From marine to fork: Effects of different cooking methods on the composition of sea lettuce

Abstract

The nutritional, functional and technological richness exhibited by seaweeds has encouraged in recent years their use for culinary purposes. Their broad range of colors, textures and flavors makes of them an ideal ingredient for the preparation of a wide variety of novel and imaginative dishes. However, few studies have been carried out on the effect that thermal cooking treatments have on seaweeds. This study intends to evaluate the influence of certain cooking processes (boiling, steaming and sous-vide) on the physicochemical and functional composition of Ulva sp. collected from the earthen ponds in Cadiz. Sea lettuce has been cooked using three different methods and at three different temperatures (50, 70 and 100 °C) for three different periods of time (5, 10 and 15 min). After the treatments, it could be observed that the structure, physicochemical composition and functional characteristics of Ulva sp. were significantly affected by the cooking method used. The effect of cooking on the alga's properties depended both on the method itself and on the time used. In relation to its nutritional composition, boiling was the culinary method that most affected ash, protein, lipid, unsaturated fatty acid and mineral (K, Ca, Mg and Cu) contents, with longer cooking times leading to their significant or total loss either through chemical reactions or leaching. In contrast, sous-vide cooking proved to be a technique that preserves and can even enhance the nutritional benefits of raw seaweeds.