Food Flavourings :
The flavour of food results from the stimulation of the chemical senses of taste and smell by specific food molecules. Taste reception is carried out in specialized cells located in the taste bud . The four basic taste sensations which are sweet, salty, bitter, and sour are detected in separate regions of the tongue because the taste cells in each region are specific for certain flavour molecules.

Flavourings are used in a wide range of food products. A flavour additive is a single chemical or blend of chemicals of natural or synthetic origin that provides all or part of the flavour impact of a particular food. These chemicals are added in order to replace flavour lost in processing and to develop new products. Flavourings are used in food products at very low concentrations. They are normally made from a mixture of substances which provide a flavouring of suitable strength that can be stored and then used in the food production process. Flavourings are divided into three categoties such as natural flavouring, nature-identical flavouring and artificial flavouring.


Natural Flavourings
Derived or extracted from plants, spices, herbs, animals, or microbial fermentations by physical, microbiological or enzymatic processes. They can be either used in their natural state or processed for human consumption, but cannot contain any nature-identical or artificial flavoring substances.

• Natural citral is extracted from lemon grass.
  
• Natural benzaldehyde is extracted from bitter almonds.

Nature-Identical Flavourings
Chemically identical to natural flavourings naturally present in products intended for human consumption but are prepared or extracted using chemical methods. They are identical to the molecules found in nature and the body cannot distinguish between them. They cannot contain any artificial flavouring substances.

• Ethyl acetate (identical in nature to many fruits)
• Decanal (nature identical to orange)
• Vanillin may be obtained from vanilla pods but the flavour is now produced chemically from a plant material called lignin.

Artificial Flavourings
Mixtures of synthetic compounds which are not chemically identical to natural flavourings. They are often used in food products because of the high cost, lack of availability, or insufficient potency of natural flavourings.

• Ethyl vanillin (vanilla flavour)
  
• Ethyl maltol (sugar, cotton candy flavour)

Flavour Enhancers :

Flavour enhancers are compounds that are added to a food in order to supplement or enhance its own natural flavour to make them taste more 'savoury'. The concept of flavour enhancement originated in Asia, where cooks added seaweed to soup stocks in order to provide a richer flavour to certain foods. The flavour-enhancing component of seaweed was identified as the amino acid L-glutamate and monosodium glutamate (MSG) become the first flavour enhancer to be used commercially.

• Monosodium glutamate (MSG) is a salt of sodium with glutamid acid which is one of the building blocks that make up animal and vegetable proteins. When dissolved in water or saliva, it rapidly dissociates into free sodium and glutamate. Glutamic acid is one of the twenty amino acid that make up human proteins. It is critical for proper cell function but not considered an essential nutrient because the body can manufacture it from simpler compounds. MSG is found naturally in seaweed and fermented soy products and especially yeast extract. It occurs in virtually all protein containing foods including meats, fish, vegetables and dairy products. Various cheeses, tomatoes, peas and mushrooms are among the foods richest in glutamate. It is used commercially in much greater concentrations, adding extra flavour to snack foods, frozen dinners, and instant meals such as the seasoning mixtures for instant noodles.

Food Colorings :
A food coloring is any dye, pigment or substance that can impart colour when added or applied to a food, drink, drug or cosmetic to preserve the colour loss due to extremely exposure to environment, to correct natural variations in colour, to enhance colour that occur naturally, to provide a colourful identity to foods and to protect flavours and vitamins that may be affected by sunlight during storage. Food coloring is divided into two major categories such as natural food dyes and artificial colourings.


Natural Food Dyes

Artificial Colorings

Food Sweeteners:
These are substances that sweeten foods, beverages and medications such as sugar, saccharine or other low-calorie synthetic products. They can be termed as sweeting agents which are called artificial sweeteners as they are usually not a component of the product they are added to. The most commonly used sweeteners are sucrose, glucose, fructose and lactose, with sucrose being the most popular. These substances can be classified as nutritive and non-nutritive.

Nutritive Sweeteners

• Fructose is the only carbohydrate with a greater sweetness than that of sucrose. It is more slowly absorbed than sucrose and glucose and does not stimulate the insulin. So, it is a recommended sweetener in dietetic foods such as breakfast, beverages and ice-cream.
• Sugar alcohols are produced by the hydrogenation of sugars and syrups with the aid of catalyst. They include sorbitol, mannitol, xylitol, maltitol and lactitol which are functionally similar to sucrose.
• Sorbitol has special properties of high viscosity, humectancy and crystalline form. It is used in confections, candies, preserves, jelly and table-top sweeteners.
• Mannitol is a good anti-adhesion agent used in the manufacture of sugar-free shewing gum,sweets and ice-cream.
• Xylitol is primarily used in sugarless confectionery products and diabetic foods.
• Maltitol has excellent heat stability and aids moisture retention in baked goods.

