by Sudha Bhat on  July 25, 2014 at 12:08 PM Health In Focus
 Umami and Hunger
Our sense of taste has evolved over time to detect key components in food which are important for our healthy development and those which we need to avoid. The pleasure and benefit we get from food is determined by a complex combination of factors such as aroma, texture, temperature, environment and food culture.

Most people are well aware of the four basic tastes: sweet, salty, sour and bitter. But did you know that we all have a taste quality that cannot be described by any of these four sensations. So what is this other taste sensation? Japanese scientists have discovered a peculiar taste arising from fish or meat, which they believe is distinct from the four known tastes. They called this fifth taste "umami" and found that it is evoked by glutamic acid and its salts.

"Umami" has been described as "rounded, rich and savory" and means "deliciousness" in Japanese. The literal translation means "pleasant, savory taste". After many years of research, scientists have now added umami as the mythical fifth taste of glutamates and nucleotides.

Umami captures what is sometimes described as the taste of protein. Umami-rich foods include tomatoes, parmesan cheese, cured ham, vegemite, marmite, soy sauce, oyster sauce, dried shiitake mushrooms and asparagus.

When foods age, like cheese, or when meat begins to cook under the heat of an open flame, the proteins within undergo a molecular change and are broken apart into various units, one of which is called L-glutamate, which is the singular molecule responsible for umami. Similar to the other four basic tastes, umami is sensed when L-glutamate binds to specific receptors on your tongue which causes a chain reaction of chemical processes resulting in taste.

Despite the controversy, monosodium glutamate (MSG), is widely used in cooking and food production the world over. It is actually the easiest way to increase umami in food as it produces no other tastes or flavours to the final dish.

A new study reveals that the so-called 'fifth taste' in sauces and meat helps us feel satisfied faster and thus helps keep our weight in check. This study, which is published in The American Journal of Clinical Nutrition, found that monosodium glutamate (MSG) can make food tastier and has been shown to increase satiety when combined with protein.

The researchers studied the correlation between MSG and appetite when it was combined with a carbohydrate-heavy meal. The study participants included 27 people who all had the same breakfast. They were split into 2 groups. Before lunch, one group received a soup with no MSG, the other group got a bowl with plenty of MSG as well as IMP (Inosine Monophosphate), which is a nucleotide that is often used to boost umami flavours.

The lead author said 'It's the additional IMP mixed with the MSG that reduced intake whilst maintaining satisfaction. IMP is normally found in very high protein foods such as skipjack tuna and some forms of seaweed.'

The authors observed that when it came to eating lunch, those who'd consumed the soup with MSG before ate less and were satisfied by their smaller meal, suggesting umami can help control appetite.

Recognizing the power of umami can help us understand our food cravings. It also helps explain why we crumble cheese on a roasted beet and arugula salad or why we add a dollop of tomato paste to a stew or splash soy sauce in a stir-fry. They all make a meal more satisfying.

Source: Medindia

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