THE SCIENCE OF CLEANING OF DAIRY FOULING LAYERS

The science underlying the removal of dairy fouling layers, and particularly the dissolution of proteinaceous deposits in alkaline solution, is relatively poorly understood even though this is a critical feature of many cleaning-in-place operations. We report key results from a series of investigations on heat-induced gels of β- lactoglobulin, the primary whey protein component in milk and whey foulant. These model systems were used to elucidate the reaction behaviour of gels and aggregates whereby the proteinaceous material is converted to a softer, swollen form that can then be removed by fluid shear or diffusion. We show that several features, such as the occurrence of an optimal pH for cleaning, can be related by analogy to the behaviour of synthetic polyelectrolyte polymers. The structure and history of the foulant, pH, ionic strength and salt concentration in the cleaning solution are all shown to be important factors in the chemistry of inter- and intra-molecular interactions explaining why it has been difficult to generalise about the mechanisms involved and to write simple models of their kinetics

A Dual Fluorescence–Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM–EPR Spectroscopy

Simultaneous visualization and concentration quantification of molecules in biological tissue is an important though challenging goal. The advantages of fluorescence lifetime imaging microscopy (FLIM) for visualization, and electron paramagnetic resonance (EPR) spectroscopy for quantification are complementary. Their combination in a multiplexed approach promises a successful but ambitious strategy because of spin label-mediated fluorescence quenching. Here, we solved this problem and present the molecular design of a dual label (DL) compound comprising a highly fluorescent dye together with an EPR spin probe, which also renders the fluorescence lifetime to be concentration sensitive. The DL can easily be coupled to the biomolecule of choice, enabling in vivo and in vitro applications. This novel approach paves the way for elegant studies ranging from fundamental biological investigations to preclinical drug research, as shown in proof-of-principle penetration experiments in human skin ex vivo

Análisis de la pernoctación sobre el nivel de satisfacción en un destino complementario: Caso Ronda

El crecimiento del sector turístico es actualmente una evidencia y, sobre todo, el aumento de la demanda de los destinos turísticos de interior, como oferta principal y complementaria. Este estudio de investigación pretende conocer el nivel de satisfacción generado por aquellos turistas que pernoctan en el destino complementario y si tiene influencia sobre su nivel de fidelización y recomendación del destino. Nuestro caso de estudio está focalizado en Ronda (España). El análisis de los resultados nos permitirá una mejor comprensión y conocimiento sobre el comportamiento de los turistas en los destinos complementarios, con la intención de proporcionar información a las entidades público-privadas para la toma de decisiones y mejoras de la calidad del servicio

Special Issue "selected Papers from the First International Food Operations & Processing Simulation Workshop - FoodOPS 2015 (September 21-23, 2015, Bergeggi, Italy)"

