Chemical and Physical Characteristics of Twenty One Sweet Potato Genotypes Collected from Malaysia

Abstract

<p>The chemical and physical characteristics of sweet potatoes are essential in terms of quality and preference of the products. Breeding of sweet potatoes has resulted in a large number of genotypes which generates variation in chemical composition and physical properties. Therefore, such characteristics of 17 sweet potato germplasm accessions and four commercial cultivars originated from Malaysia were evaluated to be able to select them for breeding and food purposes. The starch contents were significantly different (p<0.05) that ranged from 10.67 to 25.40% fresh weight basis (fwb). The purple-fleshed group showed a higher amylose content than those of the orange, white, and yellow-fleshed groups. A variation in sugar contents was also noted and the highest amount of fructose was observed in the yellow-fleshed group, followed by the orange, white, and purple-fleshed groups. However, glucose, sucrose, and maltose could not be grouped according to their tuber flesh colors. The textural properties of steamed tubers considerably varied between sweet potato genotypes. The white-fleshed sweet potato showed the lowest hardness value, followed by the orange, yellow and purple-fleshed genotypes. Moisture, starch, and amylose contents significantly correlated with hardness of the steamed tuber with r = -0.83**, 0.60**, and 0.61**, respectively, while adhesiveness was affected by moisture and amylose contents with r =0.54** and -0.37**, respectively. Springiness had a positive correlation with adhesiveness and chewiness exhibited a negative correlation with moisture content, however, it positively correlated with hardness. Sweet potatoes with low hardness and chewiness are suitable to be used as raw material for juice and jam, while those with medium hardness and chewiness are suitable for products made from mashed tubers. Sweet potatoes with firm texture are tailored for flour preparation, which can be further used for flour-based products. This study reflects a great variation in chemical and physical characteristics of sweet potato genotypes that can be further used for the breeding of improved varieties with desired criteria as well as suitability for particular food products.<br /><br /></p>