Anti-oxidative effects of rooibos tea extract on autoxidation and thermal oxidation of lipids.
Powdered rooibos tea extract (RTE), which is rich in polyphenols, is made from rooibos tea by freeze-drying. "Rooibos" is Afrikaans for "red bush," and the scientific name is "Aspalathus linearis." It is a broom-like member of the legume family of plants and is used to make an herbal tea which has been popular in South Africa for generations and is now consumed in many countries. In the present work, the anti-oxidative effect of RTE on oils and fats in autoxidation or thermal oxidation was studied, and it was confirmed that RTE has a very strong anti-oxidative effect on emulsifying oils owing to the water-soluble polyphenols such as rutin and quercetin contained in RTE. RTE was found to have a strong ability to quench radicals generated in the water phase, and to confer higher thermal stability against deep fat frying than tocopherol. But RTE showed little anti-oxidative effect on frying oil because of its lower oil-solubility.
Department of Materials and Life Science, Faculty of Science and Technology, Seikei University, Musashino-shi, Tokyo, Japan.
Ryo
R
Fukasawa
Ayato
A
Kanda
Setsuko
S
Hara
D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D036903:Aspalathus / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000378:metabolism; D019343:Citric Acid / Q000494:pharmacology; D004952:Esters; D005419:Flavonoids / Q000032:analysis; D016166:Free Radical Scavengers / Q000494:pharmacology; D019787:Linoleic Acid / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects*; D010084:Oxidation-Reduction / Q000187:drug effects; D010545:Peroxides; D010636:Phenols / Q000032:analysis; D010714:Phosphatidylethanolamines / Q000494:pharmacology; D010851:Picrates / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D059808:Polyphenols; D012450:Safflower Oil / Q000737:chemistry; D013024:Soybean Oil / Q000737:chemistry / Q000302:isolation & purification; D013662:Tea / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
D000975:Antioxidants; D001713:Biphenyl Compounds; D004952:Esters; D005419:Flavonoids; D016166:Free Radical Scavengers; D010545:Peroxides; D010636:Phenols; D010714:Phosphatidylethanolamines; D010851:Picrates; D010936:Plant Extracts; D059808:Polyphenols; D013662:Tea; D019343:Citric Acid; C483858:phosphatidylethanolamine; D013024:Soybean Oil; D012450:Safflower Oil; D019787:Linoleic Acid; C004931:1,1-diphenyl-2-picrylhydrazyl; D001205:Ascorbic Acid