Physical, Chemical and Sensory Changes in Irradiated Fresh Pork Packaged in Modified Atmosphere

The effects of irradiation dose (0, 0.5 and 1.0 kGy), headspace oxygen (0, 10 and 20% O₂, balance nitrogen) and storage temperature (5, 15 and 25°C) on the physical, chemical and sensory changes in fresh pork were studied using factorial design experiments. Irradiation in the absence of oxygen extended the sensory shelf life of pork from 9 to 26 days at 5°C and from & lt; 2 to 2 days at 25°C. Oxygen in the package headspace combined with irradiation adversely affected physical, chemical and sensory characteristics of the end product.     

DATA ADJUSTMENT FOR NON-REACTIVE BATCH OR STEADY-STATE PROCESSES

An analytical method was developed to adjust inconsistent process data by a least-sum-of-squares technique to “best” meet all material balance constraints. One complete data set composed of “M” stream flow rates with “N” components in each stream was used from either batch or steady-state non-reactive processes to define an unconstrained sum-of-squares adjustment function

Derivatives of the unconstrained sum-of-squares adjustment function with respect to each variable were set to zero yielding a set of non-linear algebraic equations. The entire non-linear set was solved by converging on only M— 2 search variables as compared to conventional methods requiring N(M — 1) — 1 search variables.     

LIQUID CIRCULATION PATTERNS AND THEIR EFFECT ON GAS HOLD-UP AND AXIAL MIXING IN BUBBLE COLUMNS

Liquid velocity profiles in a bubble column were measured with the aid of a hot-film anemometer. Two different types of profiles were detected that were characterized by the formation of a boundary layer at the column wall. Under slow flow conditions, the boundary layer is large and controls the liquid velocity profile, but in turbulent flow the boundary layer is very small and has no significant effect on the velocity profile. Microscopic and macroscopic balances were used to predict both the liquid velocity profile and the average liquid velocity.

The effect of the liquid velocity profile and average velocity on axial dispersion and gas-hold-up are analyzed and design procedures are recommended.     

ZINC ELECTRODE CYCLE-LIFE PERFORMANCE IN ALKALINE ELECTROLYTES HAVING REDUCED ZINC SPECIES SOLUBILITY

Electrolytes having 3.5 M hydroxide-ion concentration were tested in 1.35 Ah Zn/NiOOH cells to evaluate their ability to reduce the extent of zinc species migration and slow the rate of cell capacity decline. Alkaline-fluoride and alkaline-borate electrolytes, in which ZnO solubility is approximately 25° of that in standard 7.4 M KOH electrolyte, exhibited 0.09-0.14^°/cycle zinc-electrode area loss, which may be compared to a value of 0.46^°/cycle observed in standard electrolyte, In addition, no zinc penetration of the separator occurred in cells that employed alkaline-fluoride and alkaline-borate electrolytes, even when zinc-electrode overpotcntials reached 290 mV at the end of charge. Less than 2^° of the zinc remaining after cycling was electrochemically inactive.     

CHALLENGE STUDIES WITH CLOSTRIDIUM BOTULINUM TYPE E IN A VALUE-ADDED SURIMI PRODUCT STORED UNDER A MODIFIED ATMOSPHERE

Challenge studies were carried out on raw, cooked, and sterilized surimi nuggets, inoculated with 10⁴ spores/g of C. botulinum type E spores. All products were packaged in air and air with an Ageless SS oxygen absorbent and stored at 4, 12 and 25C. Toxin was not detected in any raw product throughout storage (28 days). The absence of toxigenesis was attributed to the low pH (4.1–4.3) due mainly to the growth of lactic acid bacteria (10⁷CFU/g). Toxin was also not detected in any cooked product after 28 days. Product pH did not decrease as previously (due to the absence of LAB), but counts of C. botulinum still decreased throughout storage.
In sterile nuggets , C. botulinum counts increased to 10⁶ cfu/g at both 12 and 25C, respectively, by 28 days. Lactic acid bacteria and Bacillus spp. were not detected throughout the 28 days storage period. Toxin was detected by days 28 and 14 at 12 and 25C, respectively, and toxigenesis preceded spoilage. The absence of toxin in cooked nuggets was attributed to the anti-botulinal role by Bacillus species, the predominant spoilage bacteria in cooked nuggets.     

X100试验管线钢管的规范和生产

介绍了位于英国诺林伯利亚,钢管直径1 219 mm(48 in),输气压力18 MPa(180 bar),由英国BP公司承建的X100试验管线的建设概况.根据X100试验管线的设计参数制定了相应的钢管规范,设计了X100管线钢管母材、焊缝金属和热影响区的合金成分.按设计的合金成分由住友金属鹿岛钢铁厂生产了钢材、钢板,并...     

EFFECT OF FILMS OF DIFFERENT OXYGEN TRANSMISSION RATE ON TOXIN PRODUCTION BY CLOSTRIDIUM BOTULINUM TYPE E IN VACUUM PACKAGED COLD AND HOT SMOKED TROUT FILLETS

Studies were done to determine the effect of film oxygen transmission rate (OTR) on the time to toxicity in vacuum packaged cold and hot smoked rainbow trout fillets challenged with C. botulinum type E (10² spores/g) and stored at refrigerated conditions (4C), and under mild (8C) and moderate (12C) temperature abuse conditions. While no samples were toxic at 4C, toxin was detected within 28 days at 8C for cold smoked trout fillets vacuum packaged in films with high OTR. Toxin was also detected for most vacuum packaged hot smoked trout fillets within 14–28 days at 8C, with the exception of trout fillets packaged in films with an OTR > 10,000 cc/m²/day. In most cases at 8C, spoilage, based on odor/color scores, preceded or occurred simultaneously with toxigenesis. At 12C all cold and hot smoked trout were toxic after 14–21 days and samples packaged in films with an OTR <5000 cc/m²/day became toxic before, or at the same time as, samples became spoiled. This study has shown that vacuum packaging of trout fillets in low gas barrier films, ranging in OTR from approximately 3,000 to approximately 10,000 cc/m²/day at 24C and 0% relative humidity (RH), did not prevent the growth and toxin production by C. botulinum in vacuum packaged cold and hot smoked trout fillets at 12C. Additional barriers, other than the OTR of the packaging film, need to be considered to ensure the safety of vacuum packaged trout fillets, particularly at mild to moderate temperature abuse storage conditions.     

Lactose Crystallization from Whey Permeate in an Ethanol-Water Mixture

A 30% concentrated permeate of a whey ultrafiltration process was used for producing crystalline a-lactose monohydrate. Effect of pH (2.75–5.5 pH units) at solvent to solute ratio 10:1 v/w, agitation and seeding (0.004–0.02%) on rate of lactose crystallization were examined. Conditions which were favorable in terms of crystallized lactose yield, and time of crystallization were: pH 5.5, agitation with or without seeding and 22°C. The first-order reaction-rate constant for crystallization ranged from 0.0178 to 0.200 hr^?1 depending on conditions.     

Effect of Atmosphere on the Electrical Conductivity of Sodium Tungstophosphate Glasses

The dc electrical conductivity of sodium tungstophosphate glasses was measured as a function of glass composition, melting history, and ambient atmosphere. The color of the glasses was a strong function of both glass composition and melting history. The electrical conductivity was found to be strongly dependent upon the concentration of protons in the surrounding atmosphere. The colorless glasses were found to be electrochromic only so long as protons were present in the atmosphere. A model is suggested to explain these results.