Abstract: This study aimed to evaluate the antioxidant capacity of glycosylated zein (glu-zein) as a wall material and improve the antioxidant properties of algal oil during storage. The storage stability of algal oil microencapsulated with glu-zein was analyzed and its shelf life was predicted. The optimal processing conditions that provided maximum anti-lipid peroxidation activity of glu-zein (72.31%) were obtained as 1:12, 30 min and 400 W for mass ratio of glucose to zein, reaction time and ultrasonic power, respectively. The anti-lipid peroxidation capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, reducing capacity, hydroxyl radical scavenging activity, and superoxide anion radical scavenging capacity of glu-zein were significantly increased over those of zein (P < 0.05). During accelerated storage, the peroxide value (POV) and thiobarbituric acid reactive substances (TBARS) value of algal oil microencapsulated with glu-zein were lower than those of free algal oil and algal oil microencapsulated with zein, with a decrease in POV by 3.68 and 39.14 mmol/kg being found after 18 days of storage at 60 ℃, respectively. At room temperature, the shelf life of algal oil microencapsulated with glu-zein was extended by 240 days when compared with that of free algae oil. At the end of the storage period, algal oil encapsulated by glu-zein had the highest retention rate of docosahexaenoic acid (DHA) (96.95%). The results of this study provide a theoretical basis for expanding the application potential of modified zein as a wall material for the delivery of bioactive substances susceptible to oxygen.

Key words: zein; glycosylation; algal oil docosahexaenoic acid; oxidation resistance; shelf life