How to burn fat without gaining muscle?

I would suggest you stay with the cardio workout and add abdominal exercises such as crunches and leg raises. Do not worry about getting a six pack from this, it is nearly impossible for girls to get abs. Also remember, cardio promotes fat loss in the entire body, so even if you only feel soreness in your legs, you will still burn stomach fat as well. Keep working out every day for as long as you already are, and if you decide to add ab exercises, spend 5-10 minutes on those. Your diet is good, but remember that rice has carbs, which result in fat storage, so if you are unhappy with the results from exercising then try cutting the carbs. Good luck with your goal!