DEVELOPMENT OF PASTEURIZATION PROCESS FOR ROCK CRAB MEAT (CANCER IRRORATUS)

Rock crab (Cancer irroratus) is abundant in the southern Gulf of St. Lawrence and along coastlines of the Atlantic region of Canada. The objective of this work was to prepare a pasteurization schedule for Atlantic Canadian Rock Crab meat (claw, leg and body). Samples of 175 g of meat plus 52 g of 2% w/w brine or 125 g meat plus 102 g brine were placed in an 8 oz polypropylene container with an aluminum pull-top lid. The slowest heating spot for a conductively heating product was found to be 3.0 cm below the lid. Pasteurization was evaluated at 81C, 82C and 83C to a pasteurization lethality of 40 min at 85C (z = 8.89 C). The heat penetration parameters obtained were j_h= 1.703, f_h= 34.8 min, j_c= 1.549 and f_c= 51.0 min. The optimal process was found to be 83C for 130 min. The shear strength for unprocessed crab leg samples was, on average, 0.33 N/mm² (±0.06) compared to 0.24 N/mm² (+0.02) for processed samples. This represents 27.4% reduction in the shear stress that is largely attributed to the processing method. Thirty two free amino acids were determined including 9 essential amino acids, and their total amounts ranged between 24.8% and 30.0% of the sample, on dry basis. The total amounts of essential amino acids in the processed and unprocessed samples were, respectively, 15.3 and 17.8 mg/g sample. No significant losses in the amounts of essential amino acids was observed between processed and unprocessed samples, except for methionine, isoleucine and lysine, which were significantly reduced in the processed samples.     

Yeast viability during fermentation and sur lie ageing of a defined medium and subsequent growth of Oenococcus oeni

Interactions between the yeast strain used for primary oenological fermentation and the bacterium used to conduct subsequent malolactic fermentation were studied under model winemaking conditions. A commercial Saccharomyces cerevisiae wine yeast (strains, EC 1118, AWRI 835 and CY-3079) was grown in a defined medium whose composition approximated grape juice. Fermentations by all strains reached dryness, and retained a cell viability of greater than 90% upon completion of fermentation. Highest total viable cell number and percentage of viable cells were recorded for EC 1118. A sur lie ageing of the fermented medium over a 12 week period revealed a bi-phasic decay of culture viability for all strains. Thus 99% of cells had died within 2 weeks post-fermentation. Viabilities were then stable for the subsequent 4–6 week period before a second decline phase ensued and ended in either a minimal ( ca 100 CFU/mL, EC 1118) or no viable cells being detected at 12 weeks of ageing. The growth response of an Oenococcus oeni inoculum to yeast culture supernatants, previously aged for up to 12 weeks in the presence or absence of yeast lees, was evaluated in a bio-assay. In this way, yeast strains could be designated as being either inhibitory, neutral or stimulatory to the growth of O. oeni (strain Lc5p). Inhibition by supernatants of strain EC 1118 was evident, but found to be reduced by ageing the supernatant (with or without lees). Conversely, longer ageing on yeast lees increased the magnitude of the stimulatory response in O. oeni (strain Lc5p) to the supernatant from the wine yeast (strain CY-3079).     

Factors Affecting 1-Octen-3-ol in Mushrooms at Harvest and During Postharvest Storage

Harvesting experiments revealed that immature whole mushrooms with closed veils had higher 1-octen-3-0l levels than more mature whole mushrooms with open veils. The l-octen-3-01 content of the gills was higher in immature mushrooms with closed veils, gradually decreased with maturity as the veil opened, and finally increased after the gills were well exposed. Postharvest experiments demonstrated that storage temperature influenced the activity of lipoxygenase-hydroperoxide lyase, but no differences in 1-octen-3-01 content were observed. Enzyme activity as well as 1-octen-3-01 content decreased during storage. Addition of calcium chloride to irrigation water, employed to improve quality and shelf life of fresh mushrooms, increased the amount of l-octen-3-01 immediately after harvest.     

