Growth rate and carrageenan properties of three varieties of Kappaphycus alvarezii (Rhodophyta) farmed in Tangal, Semporna, Sabah

Abstract

Relative growth rate, semi-refined carrageenan yields, gel strength, viscosity, gelling temperature, melting temperature and IR spectra of gel were investigated in three varieties of K. a/varezii (K. alvarezii var. 'tambalang', K. alvarezii var. 'babaei', K. alvarezii var. 'aring-aring') farmed at Tangal, Semporna, Sabah for 35 days cultivation using the long-line culture method in a sandy seafloor area and coral seafloor area. These three varieties of K. alvarezii produce K-carrageenan which has the greatest market demand now days. Study showed higher growth rates were achieved by K. alvarezii var. 'aring-aring' (4.49-5.18% day- 1 ) than K. alvarezii var. 'tambalang' (3.47-3.68 % day-I) and K. alvarezii var. 'babaei' (3.96-4.06% day- 1 ). The K. alvarezii var. 'tambalang' and K. a/varezii var. 'babaei' exhibited lower growth rates, but produced higher semi-refined carrageenan yields and greater gel strength than K. alvarezii var. 'aring-aring '. All varieties showed negative correlation between growth rate and semi-refined carrageenan yields and same goes for gel strength.