DISTRIBUTION OF OCHRATOXIN A IN CHICKEN TISSUES AND EGGS

The kinetics of distribution of ochratoxin A (OA) in chicken tissues was studied. Day-old chicks were fed a starter diet alone or containing 1 ppm OA. After 5 weeks, all chicks were intubated with 50 μg ³H-OA per chick. The highest level of radioactivity was found in kidney and liver 8 hr after intubation. Peak levels of OA in kidney, liver and breast were found to be 12, 4, and 0.2 ppb, respectively. Over 90% of the radioactivity was eliminated 48 hr after intubation. Moreover, when laying hens were fed a diet containing 0.5 or 5.0 ppm of OA for 2 weeks, the highest levels of OA were found in the kidney (124 ppb) and liver (80 ppb) also. Levels of OA in breast, leg and eggs of laying hens were found to be 8, 7, and 2.8 ppb, respectively.     

Electrical Stimulation and Hot Boning: Cooking Losses, Sensory Properties, and Microbial Counts of Ground Beef

Six batches of ground beef, approximately 10, 15, or 20% fat, were fabricated from flanks (lean and fat trim) of electrically stimulated-hot boned (ESHB) or conventionally chilled (CC) beef sides. Patties (2.5 × 7.6 × 8.2 cm) from each batch were modified broiled for 35 min at 177°C. Generally, ESHB and CC products were comparable in cooking and sensory properties and in microbial counts of raw products. ESHB products had slightly higher cooking losses, more intense beef flavor, and were slightly juicier than CC products. Small differences between ESHB and CC products more often were attributable to fat content than to processing treatment (ESHB or CC).     

Diffusion Sintering: II, Initial Sintering Kinetics of Alumina

The initial sintering kinetics of alumina have been studied by measuring the isothermal shrinkage of compacts of several alumina powders in air. The shrinkage of these compacts can best be described by a grain-boundary vacancy diffusion model for the temperature range 1200° to 1600°C. The behavior of the compacts is consistent with the model after an initial shrinkage has occurred. The magnitude of this initial shrinkage is constant for identical specimens and is independent of the sintering temperature.     

Optical, Structural, and Chemical Characteristics of Lead-Indium Phosphate and Lead-Scandium Phosphate Glasses

Two new glass systems based on a range of lead-indium phosphate and lead-scandium phosphate compositions have been developed and characterized. These glasses have a relatively high index of refraction ( n = 1.75 to 1.83) in the visible region and exhibit moderate dispersion (Abbe number ∼30). The ultraviolet absorption edge occurs near 300 nm and the glasses strongly absorb in the infrared at wavelengths greater than 2800 nm. Both glass types can be prepared at relatively low temperatures (900° to 1000°C) and are easily poured down to ∼800°C because of their low melt viscosities. The glasses exhibit good chemical durability and resistance to both weathering and intense γ-radiation. These materials have a glass transition temperature of about 430°C, a softening point of about 460°C, and thermal expansion coefficients in the range of 10.8 × 10⁻⁶ to 12.0 × 10⁻⁶/°C. The structure of these phosphate glasses is shown to consist of a distribution of chains of PO₄ tetrahedra held together by bonding between the non-bridging oxygens of the tetrahedra and the metal cations. The polyphosphate chain length distribution was determined by a liquid chromatographic technique. Potential aqueous corrosion mechanisms are discussed and some general guidelines for forming a chemically durable phosphate glass are given.     

A METHOD FOR DETERMINING THE CONVECTIVE HEAT TRANSFER COEFFICIENT DURING IMMERSION FRYING

The convective heat transfer coefficient is a useful parameter in characterizing heat flow across a fluid/solid interface when the fluid flow field is complex and solution of the coupled transport equations impractical. While convective heat transfer coefficient values for many unit operations have been tabulated, the boiling phase of immersion frying has not been quantified. The objective of this study was to develop a laboratory method for the measurement of the convective heat transfer coefficient during immersion frying. The method that was developed was applied to the immersion frying of potato cylinders at an oil temperature of 180C. The convective heat transfer coefficient was initially 300 W/m²K, it increased sharply to 1100 W/m²K, and gradually decreased to 300 W/m²K over the duration of the process. Use of this new method will allow the study of the effects of oil temperature, oil quality, product shape/size, and product quality on heat transfer coefficients.     

Effects of Cation Substitution on Electrical and Thermal Transport Properties of YCrO3 and LaCrO3

High-temperature electrical conductivity, Seebeck coefficient, and thermal conductivity measurements were used to study the effects of different cation substituents on electrical and thermal transport in YCrO₃ and LaCrO₃. The substitution of divalent Ca and Sr for Y and La, respectively, resulted in the formation of small polarons as charge carriers. The additional substitution of Mn for Cr resulted in the formation of a second charge carrier associated with the Mn. The electrical conductivity results were consistent with thermally activated transport by hopping of a temperature-independent carrier concentration. The activation energies were 0.20 and 0.12 eV for (Y,Ca)CrO₃ and (La,Sr)CrO₃, respectively, and increased to about 0.50 eV with the substitution of Mn for Cr. The Seebeck coefficient increased linearly with temperature and decreased with substituent concentration for both (Y,Ca)CrO₃ and (La,Sr)CrO₃. The substitution of Mn for Cr resulted in a Seebeck coefficient with a more complex dependence on temperature and substituent concentration. The thermal conductivity did not change significantly with either cation substitution or temperature.     

Some Properties of Hafnium Oxide, Hafnium Silicate, Calcium Hafnate, and Hafnium Carbide

The behavior of hafnium oxide was studied particularly in the temperature range 1500° to 18OO°C. Properties of HfO₂ at these temperatures and its reactions with ZrO₂, SiO₂, and CaO are given in terms of lattice and other physical measurements, many of which are new. Mono-clinic hafnium oxide is stable to 1700°C., which is 600° higher than the corresponding inversion temperature of zirconia. Otherwise HfO₂ closely resembles ZrO₂ (a) in its lattice dimensions and sintering behavior, (b) in forming a high-temperature tetragonal phase closely resembling tetragonal ZrO₂, (c) in forming a continuous series of solid solutions with ZrOz, (d) in forming with silica a single compound (HfO₂.SiO₂) similar to zircon, (e) in forming a carbide, (f) in uniting with up to 40% CaO to form cubic solid solutions; thereafter a compound CaO.Hf O₂ appears which is very similar to the corresponding zirconia compound.     

Debittering Casein Hydrolysates with Octadecyl-Siloxane (C18) Columns

Three casein hydrolysates (degree of hydrolysis (DH) of 23, 47, and 65.5 (%)) were debittered using three different hydrophobic adsorption columns, C18, C8, and phenolic resin (PR). Higher DH hydrolysates resulted in higher total nitrogen yields through the debittering process. The C18 and PR columns had more effective debittering than the C8 column, which had the highest processing yield. The PR column had much lower processing yield than the C18 column. Q-value correlated with bitterness in the hydrolysates. Antigenicity of treated hydrolysates was reduced by the debittering process.