Carvacrol

Carvacrol, a naturally occurring monoterpenic phenol and food additive, has been shown to have antimicrobials, antitumor, and antidepressant-like activities.

The phenolic monoterpene carvacrol [2-Methyl-5-(1-methylethyl) phenol] is a major constituent of the essential oil of Origanum vulgare (oregano), as well as a major constituent of oil of Thymus vulgaris (thyme), and is also obtainable from Citrus aurantium bergamia (wild bergamot), Lepidium flavum (pepperwort), and Lippia berlandieri Schauer (Mexican Oregano).

An inhibitor of bacterial growth, carvacrol has been widely used both as a food or food additive in the food industry for long time. It is being used as food flavoring, and preservatives. Carvacrol is also used as a fragrance in cosmetic products.

The in vitro antimicrobial activities of carvacrol are recognized to be effective against a variety of foodborne pathogenic and spoilage microorganisms. Carvacrol antimicrobial activity is higher than that of other volatile compounds present in essential oils due to the presence of the free hydroxyl group, hydrophobicity, and the phenol moiety.

Carvacrol has been classified as GRAS (Generally Recognized As Safe) and approved for food use.
Carvacrol

Essential oils

Driven by the growing interest of consumers for natural ingredients and their concern about potentially harmful synthetic additives, the global demand for essential oils is increasing nowadays.

Essential oils (also called volatile or ethereal oils) are aromatic oily liquids obtained from plant material (buds, flowers, leaves, bark, twigs, seeds, herbs, wood, fruits and roots) and possess radical scavenging characteristics.

The significance of essential oils in food industry applications is attributed to their antimicrobial, antioxidant, antiviral, antimutagenic and anticarcinogenic characteristics. Their main active components are: thymol, carvacrol, eugenol, cinnamaldehyde and linalool, although their mechanism of action is still poorly understood.

Radicals involved in lipid peroxidation can be scavenged by antioxidants. Because of health protective role of antioxidants, essential oils can be used as food additives. Since ancient times, spices in different types of food to improve flavors are well known for their antioxidant capacities.

The essential oils effectiveness is attributed to the presence of phenolic natural compounds and they are an important and healthy alternative to synthetic preservatives and chemical additives. The FDA treats antimicrobial agents of natural origin as GRAS type products, including plant products and their essential oils.
Essential oils

Phenolic compounds as food additive

Plant phenolic and polyphenolic compounds, can be defined as compounds possessing one or more aromatic rings bearing hydroxyl substituent(s), and are the secondary metabolites of phenylalanine and to a lesser extent tyrosine in plants.

Polyphenols are the natural antioxidants prevalent in fruits, vegetables, beverages (tea, wine, juices), plants, seaweeds, and some herbs and show antioxidative and antimicrobial activities in different fish and fish products.

These compounds are too directly related to sensory characteristics of foods such as flavour, astringency, and colour.

The use of phenolic compounds also appears to be a good alternative for sulphiting agent for retarding melanosis in crustaceans. Phenolic compounds have also been successfully employed as the processing aid for texture modification of fish mince and surimi.

Phenolic antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and monotertiary butylhydroquinone (TBHQ) are hindered phenols with antimicrobial activity. The use of phenolic antioxidants in food products is regulated by federal agencies. In general, these compounds are permitted in concentrations up to 200 ppm, based on the fat or oil content of the food product.
Phenolic compounds as food additive

Food additive of vitamin C

Vitamin C or ascorbic acid is the most commercially important vitamin use as a food additive in terms of volume. Vitamin C is used as an antimicrobial and antioxidant in foods. It is preferentially oxidized in place or other substrates and complements very well as a synergist to other antioxidants, such as BHA and BHT in polyphase food system.

The addition of vitamin C to meat is to improve color, flavour and odor as well as lowering the amount of nitrite which has to be used in curing.

Ascorbic acid

Vitamin C occurs naturally in citrus fruits, berries and most other fruits. It is commercially produce exclusively from glucose to sorbitol.

The most important applications for vitamin C include fruit juices, fruit flavored drinks, juice added sodas and dry cocktail or beverage power mixes. Vitamin C is very widely used in bread baking, where it is present as a ‘flour improver’.
Food additive of vitamin C

Propionic acid

E number: E 280
Chemical formula: C3H6O2.

Propionic acid is found in nature where propionic acid fermentation occurs, e.g. in Emmental cheese, in which it is present up to 1%.

According to Scientific Committee on Food (SCF), it is assumed that effects on human health due to the use of propionic acid as a food additive in the quantities currently employed are unlikely.

Propionic acid is a naturally occurring organic acid. It is miscible with water and ethanol. Its antimicrobial activity is mostly against molds, less so against bacteria. Propionic acid has practically no effect against yeasts. I(t is recommended and used up to pH 5 and only occasionally up to pH 6.

Propionic acid and its salts are used primarily in baked products to suppress bacteria causing ‘rope’ in the center of bread and the growth of mold on both bread and cakes. It also acts as a mold inhibitor in cheese foods and spreads.
Propionic acid

Antimicrobial property of vanillin

Vanillin is the major component of vanilla flavor, which is extracted from the cure pods of the flowers of the vanilla vine, a member of the Orchidaceae.

