MONOSODIUM GLUTAMATE

Monosodium glutamate (MSG), marketed in Japan and elsewhere as Aji-no-moto (‘the essence of taste’), in China as wei jing (‘the essence of flavour’), in SE Asia as Ve-tsin, in the West as Accent and under other trade names, MSG is a flavour-enhancing chemical compound which, when added to food, creates the flavour of umami. It seems to make the tongue, and to a lesser extent the palate, more receptive to savoury, salty tastes. It therefore makes bland food more interesting, and has been widely used by the food-processing industry throughout the world. It is also used by chefs and cooks in some Asian and oriental-style restaurants, and in domestic kitchens in some Asian countries.

MSG is manufactured on a large scale in many countries—total world output is said now to be well over a quarter of a million tonnes per year. It is a white, coarse powder, with very little flavour of its own. Chemically, it is the sodium salt of glutamic acid. It was first isolated in the laboratory by a Japanese researcher in 1908; commercial production began in the following year. Initially it was manufactured from wheat gluten but now (since about 1973) it is cultured by bacterial fermentation on a basis of beet molasses. It is identified in Europe by the number 621 and has an E-rating of E621.

The effect of MSG has been known for centuries to the Japanese, who have long used Laminaria seaweeds (konbu) as a natural source of this mysterious substance. The broad, flat strands of this seaweed are often scored before cooking to help release it. Why the process of evolution should have endowed Laminaria spp in this way is not at all clear.

A pinch of MSG certainly helps to bring out (though it cannot create) the flavour of almost any soup, meat, vegetable, poultry, or fish dish. However, it acquired a bad reputation in the late 1960s when it was blamed for the ‘Chinese restaurant syndrome’ although this has never been explained or confirmed under controlled conditions.

MSG has had a profound effect on modern Japanese cooking, as well as food worldwide. It greatly accelerated the processes required to impart flavour into a cuisine that might veer to the bland; it changed the Japanese appreciation of meaty flavours, perhaps allowing the development of dishes such as ramen; it enhanced the capacity of the food processing industry.

By Alan Davidson in "The Oxford Companion of Food", edited by Tom Jaine, Oxford University Press, UK, 2014, excerpts pp.1550-1551. Adapted and illustrated by Leopoldo Costa.