Non-Nutritive Sweeteners

• Saccharin is the most widely used sugar substitute because of its low cost and high stability. It is the only non-caloric sweetener that can withstand heating, baking and high acid and it can be used in virtually and dietary products.
• Aspartame is the prime sweeetener for many dietic foods such as soft drinks, ice-cream and chewing gum. Its good taste has promotes its acceptabillity even though it costs more than other sweetener or sugar.It is disintegrated into aspartic acid, fenylalanine and methanol in the body on digestion.
• Cyclamate is a calorie free sweetener. It is metabolized in the gut by few individuals and generally expelled as such. It is generally used in combination with other sweeteners. It has a pleasant taste, and is stable at high temperatures and is economical. It is banned in the UK and USA because of its association with tumors in rats.
• Acesulfame-K is a recently introduced 0 calorie sweetener that are still being evaluated. It is not metabolized by the body. The only limitation it has is that if used in large quantities, it has an after taste. It is used in fruit preserves, dairy products and all types of beverages. It is used to reduce the calories of the products. It is heat resistant and enhances flavors.

Food Preservatives:
Antimicrobial preservatives combined with good manufacturing practice,provide a useful role to ensure safe food products. The purpose is generally to avoid spoilage during the transportation time and extend the shelf-life of foods, thus reducing waste, diposal and costs. Food preservatives are divided into two categories such as organic acid and salts.

Organic Acids

• Commonly used for flavour and tartness to stabilize colour, reduce turbidity, enhance gelling and as anti-microbial agent.
• Acetic acid is effective against yeast, bacteria and molds. It is used as a pickling agent in condiments, cheese, dairy product analogues, sauces, gravies and meats.
• Lactic acid is the primarily preservative in fermented products as well as being a pH-control agent and flavouring. It used in salad dressings, sauces, soups and desserts.
• Propionic acid and propionate are used against molds, some yeasts and bacteria in flour, bread, whole-meat products and cheese products.
• Citric acid although not used directly as an anti-microbial agent but it has activity against some molds and bacteria.
• Benzoic acid and sodium benzoate are used to control yeasts ans molds which are most effective at pH 2.5-4.0 and least effective at pH above 4.5
• Sodium benzoate is extensively used in beverages, salad dressings, condiments margarine, sauces, gravies and pastry fillings.
• Other organic acid include malic, succinic, tartaric and caprylic acids.

Salts

• Sodium nitrite primarily function as an antimicrobial agent is to inhibit the growth and toxin production Clostridium botulinum in bacon, sausage, and other poultry products.
• Sulphur dioxide and its salts are used as anti-microbial agents and prevent enzymatic and non-enzymatic discolouration in foods.
• The sulfites are primarily used in fruit and vegetable products to control acetic acid producing, fermentation and spoilage yeasts and molds.
• Sorbates (potassium, calcium or sodium salts) are effective inhibitors of fungi. Its effectiveness depends on pH, processing, packaging, storage temperature and length and other ingredients.

Food Stabilizer:

Stabilizers or texturing agents are food additives used in the greatest total quantity. Starches, emulsifiers and gums are the primary ingredients in this category. The purpose of these food additives is to maintain consistent texture, maintain the uniform dispersion of substances in solid and semi-solid foods and to prevent the separation of oil and water in layers.

Starches

• Starches in their native or modified form are used extensively in the food industry.
• They are relatively inexpensive and easily available.
• Most starches are extracted from corn, wheat, sorghum, rice, potatoes and tapioca and the character of the starch depends on its source.
• Modifications such as cross-linking allow the starches to perform better under numerous adverse conditions such as extreme pH, temperature, physical abuse and interactions with other ingredients.
• Pre-gelatinized starches have the same behavioural patterns of cook-up starched but swell in cold water.Their applications include salad dressings and desserts.

Emulsifiers

• The major function is to assist the stabilization and formation of food emulsions and reduce surface tension at the oil-water interface.
• The most common examples of emulsions are mayonnaise and margarine.
• Monoglycerides and diglycerides are very often used as emulsifiers in margarine, ice-cream and baked goods.
• Lecithin is a naturally occuring emulsifier widely used in margarines, sauces, gravies and confections. It is also the emulsifying component in eggs which are used in mayonnaise and baked goods.
• Polysorbate 60 is used in salad dressings and sauces while polysorbate 80 is contained in flavour emulsion.

Gums

• Gums are edible polymeric materials that are soluble or dispersible in water and provide some properties in food system such as thickening, gelling, suspending, emulsifying, stabilizing and film-forming.
• They are effectively primarily in oil-water emulsions, usually used at relatively low concentration (0.1-2.0%) and have varied tolerances to pH, salt and processing conditions.
• Many gums are difficult to disperse directly into water. So, it is advisable to use sugar or some other powdered ingredient in the formulation as a dispersing agent.
• Xanthan gum is the most widely used gums in the food industry. It is effective in very low concentration and quite tolerant to many processing and storage conditions which is used for emulsion stability in salad dressings, uniform viscosity in sauces and gravies and suspension of solids in toppings and beverages.