Aji Prasetyaningrum

Carrageenan drying with dehumidified air: drying characteristics and product quality

Abstract Applying dehumidified air is considered as an option to retain quality in carrageenan drying. This work concerns the effects of operational temperature, air velocity, and carrageenan thickness on the progress of drying and product quality when using dehumidified air. Final product quality and progress of drying were measured by experiments, and a two dimensional model was developed to analyze progress of drying for the different operational conditions. The experimental and modeling results showed that air dehumidification with zeolite reduces the drying time the most at low temperatures. Under these conditions the carrageenan qualities whiteness and gel strength are the least affected by the exposure to the drying temperature. The drying time is the shortest at 120°C, but at this temperature the carrageenan quality degrades the most and is not be improved by air dehumidification. Moreover, the quality is improved by increasing the air velocity and by drying thin carrageenan sheets.

Effect of deacetylation on functional properties of glucomannan

Glucomannan is one of the highest viscosity polysaccharides with high water absorbing capacity. This property limits glucomannan applications; hence, it requires modifications. Glucomannan has 5-10% acetyl group which confers its functional properties. Replacing the acetyl with alkali transforms the functional characteristic of modified glucomannan. The aim of this study was to determine the effect of deacetylation conditions on the functional properties of glucomannan of A. oncophyllus. Effects of concentration of Na2CO3 (0.1-0.5 M), reaction time (1-5 h) and temperature deacetylation (40-80°C) were studied on glucomannan solubility, viscosity and water binding capacity (WBC). Deacetylation conditions affected solubility, viscosity and WBC of deacetylated glucomannan differently. Concentration of Na2CO3 showed negative impact on solubility, viscosity and WBC of deacetylated glucomannan. Solubility increased with increasing temperature and extending duration of deacetylation. Meanwhile, temperature and re...

Optimasi Proses Ozonasi pada Depolimerisasi κ-Karagenan dengan Metode Respon Permukaan

A bstract OPTIMIZATION OF OZONATION PROCESS FOR κ-CARRAGEENAN DEPOLYMERIZATION USING RESPONSE SURFACE METHODOLOGY . The objective of this research is to optimize the operating parameters in depolymerization of κ-carrageenan by ozone treatment. The optimization is done by using Box-Bhenken Design (BBD) model with ozonation time (5-15 minute), pH (3-11) and temperature (20-40 o C) as the independent variables.The response of ozonation process is the degree of d epolymerization of κ-carrageenan (DP). The initial molecular weight of refined κ-karagenan was 271 kDa. The κ-carrageenans powder was completely dissolved in distilled water to form 1% (weight/volume). The experiments were carried out in a 2000 ml of a glass reactor with an ozone gas sparger. The inlet ozone concentration was 80±2 ppm. The result shows that ozonation time , pH and temperature have significant effects during ozonation process (p< 0.05). Analysis of variance show s that the experimental data fit the model very well with the R 2 value of 0.98. T he optimum conditions during ozonation process are achieved at the reaction time of 15 min, ozonation pH of 3 and reaction temperature of 25 o C. Under these optimum conditions the DP of κ -carrageenan is 91.513 % . Keywords: depolymerization; κ-carrageenan ; optimization; ozonation process Abstrak Tujuan penelitian ini adalah menentukan kondisi optimum parameter operasi depolimerisasi κ-karagenan dengan perlakuan ozonasi. Optimasi dilakukan dengan menggunakan model statistika Box-Bhenken Design (BBD) dengan variabel yang digunakan yaitu waktu ozonasi (5-15 menit), pH (3-11), dan suhu (20-40 o C). Respon dari proses ozonasi adalah derajat depolimerisasi κ-karagenan (DP). Berat molekul awal refined κ-karagenan adalah 271 kDa. Sampel κ-karagenan dilarutkan secara sempurna dalam air distilasi dan konsentrasi diatur 1% (berat/volume). Percobaan dilakukan dalam reaktor gelas volume 2000 ml yang dilengkapi dengan sparger gas ozon. Konsentrasi gas ozon yang masuk adalah 80±2 ppm. Hasil penelitian menunjukkan bahwa waktu ozonasi, pH, dan suhu berpengaruh secara signifikan terhadap proses ozonasi (p<0,05). Analisis varian menghasilkan ketelitian yang tinggi antara data eksperimen dan prediksi, dengan nilai koefisien R 2 = 0,98. Kondisi optimum diperoleh pada waktu ozonasi 15 menit, pH ozonasi 3 dan temperatur reaksi 25 o C. Pada kondisi optimum ini diperoleh DP κ-karagenan sebesar 91,513 % . Kata kunci: depolimerisasi; κ-carrageenan;optimasi; proses ozonasi