MONTE CARLO SIMULATION OF ORANGE JUICE PECTINMETHYLESTERASE (PME) INACTIVATION BY COMBINED PROCESSES OF HIGH HYDROSTATIC PRESSURE (HHP) AND TEMPERATURE

The variability effect of kinetic data was investigated by simulating orange juice pectinmethylesterase (PME) inactivation with combined processes of high hydrostatic pressure-temperature (100-500 MPa; 20-40°C), applying the Monte Carlo method. Parameters from an Eyring-Arrheniius model that predicts the kinetic inactivation constant (k) as a function of both pressure and temperature were found reported in literature and considered for the analysis. The kinetic analysis was carried out with both Monte Carlo simulations and the traditional deterministic approach, which only considers mean values and does not take into account data variability. Simulations with the Monte Carlo method demonstrated that residual PME activity predicted with deterministic calculations greatly differed from those obtained through confidence intervals of simulated probabilistic distributions. Mean values overrated residual enzyme activity from 4% to ≈2,800% when compared to the 95% confidence intervals generated with the Monte Carlo method. This divergence augmented as both applied pressure and temperature levels increased. Similar risk analysis projects can be further developed to establish the foundations for future food processing regulations of enzymatic control.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Universidad Autónoma Metropolitana Unidad Iztapalapa and can be found at: http://www.redalyc.org/revista.oa?id=620.Keywords: Process simulation, High hydrostatic pressure (HHP), Orange juice, Pectinmethylesterase (PME), Monte CarloKeywords: Process simulation, High hydrostatic pressure (HHP), Orange juice, Pectinmethylesterase (PME), Monte Carl

Utilization of galactomannan from Gleditsia triacanthos in polysaccharide-based films : effects of interactions between film constituents on film properties

The objective of this work was to evaluate the effect of the concentrations of Gleditsia triacanthos galactomannan and glycerol and the presence of corn oil in the physical properties of edible films. The influence of interactions between those constituents on films' permeability to gases (water vapour, CO2 and O2), solubility in water, mechanical properties and colour was evaluated. The effects of those variables were analysed according to a 23 factorial design; regression coefficients were used to understand the influence of each variable (factor) on the studied properties, and a multifactor model was developed. Results show that galactomannan concentration is the most significant factor affecting the studied properties; moreover, the increase of plasticizer concentration and the presence of oil showed to be the most influent in the particular cases of solubility and transport properties (water vapour permeability and O2 permeability), respectively. These results show that galactomannan films' properties can be tailored to allow their use as alternative to non-biodegradable, non-edible packaging materials.The author M. A. Cerqueira is recipient of a fellowship from Fundacao para a Ciencia e Tecnologia (FCT, SFRH/BPD/72753/2010) and B. W. S. Souza is a recipient of a fellowship from the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior, Brazil (Capes, Brazil)

Effects of interactions between the constituents of chitosan-edible films on their physical properties

The main objective of this work was to evaluate the effect of chitosan and plasticizer concentrations and oil presence on the physical and mechanical properties of edible films. The effect of the film constituents and their in-between interactions were studied through the evaluation of permeability, opacity and mechanical properties. The effects of the studied variables (concentrations of chitosan, plasticizer and oil) were analysed according to a 2 3 factorial design. Pareto charts were used to identify the most significant factors in the studied properties (water vapour, oxygen and carbon dioxide permeability; opacity; tensile strength; elongation at break and Young's modulus). When addressing the influence of the interactions between the films' constituents on the properties above, results show that chitosan and plasticizer concentrations are the most significant factors affecting most of the studied properties, while oil incorporation has shown to be of a great importance in the particular case of transport properties (gas permeability), essentially due to its hydrophobicity. Water vapour permeability values (ranging from 1. 62 × 10 -11 to 4. 24 × 10 -11 g m -1 s -1 Pa -1) were half of those reported for cellophane films. Also the mechanical properties (tensile strength values from 0. 43 to 13. 72 MPa and elongation-at-break values from 58. 62% to 166. 70%) were in the range of those reported for LDPE and HDPE. Based on these results, we recommend the use of 1. 5% (w/w) chitosan concentration to produce films, where the oil and plasticizer proportions will have to be adjusted in a case-by-case basis according to the use intended for the material. This work provides a useful guide to the formulation of chitosan-based film-forming solutions for food packaging applications.The author MA Cerqueira is a recipient of a fellowship from Fundacao para a Ciencia e Tecnologia (FCT, SFRH/BD/23897/2005) and BWS Souza is a recipient of a fellowship from the Coordenacao Aperfeicoamento de Pessoal de Nivel Superior, Brazil (Capes, Brazil)

