KINETIKA PERUBAHAN DENSITAS DAN BRIX SERTA ANALISIS DISTRIBUSI UKURAN KRISTAL PADA PENGOLAHAN GULA SEMUT MENGGUNAKAN KRISTALISATOR BERPEMANAS UAP

The aims of this study are examining the changes in density and brix during the crystallization process and analyzing the crystal size distribution of the product in the processing of palm sugar using steam heater crystallizer. This experiment used the variation of capacity and additional of crystal seeds. The raw material is 5 kg of mold palm sugar that was dissolved in 500 ml water and 8 kg of mold palm sugar that was dissolved in 800 ml water. The solution was put into the crystallizer�s wok while the water inside the crystallizer tube was heated. During crystallization, density and brix was measured with the time interval every 5 minutes for evaporation and 3 minutes for crystalization. At the end of the process, the granule palm sugar was dryed using cabinet dryer at 60 oC. It was sieved using Tyler screen and the crystal size distribution was analyzed. Avrami model is used to determine coefficients of brix and density changes. With empirical equations derived from the modified Avrami models, the value of brix prediction and density prediction can be determined. The coefficient on the crystallization process changes brix palm sugar with a capacity of 5 kg and 8 kg without crystal seeds of 4,4.10-5 - 1,094.10-4 per minute and 1,094.10-4 - 1,154.10-4 per minute while the seedlings ranged 1,154.10-5 per minute and 1,054.10-5 - 2,554.10-5 per minute. The coefficient of variation of density changes for a capacity of 5 kg and 8 kg without seeds ranged 4,54.10-6 - 1,09.10-5 per minute and 4,34.10-6 - 6,44.10-6 per minute while the seedlings ranged 2,64.10-6 -8,40.10-6 per minute and 5,4.10-6 - 5,94.10-6 per minute. Avrami model can be used to predict changes in brix and density during the crystallization process of palm sugar. FM value by an average of 4.095 to 5.866, the average uniformity index for coarse size parameter is in the range of 7.0 to 9.8, medium 2,5, and fine size 0,4. The average diameter size of sugar crystals for variations capacity of 5 kg and 8 kg without seeds of 0,123 to 0,190 and from 0,150 to 0,239, while the average diameter size of the sugar crystals to variations in the capacity of 5 kg and 8 kg of the seeds of 0,173 to 0,219 and 0,133 to 0,175. The data showed that the palm sugar crystal size is rough. Statistical analysis showed that there was no significant effect of variations in the mass and seed multiplication product of palm sugar because the effect only occurs in brix sugar levels, but had no significant effect on other aspects such as density and diameter of the sugar crystals products. Keywords: density, brix, palm sugar, crystallizer