Effects of sun/open-air drying and oven-drying on chemical composition and functional properties of dried Ulva intestinalis

Seaweeds are important sources of macro- and micronutrients used as food, minerals, and as important sources of many bioactive compounds. Due to high water content, seaweeds are highly perishable and  should be immediately subjected to drying process to increase their shelf-life. The present study aimed to investigate the effect of oven-drying in comparison with conventional sun/open-air drying on the chemical composition, functional properties and fatty acid profile of Ulva intestinalis. The results showed significantly lower water holding capacity in sun/open-air dried samples (۸.۸۳ mL g-۱) compared to oven-dried ones (۱۰.۸۳ mL g-۱; p > ۰.۰۵). There was no significant difference between oil holding capacity, emulsifying activity and swelling capacity of dried U. intestinalis and two different drying methods (p > ۰.۰۵). The EPA and DHA contents in sun/open-air and oven- dried samples were ۱.۲۸۲ and ۰.۸۰۶ (g/۱۰۰g for EPA), while ۲.۳۷۷ and ۱.۹۷۲ (g/۱۰۰g for DHA), respectively. N-۳/n-۶ ratio in the above-mentioned samples were ۰.۹۵۹ and ۰.۳۴۰, respectively. Based on the results, oven-drying method is suggested for drying this algae regarding to higher water holding capacity and higher content of highly unsaturated fatty acids.

Keywords:

Green algae , Drying methods , Functional properties , Water holding capacity , Fatty acid profile