MEXICO CITY — Operating income of Gruma Corp., the U.S. and U.K. segment of Gruma S.A.B. de C.V., in the first quarter ended March 31 was 657 million pesos ($50 million), up 25% from 525 million pesos in the same period a year ago. Sales were 7,030 million pesos ($537 million), up 1% from 6,964 million pesos. Sales volume, though, was down 1% to 402,000 tonnes. “Sales volume was flat at 402,000 tonnes, reflecting a 3% increase at the U.S. operations, which was offset by reductions at the European corn milling operations due to extraordinary sales of corn during 1Q,” Gruma said. Majority net income of Gruma S.A.B. de C.V. in the first quarter was 622 million pesos ($47.5 million), up 197% from 209 million pesos in the first quarter of 2013. Net sales were 13,398 million pesos ($1,023.6 million), up 3% versus the year earlier period.