Seasonal variation of biochemical content and nutritional composition of the newly recorded alga Grateloupia gibbesii, Alexandria, Egypt

In the present study, the newly recorded red alga Grateloupia gibbesii was collected from the Eastern Harbor, Alexandria, Egypt in order to determine the biochemical content, total nitrogen and phosphorus content during winter and spring 2012 in addition to summer 2016. The study moisture, ash content, amino-acids profile, macro-elements (calcium, sodium, potassium, magnesium), and trace elements (copper, zinc, iron, cobalt, manganese, selenium, cadmium, lead, nickel and mercury) were addressed during spring 2015 & summer 2016. The concentration of the total carbohydrates, protein, nitrogen, and phosphorus content in the alga was relatively high during summer 2016 (394.30, 268.20, 39.10 mg/g and1680 mg/100 g, respectively). However, the lipid content of Grateloupia gibbesii experienced low values during the study period. The fatty acids profile showed the highest concentration during winter 2012 (922.09 μg/g). The moisture and ash content of Grateloupia gibbesii recorded the highest percentages (24.01 and 27.72%) during spring 2015, respectively. The total amino acids (EAA) attained a maximum of 732.20 mg/g during spring 2015. The macro-elements and trace elements mostly showed higher content during spring 2015 compared to summer 2016. The results of ANOVA test revealed that the seasonal variation in all the biochemical contents recorded a highly significant difference (P˂ 0.0001). The moisture and ash content showed a significant difference (P˂ 0.0001) during spring 2015 & summer 2016. For the macro-elements, the values of potassium and magnesium were significantly different during spring 2015 & summer 2016, while sodium and calcium were not significantly different during the two seasons. All the trace metals were not affected by seasonal variation, except for nickel, iron, selenium and mercury (P˂ 0.0001).