Comparative study of the chemical composition and caloric value of Ulva ssp. collected in two different areas of the Bay of Cadiz

Resumen

Seaweeds are a rich source in protein, fiber, vitamins, minerals, polyunsaturated fatty acids and essential amino acids. They also contain a variety of components that possess technological properties (agar,carrageenan, alginates) and functional ones (carotenoids, terpenes, polyphenols) such as antioxidant,anticancer and antiviral effects. These nutritional, functional and technological characteristics makeseaweeds a very interesting product in different fields (food, cosmetics, pharmaceuticals, etc). In recent years, the demand has increased, particularly in the field of food which is consumed as fresh andprocessed (dried, canned, prepared dishes, etc.).However, numerous studies have shown that the nutritional composition of the seaweeds is variabledepending on environmental factors, such as water temperature, salinity, light, and nutrients. Most ofthese environmental parameters vary with the season and ecological conditions. So, the biosynthesisof various nutrients would be stimulated or inhibited. Therefore, proximal composition of seaweed andtheir calorific value are related to the area and time of collection.The Cadiz coast and its marshes are a source of marine resources which are not currently used, including ´a large number of species of seaweeds such as Ulva ssp.The geographical location of the Gulf of Cadiz is a particular area due to the influence from the Mediter- ´ranean and Atlantic streams, the wind system and marshes in the Bay of Cadiz. These characteristicscould influence on the nutritional composition of seaweeds which are developing in these areas.The main of this work was to establish the influence of the environment in the proximal compositionof Ulva ssp comparing two collecting areas of Cadiz such as the marsh “The Pastorita” in Chiclana ´de la Frontera, and in an area close to the estuary of Barbate (Bay of Cadiz). Moisture, protein, fat, ´carbohydrates, ash and fiber were analysed according to different methods for determination of foodnutrients.The results showed that the moisture content (84.7% of estuary and 86.5% of marsh) and carbohydratecontent (11.7% of estuarine and 14.2% of saltmarsh) were very similar. However, significant differenceswere found for protein content (7.2% of estuary and 1.5% of marsh), fat content (3.4% of estuary and6.4% of marsh), ash content (34.2% of estuary and 52.7% of marsh) and fiber content (9.5% of estuaryand 3.1% of marsh). On the other hand, caloric values for Ulva ssp. in both areas (106.5 Kcal/100g ofestuary and 120.5 Kcal/100g of marsh showed low values. Therefore, Ulva ssp. could be considered ahealthy product with high nutritional value.In short, the proximate composition of seaweed depends largely on the collection area, being the saltmarsh a good alternative for growing and harvesting seaweed for human consumption