รื่นรมย์ เลิศลัทธภรณ์. Effects of Crushed Size and Variety on Cassava Starch Extraction Efficiency. Master's Degree(Food Engineering). King Mongkut's University of Technology Thonburi. KMUTT Library. : King Mongkut's University of Technology Thonburi, 2010.
Effects of Crushed Size and Variety on Cassava Starch Extraction Efficiency
Abstract:
Thailand produces and exports cassava products, especially starch, approximately 65-
80% of the total world's production. Reduction of starch loss during the production
process increases the production efficiency and subsequently increases the efficiency of
resources and energy use. In typical cassava starch factories, the highest starch loss
occurs in the extraction unit. This research, therefore, aimed to improve the starch
extraction efficiency by studying the effects of relative centrifugal force, pressure drop
across the resistance, crushed size, and variety of cassava on the starch extraction
efficiency. The experiments were conducted to study both the centrifugation and
filtration mechanisms in the extraction process. Three varieties of cassava, consisting of
Rayong 9, Rayong 11 and Kasetsart 50, with the crushed cassava sizes of less than 300,
300-500, 500-710, and 710-1000 um were used in this study. Experiments were
conducted at 3 different relative centrifugal forces (RCF) of 490g, 650g and 810g and
pressure drop across the resistance of 20, 28 and 35 kPa. The performance indices to
predict the starch extraction efficiency were the starch contents in pulps and in starch
slurry. Experimental results showed that the fiber contents of Rayong 9, Rayong 11 and
Kasetsart 50 were 3.44, 3.14 and 3.77%, respectively. Rayong 11 led to the highest
extraction efficiency due to its lowest fiber content, resulting in easier extraction of free
starch from the fiber complexes. Extraction efficiency decreased with increasing
crushed cassava size. This is because small crushed cassava size contained a higher free
starch content than the larger one. RCF at 650g provided the highest extraction
efficiency. Low RCF was insufficient to extract starch from fiber complexes, while too
high RCF compressed the cake, resulting in an increase in medium resistance. Pressure
drop across the resistance at 28 kPa yielded the highest starch extraction efficiency. A
higher pressure drop lowered both cake thickness and cake porosity, resulting in a
higher cake resistance.
King Mongkut's University of Technology Thonburi. KMUTT Library