Characterization of potato starch isolated from four potatoes varieties grown in Kenya

In Kenya, there is a wide range of variability of potato cultivars with different physical and chemical properties. These differences define the nature of their starch characteristics which influence their suitability for processing. The present study was conducted to characterize potato starch from four popular potato varieties grown in Kenyan namely: Shangi, Unica, Dutch robjin, and Wanjiku. The tubers were characterized physico-chemically (specific gravity, dry matter content, starch content, and moisture content). Other properties determined included the starch yield (%), particle size, and microstructural characteristics. The Dutch robjin variety had the highest specific gravity (1.081g/cm3), dry matter (21.9%), and starch content (13.96%) while Unica had the lowest specific gravity (1.076g/cm3), dry matter (17.19%) and starch content (12.98%). Particle size analysis revealed that the native starch extract consisted of particles that exhibited a normal distribution curve. The average diameter of the starch granules was 39.06, 39.56, 41.78, and 44.01 μm for Dutch robjin, Shangi, Unica, and Wanjiku, respectively. It was observed that when the size of the particle decreased, the percentage of starch content increased. Furthermore, starch granules revealed oval shapes for all the varieties. These differences in physico-chemical properties might indicate pronounced differences in the functional properties of the starch derivatives. Keywords: Dry matter, potato, particle size, specific gravity, scanning electron microscope, starch