No abstract

Due to the high intensification of poultry production in recent years, white chicken breast striping is one of the most frequently seen myopathies. The aim of this research was to develop a spectrophotometry-based sensor to detect white striping physiopathy in chicken breast meat in whole chicken carcasses with skin. Experiments were carried out using normal and white striping breasts. In order to understand the mechanism involved in this physiopathy, the different tissues that conform each breast were analyzed. Permittivity in radiofrequency (40 Hz to 1 MHz) was measured using two different sensors; a sensor with two flat plates to analyze the whole breast with skin (NB or WSB), and a two needles with blunt-ended sensor to analyze the different surface tissues of the skinless breast. In the microwave range (500 MHz to 20 GHz), permittivity was measured as just was described for the two needles with blunt-ended sensor. Moreover, fatty acids composition was determined by calorimetry techniques from −40 °C to 50 °C at 5 °C/min after previously freeze-drying the samples, and pH, microstructure by Cryo-SEM and binocular loupe structure were also analyzed. The results showed that the white striping physiopathy consists of the partial breakdown of the pectoral muscle causing an increase in fatty acids, reducing the quality of the meat. It was possible to detect white striping physiopathy in chicken carcasses with skin using spectrophotometry of radiofrequency spectra.

Previous works show that the addition of trehalose and gums in β-galactosidase (lactase) Ca(II)-alginate encapsulation systems improved its intrinsic stability against freezing and dehydration processes in the pristine state. However, there is no available information on the evolution in microstructure due to the constraints imposed by the operational conditions. The aim of this research is to study the time course of microstructural changes of Ca(II)-alginate matrices driven by the presence of trehalose, arabic and guar gums as excipients and to discuss how these changes influence the diffusional transport (assessed by LF-NMR) and the enzymatic activity of the encapsulated lactase. The structural modifications at different scales were assessed by SAXS. The incorporation of gums as second excipients induces a significant stabilization in the microstructure not only at the rod scale, but also in the characteristic size and density of alginate dimers (basic units of construction of rods) and the degree of interconnection of rods at a larger scale, improving the performance in terms of lactase activity.

This research develops a thermodynamic model able to describe mass transfer and kiwifruit deformation during OD and using PEF as a pre-treatment. Moreover, a deep analysis of active and passive mechanisms transports affected by PEF was done. The results of this research have demonstrated that PEF used as a pre-treatment of OD accelerated water mass transfer and removes part of the fruit natives electrolytes, affecting the functionality of the cell homeostasis system. Therefore, the present work represents an opportunity in the design of new candying products (less calories and sweetness).

β-galactosidase (lactase) is a widely used enzyme in food industry; however, it has low stability against thermal and mechanical treatments. Due to this, the purpose of present research was to analyze the encapsulation of lactase in alginate-Ca(II) beads in order to maintain its enzymatic activity towards freezing, freezing/thawing and storage. Also, the effect of the addition of trehalose, arabic and guar gums and its influence in the microstructure as well as in thermal properties and molecular mobility were studied. Lactase was successfully encapsulated in alginate-Ca(II) beads and the inclusion of trehalose was critical for activity preservation towards treatments, being improved in guar gum-containing systems. The gums increased the Tm' values which represents a valuable technological improvement. Finally, the presence of secondary excipients affected the microstructure, showing rods with smaller outer diameter and with lower compactness than alginate-Ca(II) beads. Also, beads composition greatly affects the size, shape and relaxations times.