SPME-MS-MVA as an electronic nose for the study of off-flavors in milk.
A new technique using solid-phase microextraction, mass spectrometry, and multivariate analysis (SPME-MS-MVA) was developed for the study of off-flavors in milk. The analytical column of a GC/MS system was replaced with a 1-m deactivated fused-silica column, which served as a transfer line to deliver volatiles extracted from milk samples with a Carboxen-SPME fiber to the mass spectrometer. Mass fragmentation data resulting from the unresolved milk volatile components were subjected to MVA. Principal component analysis based on SPME-MS-MVA provided rapid differentiation of control reduced-fat milk (2% butterfat content) samples from reduced-fat milk samples abused by light, heat, copper, and microbial contamination. The three psychrotrophic bacteria studied included Pseudomonas fluorescens, Pseudomonas aureofaciens, and Pseudomonas putrefaciens. SPME-MS-MVA is rapid and offers significant advantages over commercial electronic nose instruments currently being used as quality assurance tools to differentiate normal-tasting food and beverage samples from those containing off-flavors and malodors.
Marsili
R T
RT
Dean Foods Technical Center, Rockford, Illinois 61125, USA. rmarsili@hotmail.com
D000818:Animals; D013058:Mass Spectrometry; D008892:Milk / Q000737:chemistry* / Q000382:microbiology; D008970:Molecular Weight; D015999:Multivariate Analysis; D009812:Odorants / Q000032:analysis*; D013649:Taste