Phenolic Compounds

Plant phenolic and polyphenolic compounds, are 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.

 Phenolic compounds mostly present in various types of foods of plant origin. Natural antioxidants have been extensively found in fruits and vegetables, seeds of many fruits, cereals, berries, wine, tea, olive oil, and aromatic plants. The content of phenolic compounds in foods may change during processing and storage as mediated by light and temperature.

There is now considerable evidence that wine phenolics, particularly resveratrol, inhibit low-density lipoprotein oxidation and reduce platelet aggregation, two major parameters implicated in atherothrombogenesis. This provides a possible explanation for the cardio protective action of wine.

Phenolic compounds such as cafeic acid, chlorogenic, p-coumaric and ferulic are present in parts of plants that are used as spices. The antimicrobial activity of these and other acids as hydroxycinnamic and cinnamic may retard microbial invasion as well as fruit and vegetable putrefaction.

Apart from being naturally present in the raw materials used for foods, phenolic compounds are also added to certain foods and beverages as colorants or as antioxidants. Phenolic compounds have also been successfully employed as the processing aid for texture modification of fish mince and surimi.

The potential value of phenolic compounds as biopreservatives is considered for the safe extension of perishable products shelf life and these substances can be used to delay or inhibit the oxidation and growth of microorganisms. However, in food applications, the phenolic compounds could be influenced by food components, processing and storage.
Phenolic Compounds

Food Additive: Acidulants

Food Additive: Acidulants
From the root word, acid, in acidulants, one can conclude that this class of compounds tends to lower pH of any food in which the compounds are incorporated. They also enhance desirable flavors, and in many cases, such as in pickled products, are the major taste component. Vinegar (acetic acid) is added to relishes, chili sauce, ketchup and condiments as a flavor component and to aid in the preservation of these products. Since the microbial spoilage of food is inhibited as the pH of a food is lowered, acidulants are used for that purpose in many cases. Many acidulants occur naturally in foods (e.g., citric acid in citrus fruits, malic acid in apples, acetic acid – the major component of vinegar). Tartaric acid is widely used to lend tartness and enhance flavor. Citric acid is widely used in carbonated soft drinks. Phosphoric acid is one of the very few inorganic acids used as an acidulants in foods. Citric acid accounts for 60% of all acidulants used in foods.

In addition to their preservative and flavor enhancing effects, acidulants are used to improve gelling properties and texture. Acidulants are also used as cleaners of dairy equipment.

Acidulants may be used in the manufacturer of processed cheese and cheese spread for the purpose of emulsifications as well as to provide a desirable tartness.

Acid salts may be added to soft drinks to provide a buffering action to prevent excess tartness. In some cases, acid salts are used to inhibit mold growth.
Food Additive: Acidulants

Alkaline Compounds as Food Additive

Alkaline Compounds as Food Additive
Alkaline compounds are compounds that raise the pH. Alkaline compounds, such as sodium hydroxide or potassium hydroxide, may be used to neutralize excess acid that can develop in natural or cultured fermented foods. Thus, the acid in cream may partially neutralized prior to churning in the manufacture of butter. If this were not done, the excess acid would result on the development of undesirable flavors.

Sodium carbonate and sodium bicarbonate are used to refine rendered fats. Alkaline compounds are also added to chlorinated drinking water to adjust the pH to high enough levels to control the corrosive effects of chlorine on pipes, equipment, and so forth. Sodium carbonate is also used in conjunction with other compounds to reduce the amount of hardness in drinking water.

Sodium hydroxide is used to modify starch and in the production of caramel. Sodium bicarbonate is used as an ingredient of baking powder, which is used for baked products. It is also a common household item used in a variety of cooking recipe. Alkaline compounds are used in the production of chocolate and in the adjusting of acidity levels in grape juice and other fruit juices that are to be fermented in the production of wine.

Some alkaline compounds, such as sodium bicarbonate are relatively mild and safe to use, while others, such as sodium hydroxide and potassium hydroxide, are relatively powerful reagents and should, not be handled by inexperienced people.
Alkaline Compounds as Food Additive