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Evaluation of Antioxidant Activity of Rosemary Extracts, Carnosol and Carnosic Acid in Bulk Vegetable Oils and Fish Oil and Their Emulsions
Author(s) -
Frankel Edwin N,
Huang ShuWen,
Prior Elizabeth,
Aeschbach Robert
Publication year - 1996
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199610)72:2<201::aid-jsfa632>3.0.co;2-q
Subject(s) - carnosic acid , chemistry , fish oil , hexanal , emulsion , antioxidant , food science , peanut oil , corn oil , soybean oil , organic chemistry , fish <actinopterygii> , biology , raw material , fishery
The antioxidant effectiveness of two rosemary extracts, carnosol and carnosic acid, was significantly influenced by the type of system tested (bulk oils vs oil‐in‐water emulsions), by the oil substrates, the methods used to follow oxi‐dation, and the concentrations of test compounds. The rosemary extracts and compounds effectively inhibited conjugated diene hydroperoxide formation in corn oil, soya bean oil, peanut oil and fish oil, when tested in bulk. Test compounds also inhibited hexanal formation in bulk vegetable oils, and propanal and pentenal formation in bulk fish oils. In contrast, these test compounds were either inactive or promoted oxidation in the corresponding vegetable oil‐in‐water emulsions. In fish oil emulsions, however, the rosemary compounds inhibited the formation of conjugated diene and pentenal but not that of propanal. Interfacial phenomena may explain why the hydrophilic rosemary antioxidants afford more protection in the bulk oil systems by being oriented in the air–oil interface, and less protection in the oil‐in‐water emulsion systems by partitioning into the water phase.