and meat”. He termed this fifth taste “umami”, a Japanese word that is loosely translated as “savory deliciousness”, and attributed it to glutamate.
Starting with kombu, Dr. Ikeda experimented with countless chemical procedures until he finally managed to crystallize glutamic acid. Afterwards, he tested combinations of glutamate with various cations – including calcium, potassium, ammonium, and magnesium – and ultimately decided that sodium glutamate was the most soluble and appetizing product.
With an entrepreneurial mindset, Professor Ikeda patented and began to market MSG, calling it Aji-no-Moto, which means “essence of taste” in Japanese. Commercial production of MSG in Japan began in 1909, and continues to thrive today. Meanwhile, Kikunae Ikeda remains widely regarded as one of Japan’s greatest inventors.
While MSG was an overnight success in Japan, any efforts to introduce MSG to the United States were largely unsuccessful until World War II, when soldiers started to notice the use of MSG in Japanese rations. These soldiers brought the taste of the foods they experienced in Japan back to America with them.
For manufacturers of MSG, it could not have been better timing — the advent of MSG in America occurred at a time when the processed foods industry was burgeoning. By 1956, Ajinomoto started manufacturing MSG in the United States, and by 1962, the company had partnered with Kellog’s. Ac’cent, another leading brand of MSG, became a household name.
Before long, MSG was ubiquitous. As a simple and inexpensive way to make foods more flavorful, it was a panacea for the processed foods industry. MSG went into seemingly everything — canned foods, frozen foods, baby food, chewing gum, soft drinks, bread, dietary supplements, pharmaceuticals, and even cosmetics. It seemed like MSG was unstoppable. However, within a couple decades, it would undergo a precipitous drop in public opinion. What eventually caused MSG’s downfall? Read on to find out!