CHANGE IN CARBOHYDRATE COMPOSITION OF FRESH YACON (Smallanthus sonchifolius) ROOTS DURING STORAGE

Yacon (Smallanthus sonchifolius) is an Andean root, which is recognized for its prebiotics potential due to its high concentration of Fructooligosaccharides (FOS). Changes in the carbohydrates concentration, FOS, glucose, fructose and sucrose, occur during storage. The aim of this work was to evaluate the changes of carbohydrates content in fresh yacon roots stored at 25oC and 4oC, after 31 days post-harvest. Sugar and FOS in fresh yacon roots stored at 25oC and 4oC were extracted with water and analyzed in Ion Chromatograph Dionex Model ICS-5000 after 31 days post-harvest. Results indicate high variability in the carbohydrate content during 31 storage days. The content of FOS and sucrose decreases and fructose and glucose increases at the tubers storage at 25oC and 4oC. At 25oC, the FOS and sucrose content decrease from 74% to 26% and from 32% to 27% dry matter (DM), respectively, whereas fructose and glucose increase from 12 to 60% and from 9 to 22% DM, respectively. At 4oC, the FOS and sucrose content decreases from 74 to 30% and from 32 to 14% DM, respectively, whereas the content of fructose and glucose increase from 12 to 55% and from 9 to 20% DM, respectively. Fresh Yacon has a high content of FOS. The FOS and sucrose content of yacon roots decreases with storage days, whereas the content of fructose and glucose increases, consequently unsuitable for diabetics. The FOS content of yacon storage at 4°C also decreased but in less proportion than at 25°C. For beneficial effects of yacon in glycemic control, the study revealed that yacon roots have a good content of FOS, and the FOS content of yacon root storage at 4°C also decreased but in less proportion than at 25°C. To preserve the FOS content of fresh yacon roots appropriate handling methods post-harvest must be developed.