Plant extract combos boost shelf life of encapsulated oils

"By simply mixing and adding natural plant extracts at proper combinations during the microencapsulating process of high oleic sunflower oil, lipid oxidation was significantly reduced," wrote lead author Jang-Hyuk Ahn and co-workers from the Korea Advanced Institute of Science and Technology.

The study, published on-line ahead of print in the Journal of Food Engineering , taps into an ever growing trend to use natural extracts as antioxidants and preservatives as alternatives to artificial additives, such as like butylhydroxyanisole (BHA) and butylhydroxytoluene (BHT).

According to a 2003 report by Frost and Sullivan, the synthetic antioxidant market is in decline, while natural antioxidants, such as herb extracts, tocopherols (vitamin E) and ascorbates (vitamin C) are growing, pushed by consumer desire acceptance and easier market access.

While studies have already investigated and documented the efficacy of rosemary extracts to act as antioxidants, according to background information in the article, no studies have looked at the combined antioxidant effect of natural plant extracts (NPE) such as broccoli sprout or citrus on various seed oils.

Oxidation processes in food can lead to organoleptic deterioration in taste, colour and texture.

The researchers microencapsulated high oleic sunflower oils using a dextrin-coating method in the presence of the natural plant extracts in varying concentrations.

Ahn and co-workers report that the maximum antioxidant effect was observed using a mixture of rosemary (0.05 per cent), broccoli sprout extract (one per cent) and citrus extract (one per cent).

"Based on these results, it is evident that natural plant extracts have a combined effect as an antioxidant on microencapsulated high oleic sunflower oil (MEHS).

From the viewpoint of chemical components, it is likely that the antioxidant effect of NPEs on the MEHS mainly resulted from the combined effect of polyphenols, carnosolic acid, flavonones, and some minerals," said the researchers.

"Although HS contained large amounts of oleic acid which is less vulnerable to lipid oxidation, extended storage of MEHS at high temperature also led to sever lipid oxidation.

In this regard, the use of NPEs will ensure the prolonged stability of microencapsulated oil products as an effective antioxidant," they concluded.

Source: Journal of Food Engineering (Elsevier) Published on-line ahead of print, doi: 10.1016/j.jfoodeng.2007.05.029 "Antioxidant Effect of Natural Plant Extracts on the Microencapsulated High Oleic Sunflower Oil" Authors: J.-H.

Ahn, Y.-P. Kim, E.-M. Seo, Y.-K. Choi and H.-S. Kim