Efficient extraction of fructans from sotol plant (Dasylirion leiophyllum) enhanced by a combination of enzymatic and sonothermal treatments.

Abstract

The effects of different extraction methods of water-soluble carbohydrates (WSC) from the sotol plant (Dasylirion leiophyllum) were investigated. Sotol fragments were extracted at 40 and 70 °C, under thermal treatment (T), pre-enzymatic thermal treatment (PET), sonothermal treatment (ST), and pre-enzymatic sonothermal treatment (PEST) conditions: fructose, glucose, sucrose, and fructans were analyzed by HPLC and the total water soluble carbohydrates was determined. At 70 °C, the highest WSC values (482 mg/gd.m.) were obtained, with a fructan proportion of 69%. Pre-enzymatic treatment at 70 °C resulted in a high WSC content with the highest fructans proportion (87%) and lowest contents of RS and sucrose. The effect of the interaction between ultrasound and enzymatic treatments was limited by the high-temperature effect (70 °C), thereby minimizing the extraction. Microscopy analyses showed cell-wall modifications with the ST and PET treatments, which caused an increase in the total soluble sugars. The combination of enzymatic and sonothermal treatments at 70 °C resulted in the extraction of fructans in a higher yield and with less degradation. This circumvents the need for traditional high-energy processes, which could be beneficial for the extraction of WSC such as fructans from sotol or other economically important plants.