Cast as villains for their role in spearheading Maryland's new interest-rate reform law, the state's six largest banks emerged this week as the guys in the white hats.

The six banks, including Suburban Bank of Bethesda, have committed $22.5 million in low-interest loans backed by guarantees from the state, for a special program to spur minority business development.

"The Maryland banking community should be congratulated for this effort," said James O. Roberson, secretary of the Maryland Department of Economic and Community Development. "The banks are making a good move here . . . They really put their money where their mouth is to benefit the minority community."

Compared with loans that banks routinely make to a single large company or an individual businessman, $22.5 million won't qualify as big bucks.

But as the first reliable source of long-term financing for minority firms in Maryland, the pool of funds provided by the banks addresses critical needs that are unique to that segment of the state's business community.

Moreover, the funds are earmarked specifically for minority firms that heretofore have been unable to obtain financing through conventional means and, as such, they guarantee access to capital.

It's little wonder, then, that Roberson calls the banks' involvement a good move. And the secretary is right on another count. Congratulations are in order.

Loans in the new financing program will be made through the Development Credit Fund Inc., a private, nonprofit corporation set up jointly by the participating banks solely to finance minority business growth. Each loan will be guaranteed up to 80 percent by the Maryland Small Business Development Financing Authority, an agency of the department of economic and community development.

Maryland businesses that are at least 70 percent owned by minorities may apply for up to $500,000 for working capital or equipment purchases. The six banks have committed $7.5 million to the program in its first year and a total of $22.5 million by 1985.

Minority firms often find it difficult to obtain long-term financing because they are considered too risky. Most are at a disadvantage when seeking conventional financing because they either don't have a track record or the necessary collateral to qualify for loans at reasonable rates, as Roberson pointed out.

Indeed, Rep. Parren Mitchell (D-Md.) expressed frustration this week over his unsuccessful efforts in Congress to win passage of legislation to help minority business. "They don't have access to capital," Mitchell declared.

Daniel P. Henson III, chairman of the Development Credit Fund, agrees with Mitchell and Roberson, but he notes, "banks are not equipped to handle loans on an individual basis" for minority firms.

"Their lending offices are not set up to make the perfect deal," says Henson. "Deals have to be structured in a certain way" to assist the minority business borrower.

That hasn't been done in large measure, Henson indicated, because banks either lack experience in tailoring loans for small firms or are reluctant to restructure their loan departments to address the special needs of minority business.

Maryland's joint partnership, in which banks are the key players, should go a long way in correcting that deficiency.

"It's a tremendous boost as we study the problems of minority business," said Henson, a former executive director of a committee formed by the Greater Baltimore Committee to study problems facing minority business.

The special fund is an outgrowth of a GBC study that began in 1979. A major part of that study was devoted to the problems minority businesses encountered in gaining access to debt and equity capital.

In the meantime, "We were all sensitive to the issue that the federal government was cutting back on programs," recalled Alan P. Hoblitzell Jr., former chairman of the GBC committee on minority business and president of Maryland National Bank.

The association of business leaders "came up with a solution and got the state to embrace it," Hoblitzell recalls.

More important, the banks embraced the idea and for that, at least, they deserve the plaudits of government and business.