Chemical Composition of Royal Jelly and Effects of Synbiotic with Two Different Locally Isolated Probiotic Strains on Antioxidant Activities

This study was carried out to investigate the antioxidant properties of synbiotic product, Lactobacillus acidophilus supplemented with 2.5% royal jelly in skim milk and Bifi dobacterium bifi dum supplemented with 7.5% royal jelly in skim milk, using DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical scavenging assay, reducing power, total antioxidant in linoleic acid system and formation of diene-conjugation assay. Results showed that the synbiotic effect of royal jelly and probiotic bacteria provided substantial antioxidant activities. Milk samples fermented by B. bifi dum supplemented with 7.5% royal jelly and L. acidophilus supplemented with 2.5% royal jelly exhibited high scavenging activity with 96.8 and 93.3%, respectively, at a concentration of 500 μg/mL. IC50 values were estimated at 226.7 μg/mL for B. bifi dum supplemented with 7.5% royal jelly and at 210.2 μg/ml for L. acidophilus supplemented with 2.5% royal jelly. On the other hand, L. acidophilus supplemented with 2.5% royal jelly and B. bifi dum supplemented with 7.5% royal jelly exhibited signifi cantly high reducing power at a concentration of 1000 μg/mL. The percentages of peroxide inhibition of L. acidophilus supplemented with 2.5% royal jelly and B. bifi dum with 7.5% royal jelly were 52% and 42%, respectively. Signifi cant inhibitions were found in the formation of conjugated diene at 66.9% and 65.8% for L. acidophilus with 2.5% royal jelly and B. bifi dum with 7.5% royal jelly, respectively. These results were compared with standards BHT, ascorbic acid and Trolox. Original article Section: Food Chemistry