Despite the glamour of high technology, the most profitable businesses over the last five years were the low-tech and fairly pedestrian realms of soft drinks and tobacco products, Forbes magazine says in its Jan. 1 issue.

The soft-drink industry had a 27.1 percent return on equity over the last five years, Forbes said. Alcoholic beverages brought an 18.3 percent return on equity, bringing the combined return on equity for the entire beverage industry to 22.4 percent.

The tobacco industry's return on equity was 20.3 percent over the past five years, the biweekly business magazine said in its 37th Annual Report on American Industry. The magazine is scheduled to be delivered to subscribers on Monday.

Oil-field drilling equipment and services finished third in five-year industry profitability, with a 20.1 percent return on equity, Forbes said.

Return on equity is profit as a percentage of the combined value of all common and preferred stock.

The health-care industry finished fourth, with a five-year return of 19.9 percent. The publishing industry finished fifth, with a 19.2 percent return, and the petroleum industry was sixth, with an 18.9 percent return on equity.

In seventh place was the service industry, including fast-food chains, food distributors, and industrial and office service companies. This group had a combined return on equity of 18 percent over the past five years.

Rounding out the top 10, by industry and return on equity, were: electrical equipment, 17.7 percent; computers, 17.4 percent; and broadcasting, 16.9 percent.

At the bottom of the list, in 42nd place, was the motor vehicle industry, with a 1.3 percent return on equity over the last five years. But Forbes noted that this industry has recovered from the depths of the recession with a healthy 18 percent return on equity in 1984.

Forbes said the five most profitable companies over the past five years and their returns on equity, were MCI Communications, 125.3 percent; Apple Computer, 113.8 percent; Lockheed Corp., 87.1 percent; NIKE, 83.2 percent; and Price Co., 65.7 percent.

The magazine said the fastest-growing company, in terms of earnings per share over the past five years, was Jefferson Smurfit, whose earnings per share were up 139.4 percent.