Judul: Analysis of growth rate amd carrageenan quality of Kappaphycus alvarezii planted at diffrent depths
Abstrak: Kappaphycus alvarezii is one type of red algae that has a distribution and productivity were affected by physical and chemical factors of water, such as current, temperature, salinity, nutritional contents (nitrate and phosphate) and light intensity for photosynthetic process. In each layer of water, there are differences nutrient content and other physico-chemical conditions that can affecting performance of the growth of algae. The main determinant of the growth rate and quality of carrageenan K. alvarezii and other algae is photosynthetic. The process of photosynthesis going well when the intensity of light received optimal, while the excess of the exposure will result thallus become pale, white or loss of pigment. Lack of light intensity received by K. alvarezii will impact on the ability of photosynthesis thus negatively impacting the growth rate and quality of carrageenan. Primary pigment in algae to absorb light for photosynthesis are chlorophyll-a. In anticipation of the limitations of light and other adaptations, red algae (K. alvarezii) forming other pigments is called phycoerythrin. The function of phycoerythrin is as a pigment complement in optimization of capture the sunlight. This study was aimed to determine the abundance of photosynthetic pigments and growth performance of K. alvarezii planted at different depths. This experiment was used K. alvarezii strain Tambalang merah as seeds with an average weight of ±100 g for each unit. K. alvarezii were planted at five different depths, which are 15 cm (K, Control), 50 (A), 100 (B), 150 (C) and 200 cm (D), each subsequent treatment repeated four times, in order to obtain 20 units of treatment. Seaweed is planted during the planting period (45 days), and then further were analyzed the productivity. The measurement of quality of carrageenan was done by dried seaweed extract as much as 40 g obtained from each unit to obtain flour carrageenan treatment. The sample was made pale by immersion for ±24 hours and then blended. Extraction was conducted by boiling the samples using a perssure cooker at 120 ºC for 15 minutes, with a ratio of 1 g of sample: 30 ml of fresh water. Furthermore, the samples were pressured at a temperature of 90-95 ºC for 2 hours until forming the gel. Cellulose separation process conducted by filtration using nylon mesh size of 300 mesh. The filtrate obtained was precipitated by using isopropanol in the ratio 1:2. The precipitate obtained by drying oven dried at a temperature of 70-80oC to form sheets of dried carrageenan. Dried carrageenan made of flour and were analyzed the quality. Parameters observed in this experiment include: chlorophyll-a (Jeffrey and Humphrey 1975); phycoerythrin (Evans 1988); daily growth rate (Dawes 1981); weights harvest; percentage of dry weight; yield of carrageenan (SNI 2012); levels of sulfate (FMC corp. 1977); gel strength (FMC corp. 1977); viscosity (AOAC 1995), and water content (AOAC 1995). Data obtained from observations of all parameters analyzed by one-way analysis of variance (ANOVA) and least significant difference test (LSD) respectively on the real level of 5%.
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