Shima Jahanfara, Mehrdad
Gahavamia, Kianoush
Khosravi-Darani*b, Mahshid Jahadic
a Department of Food Science and Technology, Faculty
of Agriculture and Natural Resources, Science and Research Branch,
Islamic Azad University, Tehran, Iran.
b Department of Food Technology Research, National
Nutrition and Food Technology Research Institute, Faculty of Nutrition
Sciences and Food Technology, Shahid Beheshti University of Medical
Sciences, P.O. Box: 19395-4741, Tehran, Iran.
c Department of Food Science and Technology, Isfahan
(Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.
Abstract: In the present study, green tea extract was
encapsulated in liposomes prepared by Mozafari method (without any
organic solvents) and characterized for its physicochemical properties
e.g. encapsulation efficiency, particle size and z- potential. The
obtained results for encapsulation efficiency, particles size and z-
potential were 51.34, 419 nm and -57 mV, respectively. Total polyphenol
content of green tea was obtained 164.2 mg gallic acid /g extract. Free
radical scavenging activities of free and liposomal extract, with using
DPPH method were measured 90.6% and 93.37% respectively. Antioxidant
activity of ethanolic extract of green tea in free and liposomal form
were measured at concentration of 200, 600 and 1000 mg/L on the
oxidative stability of canola oil during 60°C temperature for 0, 4, 8,
12, 16, 20, 24, 28 and 32 days. The results compared with synthetic
antioxidant butylated hydroxytoluene at 200 mg/L. To evaluate
antioxidant activity on canola oil stability, peroxide value,
Thiobarbitoric acid, anisidine value, TOTOX and rancimat test measured.
Results showed that liposomal green tea extract acted more effective
than free extracts. Also, 600 mg/L concentration of green tea extract
showed significant antioxidant activity in compare to others. The
increasing storage time and different concentrations of ethanolic green
tea extracts had significant effects on canola oil stability (P≤0.05).
The obtained results showed green tea extract could act as an effective
antioxidant. Green tea extract in free and liposomal form at 600 mg/L
concentration resulted stronger function than butylated hydroxytoluene
synthetic antioxidant.
Keywords Green tea extract, Liposome, Canola oil, Oxidative
stability