INITIAL STUDY ON KOH SOLVENT FOR SEAWEED EXTRACTION AND ITS EFFECT ON PROTEIN IN THE EXTRACT

Abstract

Seaweed is usually used as foods, main gradients in fuctional food, cosmetics, and for producing fertilizers. Extract from sea weed is able to be used as folar fertilizers for various types of crops. Fresh Porphyra vietnamensis was primarily processed, including washing sands and wastes, and sun-drying before extraction. The processed seaweed and solvent was mixed with weight to volume ratio 0.5 g to 25 ml. Four types of solvents HCl, H₂SO₄, NaOH and KOH, extraction time from 1 to 11 hours, extraction temperature 28, 55 and 95^oC were the factors studied for seaweed extraction. The results showed protein content in extract using NaOH or KOH was 5 – 6 time as many as that in extract using HCl or H₂SO₄. The higher extraction temperature or time, the higher protein content in the extracts was. With solvent KOH 5%, the protein content in extract obtained at 95^oC was 2.3 – 3.6 times as many as that at 28 or 55^oC. What extracted using KOH solvent for 9 hours and at about 100^oC was the most apperoriate, the highest protein content compared to the other experiment conditions studied. In addition, the extract using KOH solvent had higher total N and total K₂O than that using H₂SO₄. Choosing appropriate KOH concentration for seaweed extraction is nessessarily based on types of crops and their growth and development stages. Potassium hydroxide is a potential solvent for extracting seaweed for foliar fertilizers because it provides macroelement Potassium and higher quality of the extract as well.