The first edition of the international Food Operations & Processing Simulation Workshop (FoodOPS2015) was held in Bergeggi, Italy, from September 21 to 23. The workshop was intended to extend a track managed in previous years (“Modelling and Simulation of Food Processing and Operations”) for the International Multidisciplinary Modelling & Simulation Multiconference (I3M) conference. The aim of the FoodOPS initiative was to promote the particular nature of the food sector, giving the possibility to present results and critical issues concerning processes design and operations management in food industry, using modelling and simulation as the methodological approach. Specific topics covered included:(i) Modelling and Simulation of food properties; (ii) Modelling and Simulation of food processing and (iii) Simulation of Food Supply Chain. . Food processing simulation grounds on the development of mathematical models to determine relationships between inputs and outputs of a given process, with the ultimate objective to gain insights for process improvements using the predictive capabilities of the models developed (Bakalis, Knoerzer and Fryer, 2015) ;). With the same aim, simulation models are used also for the analysis of food supply chains or food plants (Van der Vorst, Trompb, & van der Zeec, 2009). Food supply chains are becoming increasingly complex and their analysis includes issues from farm to fork, taking into consideration demand management, safety issues and sustainability of food sources for a growing population (Dani, 2015). This special issue collects the best papers presented at the first FoodOPS workshop during the 12th I3M conference, thus trying to propose the highest-quality contributions related to modelling and simulation in the food area. Overall, the first edition of the workshop received approx. 20 papers. Among them, 6 papers were accepted, after peer review, for publication in the special issue. The papers included in this special issue cover both food supply chain topics and food processing ones, all dealt with by simulation and modelling approaches. Among the papers dealing with food supply chain, the first paper, by Mosna et al., investigated a sustainability issue of the food supply chain. In particular, the authors evaluate, through the life cycle assessment (LCA) methodology, the suitability of flour food products wasted during the distribution phase of a food supply chain to be used as raw material for the production of animal feed. This is expected to avoid landfilling of food waste, which is nowadays the most adopted end of life option for flour food products. Their results show that the new scenarios lead to environmental benefits for all the considered impact categories. In the second paper, Laganà et al. analysed a vendor-managed inventory (VMI) coordination mechanism for the food supply chain. Their analysis is motivated by real issues arising in the food engineering field, relating to the timing and level of customer’s replenishment. Their VMI strategy is applied to a logistic system in the supermarket supply chain. The system includes a distribution centre and several retail outlets. An effective heuristic method for tackling the inventory-routing problem related to the coordination mechanism is discussed and numerical results are presented. Looking at the papers dealing with process modelling, Kotzur et al. studied the pneumatic conveying of food products. In particular, they developed a model to predict the breakage behaviour of particulate materials, considering two different particulate materials (salt and golden breadcrumbs) across a range of particle sizes, and evaluated the effect of different factors on the particle attrition. In the fourth paper, Armenzoni et al. developed a simulation model aimed at reproducing and optimizing the milking process of a cowshed, located near Parma (Italy), which provides milk to some dairy companies, for the production of Parmigiano Reggiano cheese. The ultimate goal of the analysis was to reduce the time required for milking operations, thus optimizing the whole management of the farm processes. The model developed makes use of real data collected from the direct observation of the farm and is validated by comparing the results provided with the real performance of the milking activities. Two alternative configurations of the farm layout were also analysed and evaluated through simulation. The fifth paper, by Rinaldi et al., investigated two different geometries of spargers for beverage carbonation. The geometries were modelled by means of CFD technique, taking into consideration three different flow rates. The first geometry presented a radial inlet of liquid food while the second one a tangential one. Calculation allowed to study the effect of fluid velocities on mixing and to identify the best solution. CFD simulation is used also in the last paper, by Spanu et al., who analysed the gas flow in a packaging machine used to fill polymeric capsules with coffee. The final goal of the analysis was to optimize the geometry of some mechanical components in the machine’s sealing station, to reduce the inert gas consumption achieving an O2 residual less than 1% by mass at the centre of the capsule. Thanks to the variety of topics addressed (i.e. process modelling, plant simulation and supply chain modelling), this special issue aims at providing the scientific community with valuable information and knowledge in the food area, with a particular focus on the use of modelling and simulation for decision support in that field. Obviously, the value-added of a special issue is only as good as the contributions of the manuscripts it receives, and the quality of the feedback provided by its reviewers. We are therefore very grateful to all the authors, who supported this special issue through their contributions, and we are indebted to the reviewers, who helped us in managing the papers received in a timely manner and provided useful and professional reports about the papers. Finally, we would like to express our gratitude to the Editor in Chief of International Journal of Food Engineering, which gave us the possibility of organizing the special issue and helped us in its successful completion

Probing the mechanisms limiting dissolution of whey protein gels during cleaning

The chemistry and kinetics of cleaning of whey protein gels in alkaline solutions is investigated by studying the dissolution of heat-induced β-lactoglobulin gels in sodium hydroxide. Below pH 13 dissolution is strongly influenced by the conditions under which the gel is formed. The dissolution rate decreases with extended gelation time and higher gelation temperature, and is strongly correlated to the fraction of crosslinked proteins present in the gel. Analysis of the cleavage kinetics shows that these reactions are not the main controlling step. At high dissolution pH (>13), relatively low dissolution rates are observed, which are almost independent of the gelation conditions. The dissolution rate decreases markedly in strong ionic solutions, most probably due to the reduction in swelling caused by the screening effect of the cations. The observations suggest that the disengagement of protein clusters is a key step in the dissolution process across the whole range of pH studied, 12.2 < pH < 14; this can explain the occurrence of an optimal NaOH concentration in cleaning. The dissolution of these gels at low temperatures and in the absence of erosion is limited by the disentanglement of protein aggregates through the swollen layer, and the cleavage of the disulphide bridges. The limiting mechanisms under other dissolution conditions are also discussed

Swelling and Dissolution of β-Lactoglobulin Gels in Alkali

It is well documented in the literature that during the dissolution of whey protein gels in alkali, the gels swell to a great extent. However, the relevance of the swelling step in the dissolution process of the protein gel remains unknown. In the present article we present a systematic study on the swelling of β-lactoglobulin gels at different alkaline pH and ionic strengths. The equilibrium swelling degree at different conditions has been modeled using a simple model developed for polyelectrolyte gels, modified to take into account the ionization of the residues in a protein. The model can describe the swelling behavior of the gels over a wide range of conditions, but it underpredicts the equilibrium swelling under conditions close to those when dissolution is observed. Dissolution is only noticeable above pH 11.5−12 and only for those gels that are swollen over a minimum degree, suggesting the existence of a dissolution threshold