Smell of dish is the property of food that is reflected to brain through nose.
Generally, man sees dish first, feels its smell through nose second and finally feels taste through its tongue.
In other word, taste of dish is felt firstly by eyes, secondly by nose and finally assessed by its tongue.
Even though it had high nutritive value and it was good to see and hear, such dish can not be assessed to be good if it had bad smell.
There are manyl kinds of substance giving smell.
Among them, the main substances which characterize the smell of dishs are alcohol, phenol, aldehide, ketone, organic acid, ester, and sulfide and so on
These substances are called as essential elements.
To improve smell of dish, it is important to understand well the composition and characteristics of such smell substances contained in the dish ingredients and the changes arising in the materials during cooking and cook the dish scientifically.
First, it is essential to use fresh raw materials and store them well so that they should not be corrupted or contaminated by bad smells and select properly the subsidiary materials according to the characteristics of main ingredients during processing.
As the natural smell components of raw materials are the main elements of characterizing the smell of dish, it is the essential method in improving the smell of dish to choose the right ingredients and preprocess them well.
 For example, fish gives fishy smell in a living state but it gives fishier smell in a dead state as trimethylamin oxide, the main substance changes to trimethylamin. And sticky component, protein and amino acids form various enzymes by action of germ to make fishy smell.
By the way, most of fishy smell components are mainly on the skin. So it’s better to make fish dish after preserving it in salt for 20~30minutes before heating. Then, since salt will permeat the flesh of fish by permeability and air comes out of fish and at the same time some bad smell components disappear, the taste of fish dish improves much.
Next, it is also important to pay due attention to do the main processing including heat processing according to the scientific principle. Smell components may disappear or appear during processing. Fishy smell or stench taste of meat or fish nearly disappears during heat processing and the savory smell gets stronger as the temperature gets higher.
For example, more than 20 kinds of new smell components are generated when boiling meat and more than 60 kinds of new smell components are generated when roasting at the high temperature. So the roasted dish will give the more unique smell than the boiled or steamed one.
To make dish smell better, it is important to use the seasonings well. If selecting and using the spices like crown daisy, onion, garlic, parsley, and ginger according to the target dishes, the bad smells including the fishy smell are hidden by these strong volatile aroma or the new aroma forms due to the co-activity of the aroma component and the protein of raw material.
However, if using too much seasoning, the inherent smell of raw can be hidden. So it is good to use the adequate amount of seasonings according to the raw materials and the characteristics of processing method