Effect of γ-irradiation on structure, physicochemical property and bioactivity of soluble dietary fiber in navel orange peel

Abstract

Soluble dietary fibers are widely used in functional food. In this work, the effects of γ-irradiation on molecular weight, structure, physicochemical properties and bioactivities of soluble dietary fiber in navel orange peel (OSDF) were investigated. Γ-irradiation enhanced the extraction yield of OSDF. The molar ratio of glucose and galacturonic acid was increased. The molecular weight profile of OSDF was modified. Γ-irradiation (3–6 kGy) improved the water holding capacity, water swelling capacity, oil holding capacity, cation-exchange capacity, nitrite adsorption capacity and total antioxidant capacity of OSDF. Glucose adsorption capacity and bifidobacterium proliferation capacity of OSDF were improved in a dose-dependent behaviour. Moreover, γ-irradiation promoted the cracking of microstructure. FT-IR spectra showed that more carboxyl groups were newly formed by γ-irradiation. These findings indicated that γ-irradiation treatment was an efficient technique for improving physicochemical properties and health benefits.

Keywords

• Dietary fiber
• Polysaccharide
• Molecular weight
• Structure
• Pectin