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Five unexplored Andean tubers grown in Ecuador were characterized. Yacon (Smallanthus sonchifolius, var. INIAP-ECU-1247) showed a high level of prebiotic inulin-type fructooligosaccharides with a degree of polymerisation from 2 to 6 and the highest content of phenolic compounds. Mashua (Tropaeolum tuberosum, var. INIAP-ECU-Izaño) showed high antioxidant capacity, attributed to its high carotenoid and vitamin C content. Melloco (Ullucus tuberosus, var. INIAP-ECU-amarillo-rosa) had the highest content of fibre and crude protein, while purple sweet potato (Ipomea batatas, var. INIAP-ECU-morado) and white carrot (Arracacia xanthorrhiza, var. INIAP-ECU-blanca) showed a high yield of starch rich in amylose, with possible better functional properties than potato starch. Fructose, glucose and sucrose were found in all samples. These ancestral crops can be useful as non-traditional sources of bioactive compounds with applications in the development of biomaterials, pharmacological products or new functional ingredients. [ABSTRACT FROM AUTHOR]

• Mashua and melloco starches have better technological properties than potato starch. • Mashua and melloco starches possess high digestibility and thermal resistance. • Phenolic compounds of mashua flour seem to reduce its digestion rate. • Mashua and melloco starches can be used as novel gelling additives. • Mashua and melloco starches can be considered nutritional ingredients for new foods. Morphological, technological and nutritional analyses were done in two scarcely studied starches from Andean tubers (mashua and melloco). The low sedimentation values, and the high zeta potential of mashua and melloco starches in cold dispersions, as consequence of their electronegativity, indicated a better behaviour as stabilizer than potato starch. During heating, mashua and melloco starches presented much higher viscosity than potato starch, associated with their higher average particle size and greater amylose content. DSC and TGA analyses indicated that melloco starch had the highest gelatinization enthalpy ΔH gel (12.32 J g−1) and degradation temperature (270 °C), in comparison with potato starch, which are indicators of a better thermal resistance. Consequently, extracted mashua and melloco starches could be excellent and cost-effective thickening or gelling agents in both foods and a wide range of biomaterials. Mashua and melloco starches exhibited a digestion rate close to 80%, which agreed with the low resistant starch content. [ABSTRACT FROM AUTHOR]

• Tuber analysed showed phenolic acids and flavanoids of known bioactive potential. • Hydroxycinnamic acid derivatives were predominant in yacon tuber. • Yacon and purple sweet potato could be good source of important phenolic compounds. • Mashua was the only tuber that presented flavan-3-oles. • This is the first study about the elucidation of phenolic compounds in melloco. In this work, the phenolic compounds of four Andean tubers grown in Ecuador, such as yacon (Smallantus sonchifolius), mashua (Tropaeolum tuberosum), melloco (Ullucus tuberosus) and purple-sweet potato (Ipomea batatas) were analyzed by HPLC–DAD–ESI/MSn. Non-flavonoid compounds, such as hydroxycinnamic derivatives were identified in yacon, purple sweet potato and melloco samples, accounting for 100, 26 and 15% of the total of phenolic compounds, respectively. Mashua sample revealed the presence of flavan-3-ol monomers that were not found in the other samples, being (-)-epicatechin the most abundant (9.22 μg/g DM). Quercetin-3- O -rutinoside (40.6 μg/g DM), kaempferol- O -dirhamnosil-hexoside (29.5 μg/g DM) and kaempferol- O -dihexoside (46.22 μg/g DM) were the main flavonols present in mashua, melloco and purple sweet potato, respectively, being this last specie which presented the highest concentration in flavonols (89.32 μg/g DM). Purple sweet potato also had anthocyanins (157.16 μg/g DM), not detected in the other samples. The presence of these compounds and the consideration of the total phenolic content suggest the use of these Andean tubers as promising sources of natural antioxidants of wide use in the food industry. Therefore, these tubers could be considered as novel and inexpensive sources of bioactive compounds for their potential use in functional foods and nutraceuticals. [ABSTRACT FROM AUTHOR]