ABSTRACT
The objective of this work was to evaluate the influence of vacuum application and partial replacement of NaCl with KCl in the manufacturing of ready-to-eat charque with low sodium content. The application of four vacuum pulses (4VP) resulted in greater salt reduction and lesser water gain when compared to the desalting process conducted at atmospheric pressure (Patm). In addition, the vacuum-assisted desalting contributed to a more homogeneous salt distribution in the product. The time required for the samples to reach an approximate NaCl concentration of 2.5% in the desalting stage was 48 h, regardless of the process conditions. The initial Na+ concentration was reduced by 50% with the replacement of NaCl with KCl in both process conditions (either Patm or 4VP) when compared to charque traditionally desalted.
ABSTRACT
The aim of this study was to compare the vacuum and air cooling of cooked chicken breast samples arranged in stacks with one, two and three layers (1 kg per layer). The cooling rate obtained with vacuum cooling was approximately three times faster than that of air cooling. Moreover, a more homogeneous cooling was obtained with vacuum cooling, with similar temperature reductions for samples at different positions of the stack. On the other hand, vacuum cooling led to mass losses of 11-12%, while air cooling led to losses of 7-8%. The counts of mesophiles and psychrophiles of the vacuum-cooled samples were lower than those observed for air-cooled samples after ten days of product storage. Thus, the results presented in this work illustrate the potential benefits and disadvantages of the vacuum cooling technique as compared to the air cooling, especially for the processing of small meat cuts.
ABSTRACT
The addition of nanoclay or cellulose fibers has been presented in the literature as a suitable alternative for reinforcing starch films. The aim of the present work was to evaluate the effect of the simultaneous incorporation of nanoclay (bentonite) and cellulose fibers on the mechanical and water barrier properties of the resultant composite-films. Films were prepared by casting with 3% in weight of cassava starch, using glycerol as plasticizer (0.30 g per g of starch), cellulose fibers at a concentration of 0.30 g of fibers per g of starch and nanoclay (0.05 g clay per g starch and 0.10 g clay per g starch). The addition of cellulose fibers and nanoclay increased the tensile strength of the films 8.5 times and the Young modulus 24 times but reduced the elongation capacity 14 times. The water barrier properties of the composite-films to which bentonite and cellulose fibers were added were approximately 60% inferior to those of starch films. Diffractograms showed that the nanoclay was intercalated in the polymeric matrix. These results indicate that the simultaneous addition of bentonite and cellulose fibers is a suitable alternative to increase the tensile strength of the films and decrease their water vapor permeabilities.
Subject(s)
Bentonite/chemistry , Cellulose/chemistry , Food Packaging/methods , Starch/chemistry , Elastic Modulus , Microscopy, Electron, Scanning , Models, Theoretical , Nanoparticles/chemistry , Permeability , Plasticizers/chemistry , Steam , Tensile StrengthABSTRACT
Vacuum impregnation (VI) is a food processing method by which air and native solution are removed from porous spaces within a food and replaced by an external solution. In this study, an experimental device based on a previous design was built, including some modifications, in order to investigate the dynamics of the VI process. The device measured the net force exerted by a food sample submitted to the VI process using a load cell. The influence of the vacuum level and sample geometry was well quantified by the experimental procedure and the modified equipment using apple samples (Fuji var.) as a food model. The results indicated that the experimental device proposed in this study, together with the suggested procedure, is a useful tool to investigate the dynamics of VI processes. It is robust and versatile, and has the advantage of not requiring the determination of the water evaporated during the VI process in a separate experiment, which represents an increase in the accuracy of the results.
