Food Chemistry Chemical Constituents of Sweetpotato Genotypes in Relation to Textural Characteristics of Processed French Fries Ai Sato, Van-Den Truong , Suzanne D. Johanningsmeier, Rong Reynolds, Kenneth V. Pecota, and G. Craig Yencho Abstract: Sweetpotato French fries (SPFF) are growing in popularity, however limited information is available on SPFF textural properties in relation to chemical composition. This study investigated the relationship between chemical components of different sweetpotato varieties and textural characteristics of SPFF. Sixteen sweetpotato genotypes were evaluated for (1) chemical constituents; (2) instrumental and sensory textural properties of SPFF; and (3) the relationship between chemical components, instrumental measurements, and sensory attributes. Dry matter (DM), alcohol-insoluble solids (AIS), starch, sugar, and oil content, and also α- and β -amylase activities were quantified in raw sweetpotatoes and SPFF. Peak force and overall hardness describing instrumental textural properties of SPFF were measured using a texture analyzer. Descriptive sensory analysis was conducted and 10 attributes were evaluated by a trained panel. Results showed that DM, AIS, and starch content in raw sweetpotatoes were significantly correlated (P < 0.05) with instrumental peak force and overall hardness (r = 0.41 to 0.68), and with sensory surface roughness, hardness, fracturability, and crispness (r = 0.63 to 0.90). Total sugar content in raw sweetpotatoes was positively correlated with sensory smoothness and moistness (r = 0.77), and negatively correlated with instrumental peak force and overall hardness (r = –0.62 to –0.69). Instrumental measurements were positively correlated with sensory attributes of hardness, fracturability, and crispness (r = 0.68 to 0.96) and negatively correlated with oiliness, smoothness, moistness, and cohesiveness (r = –0.61 to –0.91). Therefore, DM, AIS, starch, and total sugar contents and instrumental measurements could be used as indicators to evaluate sweetpotato genotypes for SPFF processing. Keywords: descriptive sensory analysis, French fries texture, instrumental measurement, Ipomoea batatas, sweetpotato French fries Practical Application: In recent years, sweetpotato French fries (SPFF) have grown in popularity, but limited information is available on SPFF textural properties in relation to the differences in chemical constituents among sweetpotato varieties. This study demonstrated that sensory texture attributes of SPFF varied widely and were significantly correlated with chemical components such as dry matter, starch, and total sugar contents of raw sweetpotatoes and instrumental texture measurements of SPFF. The knowledge generated from this study will benefit the food industry and breeding programs with the selection of sweetpotato varieties for improved SPFF quality. Introduction Sweetpotato (Ipomoea batatas L.) is an economically important crop and an excellent source of carotene, dietary fiber, and vita- mins. There are numerous sweetpotato genotypes with different sensory characteristics such as taste, texture, and flesh color. Vari- eties with high dry matter (DM) content have a firm and mealy texture after cooking, although those with low DM content have JFDS-2017-1121 Submitted 7/11/2017, Accepted 10/15/2017. Author Sato is with Dept. of Food, Bioprocessing and Nutrition Sciences, North Carolina State Univ., 400 Dan Allen Drive, Raleigh, NC 27695, U.S.A. Authors Truong, Ja- hanningsmeier, and Reynolds are with USDA-ARS, SEA, Food Science Research Unit, North Carolina State Univ., 322 Schaub Hall, Raleigh, NC 27695, U.S.A. Authors Pecota and Yencho are with Dept. of Horticultural Science, North Carolina State Univ., Raleigh, NC 27695, U.S.A. Direct inquiries to author Truong (E-mail: Den.Truong@ars.usda.gov). Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U. S. Dept. of Agriculture or North Carolina Agricultural Research Service, nor does it imply approval to the exclusion of other products that may be suitable. USDA is an equal opportunity provider and employer. a soggy texture after cooking (Truong and others 2011). Although commonly processed sweetpotato products are flours, starches, juices, and purees, new processed products such as French fries have been developed in the past several decades. Recently, con- sumer demand for sweetpotato French fries (SPFF) has increased. Currently, SPFF are processed using the existing sweetpotato cul- tivars that were developed for the fresh root market, but SPFF produced from these existing cultivars have an undesirable soggy texture. Therefore, there is a need for the development of sweet- potato genotypes that will produce high-quality SPFF. Previous studies on SPFF have focused on processing conditions in relation to SPFF quality. Walter and others (1992) reported that increased firmness of SPFF could be achieved by sweetpotato tissue acidification. In a study with purple-fleshed SPFF, SPFF without a prior blanching treatment had the highest crust hardness and poor texture quality, which was described as hard or rubbery (Oner and Wall 2012). In addition, pre-drying of the blanched strips before frying resulted in increases of DM content and improvement of the SPFF texture (Walter and Hoover 1986; Truong and others 2014). C  2017 Institute of Food Technologists R  60 Journal of Food Science  Vol. 83, Nr. 1, 2018 doi: 10.1111/1750-3841.13978 Further reproduction without permission is prohibited