Calorimetry and thermal analysis in food science : an updated review

Food science is a domain of life science. Applications of thermal analysis and calorimetry (TAC) to food products deal with many investigation targets spanning from the characterization of the systems at molecular and supramolecular level to the description of the microbial metabolism. Food products are multi-phase and multi-component metastable systems where several processes can occur simultaneously during the preparation process and the shelf life. One therefore has to disentangle various contributions to the overall instrumental outputs, using appropriate data treatments and kinetic models, and/or results from other experimental approaches. The paper reports an updated survey of TAC applications to food products through specific examples of data treatments

Water activity in biological systems. A review

Water deserves a major attention by researchers dealing with biological systems and related materials, like food, since it is ubiquitous and can be used like a \u201cnative\u201d probe to garner information about the hosting system, provided it may be freely displaced across. Its thermodynamic potential, namely, the water activity, aW, is related to that of the other compounds of the system considered via the Gibbs-Duhem relationship refl ecting the extent of the residual availability of water to solvate further solutes and sustain the molecular mobility of the bio-polymeric compounds. As for the experimental approaches to aW, this short review re-addresses the reader to other publications, while devotes a section to the Knudsen thermo-gravimetry that was used by the authors to determine the desorption isotherms of many food systems and related aqueous compounds. The paper remarks the importance of a preliminary assessment of water mobility and recalls the concept of \u201ccritical aW\u201c that takes into account the reduced mobility of water molecules in the vicinity of the glass transition. This opens the question of the reliability of sorption isotherms which encompass a wide aW range and the interpretation of the observed adsorption/desorption hysteresis. The multi-phase character of many biological systems is another issue of interest related to the reliability of the experimental approaches to aW. As examples of the role of aW on the stability of bio-systems and on the practice of a technological treatment, protein unfolding and osmo-dehydration of fruit pulps are reported

An Operations management approach for radiology services

This paper focus on the application of Operations Management techniques in the context of radiological and diagnostic imaging services provision. More specifically, the outpatient appointment scheduling problem for MRI diagnostic imaging services in a radiology clinics is approached and solved taking into account set-up time minimization. This is pursued trough the design of an innovative system for the on-line assignment of appointments for specific diagnostic imaging scans. An appointment rule, a patient classification and an heuristic procedure for the booking process are defined in order to better manage uncertainty and improve system performance. The proposed approach was validated on the case of a diagnostic centre of Alliance Medical, a primary multinational company in the field of diagnostic imaging services

Depannage and other maintenance strategies for transportation fleets

This paper addresses the problem of designing a depannage service network for freight transportation fleets in order to fill up an evident gap in Operations Management literature. As a matter of fact, breakdowns have a significant impact on service level and an efficient and effective assistance service is needed in order to guarantee competitive advantage. Aiming at laying the foundations for further research on modelling and solving the considered problem, a literature review is performed for identifying analogies with other problems, already approached in the past, and stating the problem. Finally, parameters, decision variables and objective function that should be considered for modelling and solving the problem are proposed, trying to stimulate the discussion on a new research theme and, more specifically, on the integration of decisions at strategic, tactical and operational level into a systemic model

Simplifying the Virtual Safety Stock formula

The paper deepen the analysis into the Virtual Safety Stock theory, which is an approach intended to drastically reduce safety inventory levels exploiting the eventual time lag between the moment when a product is ordered and the time the product needs to be available, while preserving the same performance as a production system that operates with physical safety stock. The original virtual safety stock definition embeds two major problems: a double Gaussian integral in the formulation together with the heritage of the unrealistic assumptions already included in the earliest Hadley and Whitin’s safety stock conception. This paper describes an alternative approach in which the virtual safety stock is defined with a closed-form expression much easier to compute and use in operations management practice

Microbioreactor (micro-Matrix) potential in aerobic and anaerobic conditions with different industrially relevant microbial strains

Microscale fermentation systems are important high throughput tools in clone selection, and bioprocess set up and optimization, since they provide several parallel experiments in controlled conditions of pH, temperature, agitation, and gas flow rate. In this work we evaluated the performance of biotechnologically relevant strains with different respiratory requirements in the micro-Matrix microbioreactor. In particular Escherichia coli K4 requires well aerated fermentation conditions to improve its native production of chondroitin-like capsular polysaccharide, a biomedically attractive polymer. Results from batch and fed-batch experiments demonstrated high reproducibility with those obtained on 2 L reactors, although highlighting a pronounced volume loss for longer-term experiments. Basfia succiniciproducens and Actinobacillus succinogenes need CO2 addition for the production of succinic acid, a building block with several industrial applications. Different CO2 supply modes were tested for the two strains in 24 h batch experiments and results well compared with those obtained on lab-scale bioreactors. Overall, it was demonstrated that the micro-Matrix is a useful scale-down tool that is suitable for growing metabolically different strains in simple batch process, however, a series of issues should still be addressed in order to fully exploit its potential

