Impact of Lacticaseibacillus paracasei RH5 fermentation on flavor of butter: Insights from GC-MS, GC-IMS and E-nose analysis

This study isolated Lacticaseibacillus paracasei RH5 ( L. paracasei RH5) from traditional fermented yogurt and evaluated its potential as a novel starter culture for butter fermentation. Comprehensive analysis using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), and electronic nose (E-nose) revealed that butter fermented with L. paracasei RH5 contained a greater diversity and higher concentration of key flavor compounds, including acids, aldehydes, alcohols, ketones, lactones, and esters. Notably, discriminant flavor compounds such as acetoin, butanoic acid, octanoic acid, decanoic acid, pentanal, butanal, hexanal, 1-propanol, 2-heptanone, 2-nonanone, 2-undecanone, 2-octanone, 1-penten-3-one (M), 2-heptanone (M), 2-pentanone (M), δ -octalactone, δ -decalactone, γ -dodecalactone, δ -dodecalactone, ethyl butanoate, isobutyl hexanoate, and 2,5-dimethylpyrazine were identified as major contributors to the characteristic sour, creamy, and fruity notes in the fermented butter. Multivariate analysis clearly distinguished the fermented butter from unfermented and commercial butter, demonstrating the significant impact of L. paracasei RH5 on the flavor profile. These findings provide a foundation for the potential application of L. paracasei RH5 in producing value-added fermented butter with an enhanced flavor profile. • Lacticaseibacillus paracasei RH5 was successfully isolated and identified from traditional fermented yogurt. • HS-SPME-GC-MS, HS-GC-IMS, and E-nose comprehensively characterized the volatile flavor compounds of the fermented butter. • RH5 has been demonstrated to be a promising starter culture for producing butter with a more pleasant and complex flavor profile.