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United States Department of Agriculture

Agricultural Research Service

Research Project: Pre and Postharvest Treatment of Tropical and Other Commodities for Quarantine Security, Quality Maintenance, and Value Enhancement

Location: Tropical Crop and Commodity Protection Research

Title: Processing and cooking effects on the quality of purple-fleshed sweet potato fries

Authors
item Oner, Manolya
item Wall, Marisa

Submitted to: National Meeting of Institute of Food Technologists/Food Expo
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2012
Publication Date: June 25, 2012
Citation: Oner, M.E., Wall, M.M. 2012. Processing and cooking effects on the quality of purple-fleshed sweet potato fries. National Meeting of Institute of Food Technologists/Food Expo.

Interpretive Summary: Sweet potato is a major crop produced in Hawaii, however 85% of the food consumed in Hawaii is imported from the U.S. mainland and other sources. Development of value-added food products from Hawaii-grown sweet potatoes is one way to reduce dependence on food imports and improve agriculture by providing alternative local products that are ready-to-eat or ready-to-cook. The objective of this research was to determine the effects of processing conditions and cooking methods on the physical quality, anthocyanin content and sensory attributes of frozen French fries made from Hawaii-grown purple-fleshed sweet potatoes (PFSPs).

Technical Abstract: Sweet potato is a major crop produced in Hawaii, however 85% of the food consumed in Hawaii is imported from the U.S. mainland and other sources. Development of value-added food products from Hawaii-grown sweet potatoes is one way to reduce dependence on food imports and improve agriculture by providing alternative local products that are ready-to-eat or ready-to-cook. The objective of this research was to determine the effects of processing conditions and cooking methods on the physical quality, anthocyanin content and sensory attributes of frozen French fries made from Hawaii-grown purple-fleshed sweet potatoes (PFSPs). PFSP strips were blanched in boiling water (98 °C) for 0, 5 or 10 min, par-fried at 180 °C for 0 or 1 min, stored at - 20 ± 2 °C for one week and then oven baked at 180 °C for 8 min or deep-fat fried at 180 °C for 3 min. Blanching decreased firmness and increased moisture content significantly. A 10 min blanch increased oil content up to 38% in deep-fat frying conditions. Nevertheless, PFSP French fries treated with 10 min blanching, no par-frying and deep-fat frying was the most acceptable treatment combination based on sensory quality. The combination of par-frying and deep-fat frying increased brown color formation and thus decreased color quality of fries. However, par-frying increased acceptability of oven baked fries based on sensory evaluation. Heat treatments, 1 min par-frying and 10 min blanching, increased total monomeric anthocyanin content and decreased percent polymeric color significantly. For the 12 different treatment conditions, the total monomeric anthocyanin content and polymeric color in PFSP fries ranged from 14.5 to 36 mg cyanidin-3-glucoside/100 g dw and 7.6 to 34.2%, respectively. The results indicate that PFSP French fries may be considered as a potential value-added food product for local consumption in Hawaii.

Last Modified: 8/21/2014