Chemical composition and functional properties of two brown seaweeds from the Qeshm Island, Iran

Seaweeds have been introduced as an important sources of food and pharmaceutical active agents since last century. In this study, the chemical composition and functional characteristics of (common names) Nizamuddinia zanardinii and Iyengaria stellata, were investigated. The total carbohydrate and ash contents were the two most abundant components in these seaweeds but their crude lipid and fiber contents were low. The protein content was higher in I. stellata followed over N. zanardinii. Atomic absorption spectrophotometry of the ashes showed that I. stellata contained higher amounts of both macrominerals (Ca, Mg) and trace elements (Fe, Zn) than N. zanardinii. Results of antioxidant properties showed that total phenolic (3.37 mg 100g^-1), total antioxidant (27.08 mg g^-1) and reducing power (22.76%) were higher in N. zanardinii than I. stellata, while DPPH free radical scavenging (7.16%) was higher in I. stellata. The results suggest that both the seaweeds could be used as a potential source of nutrient and antioxidant compounds in food and pharmaceutical industries