Flavor and Stability of "Horchata De Chufas"

Horchata is a sweetened water extract of chufa tubers (Cyperus esculentus) which is very popular in Spain, and has potential in the U.S. The objectives of this research were to characterize horchatas from different types of chufa, and to monitor flavor and stability of unheated and pasteurized horchatas during storage (2°C). Trained panelists rated the following attributes: color, chalkiness, sweetness, vanilla-like, nutty, earthiness, bitterness, and off-flavor. Horchatas made with chufa grown in Spain and chufa from Spain but grown in Florida showed higher vanilla and nutty levels than horchata from the Florida type. During storage (2°C), vanilla, nutty, and sweetness decreased, and other attributes increased. Heating to 70 and 95°C for 1 min did not alter sensory attributes initially, prevented off-flavor development, and slowed changes in desirable attributes for 35 days.     

Thermal Decomposition of Europium Hydroxide

The thermal decomposition of europium hydroxide in an air atmosphere was investigated by means of weight-loss measurements, infrared spectroscopy, X-ray diffraction analysis, and electron microscopy. These studies showed that EU(OH)° decomposed at temperatures between 225° and 300°C into EuOOH, which was stable up to about 425°C. Between 435° and 465°C this compound decomposed into cubic Eu₂O₃, which was stable until its inversion to the high-temperature monoclinic form. X-ray diffraction data were collected for Eu(OH)₃ and EuOOH and showed that the trihydroxide has a hexagonal crystal structure and the oxyhydroxide is possibly orthorhombic. The Eu(OH)₂, EuOOH, and cubic EunOa powders contained particles up to several microns in size consisting of agglomerates of crystallites in the size range 200 to 400 A. The single monoclinic Eu₂O₃ sample studied contained crystallites whose average size was greater than 2000 A.     

Preparation and Magnetic Properties of Some Hexagonal Magnetic Oxides

The preparation of nonoriented as well as magnetically oriented specimens of 2MeO · 2BaO·-6Fe₂O₃ and 2MeO·3BaO·12Fe₂O₃ is described. The MeO component is limited to NiO, ZnO, CoO, and CuO and mixtures of these in this discussion. The orienting apparatus and technique employed are briefly described. The magnetic permeability and loss as measured at 250 Mc is shown for many of these prepared compositions. The effect of the orienting magnetic field strength as well as firing temperature on the observed magnetic properties is discussed.     

Substitution of Aluminum and Gallium in Single-Crystal Yttrium Iron Garnets

Single crystals of yttrium iron garnet with substitutions of aluminum and gallium were grown from lead oxide-fluoride, lead borate, and barium borate fluxes. Crystals were grown both by slow cooling and by the gradient technique. The aluminum and gallium contents of these crystals were measured; the amount of substitution and its distribution in one crystal and in the mass of crystals in a run were determined. Crystals grown by slow cooling were badly segregated with respect to aluminum and gallium content whereas gradient-grown crystals were very uniform.     

High/Low Modulus Si3N4-BN Composite for Improved Electrical and Thermal Shock Behavior

High-density Si₃N₄+6% CeO₂ composites with 5 to 50% BN were fabricated by hot-pressing. BN remained as a discrete phase. Dielectric constants were 4 to 8 and loss tangents were 0.0008 to 0.06 for the room temperature to 1100°C range for compositions with 10 to 50% BN. Thermal-expansion values perpendicular to the hot-pressing direction were somewhat less than those of hot-pressed Si₃N₄+6% CeO₂. Flexure strengths at room temperature were considerably lower than those of hot-pressed Si₃N₄+6% CeO₂ but values at 1000°, 1250°, and 1400°C in air were only slightly lower. Young's modulus values were found to decrease with increasing BN content at all temperatures. Better thermal shock resistance was found than for commercial hot-pressed Si₃N₄.     

BIOLOGICAL SYSTEMS AS ORGANIZATIONAL PARADIGMS†

It is suggested that biological systems provide the best source of paradigms for the consideration of the kinds of organizations which we find in human systems; social, political or economic. A brief review of the several ways in which biological activities can be mathematically modelled is given, together with indications of the manner in which these ideas can be extended and applied beyond biology.