Antioxidant properties and total polyphenolic contents of post distillation solid residue extract from gamma-irradiated clove buds [electronic resource]

Includes bibliographic reference

The current study was carried out to investigate the antioxidant activities of the solid waste residue obtained after removing the essential oils through the distillation of γ-irradiated clove buds at three levels of doses (0, 5 and 10 kGy). The total phenolic and flavonoid contents (TPC and TFC) were assessed followed by HPLC identification and quantification. The DPPH and FRAP methods were used to measure the antioxidant activity. The obtained results showed that 10 KGy doses greatly improved the TPC, TFC, and antioxidant activities of the solid residue of clove buds. Ten phenolic components and eight flavonoid compounds were detected in non-irradiated and irradiated at 10 kGy in methanolic extracts by HPLC. Various levels of methanolic extract of the solid residue of irradiated clove buds at dose level of 10 kGy (100, 200, and 400 mg/L) were tested for these antioxidant activities against the oxidative changes in sunflower oil compared with control and BHT-treated samples. The sample containing clove solid residue at levels of 400 mg/L showed a good potential for oxidative stability (6.95h). Finally, the data obtained demonstrated that clove extracts are a promising source of bioactive components and a natural supply of antioxidant compounds. Hence, it also offers a variety of possible applications in the food and pharmaceutical industries.
Keywords: Gamma irradiation; Clove buds (Syzygium aromaticum) ; Antioxidant activity ; post-distillation waste residue; Oxidative stability

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