Food Flavours: Understanding Food Additives

Flavour is a sensory phenomenon which is a combination of the sensations of taste, odour or aroma, heat and cold, and texture or “mouthfeel”.

- Sweta Rai, Sabbu Sangeeta and Santoshi Rawat*

The appearance of food is important, but it is the flavor that ultimately determines its quality and acceptability. Natural flavouring materials such as spices, essential oils and fruit juices have been used for long in food preparations but as their supply has not kept up with the demand, with a consequent rise in their cost, natural flavouring agents have been largely substituted by synthetic ones. Thousands of these synthetic compounds are now being used as food additives. There are four basic tastes: salty, sweet, sour and bitter.

Salty: Sodium chloride is the only salt that has a pure salty taste. Besides imparting flavor to food, it is also an essential nutrient. Other salts have different tastes, e.g., some iodides and bromides are bitter while some salts of lead and beryllium are sweet.

Sugar: Sugar is used more to impart sweetness than flavor to food. Fructose present in honey is the sweetest sugar followed by sucrose and glucose, whereas lactose in milk is slightly sweet and gives less flavour. Natural sweet compounds are generally polyhydroxy compounds with a straight-chain structure, such as sugars and the hexahydroxy cyclic alcohols, mannitol and sorbitol. Diverse compounds, such as saccharin, some peptides and cylcamates are also sweet.

Sourness: Sourness of food is due to the presence of organic acids of which citric, tartaric and malic are the most common. Acetic acid produced by fermentation of alcohol is common in processed fruits. Ascorbic acid is abundantly present in fruits and vegetables. Oxalic acid found in spinach and phosphoric acid and its salts are often used in the food industry. Remarkably, the hydrogen ion is mainly responsible for sour taste. Except for oxalic acid, all other acids are weak acids and the degree of sourness is not proportionately related to the hydrogen ion concentration.