In common with many other low-molecular weight phenolic compounds, vanillin displays antioxidant and antimicrobial properties and hence has the potential for use as food preservation.

Vanilla

Vanillin is structurally similar to eugenol from cloves and is known to be antimyotic and bacteriostatic. Vanillin can be effective in inhibiting bacteria, yeasts and molds, the antimicrobial activity of vanillin depending on the time of exposure, concentration, and the target organism.

Vanillin inhibits pathogenic and spoilage microorganisms in vitro and aerobic microbial growth in fresh-cut apples.

Vanillin inhibited respiration of E. coli and Listeria innocua cells, and disrupt the potassium and pH homeostasis of Lactobacillus plantarum cells.
Antimicrobial property of vanillin

Sorbic acid

Sorbic acid and its salt are effective antimicrobial agents against many yeasts and molds, as well as bacteria.

Sorbic acid, first manufactured by Hofmann from rowan berry oil in 1859, was discovered in Germany by Muller in 1939 and independently, a few months later by Gooding in the USA.

Sorbic acid first became available from industrial production in the mid-1950s and has since been used to growing extend for food preservation throughout the world.

As yeast inhibitors, the compounds are useful in fermented vegetables products, fruit juices, wines, fried fruits, meat, and fish products. Specific products protected from yeasts by sorbates include carbonated beverages, salad dressings, tomato products, syrups, jams, jellies, candies and chocolate syrup.

Sorbic acid is particularly effective in preventing mold growth, and it contributes little flavor at the concentrations employed (up to 0.3% by weight).

The activity of sorbic acid against microorganism is a function of synergistic or antagonistic interactions with product composition, pH, water activity, microbial flora, chemical additives, storage temperature, gas atmosphere and packaging.

The activity of sorbic acid increases as the pH decreases, indicating that the undisssociated form is more inhibitory than the dissociated form. In general, sorbic acid is effective up to pH 6.5, which is considerable above the effective pH ranges for propionic and benzoic acids.
Sorbic acid

Sulfur dioxide as food additive

Sulfur dioxide has been used since olden times in the form of 1-2% aqueous solutions as a disinfectant for equipment, barrels, bottles, corks and other ancillary items for the wine, drinks and food industries.

Fumes of burning sulfur were used as a sanitizing agent in wine-making by the ancient Egyptians and Romans. The practice is continued by the modern wine industry.

The compound is a colorless, nonflammable gas or liquid under pressure, with a suffocating, pungent odor.

Sulfur dioxide is used to prevent browning in certain dried fruits and to prevent wild yeast growth in wines used to make vinegar.

Sulfur dioxide also is used to control the growth of undesirable microorganism in soft fruits, fruit juices, wines, sausages, fresh shrimp, and acid pickles and using extraction of starches.

It is added to expressed grape juices used for making wines to inhibit molds, bacteria, and undesirable yeasts.

The most obvious drawback of sulfur dioxide is its intense pungent odor, which may be apparent in foods it is used to treat.
Sulfur dioxide as food additive

Functions of Food Additives

Functions of Food Additives
Hundreds of chemical additives are incorporated into foods directly or migrate into foods from the environment or packaging materials. A food additive can be sometimes defined as a substance whose intended use will lead to its incorporation into the food or will affect the characteristics of the foods.

These additives generally provide some types of benefits to the food producer, processor or consumer. For the consumer, additives can improve organoleptic qualities of foods, improve the nutritive value, or ease the preparation of ingredients and meals. Typical additive benefits to the food producer or processor include improving product quality, safety and variety.

Additive may found in varying quantities in foods, perform different functions in foods and ingredients, and function synergistically with other additives. Their functions can usually be classified as one of the following:

• To maintaining or improve nutritional quality

• To maintain or improve product safety or quality

• To aid in processing or preparations

• To enhance sensory characteristics

Additives that affect nutritional quality are primarily vitamins and minerals. In some foods, these may be added to enrich the food or replace nutrients that may have been lost during processing. In other foods, vitamins and minerals may be added for fortification in order to supplement nutrients that may often be lacking in human diets.

Preservatives or antimicrobial substances are used to prevent bacterial and fungal growth in foods. These additives can delay spoilage or extend the shelf life of the finished product. Antioxidants are additives that also can extend the shelf life of foods by delaying rancidity or lipid oxidation.

Additives that maintain product quality may also ensure food product safety for the consumer. For, example, acids that may be added to prevent the growth of microorganisms that cause spoilage may also prevent the growth of microorganisms that can cause foodborne illness.

Additives that are used as processing or preparation aids, usually affect the texture of ingredients and finished foods. Some of these are classified as emulsifiers, stabilizers, thickeners, leavening agents, humectants and anti-caking agents. Chemical in this group of food additives are also used to adjust the homogeneity, stability and volume of foods.

The fourth major, function of food additives is to enhance the flavor or color of foods to make them more appealing to the consumer. Flavoring chemicals may be used to magnify the original taste or aroma of food ingredients or to restore flavors lost during processing. Natural and artificial coloring substances are added to increase the visual appeal of foods, to distinguish flavors or foods, to increase the intensity of naturally occurring color or to restore color lost during processing.
Functions of Food Additives