Pico Advanced Mass Spectrometry for Food Safety and Quality

1. Auflage 2015
ISBN: 978-0-444-63392-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, Band Volume 68, 734 Seiten

Reihe: Comprehensive Analytical Chemistry

Advanced Mass Spectrometry for Food Safety and Quality provides information on recent advancements made in mass spectrometry-based techniques and their applications in food safety and quality, also covering the major challenges associated with implementing these technologies for more effective identification of unknown compounds, food profiling, or candidate biomarker discovery. Recent advances in mass spectrometry technologies have uncovered tremendous opportunities for a range of food-related applications. However, the distinctive characteristics of food, such as the wide range of the different components and their extreme complexity present enormous challenges. This text brings together the most recent data on the topic, providing an important resource towards greater food safety and quality. - Presents critical applications for a sustainable, affordable and safe food supply - Covers emerging problems in food safety and quality with many specific examples. - Encompasses the characteristics, advantages, and limitations of mass spectrometry, and the current strategies in method development and validation - Provides the most recent data on the important topic of food safety and quality

Autoren/Hrsg.

Pico, Yolanda

Leseproben

3. Matrix-Assisted Laser Desorption Ionization Coupled to Time-Of-Flight Mass Spectrometry (MALDI-TOF)

MALDI-MS has a considerable impact on food safety and quality because it covers from proteomics to lipidomics [56], including polymer analysis [57] and, more recently, even low molecular weight analytes due to the introduction of matrix-less ionization techniques [e.g., desorption ionization on porous silicon (DIOS)] or new matrices such as ionic liquids, proton sponges, and metal nanoparticles. However, protein identification by peptide mass fingerprint still remains the main routine application [8]. This identification has played a relevant role in food chemistry especially in detection of food adulterations [30], characterization of safety, quality and food allergens, and investigation of protein structural modifications induced by various industrial processes that could be detrimental for food quality and safety [58–60]. Sample handling and pretreatment is a crucial step in these cases that can be very different depending on the physical state of the sample. Two major factors restricting the wider application of this technique have been throughput and cost per data point. Classic approaches are based on long, tedious, and expensive procedures (e.g., SDS gel electrophoresis separation followed by in-gel digestion). However, in recent years, novel molecular tools, the re-invention/re-application of mature technologies, and miniaturization of technology have both increased throughput and significantly reduced these costs (e.g., faster in-solution digestion of whole samples) [61–64]. Table 2 outlines a list of relevant applications recently published.

The capacity of MALDI-TOF-MS of identify proteins also offers a safe, cost-effective, and adaptable system for rapid identification of bacteria and fungi. Species differentiation of food pathogenic and spoilage bacteria is important to ensure food quality and safety. The growth of microbial contaminants in industrially produced beverages can cause turbidity, haze, and off-flavors resulting in quality loss often rendering the product undrinkable. MALDI-TOF-MS could deliver discriminative peptide mass fingerprints within minutes and could thus be a rapid and reliable tool for identification and differentiation [65]. To this end, different sample preparation methods ranging from plain cell smears to more elaborate extraction procedures including mechanical and enzymatic disruption of cells have been investigated [66,67]. Methods can be based on the analysis of whole bacterial cells that were suspended in an organic solvent or applied directly to the sample target. In a different sample preparation technique, cell extracts were obtained from intact bacterial cells by a dissolution/centrifugation step. The protocol applied for the study of cell extracts was shown to be very fast and simple, allowing the standardization of sample preparation. Furthermore, the analysis of cell extracts had several advantages with respect to the analysis of suspensions of whole bacterial cells. Thus, spectral profiles obtained from cell extracts showed less noise and more reproducible peaks as compared to spectra obtained from intact cells [68].

MALDI-TOF can also be used for DNA determination. Recently, MALDI-TOF-MS has been applied to single nucleotide polymorphism (SNP) detection by analysis of the mass of single base extension oligonucleotides specific to the SNP of interest. Sequenom® MassARRAY® MALDI-TOF-MS were tested as a medium-throughput platform for cereal varietal identification and found that MALDI-TOF-MS could produce SNP profiles specific to barley varieties [63]. A representative mass spectrum barley variety Baudin (Multiplex C) is shown in Figure 4.

Figure 4 MALDI-TOF SNP mass spectrum for barley variety Baudin, Multiplex C. Reproduced from Ref. [63] with permission of Elsevier.

