help on securing loan with property

[Gloria Mirza]

I borrowed money from my mom to purchase a rental property. I would like to treat the loan as a home equity loan on my primary residence. Currently I pay her interest only payments and we have a very basic written agreement. I plan on sending the IRS a 1099-int for her so that she pays taxes on the interest and I can deduct it. I have done some research online and read that the loan needs to be secured for me to be able to deduct it from my taxes. My question is how do I secure the loan and will it affect my DTI? I don't know if it matters but I am in California.