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Raw Sugar

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By Bento, Luis San Miguel
Posted on 2006-09-18    Last edited on 2010-12-16

 Raw sugar is the product obtained in cane sugar mills.  In the mills, the juice extracted from sugar cane is  purifyed and after crystallization a brownish sugar is produced, the raw sugar. In the past, beet sugar industry also produced raw sugar, as in cane industry. Nowadays high purity white sugar is produced directly from sugar beets in beet factories. However, in cane sugar industry, raw sugar produced in cane sugar mills must be re-processed in re


 Typical analysis
Polarisation
Reducing Sugars
Ash
Humidity
Granulometry MA
CV
Colour
Colur in the crystal
IV
Starch
Dextran

98.5 Z
0.50%
0.30%
0.30%
0.70 mm
40
4500 IU
2100 IU
2.2
120 ppm
400 ppm

Raw  sugar, containing normally between 97.5 and 99.5% of sucrose,  presents a brownish yellow colour and a crystal size about 1mm MA (mean aperture). A syrup layer, containing the great part of these colourants, covers the sucrose crystals. This layer is separated in the first refining operation, Affination. Other part of colurants will remain in the crystals.
In the last decades, raw sugar quality has evolved from a Pol of 96º in the sixties of XX century, till the VHP (very high pol) raw with a Poll higher than 99º. Recently, in Australia, a new raw sugar type was produced, the VLC sugar, presenting a high Pol and a low colour (Burns and Field, 1998). The objective of VLC production is to transfer to the mills the majority of the purification process. With this process, in refineries, VLC is melted, filtered and crystallized, avoiding affination and decolourization processes. Recovery section can also be avoided if residual refined syrup is used to produce liquid sugar or soft sugars, as areado sugar.

Bibliography

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         S.I.T. Conf.
,101-109
Meadows D.M.,P.M. Schorn, M.Moodley, S.D. Peacock, A. Bindorf, 2005, South
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Paton N.H., 1992, The origin of colour in raw sugar, Proc. of Aust. S.S.C.T. Conf.,
          14, 8-17


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