Table 2

Selected Applications of MALDI for Food Safety and Quality

Small Molecules

PFOS and PFOA

Drinking water

DIOS-TOF-MS

Detect PFOS but not PFOA. In DIOS, only analytes are deposited on DIOS chips without using organic matrix for ionization. It was demonstrated that DIOS can be are suitable for the analysis of PFOS with the high sensitivity (1 ppt) and the quantitative analysis from 2.5 to 10 ppb, compared to the traditional MS methods such as MALDI-MS and ESI-MS.

[58]

Polymer Analysis

Thermomechanical degradation of PET

Food contained plastic bottles

MALDI-MS

MALDI-MS data coupled to PCA analysis monitor the wt% of PETpc-btg present in PET-btg blends and its overall quality as a function of intrinsic viscosity due to thermomechanical degradation. Moreover, subtle changes in oligomeric composition were also detected.

[57]

Lipids Analysis

Phospholipids

Olive oil fruits

MALDI-TOF/MS

TiO2 NP was utilized as MSPD sorbent and chloroform and methanol (1/2, v/v) as eluent. The efficiency was compared to that of the classic Bligh & Dyer method. Fast lipidomic fingerprinting of olive fruits and oils for quality control.

[56]

Table Continued

Protein Analysis

Simple protocols for protein extraction

Liquid (milk) and solid (hazelnuts)

MALDI-MS

Sample handling and pretreatment can be very different depending on the physical state. Comparison of traditional SDS gel electrophoresis and in-gel digestion and fast in-solution digestion.

[8]

Water soluble proteins

Pork meat (longissimus thoracis)

SELDI-TOF-MS

Identification of candidate protein markers for meat quality. Associations between protein peaks obtained with SELDI-TOF-MS and meat quality traits, mainly water holding capacity, texture, and skatole were observed.

[59]

Protein profiling

Liver

DIOS-TOF-MS NI-TOF-MS

The DIOS™ substrate includes a thick nano-sized porous layer, a high surface concentration of fluorocarbon and silicon oxides, and superhydrophobicity. In contrast, the QuickMass™ substrate consisted of a nonporous germanium thin-film. Higher ionization efficiency is obtained by DIOS™ substrate. However, the use of germanium (QuickMass™) suppresses better background interference of mass spectra.

[60]

Drugs, lipids, proteins, and small peptides

Skin

MALDI-IMS

Curcumin can be used as a novel MALDI matrix. Versatility of curcumin is also demonstrated by the possibility to image a.

[61]

Spatial distribution of GABA

Eggplant

MALDI-IMS

The distribution of GABA, one of the functional food factors, some other amino acids, and carbohydrates in eggplant sections.

[62]

Table Continued

DNA Analysis

Variety identification SNP-based markers

Cereals

MALDI-TOF-MS

MALDI-TOF applied to SNP detection by analysis of the mass of single base extension oligonucleotides specific to the SNP of interest. Accurate DNA sequence data is an important prerequisite for MALDI-TOF SNP assay design and genotyping. Sequenom® MassARRAY® MALDI-TOF-MS as a medium-throughput platform for cereal varietal identification.

[63]

Bacterial Identification

Characterization of moderately halophilic lactic acid bacteria

Tetragenococcus halophilus and Tetragenococcus muriaticu

MALDI-TOF-MS

Cells washed with ethanol and treated with formic acid, then ionized using x-cyano-4hydroxycinnamic acid as matrix.

[64]

Spoiling yeasts

Beverages

MALDI-TOF-MS

Discriminative peptide mass fingerprints within minutes. Optimize sample preparation and measurement parameterization using three spoilage yeasts (Saccharomyces cerevisiae var. diastaticus, Wickerhamomyces anomalus, and Debaryomyces hansenii).

[65]

Identification of spoilage bacteria

Beverages

MALDI-TOF-MS

Generation of peptide mass fingerprints, which form a distinctive protein peak pattern. The influence of environmental or physiological parameters including oxygen availability, different nutrients, cell density, and growth phase were analyzed and revealed small differences in mass fingerprints.

[66]

Table Continued

Spore analysis

22 Fusarium species

MALDI-IC/IS-TOF-MS

A Critical point for analysis is a proper sample preparation of spores, which increases the quality of mass spectra with respect...