add rice flour, cumin powder, coriander powder, red chili powder and salt. i have used rice flour to bind the patties. you can also use corn starch (called corn flour in india) to bind. other options to bind are bread pulp (soaked and squeezed bread slices), arrow root flour and even gram flour (besan). gram flour will give its taste in the patties. you can also add add buckwheat flour (kutttu ka atta), water chestnut flour (singhare ka atta). but remember the taste will change.