AOAC 133rd Annual Meeting - Final Program

Poster Abstracts | Monday

P-M-075 Yu-Ping Huang , Daniela Barile , University of California, Davis, Davis, CA, USA Comparison of Solid Phase Extraction Strategies for Purification of Bioactive Peptides and Oligosaccharides in Foods for LC-MS Analysis Proteolysis is now used in food processing for increasing protein digestibility and reducing allergenicity. To enable purification of bioactive compounds in complex food matrices, reverse phase (RP) solid phase extraction (SPE) is often used to fractionate peptides and naturally occurring oligosaccharides as well as peptide desalting, crucial steps for reducing ion-suppression in LC-MS. However, as dipeptides may not be well retained by RP SPE, to study bioactive compounds, it is needed to develop an analytical strategy able to capture small but potentially more biologically active peptides. This work evaluated the efficacy of five commercially available SPE cartridges, four RP and one mixed-mode (RP/strong cation exchange, SCX), using pure peptide standard mixtures (2-13 amino acid residues) and a real food sample (proteolyzed almond extract). The oligo- saccharide fraction was firstly eluted from the cartridge with an aqueous eluent, and the peptide fraction was then eluted with an organic eluent. For the almond extract, the peptide breakthrough of the RP/SCX SPE (<0.8% of loaded peptides) was lower than the RP SPE (6.0-7.6% of loaded peptides). Nonetheless, the RP/SCX SPE also resulted in a lower peptide recovery (53%) than the RP SPE (77-84%). LC-QTOF MS results revealed that the RP/SCX SPE, followed by C18 (500 mg), can retain more di- and tri-peptides. Testing and optimizing with various food samples is needed to make this approach more applicable in the food industry. Presenter: Yu-Ping Huang, University of California, Davis, Davis, CA, USA, Email: yphhuang@ucdavis.edu P-M-076 Justin Marsh , Melanie Downs , Philip Johnson , University of Nebraska, Lincoln, NE, USA; Charles Yang , Anastasia Kalli , Thermo Fisher Scientific, San Jose, CA, USA Development of a PRM Assay for Walnut and Hazelnut Detection in Foods MS detection of tree nuts is problematic because of the requirement for target peptides from several allergenic species (including but not limited to hazelnut, walnut, cashew, pecan, and almond). We describe the development of a targeted MS method for the detection of hazelnut and walnut based on genomic data and data-dependent analysis (DDA) of tree nuts spiked into relevant food matrices. Selection of peptide targets for allergen detection was based on the analysis of the partially sequenced genomes. Unique peptides were confirmed and quantified by DDA. Both DDA and parallel-reaction monitoring (PRM) experiments were conducted using a Thermo Scientific TM Q Exactive TM Plus Orbitrap TM mass spectrometer. Target peptides were chosen based on recovery from the matrix background and abundance. PRM experiments allowed the selection of six peptides unique to either hazelnut or walnut, and a PRM method was developed to evaluate sensitivity and performance in a chocolate matrix. All six of the selected analyte peptides derive from the 11S family of seed storage proteins. PRM resulted in a

method that could detect <2 ppm hazelnut or walnut protein in chocolate and could discriminate between these tree nuts. The method did not significantly under-report either tree nut when present in solid chocolate. The target selection strategy employed yields peptides which may be used for tree nut detection in complex food matrices and at levels of sensitivity appropriate for consumer protection. Presenter: Philip Johnson, University of Nebraska, Lincoln, NE, USA, Email: philip.johnson@unl.edu P-M-077 Vicha Ritruthai , Paria Bannazadeh , Silva Babajanian , Peter Chang , Gary Swanson , Herbalife Nutrition, Torrance, CA, USA Rapid and Cost Effective Determination of Choline by UPLC-QDa A single laboratory validation study (SLV) was conducted for a UPLC-QDa method for rapid determination of Choline in multivi- tamin tablets and powder products. The procedure consisted of a simple liquid extraction using sonication followed by dilu- tion, separation on an Agilent ZORBAX HILIC Plus RRHD UPLC column and detection with Waters Acquity QDa. Isotopically labeled Choline was used as an internal standard to correct for signal depression due to matrix interference. The current compendial methods for determination of Choline involve acidic and/or enzymatic hydrolysis of the sample followed by colo- rimetric analysis, LC-MS/MS analysis or Ion Chromatography with suppressed conductivity detection. These methods require lengthy sample and extensive solution preparation or detectors that are not commonly found in QC labs. On the other hand, the method developed in this study was targeted toward use in Quality Control labs by focusing on efficiency and cost effec- tiveness. This UPLC-QDa method was found to be rugged and suitable for the determination of Choline in tablet and powder products. Presenter: Silva Babajanian, Herbalife Nutrition, Torrance, CA, USA, Email: SilvaBa@herbalife.com P-M-078 Christiane Fæste , Amritha Johny , Christin Plassen , Norwegian Veterinary Institute, Oslo, Norway; Jan Haug Anonsen , Anders Moen , University of Oslo, Oslo, Norway; Jelena Klawitter , Uwe Christians , University of Colorado, Denver, Aurora, CO, USA; Thien Van Do , Haukeland University Hospital, Bergen, Norway Can Gluten Peptides be Transferred from Feed to Fish? Continued growth in aquaculture depends on the utilisation of sustainable protein resources since marine reserves are limited. In Norwegian salmon farming, plant-based materials currently make up 70% of the aquafeeds. Commonly used are proteins derived from wheat and legumes. This change in the diet has led to new challenges for fish health and welfare, and product qual- ity and consumer safety. In this context, the carry-over potential of allergenic peptides from plant ingredients in the feed into the edible parts of fish is relevant for the assessment of possible risks to consumer health. In the present study, we have used proteom- ics and immunoblotting for the analysis of on-growing salmon receiving wheat gluten-containing feed (15 or 30%) for 60 days. The fish fillets were extracted for proteins and processed for

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