The influence of pasteurization temperature on the physicochemical composition and colour of Murciano-Granadina goat milk

An evaluation of the physicochemical characteristics and colour in Murciano-Granadina goat milk was carried out on several samples subjected to different pasteurization treatments (72°C/15 s, 76°C/15 s and 80°C/10 s). An apparent increase in the level of caseins was observed along with a decrease in the serum protein contents at pasteurization temperatures of 76 and 80°C. This change can be partly justified by the interactions between β-lactoglobulin and K-casein in pasteurized milk. The fat content, viscosity and density of the milk showed minimal sensitivity to the thermal treatments, but the heat treatment did affect the parameters which defined the colour of the milk, as shown by a decrease in the Yellow Index and an increase in the difference in colour.     

Effect of initial microstructure on high velocity and hypervelocity impact cratering and crater-related microstructures in thick copper targets: Part I Soda-lime glass projectiles

Three uniquely different initial microstructure regimes were created in 2.5 cm thick copper targets: an as-received 98 μm grain size containing ∼1010 dislocations/cm2 (Vickers hardness of 0.89 GPa); an annealed 124 μm grain size containing ∼109 dislocations/cm2 (Vickers hardness of 0.69 GPa); and a 763 μm grain size containing ∼109 dislocations/cm2 (Vickers hardness of 0.67 GPa). Each of these target plates was impacted by 3.18 mm diameter soda-lime glass spheres at nominal impact velocities of 2, 4 and 6 km s-1. Grain size was observed to have only a very small or negligible contribution to cratering, while the dislocation density had a controlling influence on both the target hardness and the cratering process. Residual crater hardness profiles were correlated with specific microstructure zones extending from the crater wall into the target, and both hardness profiles and residual microstructures differed for each specific target, and for each different impact velocity. Microbands coincident with traces of {1 1 1} planes were associated with a zone of residual target hardening and increased with increasing grain size and impact velocity. No significant melt-related phenomena were observed, and crater-related target flow occurs by solid-state plastic flow through dynamic recrystallization, forming a narrow, softened zone at the crater wall. This revised version was published online in November 2006 with corrections to the Cover Date.     

ASSESSMENT OF ENDO-1,4-BETA-D-GLUCANASE ACTIVITY BY A RAPID COLORIMETRIC ASSAY USING DISODIUM 2,2'-BICINCHONINATE

It is widely accepted that viscometric assays are the most sensitive methods for evaluation of endoglucanase activities, because of the preferential attack of these enzymes on internal bonds of the substrate. However, due to the high sensitivity of the disodium 2,2′-bicinchoninate assay, we could measure, in a onestep method, the initial stages of the degradation of cellulose derivatives by endo-1,4-β-D-glucanases, by determining the reducing end-groups released. We report the applicability of the method for the determination of activity, and the K_m for the endoglucanase-I from Trichoderma reesei. This assay can be extended to the evaluation of reducing groups released by the action of many other carbohydrases, either with endo- or exo-type activity.     

Starch Transformation During Banana Ripening: The Amylase and Glucosidase Behavior

Banana starch disappearance during ripening originated at the central portion of the fruit radiating, afterwards, to the surface; the amylose/amylopectin ratio remained constant during the process. The amyloplast was investigated by light and scanning electron microscopy. The surface of starch granules was smooth, and the unique modification obsenred during ripening was the reduction of the granule dimensions; at advanced ripening stages, some striations were detected on the surface of both small and large granules. Several amylolytic enzymes were followed during banana ripening. Seven amylases were detected at all stages, presumably three a- and four p-amylases and, like glucosidases, their activity increased at the climacteric phase; only p-amylase activity increased before the onset of the respiratory peak. For the first time α-l, 6-glucosidase activity was detected in banana.     

GROWTH/SURVIVAL OF NATURAL FLORA AND LISTERIA MONOCYTOGENES ON REFRIGERATED UNCOOKED PORK AND TURKEY PACKAGED UNDER MODIFIED ATMOSPHERES

Listeria monocytogenes was inoculated onto fresh pork and turkey slices. Inoculated and control samples were packaged under modified atmospheres (100% N₂, and 20%/80% and 40%/60% CO₂O₂) or air in plastic bags of low gas permeability. Samples were stored at 1 and 7C. Samples stored in air showed a similar microbiological pattern to that usually observed in fresh meat stored aerobically. Packaging under modified atmospheres extended the meat shelf-life. Bacterial growth was strongly inhibited at 1C, particularly in samples stored under CO₂/O₂ enriched atmospheres. Temperature and pH were critical factors for L. monocytogenes growth. This pathogen grew only on pork (initial pH 5.3) packaged in air and stored at 7C. No L. monocytogenes growth was observed at 1C in any atmosphere assayed. However, growth on turkey (initial pH 6.0) was marked at 7C in all atmospheres tested, while at 1C, this bacterium grew weakly only on samples stored in air .     

Impact of E?×?B flow shear stabilization on particle confinement and density peaking at JET

The impact of the E×B flow shear stabilization on particle transport and density peaking at JET is analyzed in the framework of integrated modelling with the CRONOS code. For that purpose, plasmas from a power scan which show a significant increasing of density peaking with the injected neutral beam injection power have been used as a modeling basis. By means of simulations with the quasilinear model GLF23 for the heat and particle transport, a strong link between the particle confinement and E×B flow shear stabilization is found. This is particularly important close to the pedestal region where the particle pinch direction becomes strongly inward for high E×B flow shear values. Such impact introduces some non-negligible deviation from the well-known collisonality dependence of the density peaking, whose general trend has been also obtained in the framework of this modelling by performing pedestal density scans.