Effect of irradiation treatment on the functional properties of flavonoid extracts

Abstract

In this study, Pueraria mirifica, Hawthorn, and soy flavonoid extracts were irradiated with 60CO-γ rays to investigate the effects of different irradiation doses on the storage performance, antibacterial properties, and antioxidant activity of flavonoid extracts. The findings suggested that the irradiation treatment significantly eliminated aerobic bacteria, molds, and yeasts and prolonged the storage period of flavonoid extract. Furthermore, irradiation treatment had no significant effect on the composition fractions of Pueraria mirifica and soybean flavonoid extracts but decreased the rutin and hyperoside levels in Hawthorn flavonoid extracts. In the Fourier Transform Infrared Spectra of Pueraria mirifica flavonoid extracts, the -OH peak intensity was enhanced at 1443∼1365 m−1. Moreover, the -OH peak intensity of Pueraria mirifica and Hawthorn flavonoid extracts was weakened at 3100∼3700 cm−1. Besides, scanning electron microscopy validated that Pueraria mirifica and Hawthorn flavonoid extracts treated with a high irradiation dose of 12 kGy and 18 kGy but with a lower minimum bactericidal concentration (MBC) had a weakened bactericidal effect. The samples treated with low-dose irradiation had no significant effect on the scavenging ability of the DPPH, ABTS, superoxide anion, and hydroxyl radicals; however, the scavenging ability of Pueraria flavonoids and hawthorn flavone extract decreased at 18 kGy and 12 kGy.

Keywords

• Flavonoid extract
• Irradiation treatment
• Preservation properties
• Antibacterial activity
• Antioxidant activity