Food systems in developing countries are undergoing a profound transformation characterized by the emergence and expansion of modern retailers and integrated supply chains. Appropriate policies are needed to guide this transformation, presupposing a good understanding of consumer preferences. We analyze consumers’ valuation of different vegetable attributes in metropolitan areas of Vietnam, using contingent valuation techniques and a mediation framework for two specific examples. Consumers are willing to pay an average price premium of 60% for Chinese mustard that is free of chemical residues and of 19% for different convenience attributes of potatoes. Income levels and media have positive impacts on the willingness to pay, partly mediated through different consumer perceptions like food safety concerns, openness towards new food products or price consciousness. These results deepen our understanding on how consumers value new food attributes.