The team in Yorkshire and Humber said it was the first time science had tried to prove local seasonal vegetables were better for you than those from overseas.

The results could help growers promote local purchasing and give them a point of difference to increase sales and raise awareness of local and seasonal food, it said.

The project will pitch the nutritional content of seasonal asparagus grown across Yorkshire under varying conditions against that of imported produce.

Scientists will test the nutritional content of local asparagus throughout its shelf life. They will then compare these finding with those of imported asparagus, which has been kept in a cool chain to keep it fresh in transit.

Regional Food Group for Yorkshire & Humber research and development director Sarah Knapper said there was little research to justify the claims made about the superiority of regional produce."So we wanted solid evidence. We are lucky to have some of the best producers and believe the results will affect sales and open retailers' doors for local producers."

The group's chief executive, Jonathan Knight, said: "We encourage consumption of seasonal local produce and if we can prove it's better for you, it will be fantastic."

The results will be made available for supermarkets and retailers nationwide. Stockbridge Technology Centre is working with the local producers on the tests.