Studies on the quality of sugar, molasses and treacle as products of sugarcane in the Sudan

Abstract

Comprehensive physio-chemical analysis were carried out for products of sugar cane in an attempt to find the effect of extraction and refining on the quality of sugar, molasses and treacle (black honey). The study analysis were conducted on three grades of refined sugar, namely silver-sugar, green-sugar and normal-sugar in addition to treacle, molasses samples and cane syrup, massecuite at different stages of crystallization. The samples were obtained mainly from Kenana Sugar Factory, where complete refining is done, specially decolourization. The analysis included determination of sucrose, reducing sugars, invert sugars, total soluble solids (T.S.S), and sweetness in terms of purity. Ash, acidity and protein content. Similarly physical properties were measured mainly: viscosity, colour and particle size of sugar crystals. The results obtained revealed that the average percentage of sucrose of treacle (black honey) was 29.36%, molasses 32.56%, whereas it was 99.90%, 99.81%, 99.76% for silver-sugar, green-sugar and normal-sugar respectively. The reducing sugars were 50.26% for treacle and 16.88% for molasses and only 0.036%, 0.060% and 0.189% for silver-sugar, green-sugar and normal-sugar. The moisture content was 20.50% for treacle and 21.30% for molasses. However, that for refined sugar did not exceed 0.047%. Slight traces of ash were found in sugar samples. While molasses gave 12% ash as yet it was poor in nitrogen consequently in protein content. The total soluble solids were found to be 99.98%, 99.97% and 99.95% in the silver-sugar, green-sugar and normal-sugar respectively. while treacle gave 83.24% and molasses 86.98%. T.S.S. Sweetness estimated as purity was found in the range 99.81% to 99.92% for the refined sugar samples and only 37.43% for final molasses. Sugar solutions were found to be almost neutral with pH 6.5 but molasses and treacle were slightly acidic 5.6%. The viscosity was calculated at 30ºC and found to be 3.426 centistoke for treacle and 5.019 centistoke for molasses. The three refined sugar samples silver, green and normal - sugar gave 1.940, 1.942 and 1.945 centistok respectively. The mean aperture of sugar crystals was 0.54mm for silver-sugar, 0.63mm for green-sugar and 0.68mm for normal-sugar. The colour of the sugar was measured colourimetcally and was found to be 41 unt at l 420nm for silver-sugar whereas green-sugar and normal-sugar gave 129 and 519 unt. respectively. Chromatographic analysis using TLC technique revealed consistency with chemical analysis findings for sugar, treacle and molasses components of mono-and di-saccharides, namely glucose, fructose and sucrose