SIR97 is the integration of two programs, SIR92 and CAOS, the first devoted to the solution of crystal structures by direct methods, the second to refinement via least-squares–Fourier procedures. Several new features have been introduced in SIR97 with respect to the previous version, SIR92: greater automatization, increased efficiency of the direct methods section, and a powerful graphics interface. The program also provides publication tables and CIF files.

SIR97: a new tool for crystal structure determination and refinement

Consumers increasingly demand convenience foods of the highest quality in terms of natural flavor and taste, and which are free from additives and preservatives. This demand has triggered the need for the development of a number of nonthermal approaches to food processing, of which high-pressure technology has proven to be very valuable. A number of recent publications have demonstrated novel and diverse uses of this technology. Its novel features, which include destruction of microorganisms at room temperature or lower, have made the technology commercially attractive. Enzymes and even spore forming bacteria can be inactivated by the application of pressure-thermal combinations, This review aims to identify the opportunities and challenges associated with this technology. In addition to discussing the effects of high pressure on food components, this review covers the combined effects of high pressure processing with: gamma irradiation, alternating current, ultrasound, and carbon dioxide or anti-microbial treatment. Further, the applications of this technology in various sectors— fruits and vegetables, dairy, and meat processing—have been dealt with extensively. The integration of high-pressure with other matured processing operations such as blanching, dehydration, osmotic dehydration, rehydration, frying, freezing / thawing and solid-liquid extraction has been shown to open up new processing options. The key challenges identified include: heat transfer problems and resulting non-uniformity in processing, obtaining reliable and reproducible data for process validation, lack of detailed knowledge about the interaction between high pressure, and a number of food constituents, packaging and statutory issues.

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Opportunities and Challenges in High Pressure Processing of Foods

Size, Shape, Volume, and Related Physical Attributes.- Rheological Properties of Foods.- Thermal Properties of Foods.- Electromagnetic Properties.- Water Activity and Sorption Properties of Foods.- Surface Properties of Foods.

Physical properties of foods

A modern definition for whole powder pattern decomposition WPPD methods would be that they simultaneously have to refine the unit-cell parameters and extract the best estimations of the Bragg peak intensities from a complete diffractogram. This is done very fast nowadays, irrespective of the number of Bragg peaks present in a powder diffraction pattern, but we did not attain this comfortable situation without some past efforts. The WPPD methods’ introduction occurred slowly and progressively thanks to the increase in computer power, the improvements in graphical user interfaces, the diffractometer data digitalization, the availability of synchrotron and neutron radiation, and last but not least, the proposition of new algorithms. Innovations were not instantly accepted this being true for all the whole powder pattern fitting methods including the Rietveld and the decomposition methods or could not be applied immediately to every radiation source or diffractometer the hardware before adaptations made by an essential category of crystallographers being conceivers and developers of the software. Ancestors of the WPPD methods extracted peak intensities without the cell restraint, so that each peak position was a parameter to be refined as well as the peak intensity, the peak shape and its width. This is still useful if the aim is the search for the peak positions for indexing, though derivative methods can make that peak-position-hunting job faster. Taking advantage of the indexing see a recent review paper by Bergmann et al. 2004, new WPPD methods, applying cell restraint to the peak position, opened the door to a long list of new possibilities and applications including first indexing confirmation which are detailed in this paper. However, only some selected application references will be provided because the number of papers involved is quite high and increasing more than 2000 texts specify the use of WPPD methods. Contributions from Rennes by Louer’s group from 1987 to 1993 will be especially enlightened, not forgetting the other players during that same time, restraining generally to the structure determinations by powder diffractometry SDPD applications published in the early stages of this retrospection because the subsequent activity increased too considerably, by more than 850 SDPDs in the last ten years. If only a partial review of applications can be given, the evolution of the methods will be discussed as completely as possible.

