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Publications (16) View all
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Article: New developments in shockwave technology intended for meat tenderization: Opportunities and challenges. A review.
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ABSTRACT: Meat tenderness is an important quality parameter determining consumer acceptance and price. Meat tenderness is difficult to ensure in the global meat chain because the production systems are not always aiming at this purpose (ex.: cattle derived from milk production) and by the existence within the carcass of "tough" primals. Different methods can be used by the meat industry to improve meat tenderness each with its advantages and drawbacks. The application of hydrodynamic pressure or shockwaves has showed outstanding improvements by reducing the Warner Bratzler Shear Force by 25% or more. However, the technology has not penetrated into the market as first systems were based on the use of explosives and further developments seemed to lack the robustness to fulfill industrial requirements. The present paper describes the main challenges to construct a prototype for the continuous treatment of meat by shockwaves based on electrical discharges under water. Finally, improvements on the tenderness of meat by using the novel prototype are presented.Meat Science 04/2013; · 2.28 Impact Factor -
Article: Kinetics of the formation of radicals in meat during high pressure processing.
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ABSTRACT: The kinetics of the formation of radicals in meat by high pressure processing (HPP) has been described for the first time. A threshold for the radicals to form at 400MPa at 25°C and at 500MPa at 5°C has been found. Above this threshold, an increased formation of radicals was observed with increasing pressure (400-800MPa), temperature (5-40°C) and time (0-60min). The volume of activation (ΔV(#)) was found to have the value -17mlmol(-1). The energy of activation (E(a)) was calculated to be 25-29kJmol(-1) within the pressure range (500-800MPa) indicating high independence on the temperature at high pressures whereas the reaction was strongly dependent at atmospheric pressure (E(a)=181kJmol(-1)). According to the effect of the processing conditions on the reaction rate, three groups of increasing order of radical formation were established: (1) 55°C at 0.1MPa, (2) 500 and 600MPa at 25°C and 65°C at 0.1MPa, and (3) 700MPa at 25°C and 75°C at 0.1 MPa. The implication of the formation of radicals as initiators of lipid oxidation under HPP is discussed.Food Chemistry 10/2012; 134(4):2114-20. · 3.65 Impact Factor -
Article: Purification and characterisation of proteases A and D from Debaryomyces hansenii.
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ABSTRACT: The proteases A (PrA; EC. 3.4.23.25) and D (PrD; EC. 3.4.24.37) of Debaryomyces hansenii CECT 12487 were characterised after their isolation by fractionation with protamine sulfate followed by three chromatographic separations, which included two anion exchange and one gel filtration chromatographic steps. The whole procedures for PrA and PrD resulted in 1349 and 2560 purification-fold with a recovery yield of 1.4 and 1.3%, respectively. PrA was active at acidic-neutral pH with an optimum pH between 5.0 and 6.0. PrD was active at neutral-basic pH with an optimum pH between 7.0 and 8.0. The molecular mass of the native PrA was 55 kDa and (being) 42 kDa in denaturing conditions. Polyclonal-antibodies raised against PrA from Saccharomyces cerevisiae cross-reacted with the corresponding PrA from D. hansenii. PrD showed a native molecular mass of 68 kDa and 65 kDa in denaturing conditions. PrA was an aspartic protease effectively inhibited by pesptatin A while PrD was classified as a metallo protease inhibited by 1,10-phenantroline and affected by some divalent cations such as zinc, cadmium and magnesium. The homology of the PrA to the lisosomal cathepsin D suggests its possible participation in the ripening of fermented meat products.International Journal of Food Microbiology 06/2008; 124(2):135-41. · 3.33 Impact Factor -
Article: Protease (PrA and PrB) and prolyl and arginyl aminopeptidase activities from Debaryomyces hansenii as a function of growth phase and nutrient sources.
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ABSTRACT: The effects of nutrient sources and growth phase of Debaryomyces hansenii on the protease (PrA and PrB) and aminopeptidase (prolyl-[PAP] and arginyl-[AAP] aminopeptidases) activities were investigated. These activities were also monitored during growth on a whole sarcoplasmic muscle protein extract (WSPE) and on an equivalent medium but free of compounds under 10 kDa (SPE>10 kDa). The levels of specific protease and aminopeptidase activities were higher when cells were grown in urea and dipeptides than when grown in either ammonium or free amino acids as nitrogen sources. The level of each aminopeptidase (PAP or AAP) activity was preferentially induced by its own substrate (ProLeu or LysAla), suggesting a role in the utilization of exogenous peptides. Higher specific activities for all proteolytic enzymes were detected when using acetate as carbon source. The time course experiments carried out on urea or sarcoplasmic protein-containing media revealed an increase in all activities during transition and advanced stages of stationary phase of growth. In muscle protein extracts, the absence of low molecular mass nutrients (SPE>10 kDa) initially induced the production of PrA, PrB, and AAP activities, possibly involved in the breakdown of muscle oligopeptides.International Journal of Food Microbiology 04/2006; 107(1):20-6. · 3.33 Impact Factor -
Article: Sensory improvement of dry-fermented sausages by the addition of cell-free extracts from Debaryomyces hansenii and Lactobacillus sakei.
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ABSTRACT: The effects of the addition of a combined cell-free extract from Lactobacillus sakei and Debaryomyces hansenii (D+L) or just a D. hansenii cell-free extract (D) to the initial formulation of a dry-fermented sausage were evaluated. The differences found among batches in the main microbial populations, pH, moisture content and global proteolytic and lipolytic indexes (total free amino acids, non protein nitrogen, acidity and tiobarbituric acid index) were not significant. Only, the acidity value of batch D was significantly higher (p<0.05) than that of batch D+L. Thus, cell-free extract from D. hansenii accelerated the lipolysis. Moreover, there were some significant differences (p<0.05) in the amino acid profile and, especially, in the aroma profile. The combination D+L and D promoted the generation of volatile compounds derived from lipid oxidation and carbohydrate fermentation. In batch D, the production of volatile compounds derived from amino acid catabolism and microbial fermentation was also enhanced. The overall quality was improved by both treatments (D+L, D) and also the aroma by addition of the combination of extracts (D+L). It is concluded that the addition of cell-free extracts from D. hansenii and, particularly, D. hansenii plus L. sakei could be useful to improve the final quality of fermented sausages.Meat Science 03/2006; 72(3):457-66. · 2.28 Impact Factor
