Influence of enzymes and technology on virgin olive oil composition

This work aims at presenting the state-of-the-art about the influence of the activity of olive endogenous enzymes, as well as of the application of adjuvants in olive oil technology, discussing their influence on the composition of virgin olive oil, especially in phenols and volatile compounds.     

A Scalable Approach for Variational Data Assimilation

Data assimilation (DA) is a methodology for combining mathematical models simulating complex systems (the background knowledge) and measurements (the reality or observational data) in order to improve the estimate of the system state (the forecast). The DA is an inverse and ill posed problem usually used to handle a huge amount of data, so, it is a large and computationally expensive problem. Here we focus on scalable methods that makes DA applications feasible for a huge number of background data and observations. We present a scalable algorithm for solving variational DA which is highly parallel. We provide a mathematical formalization of this approach and we also study the performance of the resulted algorithm.     

Improvements in the production of Yb:YAG transparent ceramic materials: Spray drying optimisation

Spray drying parameters have been optimized for the preparation of granulated stoichiometric mixture of oxides. These oxides are used in the production of Yb:YAG laser grade ceramic materials by reactive sintering. The selected compositions were Yb_0.294Y_2.706Al₅O₁₂ and Yb_0.03Y_2.97Al₅O₁₂, i.e. YAG doped with 9.8 and 1.0 at% of Yb with respect to the overall Y + Yb amount. The influence of solid content, drying medium flux, temperature and aspiration rate of the spray drying process on the transparency of the sintered materials has been evaluated. Sintering was conducted under high vacuum and clean atmosphere in the temperature range of 1650-1735 °C and with a soaking time of 16 h. SEM analysis of the microstructure of granulated powders and sintered materials, as well as the transmittance measurement, were used as tools to guide the selection of the best spray drying parameters.     

Sorption isotherms and thermodynamic properties of grated Parmesan cheese

This study focuses on isotherms, isosteric heat of sorption and enthalpy–entropy mechanism of water sorption of grated Parmesan cheese at simulating conditions of storage and drying processes. Isotherms were determined by gravimetric method using different saturated salt solutions. Samples were submitted to different temperatures, and several models were used to fit experimental data, GAB and modified GAB being those which best represented experimental data in all temperature ranges. The isosteric heat of sorption was calculated by Clausius–Clapeyron equation, and higher values of integral isosteric sorption heat were verified for storage temperatures. Besides it, both conditions showed higher values of sorption heat corresponding to low water content. This phenomenon was supported by the enthalpy–entropy compensation study, which demonstrated a higher spontaneity of water sorption for storage temperatures, confirming that the lower the water content of food products is, the stronger the intermolecular bonds of water are.