Seasonal variation in nutritional composition of Kappaphycus alvarezii (Doty) Doty-an edible seaweed

Seasonal variation in the proximate and mineral composition of Kappaphycus alvarezii were investigated in the present study, moreover, the relationship between the nutritive components of this seaweed and the environment were also established. Carbohydrates represented the major portion of the algae (i.e. average total carbohydrate content was 23.01 ± 1.64 g/100 g DW), while the lipid content was the lowest among the constituents investigated (0.39 ± 0.04 to 0.91 ± 0.51 g/100 g DW). The protein content of K. alvarezii varied from 12.69 ± 0.6 to 23.61 ± 0.02 g/100 g DW, and the fiber content varied between 9.68 ± 0.08 to 18.57 ± 0.15 g/100 g DW. Highest total mineral content (29939.61 ± 9340.38 mg/100 g DW) was observed in April 2005, while least values were recorded in January 2006 i.e. (10997.62 ± 1120.26 mg/100 g DW). The Na/K ratio during the study ranged from 0.34 to 0.87. All the samples showed remarkable semi-refined carrageenan (SRC) yield ranging from 42.70 ± 1.07 to 63.73 ± 1.73 % (average 53.90 ± 1.37 %), and, the samples collected during December 2004 and January 2006 demonstrated maximum gel strengths i.e. 743 ± 15.28 and 783.33 ± 15.28 g·cm(-2) respectively. Various environmental parameters influenced the chemical composition of K. alvarezii, and these parameters demonstrated seasonal fluctuations. Moreover, based on the nutritional composition obtained, it could be stated that this seaweed has great scope to be incorporated into several food products as an excellent nutritional supplement, or as a value additive in animal or pet food.