May 7 (Reuters) - Bunge BG.N beat Wall Street expectations for first-quarter profit on Wednesday as the grain trader and processor benefited from higher processing margins and tariff uncertainty-fueled demand for its products.

Combined soybean, corn and wheat export volumes were up 11% year-on-year in the United States and Brazil during the first quarter. Corn was up 38% in the U.S. and soybeans rose 18% in Brazil.

"We benefited in the first quarter from tariff-related timing shifts in demand and farmer activity and remain confident in our ability to continue to execute despite the current market environment," CEO Greg Heckman said.

However, net sales from its core agribusiness segment, its largest by revenue and volume, were down 16.2% at $8.16 billion in the quarter from the previous year.

The Missouri-based company posted an adjusted profit of $1.81 per share for the three months ended March 31, compared with analysts' average estimate of $1.30 per share, according to LSEG data.