Optimization of the enzyme-assisted extraction of fructans from the wild sotol plant (Dasylirion wheeleri)

Enzymatic liquefaction conditions were evaluated to obtain fructan from wild sotol plant (Dasylirion wheeleri) using the commercial preparation Pectinex Ultra SP-L. Ground sotol head was subjected to enzymatic extraction at various enzyme activities (0.0-175.73 U/mL) and fresh sotol concentrations (4.47-28.52 g/100 mL) at 30 degrees C for 8 h, using the response surface methodology to optimize the fructan extraction. Reducing sugars (RS), total carbohydrates (TC), fructan content (FRU), fructan profile, and the average degree of polymerization (DPn) were evaluated. Additionally, RS release kinetics and the enzyme rate constant (V-0) were calculated. Enzyme concentration and substrate significantly affected (P< 0.05) the RS extraction, FRU, and V-0, while DPn was only affected (P< 0.05) by the substrate concentration. Higher RS contents were obtained at lower substrate concentrations for > 87.87 U/mL enzyme, and fructan extraction was maximal (39.08 g/100 g d.m.) at 83.04 U/mL enzyme and 6.70 g/100 mL substrate. V-0 and RS content exhibited similar trends. DPn increased as substrate concentration decreased. Optimal enzymatic liquefaction conditions were 11.6-45.6 U/mL enzyme and 9.15-12.6 g/100 mL sotol, yielding elevated fructan (38.58 g/100 g d.m.), DPn of 8-10, and low fructose (1.8 g/100 g d.m.) and glucose (2.2 g/100 g d.m.) contents. These results demonstrate the feasibility of enzymatic liquefaction for extracting fructans from sotol heads without modifying the molecular structure.