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United States Department of Agriculture

Agricultural Research Service

Title: Effects of Puree Processing Methods on the Textural Characteristics of An Alginate-Texturized Sweetpotato Product

Authors
item Walter, William
item Truong, Van - NCSU
item Espinel, Karina - CRYOVAC CORP.

Submitted to: Food Quality Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 29, 1999
Publication Date: N/A

Interpretive Summary: A food product fabricated by combining sweetpotato puree with other ingredients and molding the resultant formulation into a patty-type product has recently been developed. This product is typical of a class of food products called restructured products. Although puree preparation methods can exert a significant effect on the sweetness and texture of pureed sweetpotato products, the original research conducted on restructuring of sweetpotatoes used a single puree preparation method. The objective of the present research was to prepare sweetpotato purees using a variety of processing conditions and, after restructuring, determine product quality. We found that the most efficacious process was to cook sweetpotato slices, puree, and restructure into products. Restructured sweetpotato products have significant market potential because, by using this technology, a consistent product can be manufactured, regardless of the post-harvest history of the sweetpotatoes. In addition to texture consistency, restructuring of sweetpotato puree offers the further advantage that all grades of sweetpotatoes can be used, thus allowing utilization of the entire crop. Adoption of this technology will permit processors to develop different types of restructured products, thus providing consumers with high quality, nutritious products which are easily prepared in the home.

Technical Abstract: The objective of this study was to determine the effect of sweetpotato (SP) puree preparation methods on the properties of texturized sweetpotato products. Five treatments were used to prepare cooked purees from SP roots. These treatments were separated into two main types in which sliced sweetpotatoes were cooked prior to puree preparation, or purees were prepared by grinding raw roots followed by heat processing using steam injection. Purees from each treatment were texturized into cylinders 12.7 cm long and 5.5 cm in diameter using an alginate-calcium system and frozen. Samples of texturized products were subjected to instrumental texture profile analysis (TPA) and sensory evaluation. Steam-cooking of SP slices hydrolyzed starch more completely than steam injecting of ground raw sweetpotato. All purees exhibited shear-thinning behavior, and those cooked purees prepared by steam injection of raw purees had higher viscosities than did purees made from cooked SP. TPA analysis revealed that texturized product made from SP cooked before puree preparation was the most fracturable and least springy of the texturized products. Although sensory panelists did not express a preference for texturized product from any of the treatments, 23% of the panelists noted a grainy texture and/or raw root aroma in products prepared by steam injection of raw purees. In view of these observations and the fact that puree preparation from cooked SP is the simplest process, it appears that this process is the best for this type of texturized SP product.

Last Modified: 9/22/2014
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