MEGARA, the new intermediate-resolution optical IFU and MOS for GTC: getting ready for the telescope

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma that is being built by a Consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). The instrument is currently finishing AIV and will be sent to GTC on November 2016 for its on-sky commissioning on April 2017. The MEGARA IFU fiber bundle (LCB) covers 12.5x11.3 arcsec2 with a spaxel size of 0.62 arcsec while the MEGARA MOS mode allows observing up to 92 objects in a region of 3.5x3.5 arcmin2 around the IFU. The IFU and MOS modes of MEGARA will provide identical intermediate-to-high spectral resolutions (RFWHM~6,000, 12,000 and 18,700, respectively for the low-, mid- and high-resolution Volume Phase Holographic gratings) in the range 3700-9800ÅÅ. An x-y mechanism placed at the pseudo-slit position allows (1) exchanging between the two observing modes and (2) focusing the spectrograph for each VPH setup. The spectrograph is a collimator-camera system that has a total of 11 VPHs simultaneously available (out of the 18 VPHs designed and being built) that are placed in the pupil by means of a wheel and an insertion mechanism. The custom-made cryostat hosts a 4kx4k 15-μm CCD. The unique characteristics of MEGARA in terms of throughput and versatility and the unsurpassed collecting are of GTC make of this instrument the most efficient tool to date to analyze astrophysical objects at intermediate spectral resolutions. In these proceedings we present a summary of the instrument characteristics and the results from the AIV phase. All subsystems have been successfully integrated and the system-level AIV phase is progressing as expected

Oxygen and Carbon Dioxide Permeability of Wheat Gluten Film: Effect of Relative Humidity and Temperature

International audienc

Ethylene permeability of wheat gluten film as a function of temperature and relative humidity

Corresponding author. [email protected] audienceThe ethylene permeability of a wheat gluten filmwas studied as a function of relative humidity (RH) (from 0 to 100%) and temperature (from 3 to 45◦C), using response–surface methodology. Ethylene permeability values ranged in a wide scale from 1 to 3098 amolm−1 s−1 Pa−1. The exponential effect of relative humidity on ethylene p ermeability was related to the boosting effect of increasing film water content on ethylene solubility and diffusivity in the hydrated film. The temperature dependency of the ethylene permeability data showed a strong disruption near the glass transition temperature value (25 ◦C at 75% RH). The glass transition phenomenon and its effect on chain mobility could explain the interesting synergic effect of both temperature and relative humidity on ethylene permeability of wheat gluten film

Gas and solute barrier properties of wheat gluten films: Application to the design of "active biopackagings"

National audienc

Impregnation Techniques for Aroma Enrichment of Apple Sticks: A Preliminary Study