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Whole powder pattern decomposition methods and applications: A retrospection

Layered metal phosphates and phosphonates : from crystals to monolayers

Effects of high pressure treatment (100–200 MPa) at low temperature on turbot (Scophthalmus maximus) muscle

The formulation of gluten-free bread, which will be suitable for patients with coeliac disease, was optimized to provide bread similar to French bread. The effects of the presence of hydrocolloids and the substitution of the flour basis by flour or proteins from different sources were studied. The added ingredients were (1) hydrocolloids (carboxymethylcellulose [CMC], guar gum, hydroxypropylmethylcellulose [HPMC], and xanthan gum), and (2) substitutes (buckwheat flour, whole egg powder, and whey proteins). The bread quality parameters measured were specific volume, dry matter of bread, crust color, crumb hardness, and gas cell size distribution. Specific volume was increased by guar gum and HPMC. Breads with guar gum had color characteristics similar to French bread. Hardness decreased with the addition of hydrocolloids, especially HPMC and guar. Breads with guar gum had the most heterogeneous cell size distribution, and guar gum was therefore selected for further formulations. Bread prepared with buckwheat flour had improved quality: an increased specific volume, a softer texture, color characteristics, and gas-cell size distribution similar to French bread. Bread with 1.9% guar gum (w/w, total flour basis) and 5% buckwheat flour (of all flours and substitutes) mimicked French bread quality attributes.

Optimization of Gluten-Free Formulations for French-Style Breads

Freezing and ice crystals formed in a cylindrical food model: part I. Freezing at atmospheric pressure

Pressure shift freezing (PSF, 200 MPa, 18 C) of whole Norway lobster was compared with air-blastfreezing and with pressurized samples (200 MPa, 5 C) without freezing for its effect on the quality in texture,structure, water, and salt soluble protein extractabilities. For the pressurized Norway lobster meat either with PSF orwithout freezing, toughness increased while salt soluble protein extractability decreased. Conversely, air-blast freez-ing did not affect the textural quality of the meat. Scanning electron micrographs showed that PSF yielded smallerice crystals than air-blast freezing.Key Words: high pressure, pressure shift freezing, texture, Norway lobster, ice crystals Introduction F REEZING IS A CONVENIENT PRESERVATION METHOD PARTICULARLY used for fish and seafood, but it usually results in undesir-able physical, chemical, and structural changes leading to quali-ty losses in color, texture, and flavor (Krivchenia and Fennema1988). The freezing rate is a major parameter of the freezing pro-cess. A slow freezing causes formation of large ice crystals that ir-reversibly damage tissues. On the other hand, a high freezingrate produces small ice crystals resulting in a much preservedstructural quality of the food (Reid 1993).Ultra-rapid freezing, as cryogenic freezing, can reduce damag-es due to large ice crystals. But it may cause lethal intracellular icecrystallization in living cells and mechanical cracking (Kalishveskyand others 1995). For conventional freezing, the velocity of thephase change front, which is related to supercooling, changes be-tween surface and center depending on the geometry and on heattransfer conditions. Supercooling (the difference between the ac-tual temperature of the sample and the expected solid-liquidequilibrium temperature at a given pressure) is the driving forceof the nucleation and is an important parameter that controls thesize and number of ice crystals. The ice nucleation rate is indeedincreased by a 10 factor for each degree of supercooling (Burkeand others 1975). Pressure shift freezing (PSF) permits to achievea large and uniform supercooling in the whole volume of the sam-ple. A much-preserved microstructure is, therefore, expectedwhen using PSF. The freezing point of water is depressed underpressure down to 21 C at 210 MPa (Bridgman 1911). PSF is car-ried out in a high pressure vessel whose temperature is regulatedat subzero temperature (that is, 18 C). The 1

A. Le Bail

Papers

Effects of high pressure treatment (100–200 MPa) at low temperature on turbot (Scophthalmus maximus) muscle

Optimization of Gluten-Free Formulations for French-Style Breads

Freezing and ice crystals formed in a cylindrical food model: part I. Freezing at atmospheric pressure

Comparison Of Air‐blast And Pressure Shift Freezing On Norway Lobster Quality

Influence of the freezing condition on the baking performances of French frozen dough