Extraction and quantification of inulin prebiotic in leaves, tubers, and in vitro seedlings of Tropaeolum pentaphyllum

The aim of this study was to evaluate the inulin prebiotic content in extracts obtained from the leaves and tubers of Crem (Tropaeolum pentaphyllum) collected before, during, and after flowering. In vitro-cultured Crem seedlings were also assessed. Extractions were performed by boiling in hot water (80 ± 2 °C) for 1, 2, and 4 h. The pre-extraction drying curve indicated that 18 h at 55 °C are sufficient for the dehydration of leaves, sliced tubers, and seedlings. All models (Lewis, Henderson-Pabis, Page, and Logarithmic) used for prediction in drying kinetics showed good fit quality parameters: coefficient of correlation (R2) (>0.9959) and root mean square error (RMSE) (<0.0180). The results revealed variations in inulin levels depending on the developmental stage, extraction time, and plant parts. We observed that seedlings had the lowest inulin levels after 4 h of extraction, with a maximum of 11.4 mg/g. In leaves collected after the flowering period, the highest levels were found, with a peak concentration of 15.03 mg/g after 2 h of extraction. Inulin levels in tubers were 5 and 7 times higher than those found in above-ground and in vitro-cultured material, respectively, reaching a value of 70.92 mg/g of inulin in the extracts of samples collected during the flowering period after 2 h of extraction.