Does information about MSG (monosodium glutamate) content influence consumer ratings of soups with and without added MSG?

Responses to recent concerns about perceived adverse health effects of monosodium glutamate (MSG) have included using prominent labels, e.g., "No added MSG", on products. Label information has been shown to create expectations for a food's sensory properties and acceptability, and influence evaluations of the product. To assess the impact of information about MSG content, subjects evaluated saltiness, richness, natural taste of, and liking for, vegetable soups with (MSG+) and without (MSG-) added MSG. Their attitudes to MSG were evaluated and found to be generally negative. Subjects tasted both soups under three information conditions, presented as an ingredient list: contains added MSG, does not contain added MSG, or no mention of MSG. The expected changes in liking and sensory properties due to added MSG were found, but there were no effects of information. A second experiment used a more obvious manipulation of information on added MSG content, as well as two soup flavors to reduce the obvious differences between the MSG+ and MSG- soups. Again, there were no effects of information. These data suggest that sensory properties are weighted more than information when products are evaluated during tasting, even when the information is highly relevant to beliefs and attitudes.