The purpose of this section is to make loans available for single-family housing to people who due to low income would not otherwise qualify for loans under the normal lending practices of the lender and the authority.

In connection with any issuance of bonds in an aggregate principal amount of fifty million dollars or more for purposes of financing residential housing, the authority shall establish within such bond issue a fund of at least one million dollars to finance mortgages for low-income persons at an interest rate below the interest rate which otherwise applies to mortgages financed from such bond issue.