Antioxidant and prooxidant activities of β-carotene in accelerated autoxidation and photosensitized model systems

Antioxidant or prooxidant activity of β-carotene was studied in autoxidized or methylene blue photosensitized lard using the depletion of headspace oxygen, p-anisidine value (p-AV), or a modified DPPH methods. β-Carotene of 1. 25 and 2. 50 μM significantly decreased headspace oxygen and β-carotene from 0. 25 to 2. 50 μM increased significantly p-AV in lard oxidized at 60°C for 60 h (p<0. 05), implying β-carotene acted prooxidantly. β-Carotene under 0. 25 μM in oxidized lard did not decrease the absorbance of DPPH significantly (p>0. 05), while 1. 25 and 2. 50 μM β-carotene decreased the absorbance of DPPH significantly (p<0. 05), indicating β-carotene over 1. 25 μM accelerated the formation of radical scavenging compounds from oxidized lipids (RSOLs). However, all the concentration of β-carotene did not cause significant changes in DPPH absorbance and headspace oxygen content (p>0. 05) in photosensitized lard at 40°C for 24 h, indicating antioxidant properties of β-carotene in photosensitization.