In Situ Method for Real-Time Discriminating Salmon and Rainbow Trout without Sample Preparation Using iKnife and Rapid Evaporative Ionization Mass Spectrometry-Based Lipidomics

Abstract

The domestic rainbow trout producers issued a standard with an aquatic association that classified rainbow trout as salmon, which raised the concern of consumers on the fish parasites infection. Herein, an in situ method was developed using "iKnife" and rapid evaporative ionization mass spectrometry based lipidomics for real-time discrimination of salmon and rainbow trout without sample preparation. A total of 12 fatty acids and 37 phospholipid species was identified and imported into statistical analysis for building an in situ and real-time recognition model. The ions with |p(corr)| > 0.5 and |p| > 0.03 were shown to be responsible for allocating samples, and the ions with high correlation values, such as of m/z 747.50, 771.49, and 863.55, indicated large weights in identification of the salmon and rainbow trout. The results indicated that this technology could be employed as a front-line test method to ensure the authenticity of salmon products.

Rapid Evaporative Ionization Mass Spectrometry: A Review on Its Application to the Red Meat Industry with an Australian Context

“…The application of REIMS in food falls into two broad areas: (i) food fraud/adulteration (pork and chicken [19] along with fish [22][23][24]) and (ii) tissue classification (meat prod-ucts [7], beef offal [8], porcine organs [4] and turtle [23]). Other areas of research have been for the screening of β-agonists in pigs [16] and boar taint [18] as well as the characterisation of beef quality [25] and lamb flavour [26].…”

“…The first is principal component analysis (PCA) which is an unsupervised method where no assumptions are made in relation to the data, and it is used as a visualisation technique to identify any patterns within the data set [29]. The use of PCA for data visualisation has been deployed for most studies [7,16,18,19,[22][23][24]27]. As noted above, prior to PCA, the data set is normalized to the base peak, but other scaling techniques can be used as well.…”

“…The second approach is partial least squares discriminant analysis (PLSDA) which is used as a classification technique and assumes that the identity of each grouping is correct [29], and as such can be regarded as a supervised method. PLSDA has been primarily used for classification [7,16,18,19,[22][23][24]27]. PLSDA is not the only technique which can be used for classification of REIMS data.…”

“…DART-MS was used to assess salmon freshness by monitoring muscle lipid abundances over time, and sample homogenisation, extraction and clean up was required prior to the analysis [49]. In contrast (and as noted), REIMS has been demonstrated to be applicable to numerous applications where samples are analysed directly [16,24,50,51] giving it a clear advantage in this regard. The remainder of the review will provide further detail of these applications in the areas of provenance, quality and safety to the red meat industry, with an emphasis on an Australian context.…”

Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry and Rapid Evaporative Ionization Mass Spectrometry Were Used to Develop a Lamb Authentication Method: A Preliminary Study

“…A Medimass REIMS source (Medimass, Budapest, Hungary) coupled to Xevo G2-XS Q-TOF mass spectrometer (Waters, Wilmslow, UK), equipped with a monopolar electrosurgical knife (Model PS01-63H, Hangzhou Medstar Technology Co, Ltd., Jiaxing, China), was applied in negative ion and sensitivity modes with continuum data acquisition. The instrument parameter settings referenced Song et al's method [29], and MS data were acquired from the range of 50-1200 m/z with a scan speed of 0.5 s/scan. The generator, Erbe VIO 50C, was operated in auto-cut mode with the power set at 30 W for electrosurgical dissection.…”