Rosemary (Rosmarinus officinalis) is a woody perennial spice plant native to the Mediterranean basin and grown in chalky soil. Aromatic oil can be extracted from stems, leaves and flowers of rosemary. The varieties of rosemary can be divided into two types according to the shape of the plant, one is the vertical type with trunk growing upward, the other is the creeping type with branches growing laterally. The name “rosemary” has nothing to do with the “rose” and “Mary”. It is derived from the Latin name “rosmarinus”, composed of the roots of “dew” (ros) and “sea” (marinus), which means “dew from the sea”. Because of its extreme drought resistance, rosemary in many places only needs water vapor from the sea to survive.
Antioxidant Activity of Rosemary Extract
Rosemary extract is popular as a natural antioxidant due to its strong antioxidant capacity and fat-soluble property. The use of rosemary extract as a natural antioxidant was first reported in 1955. Scientists found that rosemary extract as a natural antioxidant had a better antioxidant capacity than BHT and BHA. It was reported that all rosemary extracts showed strong inhibitory effects on lipid oxidation. The antioxidant capacity of rosemary extract was attributed to the presence of phenolic diterpenes that scavenge singlet oxygen, hydroxyl radicals, and lipid peroxyl radicals, thereby preventing lipid oxidation. Three types of phenolic diterpenes are found in rosemary extract: carnosic acid, carnosol, and rosmanol; with carnosic acid present as the major phenolic diterpene. In addition, studies indicated that carnosic acid was the most active antioxidant component in rosemary extracts.
Rosemary Extracts as Food Additive
It is normally only the leaves of rosemary that are commonly used as a culinary herb, flavoring agent and naturally occurring antioxidant. Today, rosemary extracts are increasingly employed not only to provide flavor but also as natural alternatives to synthetic antioxidants for the stabilization of oxygen-sensitive foods. Extracts of the plant rosemary can have both flavoring and antioxidative properties. In many cases both functions are utilized within a food, however, it can be the case that some extracts are sold primarily for their antioxidant properties. In such cases the processing of the rosemary extract can be optimized to enhance the antioxidative function and to reduce that of flavoring.
Dairy products contain lipids rich in polyunsaturated fatty acids and their esters are easily oxidized by molecular oxygen over time. Deleterious changes in dairy products caused by lipid oxidation include not only loss of flavor or development of off-flavors, but also loss of color, nutrient value, and the accumulation of compounds, which may be detrimental to the health of consumers. One of the most effective ways of retarding lipid oxidation in dairy products is to incorporate antioxidants. Supplementation dairy products with natural antioxidants (polyphenolic compounds) are better using than synthetic antioxidant and could be potentially. The use of rosemary as natural antioxidant in dairy products can reduce the rate of lipid oxidation and hydrolysis besides may be beneficial in increasing the shelf life of these products. This supplementation will move these products into the functional food area under new category as healthy dairy products.
In recent decades, traditional medicine has become more popular. A main reason of this popularity is that herbs are rich in natural antioxidants. Natural antioxidants are not usually toxic compared to synthetic antioxidants. Antioxidants have an important role in the prevention of many diseases and aging. These materials are capable of blocking initiation or propagation of oxidizing chain reactions. The Lamiaceae family seems to be a rich source of large amounts of phenolic acids, so it is revealed to be a potential source of natural antioxidant. Rosemary is a spice and medicinal herb which is widely used around the world. Several studies have found some beneficial effects for rosemary leaves such as anti-inflammatory, anti-viral, cytoprotective and anti-tumoral effects.
- Yang Y, Song X, Sui X, et al. Rosemary extract can be used as a synthetic antioxidant to improve vegetable oil oxidative stability. Industrial Crops & Products, 2016, 80:141-147.
- Gad, A. and Sayd, A. Antioxidant Properties of Rosemary and Its Potential Uses as Natural Antioxidant in Dairy Products—A Review. Food and Nutrition Sciences, 2015, 6, 179-193.