MODELING AND PREDICTING SECOND AND THIRD-ORDER FLUORESCENCE SPECTROSCOPY DATA AS A NOVEL QUALITY CONTROL STRATEGY ON MAYONNAISE

AZCARATE, SILVANA; TEGLIA, CARLA; MONTEMURRO, MILAGROS; SIANO, GABRIEL; CAMIÑA, JOSÉ M.; GOICOECHEA, HÉCTOR C.

Congreso; XVI Chemometrics in Analytical Chemistry; 2016

p { margin-bottom: 0.25cm; line-height: 120%; }Fluorescencespectroscopy has found in food analysis a large use due to that it isfast, gives direct measurement, is notdestructive and noninvasive [1].In this work, thepotential of excitation emission fluorescence matrix (EEM) datarecorded with a front face system along with chemometric methods wasinvestigated for the determination of spoilage on mayonnaise and forthe rapid prediction of changes of microbial flora (counts ofbacteria).Made in homemayonnaise and commercial mayonnaises samples were maintained at 25°Cduring four days, and stored at 37oC for three days. The microbialload on mayonnaise samples was determined per day. Total viablecount (TVC), aerobic mesophilic bacterias, Staphylococcus aureus,Escherichia coli and Salmonella were determined on mayonnaise at eachstep using culture methods.In parallel,mayonnaise samples were analyzed by 3D front-face fluorescencespectroscopy, without prior preparation,at 8 and 6 different times for the samples stored 25 °C, and 37°C,respectively. The data matrices were recorded varying the excitationwavelength between 230 and 400 nm each 10 nm, and registering theemission spectra from 300 to 600.5 nm each 0.5 nm. Thus, the EEMswere of size 18×602. PARAFAC analysis allowed capturing the changesoccurring in the fluorescence spectral data.The best PARAFACmodels showed 3 components for data recorded both temperatures.Profiles of main compounds wereextracted with this algorithm describing quality evolution on thetime. In order to meet those compounds that their concentrationdecreases and those that are produced (specifically amino acids) achromatographic analysis was performed [2]. The chromatographicanalysis confirms the decrease of tyrosine and the production oftryptophan in the time.Partial leastsquared discriminant analysis (PLSDA) was applied to data set formedby concatenating of all the fluorescence spectra at sametemperature for testing the allocation of the spectra of theindividual samples within the five and four groups corresponding tothe five and four investigated storage times. The results showedthat 100% of good classifications were obtained using 3 PLS factors.These resultsallowed the classification of samples as a function of stored time.In addition, this information can berelated to the microbial counts.In order to evaluateother quality parameters, a study with optical fibers is beingperformed. EEMs were obtainedthrough the degradation kinetics of mayonnaise produced byirradiation the samples each two minutes fora total of 20 minutes. Third order data analysis will be directed tothe fat content evaluation as well as at the content of differentdressing of mayonnaise for obtaining information about the qualitymayonnaises.