Rosemary and sage information

Rosemary is one of the most effective spices, widely used in food processing. It is the only spice commercially available for use as an antioxidant in Europe and the United States. One of the main potential uses is the suppression of warmed over flavour (WOF). However, because of their prime use as flavouring agents, rosemary extract products are not technically listed as natural preservatives or antioxidants.

Berner and Jacobson obtained a patent in 1973 for production of an antioxidant extract from rosemary using oil as a solvent. There was reported a process for the extraction of rosemary and sage, followed by vacuum steam distillation in an edible oil or fat to obtain a colourless, odourless natural antioxidant. It has been described an extraction process using peanut oil, followed by micronization, heat treatment and molecular distillation. Inahata obtained a patent in 1996 for production of odourless and safe antioxidants from rosemary by repeated extraction, evaporation, purification and dissolving procedures. More recently another technique, supercritical carbon dioxide extraction, has been used to product extracts of rosemary and sage.

Antioxidant properties of rosemary have been well documented. Rosemary was considered both lipid antioxidant and metal helator. Rosemary extract was found also to scavenge superoxide radicals. The application of rosemary extracts in food has resulted in a variability in the results depending on the test model being used.

Many different solvents have been used for the extraction of the antioxidative compounds. It was established that the greatest antioxidant activity was located in the methanol extract. The methanol extract was further purified, and the resultant fraction showed an outstanding activity in potato chips fried in sunflower oil and held at 60°C in the dark for 60 days.

The antioxidative effect of rosemary ethanol extract on butter, as well as on filleted and minced fish during frozen storage was studied. Rosemary antioxidants were found suitable for deep frying in edible oils, especially in the presence of ascorbyl palmitate. The rosemary extract inhibits the formation of polar substances, polymers and decomposition of polyunsaturated triacylglycerols, especially in the case of rapeseed oil, and improved the sensory attributes of French fries.

Salvia officinalis L, commonly known as sage (Dalmatian sage), is used in foods for flavouring and seasoning. It was found that, along with rosemary, it had the best antioxidant activity among the numerous herbs, spices and teas tested. Its extracts are also well known as efficient antioxidants.

Since methanol and ethanol were found to be the most suitable solvents for extraction of antioxidants from the plant materials, a number of publications have dealt with further purification of the alcohol extracts. Vacuum steam distillation or molecular distillation are recommended for use on production scale.

Since rosemary and sage belong to the Labiatae family, it is not surprising to find the same antioxidants in both plants: carnosol, carnosic acid, rosmanol, rosmadial, rosmarinic acid. Various methyl and ethyl esters of carnosol, rosmanol, and carnosic acid can be found in sage, as well as in other Labiatae plant extracts; in most cases the compounds are believed to be artefacts from the extraction procedures. The main antioxidative effect of sage was reported to relate to the presence of carnosic acid, carnosol and rosmarinic acid.