There has been interest in the use of plant extract as a natural preservative agent for improving the oxidative stability of vegetable oils. However, plant extracts have low stability against heat and environmental stress. In this study, the antioxidant potential of nano‐ and microencapsulated Rosmarinus officinalis L. extract (RE) obtained using the ultrasonication method was measured. The total phenolic and flavonoid content of the extract was 174.4 ± 25.9 mg gallic acid/g extract and 78.30 ± 3.2 mg rutin/g extract, respectively. Antioxidant activity of 50, 100, 200, and 400 ppm of RE was measured by DPPH free radical scavenging methods, ferric reduction assay, and β‐carotene/linoleic acid assay, and then compared to the 100 ppm of TBHQ as a common synthetic antioxidant. The results showed that the antioxidant activity increased with increasing the concentration of the extract in all evaluating methods. The antioxidant activity of 200 ppm of the free and encapsulated extract in cress (Lepidium sativum) and basil (Ocimum basilicum) seed gums at different ratios (1:0, 1:1, and 0:1) was compared to sunflower oil without antioxidants, and oil‐containing TBHQ which was stored at 60°C for 24 days. The oxidation indexes of oil samples include peroxide value, thiobarbituric acid value, and p‐anisidine value measured at 4‐day intervals. A lower oil oxidation was observed in oil‐containing nanoencapsulated extract followed by microencapsulated extract, free extract, and TBHQ. Since producing nanoencapsulated RE requires a higher time and speed of homogenization and due to no statistically significant difference between the antioxidant properties of nanocapsules and microcapsules in oil, the use of microcapsules of RE in basil seed gum to increase the shelf life of sunflower oil is recommended.

This study investigates the problem of preserving the quality and shelf life of beluga sturgeon (Huso huso) fillets under refrigeration. The aim of the research is to evaluate the effectiveness of composite edible coatings made from chitosan and fucoidan, in combination with crucian carp (Carassius carassius) protein hydrolysate (CPH). Significant methodology includes the preparation of hydrolyzed proteins using the enzyme Alcalase for 90 min, followed by encapsulation within nanoliposomes. Fucoidan was extracted from the brown alga Sargassum latifolium, and its antioxidant and antimicrobial properties were assessed. Six types of edible coatings were developed, including chitosan and chitosan-fucoidan with CPH and nano CPH (NCPH) at concentrations of 0 %, 0.5 %, and 1 %. The chemical, microbiological, and sensory characteristics of the coated and uncoated fish fillets were evaluated over a 16-day storage period. Results indicated a particle size of 102.98 nm, a zeta potential of 12.29 mV, and an encapsulation efficiency of 75.84 %. The extraction yield of fucoidan was 5.89 %, with total carbohydrate content of 59.2 %, protein content of 9.21 %, sulfate content of 21.78 %, and uronic acid content of 8.85 %. Fucoidan exhibited significant antioxidant and antimicrobial activity. The analysis of chemical and microbiological factors in the fish fillets revealed significantly lower values in the coated fillets compared to the control (P < 0.05). The use of CPH significantly reduced the rate of oxidative spoilage, and increasing CPH concentration resulted in a slower rise in microbial load (P < 0.05). The best outcomes were observed in NCPH. Ultimately, the combination of chitosan-fucoidan and 1 % NCPH maintained acceptable conditions for most microbiological, chemical, and sensory indices by the end of the storage period. These findings suggest that these edible coatings could serve as an effective method for enhancing the quality and shelf life of fish fillets in the food industry.