Mathematical modeling of off-flavor development during beef storage

Chemical Kinetic Modeling of Nutricereal based Fermented Baby Food for Shelf Life Prediction

Background:

A nutricereal based fermented baby food was investigated to predict its shelf life using chemical kinetic modeling. An optimized baby food formulation, packaged in metalized polyester packets was stored at accelerated conditions for 180 days and analyzed for Hydroxy Methyl Furfural (HMF), Thiobarbituric Value (TBA), Free Fatty Acid Content (FFA) and sensory characteristics.

Objective:

The objective of the study was to determine the shelf life of the optimized nutricereal based fermented baby food using chemical kinetic modeling.

Methods:

Chemical kinetics analysis by investigating the Hydroxymethyl Furfural content, thiobarbituric value (TBA), free fatty acid content (FFA) and sensory characteristics of the optimized baby food.

Results:

Shelf life model based on chemical and sensory acceptability was derived using Arrhenius equation modeling. Thus, the baby food had a predictive shelf life of 54 weeks when stored at 10°C in metalized polyester based on the chemical (HMF, TBA and FFA) and sensory (overall acceptability) characteristics. A most suitable model based on FFA was developed considering lowest root mean square (RMS) percentages and least deviations in actual and predicted values.

Conclusion:

Chemcial kinetics could be applied to determine the shelf life of the fermented baby foods. HMF, TBA and FFA play key role in the shelf life of the stored fermented product. A model based on FFA is most suitable to determine the shelf life of the powdered nutricereal based fermented baby food packged in metalized polyster, stored at 10°C.

Implementation of multivariate techniques for the selection of volatile compounds as indicators of sensory quality of raw beef

This study was performed in order to select volatile compounds to predict the off-odour and overall assessment of raw beef's freshness Maronesa breed, using multivariate analysis. M. longissimus dorsi packed in vacuum and MAP (70 % O2/20 % CO2/10 % N2) stored at 4 ºC were examined for off-odour perception as well as the overall assessment of freshness at 10 and 21 days post mortem. The results achieved in this study demonstrated that the selected volatile compounds could be considered as volatile indicators of beef spoilage, enclosing information for discrimination of Maronesa beef samples in sensory classes of odour corresponding to unspoiled and spoiled levels. Fifty-four volatile compounds were detected. A significant increase of aldehydes, ketones and alcohols were observed during storage in MAP. 2 and 3-methylbutanal, 2 and 3-methylbutanol, 1-pentanol, 1-hexanol, 2,3-octanedione, 3,5-octanedione, octanal and nonanal were suggested as indicators of beef spoilage. 3-methylpentane was considered as a marker in the first stages of spoilage in beef, decreasing during storage. Data were examined using PCR and PLSR models for different optimal subsets of volatile compounds. The simplicity and usefulness of the technique in using 0/1 data in preserving high levels of accuracy was also prevalent. The powerful analytical methodologies for reducing variables and the choice of optimal subsets could be advantageous in both basic research and the routine quality control of chilled beef.