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ARS Home » Southeast Area » Raleigh, North Carolina » Food Science Research » Research » Publications at this Location » Publication #90621
Title: PHYSICOCHEMICAL CHARACTERIZATION OF STARCH FROM PERUVIAN SWEETPOTATO SELECTIONS

Author
item GARCIA, ANA - ASA ALIMENTOS, LIMA, PERU
item Walter Jr, William

Submitted to: Starch
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: As with most developing countries, Peru has a significant trade deficit. Some of this deficit is due to the fact that starch, which is required for many products (food and non-food), must be imported or produced locally from imported or subsidized corn. Establishment of a starch extraction industry using locally produced sweetpotatoes as the starch source would reduce dependence on imports and permit these resources to be diverted to other uses. However, the properties of starch from Peruvian sweetpotato varieties must be established before suitable uses for Peruvian starch can be determined. To accomplish this, we evaluated starches from two types of widely grown Peruvian sweetpotato cultivars. We characterized the starches from these cultivars with regard to their composition and textural properties, and, using this information, were able to suggest what properties these starches would impart to processed foods. This research will provide sufficient information about starch properties so that interested parties can begin the development of a starch processing industry using Peruvian sweetpotatoes as the raw material.

Technical Abstract: Laboratory starch, isolated from seven sweetpotato selections grown at two locations in Peru, and commercially available Peruvian starch was characterized with regard to physicochemical properties. Chemical analyses included determination of nitrogen, ash, and amylose content. Physical characterization was based on results from differential scanning calorimetry (DSC), swelling power, solubility, and rheology of the pastes. We found that nitrogen and amylose content were not affected by location or selection, while ash content was affected by location. Results from the DSC analysis showed that selection identity (SI) did not affect enthalpy, onset, peak, and final temperatures. Location affected only peak temperature. Investigation of starch swelling power showed that SI and location did not affect swelling power above 75 deg C, and that laboratory starch samples had greater swelling power than commercial samples. Solubility was affected by location, but not by SI. Maximum viscosities of heated starch slurries were not affected by SI or location. Although laboratory and commercial samples did not differ significantly in chemical composition, physical behavior of their pastes was significantly different.