Kajian Mutu Karaginan Rumput Laut Eucheuma cottonii Berdasarkan Sifat Fisiko-Kimia pada Tingkat Konsentrasi Kalium Hidroksida (KOH) yang Berbeda

Abstract

Abstrak

Getah rumput laut yang diekstraksi dengan air atau larutan alkali dari spesies tertentu dari kelas Rhodophyceae (alga merah), lazim dinamakan dengan Karaginan yang telah banyak digunakan dalam industri pangan sebagai pengental, pengemulsi, pensuspensi, dan faktor penstabil. Larutan alkali seperti KOH mempunyai dua fungsi, yaitu membantu ekstraksi polisakarida menjadi lebih sempurna dan mempercepat eliminasi 6-sulfat dari unit monomer menjadi 3,6-anhidro-D-galaktosa sehingga dapat meningkatkan mutu karaginan. Tujuan dari penelitian ini, untuk mengevaluasi pengaruh konsentrasi KOH dengan mengatur suhu konstan 90^oC, pH 8-9, dan waktu ekstraksi 0,5 jam (30 menit) terhadap mutu karaginan berdasarkan sifat fisiko-kimia. Penelitian ini menggunakan berbagai konsentrasi KOH (2%, 4%, 6%, 8%, 10%, 12%). Karaginan terbaik yang dihasilkan dalam penelitian ini adalah perlakuan dengan konsentrasi KOH 12%. Karakteristik fisiko-kimia yang dihasilkan dari karaginan terbaik yaitu kekuatan gel 449.51 dyne/cm², viskositas 50,47 cP, titik jendal  35.88^oC dan titik leleh 25.56^oC, rendemen 45.26%, kadar air 9.23%, kadar abu 33.68%, kadar lemak 0.37%, kadar protein 0.80%, kadar serat kasar 4.12% dan kadar karbohidrat 51.81%.

Abstract

Seaweed sap which is extracted with water or alkaline solution from certain species of Rhodophyceae class (red algae), commonly named by carrageenan which has been widely used in food industry as thickeners, emulsifiers, suspending agent, and stabilizer. Alkaline solution such as KOH has two functions, which are making the extraction of polysaccharides more perfect and accelerate the elimination of 6-sulfate of monomer units from 3.6-anhidro-D-galactose to improve the quality of carrageenan. The purpose of this study is to evaluate the effect of KOH concentration with constant temperature of 90°C, pH 8-9, and the extraction time 0.5 hour (30 min) on the quality of carrageenan based on the physicochemical properties. This study used various concentrations of KOH (2%, 4%, 6%, 8%, 10%, 12%). The best carrageenan was produced by 12% KOH extraction. Physicochemical characteristics of the best carrageenan were found to be 449.51 dyne/cm² of gel strength, 50.47 cP of viscosity, 35.88^oC of gelling point, melting point was 25.56^oC. The yield was 45.26%, moisture content was 9.23%, ash content was 33.68%, fat content was 0.37%, protein content was 0.80%, crude fiber content was 4.12% and carbohydrate content was 51.81%.