comparative study of properties of starches from Irish potato (Solanum tuberosum) and sweet potato (Ipomea batatas) grown in Nigeria

• Published in: Die Stärke Vol. 66; no. 7-8; pp. 714 - 723
• Main Authors: Nwokocha, Louis M, Aviara, Ndubisi A, Senan, Chandra, Williams, Peter A
• Format: Journal Article
• Language: English
• Published: Weinheim Verlag Chemie 01.07.2014; Blackwell Publishing Ltd; Wiley Subscription Services, Inc
• Subjects: amylose; gelatinization; Irish potato; leaching; nitrogen; pastes; pasting properties; phosphorus; Physicochemical properties; potato starch; retrogradation; Solanum tuberosum subsp. tuberosum; Starch; starch granules; storage modulus; Sweet potato; sweet potatoes; swelling (materials); temperature
• ISSN: 0038-9056; 1521-379X
• DOI: 10.1002/star.201300237

Starch isolated from Irish and sweet potatoes grown in Nigeria were characterized. The starch granules of Irish potato were larger (13.39–47.00 µm) and showed a wider range of size distribution than sweet potato (2.00–25.86 µm). There was significant difference (p < 0.05) in the moisture, nitrogen, fat, phosphorus, and amylose contents of the starches. Irish potato starch had a lower gelatinization peak temperature (64.2°C) than sweet potato starch (74.9°C) and exhibited higher swelling power and amylose leaching, lower pasting temperature, higher peak and lower setback viscosities. The shear stress–shear rate profiles indicated the starch pastes were non‐Newtonian and could best be fitted to the Herschel–Bulkley model. Sweet potato starch paste exhibited a higher storage modulus than Irish potato starch paste. Irish potato starch paste showed significantly (p < 0.05) higher paste clarity and lower retrogradation than sweet potato. The starch properties dictate their food applications.