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Human milk (HM) provides optimal nutrition for infants, but infant formula (IF) serves as a potential alternative to HM when breastfeeding is not an option. However, IF possesses a more intense aroma than HM, and it is often challenging to reduce this disparity due to its stringent production regulations. Therefore, investigating the interaction between HM proteins and odor molecules is essential for comprehending the distinct odor characteristics of HM and guiding improvements in IF to mimic the aroma of HM. This research aims to characterize the HM odor and explore the influence of HM α -lactalbumin (HMLB) on the release of HM odor skeleton compounds (OSC) using a combination of computer simulation, human perceptions, and instrumental analyses. A total of 20 OSCs were identified. Notably, the release of most of these compounds was negatively correlated with the HM protein content, with the strongest negative correlations being observed for hexanal, nonanal, and decanal (|R| ≥ 0.7, P < 0.01). The molecular docking simulations demonstrated that HMLB inhibited the volatilization of hexanal, nonanal, and decanal, thereby increasing the odor threshold of these odor compounds (61.94 %, 241.5 %, and 198.6 %). This inhibition was mainly achieved through the formation of hydrogen bonding and hydrophobic interactions, a finding corroborated by multi-spectroscopic analysis. Overall, the experimental results provide valuable insights into the odor mechanism of HM and contribute to the development of IF that mimics the HM odor. [Display omitted] • Twenty odor skeleton components (OSC) that make up HM odor were characterized. • Most of the OSCs were negatively correlated with the total protein content of HM. • Non-covalent interactions of OSCs with α -lactalbumin (HMLB) affected their release. • The quenching of OSCs fluorescence by HMLB was based on a static mechanism. • The odor thresholds of OSCs were significantly increased by HMLB. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ninety-four odor-active compounds were identified from HM by DHS-GC × GC-O-MS. • Nonanal and octanal were the most important odor-active compounds in most HM. • Fat content was closely related to the amounts of odor-active compounds in HM. • Aldehydes have most abundant species and the highest correlation with fat content. • HM odor attributes were contributed by synergistic effect of odor-active compounds. Odor is an important indicator of human milk (HM) quality, with a proven function. Here, the effect of inter-individual nutrient differences on key odor-active compounds (OACs) and odor attributes of HM samples was investigated using flavor analysis techniques and correlation network analysis. A total of ninety-four OACs were identified from 30 HMs, of which 24 key OACs could represent the basic odor characteristics of HMs. Fat content was closely related to the amounts of OACs, with aldehydes being the most abundant species and having the highest correlation with fat content. Of them, nonanal and octanal were the most important OACs in HM, having both high flavor dilution factor (2 ∼ 64, 4 ∼ 128) and odor activity values (<1 ∼ 37, 2 ∼ 36) in most samples. Additionally, different pattern of synergism between key OACs contribute to each odor attribute of HM. These findings will provide insights for subsequent in-depth studies of HM flavor. [ABSTRACT FROM AUTHOR]