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Background: Variability in sugar content between raw and cooked sweetpotato storage roots impact nutritional and dietary importance with implications for consumer preference. High‐throughput phenotyping is required to breed varieties that satisfy consumer preferences. Results: Near‐infrared reflectance spectroscopy (NIRS) calibration curves were developed for analysing sugars in baked storage roots using 147 genotypes from a population segregating for sugar content and other traits. The NIRS prediction curves had high coefficients of determination in calibration (R2c) of 0.96 (glucose), 0.93 (fructose), 0.96 (sucrose), and 0.96 (maltose). The corresponding coefficients of determination for cross‐validation (R2cv) were 0.92 (glucose), 0.89 (fructose), 0.96 (sucrose) and 0.93 (maltose) and were similar to the R2c for all sugars measured. The ratios of the standard deviation of the reference set to the standard error of cross‐validation were greater than three for all sugars. These results confirm the applicability of the NIRS curves in efficiently determining sugar content in baked sweetpotato storage roots. External validation was performed on an additional 70 genotypes. Coefficients of determination (r2) were 0.88 (glucose), 0.88 (fructose), 0.86 (sucrose) and 0.49 (maltose). The results were comparable to those found for the calibration and cross‐validation in fructose, glucose, and sucrose, but were moderate for maltose due to the low variability of maltose content in the population. Conclusions: NIRS can be used for screening sugar content in baked sweetpotato storage roots in breeding programs and can be used to assist with the development of improved sweetpotato varieties that better meet consumer preferences. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

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. 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. [ABSTRACT FROM AUTHOR]

Various workers have attempted to develop a root piece planting system for sweetpotato, similar to the system used commercially for potato, but attempts to select and breed sweetpotato clones adapted to root piece planting have met with mixed success. It has been hypothesized this is the result of significant genotype x environment effects, which are complicating phenotype screening. The aim of this work was to investigate genotype x environment interactions and yield stability of sweetpotato grown from cut root pieces. Ten sweetpotato clones were grown from cut root pieces in three locations over three seasons at sites in North Carolina and Mississippi. The study found sweetpotato clones grown from root pieces were influenced by both genetic and environmental factors and that the interaction was often complicated and dependent on the trait being measured. A significant genotype x environment interaction and yield instability were found to be present. Further work will be required to understand the nature of the genotype x environment effects; however, the results suggest programs aiming to develop sweetpotato clones adapted to root piece planting will need to use appropriate multienvironment screening so as to account for genotype x environment effects. [ABSTRACT FROM AUTHOR]

Purple-fleshed sweetpotatoes (PFSP) can be a healthy food choice for consumers and a potential source for natural food colorants. This study aimed to identify anthocyanins and anthocyanidins in PFSP, and to evaluate the effect of thermal processing on these polyphenolic compounds. Freeze-dried powder of raw and steamed samples of three PFSP varieties were extracted with acidified methanol using a Dionex ASE 200 accelerated solvent extractor. Seventeen anthocyanins were identified by HPLC-DAD/ESI-MS/MS for Stokes Purple and NC 415 varieties with five major compounds: cyanidin 3-caffeoylsophoroside-5-glucoside, peonidin 3-caffeoylsophoroside-5-glucoside, cyanidin 3-caffeoyl-p-hydroxybenzoylsophoroside-5-glucoside, peonidin 3-caffeoyl-p-hydroxybenzoyl-sophoroside-5-glucoside, and peonidin-caffeoyl-feruloylsophoroside-5-glucoside. Okinawa variety showed 12 pigments with 3 major peaks identified as cyanidin 3-caffeoylsophoroside-5-glucoside, cyanidin 3-(6'',6'''-dicaffeoylsophoroside)-5-glucoside and cyanidin 3-(6''-caffeoyl-6'''-feruloylsophoroside)-5-glucoside. Steam cooking had no significant effect on total anthocyanin content or the anthocyanin pigments. Cyanidin and peonidin, which were the major anthocyanidins in the acid hydrolyzed extracts, were well separated and quantified by HPLC with external standards. Cyanidin and peonidin, which contribute to the blue and red hues of PFSP, can be simply quantified by HPLC after acid hydrolysis of the anthocyanins.