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Title: VISCOELASTIC PROPERTIES OF RESTRUCTURED SWEETPOTATO PUREE

Author
item Fasina, Oladiran
item Walter Jr, William
item Fleming, Henry
item SIMUNOVIC, NADA - NC STATE UNIVERSITY

Submitted to: International Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2002
Publication Date: 1/1/2003
Citation: Fasina, O.O., Walter, Jr, W.M., Fleming, H.P., Simunovic, N. 2003. Viscoelastic properties of restructured sweetpotato puree. International Journal of Food Science and Technology. 38:421-425.

Interpretive Summary: The consumption of sweetpotatoes (SP) in the United States is mainly in the form of baked whole roots. Roots that are not of baking quality are either not harvested or discarded after harvest. Because of this, close to 40% of the seeded acreage for sweetpotatoes is not utilized. Over the past few years our laboratory has been conducting research on the texturizing of SP puree by addition of alginate, a natural binding agent. We have been able to produce simulated baked and French fry-type SP products from this technology. In order to optimize this technology, there is the need to quantify the effect of alginate on the textural properties of the puree. This is achieved in food process engineering by dynamic rheological tests. The results from our study showed tha addition of alginate significantly improved the texture of SP puree. The texturized puree was firmer (by at least two-fold) and had gel-like characteristics. Increasing the temperature from 25 to 85 deg C reduced the firmness of the texturized puree. The results from this study will be used by processors and entrepreneurs who are involved in the value-added and post-harvest utilization of SP.

Technical Abstract: The dynamic rheological properties of alginate-texturized sweetpotato (SP) puree were determined and compared to those of non-texturized SP puree. Results from the oscillatory shear experiments showed that SP puree behaved like a gel with the storage modulus (G') predominant over the loss modulus (G"). The values of the storage modulus for the texturized SP puree indicated that the addition of the calcium/alginate complex increased the firmness of SP puree. Gel strength of both texturized and non-texturized puree was highest at room temperature (25 deg C).