Study on applications of carrageenan obtained from Kappaphycus alvarezii alga to minimize dry matter loss during preservation of frozen shrimp

Abstract

Carrageenan was extracted from Kappaphycus alvarezii alga for application in shrimp preservation to reduce the loss of dry matter during preserving frozen shrimp. The main material in this study is dried alga. The solution 3% NaOH was used to remove color compounds and lipids. The selected extraction conditions include distilled water, pH 7, the ratio of material/solvent 1/40 (w/v) at 80 °C for 2 hours, 1% CaCl₂ for the precipitation. The semi-refined carrageenan powder was ivory white, uniform smoothness, 9.21% moisture content. The recovery yield of the extraction was 65.96%. The solution used for shrimp coating was a mixture of 0.3 g carrageenan, 0.075 g glycerol, 0.075a polyethylene glycol 6000. the ratio of the mixture and distilled water 1/40 (w/w). The mixture was stirred in a heating condition at 80 °C for 30 minutes, then cooled down. Next, the shrimp were dipped in solution before freezing, shrimp samples were frozen to investigate the loss of dry matter between the control sample and the shrimp immersed in the preserved solution for 12 weeks.