Effect of Drying Methods on Pigment Stability, Nutritional Composition, and Non-enzymatic Antioxidant Retention in Wild and Cultivated Edible Green Seaweed Ulva

Seaweeds possess high nutritional value and medicinal properties, leading to their increasing application in foods and food additives. Preserving their nutritional quality and pigments during post-harvest processing is crucial, particularly when intended for edible use. The present study evaluated wild and cultivated edible green seaweeds, Ulva fasciata and Ulva lactuca, subjected to four different drying methods (sun drying, shade drying, hot-air oven drying, and solar drying) to assess the retention of pigments, nutritional components, and non-enzymatic antioxidants. A 9-h drying cycle was applied, during which the highest moisture removal was observed in wild sun-dried U. fasciata (88.41%), followed by cultivated hot-air oven–dried U. lactuca (85.78%). U. lactuca retained maximum pigment content (Chl a: 17.07 ± 0.32; Chl b: 11.95 ± 0.54; Total Chl: 37.42 ± 0.88 mg g⁻¹) under shade drying in both wild and cultivated samples. In contrast, U. fasciata showed better pigment retention under sun drying (wild material) and shade drying (cultivated material). Regarding nutritional composition, shade drying yielded the most promising results for protein retention (24.11 ± 4.77% DW in wild U. lactuca; 14.92 ± 0.44% and 18.93 ± 0.62% DW in wild and cultivated U. fasciata, respectively) and carbohydrate content (25.67 ± 0.10% and 12.00 ± 0.41% DW in wild and cultivated U. lactuca; 21.38 ± 0.36% and 22.11 ± 0.34% DW in wild and cultivated U. fasciata, respectively). Hot-air oven drying was more effective in enhancing non-enzymatic antioxidant properties. These findings indicate that tailored drying methods are essential for retaining the nutritional and functional attributes of edible seaweeds. Parameter-based drying optimization can provide promising outcomes for effective value-added product development from Ulva species.