Knudsen thermogravimetry approach to the thermodynamics of aqueous solutions

The use of isothermal TGA with Knudsen-like cells allows determination ofthe thermodynamic activity of water, aW. The typical experiment implies aslow dehydration ofthe aqueous solution atconstant temperature in dynamic vacuum conditions.The method isalternative to the classical isopiestic approach and offers the advantage ofacontinuous record onincreasing the solute concentration.These data can be directly treated according tothe classical thermodynamic relationships drawn from the Gibbs\u2013Duhem expression to evaluate the activity and osmotic coefficientofthe aqueous solutions ofelectrolytes and non-electrolytes, and,inthe case ofelectrolytes,allow determination ofsolubility ofthe solute.Discrepancies with respect to the literature data are observed when the viscosity ofthe systems becomes too high, asinthe case ofsugars with avery large solubility.Such amismatch may however beaccounted for either slowing the dehydration rate with use ofanarrower Knudsen orifice,orcorrecting the experimental aW with a calibration curve. The same approach can beapp lied tonon-aqueous solutions

Timely Supplementation of Hydrogels Containing Sulfated or Unsulfated Chondroitin and Hyaluronic Acid Affects Mesenchymal Stromal Cells Commitment Toward Chondrogenic Differentiation

Mesenchymal stromal cells (MSCs) are currently used for cartilage cell therapy because of their well proven capacity to differentiate in chondrocytes. The advantage of MSC-based therapy is the possibility of producing a high number of chondrocytes for implants. The transplant procedure, however, has some limitations, since MSCs may produce non-functional chondrocytes. This limit has been challenged by cultivating MSC in media with hydrogels containing hyaluronic acid (HA), extractive chondroitin sulfate (CS), or bio-fermentative unsulphated chondroitin (BC) alone or in combination. Nevertheless, a clear study of the effect of glycosaminoglycans (GAGs) on chondrocyte differentiation is still lacking, especially for the newly obtained unsulfated chondroitin of biotechnological origin. Are these GAGs playing a role in the commitment of stem cells to chondrocyte progenitors and in the differentiation of progenitors to mature chondrocytes? Alternatively, do they have a role only in one of these biological processes? We evaluated the role of HA, CS, and – above all – BC in cell commitment and chondrocyte differentiation of MSCs by supplementing these GAGs in different phases of in vitro cultivation. Our data provided evidence that a combination of HA and CS or of HA and BC supplemented during the terminal in vitro differentiation and not during cell commitment of MSCs improved chondrocytes differentiation without the presence of fibrosis (reduced expression of Type I collagen). This result suggests that a careful evaluation of extracellular cues for chondrocyte differentiation is fundamental to obtaining a proper maturation process

Antioxidant and hypolipidemic activity of açai fruit makes it a valuable functional food

Several plant extracts are acquiring increasing value because of their antioxidant activity and hypolipidemic properties. Among them, great interest has been recently paid to açai fruit as a functional food. The aim of this study was to test the ability of açai extract in reducing oxidative stress and modulating lipid metabolism in vitro using different cell models and different types of stress. In fact, lipid peroxidation as evaluated in a HepG2 model was reduced five-fold when using 0.25 µg/mL of extract, and it was further reduced (20-fold) with the concentration increase up to 2.5 µg/mL. With the non alcoholic fatty liver disease (NAFLD)in vitro model, all concentrations tested showed at least a two-fold reduced fat deposit. In addition, primary adipocytes challenged with TNF-α under hypoxic conditions to mimic the persistent subcutaneous fat, treated with açai extract showed an approximately 40% reduction of fat deposit. Overall, our results show that açai is able to counteract oxidative states in all the cell models analysed and to prevent the accumulation of lipid droplets. No toxic effects and high stability overtime were highlighted at the concentrations tested. Therefore, açai can be considered a suitable support in the prevention of different alterations of lipid and oxidative metabolism responsible for fat deposition and metabolic pathological conditions

Microbiological-chemical sourced chondroitin sulfates protect neuroblastoma SH-SY5Y cells against oxidative stress and are suitable for hydrogel-based controlled release

Chondroitin sulfates (CS) are a class of sulfated glycosaminoglycans involved in many biological processes. Several studies reported their protective effect against neurodegenerative conditions like Alzheimer’s disease. CS are commonly derived from animal sources, but ethi-cal concerns, the risk of contamination with animal proteins, and the difficulty in controlling the sulfation pattern have prompted research towards non-animal sources. Here we exploited two microbiological-chemical sourced CS (i.e., CS-A,C and CS-A,C,K,L) and Carbopol 974P NF/agarose semi-interpenetrating polymer networks (i.e., P.NaOH.0 and P.Ethanol.0) to set up a release system, and tested the neuroprotective role of released CS against H2 O2-induced oxidative stress. After assessing that our CS (1–100 µM) require a 3 h pre-treatment for neuroprotection with SH-SY5Y cells, we evaluated whether the autoclave type (i.e., N-or B-type) affects hydrogel viscoelastic properties. We selected B-type autoclaves and repeated the study after loading CS (1 or 0.1 mg CS/0.5 mL gel). After loading 1 mg CS/0.5 mL gel, we evaluated CS release up to 7 days by 1,9-dimethylmethylene blue (DMMB) assay and verified the neuroprotective role of CS-A,C (1 µM) in the supernatants. We observed that CS-A,C exhibits a broader neuroprotective effect than CS-A,C,K,L. Moreover, sulfation pattern affects not only neuroprotection, but also drug release