ISOLASI SELULOSA DAN SINTESIS CARBOXYMETHYL CELLULOSE DARI TANGKAI ECENG GONDOK (Eichornia crassipes Solm)

Siska Cicilia, Prof. Dr. Ir. Djagal Wiseso Marseno, M.Agr.

2013 | Tesis | S2 Ilmu dan Teknologi Pangan

Eceng gondok (Eichornia crassipes Solm) merupakan tanaman air yang memiliki kecepatan pertumbuhan yang sangat tinggi sehingga dapat mengganggu lingkungan. Untuk mengurangi efek negatif yang ditimbulkan perlu dilakukan pengolahan eceng gondok. Eceng gondok memiliki kadar selulosa yang tinggi sehingga dapat dijadikan sumber selulosa alternatif dan dapat dimodifikasi menjadi turunan selulosa seperti carboxymethyl cellulose (CMC). Tujuan dari penelitian ini adalah mendapatkan cara isolasi selulosa eceng gondok dan cara sintesis CMC dari selulosa eceng gondok. Penelitian ini dilakukan dua tahap yaitu isolasi selulosa dan sintesis CMC. Isolasi selulosa dari tepung tangkai eceng gondok menggunakan NaOH 10%; 12,5%; 15% dan 17,5% selama 3 jam pada suhu 100⁰C. Hasil isolasi berupa pulp dibleaching dengan perendaman dalam Na metabisulfit 3% selama 3 jam pada 60⁰C dilanjutkan dengan perendaman dalam NaOCl 6% selama 3 jam pada 60⁰C. Pulp kemudian dikeringkan dan dihaluskan. Selulosa yang dihasilkan dianalisa rendemen, kadar air dan abu, kadar selulosa, oil holding capacity (OHC), water holding capacity (WHC), lightness, derajat depolimerisasi (DP), dan gugus fungsional. Tahap kedua yaitu sintesis CMC dilakukan 3 perlakuan yaitu konsentrasi NaOH (6,59%; 10%; 15%; 20%; 23,41%), berat NaMCA (3,318g; 4g; 5g; 6g; 6,682g), dan suhu karboksimetilasi (46,59°C; 50°C; 55°C; 60°C; 63,41°C). Untuk menguji efek kombinasi dari ketiga variabel tersebut pada derajat substitusi (DS) CMC eceng gondok dilakukan simulasi sintesis CMC menggunakan RSM (Response Surface Methodology) central composite design dengan 20 perlakuan.Sintesis diawali dengan proses alkalisasi selama 1 jam pada suhu 25°C, dilanjutkan dengan penambahan NaMCA selama 3 jam dan pencucian menggunakan etanol. CMC yang diperoleh dikarakterisasi dengan parameter rendemen, DS, tingkat kemurnian, viskositas, OHC, WHC, lightness dan gugus fungsional CMC. Berdasarkan hasil pengamatan diketahui kondisi terbaik dalam isolasi selulosa menggunakan larutan NaOH 15% dengan rendemen 46,21%, kadar air 9,42%, kadar abu 7,37%, kadar selulosa 94,12%, lightness 81,33, OHC 3,5 g/g, DP >41 AGU, dan WHC 3,57 g/g. Kondisi optimum sintesis CMC yaitu pada konsentrasi NaOH 15% (w/v), berat NaMCA 5g pada suhu 55⁰C. Karakterisasi CMC yang dihasilkan berupa rendemen 153,31%, DS sebesar 0,75, OHC 3,02 g/g, WHC 4,42 g/g, lightness 64,1, kemurnian 96,92%, kandungan CMC 65,79%, pH 8,54 serta viskositas 7,49 cps. CMC yang dihasilkan termasuk dalam klasifikasi food grade.

Water hyacinth is a weed growth on shallow water, ponds, lake and it is growth fast so it can give negative effect in the enviroment. Many efforts has been done to reduce amount of water hyacinth. The prime component on cell wall of water hyacinth is cellulose, so it can be a alternative source of cellulose and it can be modified to be cellulose derivatives, one of them is carboxymethyl cellulose (CMC).The aims of the present study were to get method of isolation of cellulose from water hyacinth and synthesize of CMC. The research was conducted in two main steps: isolation of cellulose from water hyacinth and synthesize of CMC. Firstly, Isolation of cellulose has been done using NaOH 10%, 12.5%, 15%, and 17.5% at 100⁰C for 3 h (1:20 w/v) and resulted pulp. The pulp was bleached for twice by NaOCl and natrium metabisulfit, each bleached for 3 h at 60⁰C and then dried, milled and resulted cellulose powder. Secondly, synthesizing of CMC in which there were three variables on this research, concentration of NaOH (x1 ; 6,59%; 10%; 15%; 20%; 23.41%), amount of NaMCA (x2 ; 3.318g; 4g; 5g; 6g; 6.682g), and temperature of carboxymethylation (x3 ; 46.59°C; 50°C; 55°C; 60°C; 63.41°C). This step was started by alkalization process using NaOH, followed by adding NaMCA. In order to examine the variables on DS, the simulation of synthesis CMC has been conducted by using Response Surface Methodology (RSM) CCD with 20 treatments. The characterization of cellulose were yield, lightness, oil holding capacity (OHC), water holding capacity (WHC), degree of depolimerisation (DP), and crystalinity. The characterization of CMC were yield, lightness, WHC, OHC, degree of substitution (DS), purity, pH, CMC content, viscosity, The optimum condition of the isolation using NaOH 15% which has yield 46.21%, moisture content 9.42%, ash content 7.37%, cellulose content 94.12%, lightness 81.33, OHC 3.5 g/g, WHC 3.57 g/g, DP >41 AGU, and crystalinity 24.36%. The optimum condition for synthesis was NaOH 15% (w/v), NaMCA 5g at 55⁰C. The characterization of CMC was yield 153.31%, DS 0.75, OHC 3.02 g/g, WHC 4.42 g/g, lightness 64.1, purity 96.92%, CMC content 65.79%, pH 8.54 and viscosity 7.49 cps.

Kata Kunci : Eceng gondok, carboxymethyl cellulose, derajat substitusi