Cardboard flavor is one of the most commonly described off-flavors in whey proteins. The objective of this research was to identify volatile components that are likely sources of cardboard flavor in dried whey protein concentrate and isolates and characterize them by sensory analysis. Cardboard and brown paper samples (n = 5) soaked in deionized water and whey proteins with and without cardboard flavor were analyzed by gas chromatography mass spectrometry and descriptive sensory analysis to select the potential contributors to cardboard flavor. Compounds were evaluated by trained sensory panelists using sniff jars, dose-response experiments and whey protein models. Sensory analysis of the aroma of the chemical standards yielded no single compound exhibiting a cardboard aroma, suggesting that cardboard flavor does not result from one compound but a combination. A combination of compounds (pentanal, heptanal, nonanal, 1-octen-3-one, dimethyl trisulfide) elicited cardboard flavor in whey protein previously deemed free of cardboard flavor.


This study established that a combination of pentanal, heptanal, nonanal, 1-octen-3-one and dimethyl trisulfide elicited cardboard flavor in whey protein and can be utilized as a training reference for identifying cardboard flavor. The direct association of specific lipid oxidation products with cardboard flavor in whey protein emphasizes the necessity to control lipid oxidation to reduce this off-flavor in whey protein ingredients. These compounds could potentially be utilized to instrumentally monitor cardboard flavor in whey protein. Hexanal, while a major indicator for lipid oxidation, was not directly indicative of cardboard flavor in whey protein.