Response surface methodology was used to determine the optimum processing conditions that give maximum extraction yield, viscosity, hue and emulsion stability, as well as, minimum protein content for the gum extracted from Lepidium perfoliatum seed. Temperature (45–75ºC), processing time (1.5–3.5h), pH (5–8) and water to seed ratio (30:1–60:1) were the factors investigated. Experiments were designed according to Central Composite Rotatable Design with these four factors, including central and axial points. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Applying desirability function method, optimum operating conditions were found to be extraction temperature of 48.1ºC, pH of 8, water to seed ratio of 30:1 and process time of 1.5 h. At this optimum point, extraction yield, viscosity, protein content, hue and emulsion stability were found to be 17.36%, 463.07 mPa s, 2.84%, 60.47 and 88.96 %, respectively.

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