effect of edible coatings containing antioxidant agents on oxidative stability and sensory properties of roasted pistachio nuts (ohadi variety)

background and objectives: edible films and coatings are effective method for decreasing oxidation and increasing the shelf life of pistachios. the present study investigated the effect of an edible gelatin coating containing ascorbic acid (aa: 1% w/v) and propyl gallate (pg: 100 ppm) on the oxidative stability and sensory properties of roasted pistachio nuts. materials and methods: pistachios were subjected to one of five treatment formulations: uncoated, aa + pg, gelatin + pg, gelatin + aa, gelatin +aa+ pg. the pistachio samples were roasted, packaged, and stored in triplicate at 35°c and 50°c. chemical analysis was measurement of free fatty acid (ffa), peroxide content (meq.o2 kg-1), anisidin content, and totox. sensory evaluation (texture, rancidity, taste, overall acceptability) was performed by 20 semi-trained panelists over 3 mo of storage. results: the edible gelatin coating containing antioxidant agents, especially aa, showed a statistically significant decrease (p < 0.05) in the rate of oxidation. incorporation of two antioxidant agents had no synergistic effect on the antioxidant properties of the gelatin coating however, samples coated with gelatin containing aa + pg exhibited the greatest increase in shelf life. in addition, high temperatures during storage decreased the quality of the pistachio oil and total acceptability of the product. edible gelatin-antioxidant coating did not affect the total acceptability of the product, but protected against lipid oxidation during storage. the use of gelatin coating increased the firmness of the pistachio nuts. conclusion: edible gelatin coating containing antioxidant agents show good potential for decreasing the rate of oxidation and increasing the shelf life of pistachio nuts. keywords: antioxidant, oxidation, pistachio, edible gelatin coatings, sensory properties