Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2012
Publication Date: 12/12/2012
Citation: Oner, M.E., Wall, M.M. 2012. Processing conditions for producing french fries from purple-fleshed sweetpotatoes. Transactions of the ASABE. 55:2285-2291.
Interpretive Summary: Optimum processing conditions and cooking methods were evaluated to develop frozen French fries from Hawaii-grown purple-fleshed sweetpotatoes. The processed sweetpotato fries were acceptable based on quality analysis, anthocyanin content, and sensory evaluation. Consequently, frozen purple-fleshed sweetpotato fries may be suitable as a value-added product for wholesale, food service, or retail markets, and substitute for imported foods for local consumption in Hawaii.
Technical Abstract: The effects of processing conditions and cooking methods on the physical quality, anthocyanin content and sensory attributes of frozen purple-fleshed sweetpotato (PFSP) French fries were investigated. PFSP strips were blanched in boiling water for 0, 5 or 10 min, par-fried at 180ºC for 0 or 1 min and stored at - 20 ± 2ºC. Frozen PFSP strips were then oven baked at 180ºC for 8 min or deep-fat fried at 180ºC for 3 min. The lowest peak force values were determined in fries after 10 min blanching. However, combination of par-frying and deep-fat frying increased peak force in 10 min blanched PFSP fries, significantly. A deep purple color developed in fries treated with a combination of 5 or 10 min blanching, 1 min par-frying and oven baking. A decrease in total monomeric anthocyanin content (14.51 ± 0.45 mg/100 g dw) and a corresponding increase in polymeric color (34.23%) were measured in oven baked fries with no blanching and no par-frying. 1 min par-frying increased total monomeric anthocynanin content to the highest level (36.05 ± 0.60 mg/100 g dw) in oven baked fries without blanching. The lowest moisture content (20.1%) and highest oil content (37.9 %) was determined in fries treated with 10 min blanching, 1 min par-frying and deep-fat frying. A dark brown color was determined in fries treated with 10 min blanch, 1 min par-fry and deep-fat fry. PFSP fries treated with 10 min blanch, no par-fry and deep-fat fry had the highest sensory ratings according to a taste panel. However, the sensory quality of oven baked fries was increased when samples were par-fried. Fries treated with a 10 min blanch, 1 min par-fry and oven baked may be a more nutritious alternative with 64.3% less oil content, 27.7% more anthocyanin content and favorable overall sensory quality compared to fries treated with 10 min blanch, no par-fry and deep-fat fry.