The food industry often utilizes flavor-enriched, semifinished food products as ingredients in more complex preparations. To the best of our knowledge, there are no methods to produce minimally processed food items to which flavorings have been added. In this investigation, apple sticks were enriched with a green apple aroma using different techniques. In particular, vacuum impregnation (VI), ultrasound technology (USI), and the combination of these two techniques (VUSI) were compared with atmospheric pressure impregnation (AI). An isotonic solution of fructose containing ascorbic acid and green apple flavoring was used for impregnation of apple sticks. Different treatment times (2.5, 5.0, and 12.5 min) were investigated, and the relative amount of the major compounds of impregnation flavoring was recorded. Significant differences between treatments were detected: VI and VUSI gave the highest aroma enrichment at 5.0 min of treatment. Different impregnation behaviors were recorded for alcohols and esters: the former increased even after 5.0 min of treatment, and the other components increased until 5.0 min and then decreased, mainly when ultrasound was applied (USI and VUSI). Some possible explanations of these results are proposed, although additional studies are needed to explain the mechanisms involved

L\u2019impregnazione sotto vuoto come tecnica di funzionalizzazione della frutta: studio sulle mele cotogne.

Gli alimenti funzionali sono prodotti capaci di fornire un beneficio salutistico superiore a quello dovuto ai nutrienti tradizionali che contengono. Ad ora non esiste una definizione univoca di alimenti funzionali, ma tra quelle impiegate in passato e sicuramente comprese in questa categoria si possono citare gli alimenti arricchiti e quelli fortificati. I primi sono addizionati di nutrienti naturalmente presenti nel prodotto stesso, gli alimenti arricchiti, invece, sono addizionati di componenti non presenti nell\u2019alimento originario 1-2. L\u2019impregnazione sottovuoto \ue8 una tecnologia ampiamente impiegata nella produzione di alimenti arricchiti e fortificati. Tale tecnica consiste nell\u2019immersione dell\u2019alimento in una soluzione contenente il componente del quale lo si vuole arricchire e, grazie all\u2019applicazione del vuoto, viene facilitato l\u2019ingresso della soluzione all\u2019interno della matrice alimentare. Due sono i meccanismi coinvolti nell\u2019impregnazione sottovuoto, la deformazione dei pori dovuta all\u2019applicazione del vuoto ed il rilassamento che si instaura a partire dal momento della rottura del vuoto. L\u2019ingresso della soluzione all\u2019interno della matrice alimentare \ue8 dovuto anche al meccanismo idrodinamico, generato dal differenziale di pressione osmotica esistente tra l\u2019interno e l\u2019esterno del prodotto. L\u2019efficienza dell\u2019impregnazione \ue8 influenzata da numerose variabili, legate sia alle propriet\ue0 della soluzione, quali viscosit\ue0, densit\ue0, tensione superficiale, sia alla microstruttura del prodotto, come porosit\ue0 e deformabilit\ue0, ed infine alle variabili di processo quali la pressione di vuoto, il tempo di applicazione del vuoto e quello di rilassamento. La mela cotogna (Cidonia oblonga Miller), grazie all\u2019elevato contenuto di composti fenolici, presenta gi\ue0 un valore salutistico elevato, ma \ue8 scarsamente consumata fresca a causa della significativa astringenza legata all\u2019elevato contenuto di tannini. In questo studio preliminare sono state valutate le propriet\ue0 di impregnazione della mela cotogna, con soluzioni di glucosio, con la finalit\ue0 di ridurre la percezione dell\u2019astringenza, incrementandone l\u2019impiego fresco, oggi poco rilevante, in prodotti ready to eat, a base di frutta. La stessa metodica pu\uf2 essere utilizzata impiegando sciroppi di glucosio arricchiti di sostanze, a polarit\ue0 simile, dotate di propriet\ue0 nutraceutiche, come calcio e zinco3, allo scopo di associare il miglioramento delle caratteristiche organolettiche del prodotto all\u2019arricchimento in sostanze fisiologicamente attive. Bibliografia 1 Gras M.L. et al., Journal of Food Engineering 2003, 56, 279-284. 2 Siro, J. et al., Appetite 2008, 51, 456-467. 3 Xie J. e Zhao Y., International Journal of Food Sciences and Nutrition 2003, 54, 387-398