Thierry Goli

Chemical equilibrium of minced turkey meat in organic acid solutions.

The distribution of acid (HA), anions (A(-)), free protons (H(3)O(+)) and bound protons (H(b)), in homogenized turkey meat was evaluated at various meat/water mass ratios of (1/4-1/10) during titration with acetic acid (0.25N) or lactic acid (0.2N). H(b) concentration was determined by titration with hydrochloric acid (0.075N) and a correlation for [H(b)]=f(pH) was proposed. A procedure was used to calculate the fractions of the various species in equilibrium, starting from an initial acid concentration in a meat/water system and assuming the accuracy of the pK(a) value of the pure weak acids despite the chemical complexity of meat. Calculated results were in very good agreement (±0.15) with experimental pH values, whatever the acid, meat batch or meat/water mass ratios used. Less than 1% of the total protons were free (H(3)O(+)) and determined the meat pH.

Influence of sodium chloride and pH during acidic marination on water retention and mechanical properties of turkey breast meat

Turkey breast cubes underwent acidic marination in the presence of salt. The transfer of water, salt and acid was measured, and texture was assessed on the cooked meat. While significant mass gains were observed during marination, from 20 minutes of immersion onwards, only long durations produced an overall matter balance greater than that of non-marinated meat. From the first minutes of immersion, these transfers caused hardening, regardless of the presence of salt in the marinade. For longer durations, only in the absence of salt was significant tenderizing seen in comparison to the non-marinated control. This effect appears to be due on the one hand to passing the isoelectric pH of the meat during acidification, and on the other hand to setting up antagonistic mechanisms breaking down or reinforcing connective tissues by acid and salt respectively. The high degree of tenderization observed in a water-acid solution can be explained partly by dilution of the fiber load per section unit due to protein solubilization.

Evolution of pH during immersion of meat protein matrices in acidic marinades

The pH value is a fundamental datum to be monitored during marination. A method is proposed for calculating the evolution of pH of turkey meat cubes during marination in an acetic acid solution. It is based on measurement of the buffering capacity by acidification using a strong acid. A calculation based on the dissociation equilibrium of acetic acid is used to estimate the mean pH reached, factoring in the acid content of the meat. For long marination times, the calculated pH is over-evaluated in relation to the experimental value. This can be explained by the significant loss of buffering substances during immersion. After 6h of immersion, the matrixs proton binding capacity may be reduced to just 20% of the initial value. Hence to improve the prediction of meat cut pH during marination, it is necessary to factor in the outgoing flow of buffering substances.

Modeling of Mass Transfer During Hot-Smoking of Fish Fillets

This work aims at evaluating the mass reduction of traditionally hot-smoked catfish ( Arius heudelotii ) during hot-air drying unit operation. Drying kinetics of fish fillets are proposed from experimental investigations, taking into account the relative contributions of water evaporation and water and fat drips. The influence of the air temperature (50 to 80 ∘ C), air velocity (1 to 3 m/s) and relative humidity (15 to 40%) on drying rate functions is analyzed from a Doehlert experimental design. Based on the identification of characteristic drying rate curves, a drying model is defined and proves to be quite accurate regarding the prediction of evaporation rate during the falling rate period.

Analysis of PAH Residues and Amounts of Phenols in Fish Smoked with Woods Traditionally Used in French Guiana

Abstract Fish smoking with local wood species is a traditional practice in French Guiana. We evaluated the carcinogenic risk and the smoky taste in acoupa weakfish (Cynoscion acoupa) smoked by a small Guianese company specializing in fish smoking using local wood species. The goal of this study is to promote regional economic development by encouraging the establishment of small companies offering fish smoked with local wood species in agreement with the European health norms in terms of polycyclic aromatic hydrocarbon (PAH) content in smoked fish. The fish smoked with three species of wood traditionally used in French Guiana, Parinari campestris, Caesaria grandiflora, and Laetia procera, conformed to European standards for PAH content. Their phenol contents (correlated with the smoky taste) were close to smoked salmon, the reference in Europe. Given the low rate of extractable compounds in these woods, other flavors had little chance of predominating on the smoky taste. These three tropical wood species might be used for the production of cold smoked fish in compliance with European standards for PAH residues. The flavor and consumer’s acceptance of the smoked fish should now be investigated to characterize the added typicity of local woods in comparison to the commonly used European woods.