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IV. RESULT AND DISCUSSION
A. CHEMICAL ANALYSIS
The amylose and proximate analysis was done to identify amylose content and identify its water, ash, protein, fat, and carbohydrate content of sweet potato starch. Table 6 shows the
amylose and proximate content. Table 6. Major Chemical Composition of Jago Sweet Potato Starch
Chemical Component Sweet Potato Starch
Water Ash
Protein Fat
Carbohydrate Amylose
13.73 0.23
0.44 0.56
85.04 25.83
The water content of sweet potato starch is 13.73, protein content is 0.44, ash content is 0.23, fat content is 0.56, and carbohydrate content is 85.04. Sweet potato is classified as
tubers group so it contains high carbohydrate. The variation of water content of the sweet potato starch depend on drying method, drying time, and storage condition. Sweet potato starch also
contains protein, fat, and ash even though the contents are low. High purity of the starch is very important to keep hydrolisis enzyme runs smoothly.
Starch which is resistant to digestive enzyme in the small intestine is not only affected by processing but also but its chemical structure. Starch which contains more amylose have higher
ability to form amorphous structure because of its hydrogen bond intensiveness. The consequence is starch which can not be swelled or gelatinized better during cooking time will slowly digested
Panlasigui et al. 1991. Therefore, information about amylose content in food is important to produce optimum yield of resistant starch.
Principal of amylose analysis is iodine bound in the spiral shaped starch molecule which yields blue color then measured the absorbance by spectophotometer at 620 nm Winarno, 1997.
The result of amylose analysis showed that amylose content of jago sweet potato starch was 25.83. It was higher than wheat starch 25 and potato starch 20, but lower than corn starch
26 Pomeranz, 1992. Collado and Corke 1997 reported that amylose content in sweet potato starch have variation in range 15-27, depend on variety.
Generally, sweet potato pasta characteristic have tendency to easily retrogradated which showed by pasta viscosity in cooling phase or classified as type C based on classification by
Srichuwong 2005. The other characteristics are the very viscous pasta, stable, and it doe not show a peak in heating phase. Increasing viscosity in cooling phase indicate that retrogradation
process will be undertaken easily. Intensive of retrogradation level is required in RS3 formation. Purwani et al. 2009.
Based on amylose content analysis, it can be concluded that ingredient to produce resistant starch in this research can be classified as high amylose starch and it was expected that jago sweet
potato can be potential ingredient to produce high yield resistant starch.
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B. RESISTANT STARCH PRODUCTION
