Effect of Preservation Methods on Physicochemical Quality, Phenolic Content, and Antioxidant Activity of Stevia Leaves

Figure 2

Surface microstructure of stevia leaves: (a) commercial; (b) freeze-dried; (c) gamma-irradiated at 0.5 kGy; (d) gamma-irradiated at 1 kGy; (e) gamma-irradiated at 2 kGy.

(a)

(b)

(c)

(d)

(e)