Stabilization of Flixweed (Descurainia sophia L.) syrup using native hydrocolloids

Flixweed (Descurainia sophia L.) is a native plant with seeds that contain a number of nutraceuticals. In different parts of Iran, the seeds of this plant are used to prepare medicinal syrup (sharbat). Despite the medicinal and nutritious advantages of this product, the precipitation of flixweed seeds in syrup is one of the common problems which restrict its commercial usage. The present study investigated the use of native hydrocolloids and production parameters on the stabilization of flixweed syrup. The effect of the concentration of flixweed seeds, sugar, basil seeds, native hydrocolloids (soluble and insoluble fractions of Persian gum, PG, and gum Tragacanth, GT), pH, and thermal treatment on the stabilization, rheological and sensory properties of flixweed syrup were examined. The influence of trivalent ions (FeCl3) on the production of reversible characteristics was studied. The findings indicated that PG (1.2%), insoluble fraction of PG (0.8% wt), GT (0.3%), soluble fraction of GT (0.05% wt), and insoluble fraction of GT (0.14% wt) stabilized flixweed seeds in syrup. Furthermore, the presence of FeCl3 (0.005 mol/l) produced a reversible gel in syrups containing the soluble fraction of GT. The rheological properties of the stabilized syrups showed good fit with the Hershel-Bulkley model. In terms of sensory characteristics, the stabilized flixweed seed syrup (5% wt), basil seeds (0.5% wt), sucrose (10% wt) and soluble fraction of GT (0.05% wt) showed the greatest similarity to the control. The findings showed that native gums, in the presence of iron ions, can stabilize as well as enrich the Flixweed syrup where its sensory characteristics was very similar to the unstable regular syrup.