Rapid quantitative determination of maltose and total sugars in sweet potato (Ipomoea batatas L. [Lam.]) varieties using HPTLC
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When a raw sweet potato root is analysed, only sucrose, glucose and fructose are present but during cooking, starch is hydrolysed into maltose giving the sweet flavour to cooked roots. This study aimed at developing an HPTLC protocol for the rapid quantitative determination of maltose and total sugars in four commercial varieties and to compare them to 243 hybrids grouped by flesh colour (white, orange, purple). In commercial varieties, mean maltose content varied from 10.26 to 15.60% and total sugars from 17.83 to 27.77% on fresh weight basis. Hybrids showed significant variation in maltose content within each group, with means ranging from 7.65% for white-fleshed, to 8.53% in orange- and 11.98% in purple-fleshed. Total mean sugars content was 20.24, 22.11 and 26.84% respectively for white, orange and purple flesh hybrids. No significant correlations were detected between individual sugars but maltose and total sugars content were highly correlated. Compared to the best commercial variety (Baby), 25 hybrids (10.3%) presented a higher maltose content and 40 (16.5%) showed a higher total sugars content. HPTLC was observed as an attractive, cost efficient, high-throughput technique for quantitating maltose and total sugars in sweet potatoes. Perspectives for improving sweet potato quality for consumers’ requirements are also discussed.
KeywordsClonal generation Early screening Hybrids Phenotypic recurrent selection Sweet potato
This study would not have been possible without the financial support of the Agence Nationale pour la Recherche (ANR, France, through the Project No. ANR-10-STRA-007) and the technical assistance of the Department of Agriculture and Rural Development (DARD, Vanuatu). Special thanks are due to Charles Rogers for germplasm field maintenance and to Juanita Stevens for laboratory assistance in preparing the samples and extracts.
Compliance with ethical standards
Conflict of interest
The author declares that there are no potential conflicts of interest.
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