Iron-Enriched Bread: Interaction Effect of Protein Quality and Copper on Iron Bioavailability

These studies examined the bioavailability of iron in iron-enriched breads. The test breads also contained added protein in the form of gluten, soy or nonfat dry milk. Bioavailability was assessed based on net hemoglobin synthesis in rats initially made iron deficient and then fed bread-based diets containing 38.5 ppm iron (NRC requirement for rat, 35 ppm) and 3.75, 5.00, or 6.25 ppm copper (NRC requirement for rat, 5 ppm). More hemoglobin was synthesized on milk-supplemented (83 mg/mg iron) and on soy-supplemented (85 mg/mg iron) bread diets than on gluten-supplemented (59 mg/mg iron) bread diets. Copper appeared to have no influence on hemoglobin regeneration or on hepatic iron accumulation under the conditions of this experiment.     

QUALITY AND SWEETNESS OF BAKED CUSTARDS MADE WITH LACTOSE-REDUCED MILKS

Lactose concentrations of lactose-reduced and hydrolyzed lactose-reduced milk (12.1, 4.9 g/L milk, respectively) were significantly lower (p < .05) than the lactose concentration in the control (1% milkfat) milk (38.4 g/L milk). Lactose concentrations in custard mixes made from lactose-reduced and hydrolyzed lactose-reduced milks (6.8, 3.2 g/L mix, respectively) were significantly lower (p < .05) than the lactose concentration in the control custard mix made from 1% milk (29.9 g/L mix). Consumers ranked the lactose-reduced milk and the hydrolyzed lactose-reduced milk significantly higher in sweetness than the control milk. No differences in sweetness between the control, lactose-reduced, and hydrolyzed lactose-reduced baked custards were perceived. Firmness, color, syneresis, and water activity did not differ (p > .05) among the control, lactose-reduced, and hydrolyzed lactose-reduced baked custards.     

A complete tolerance charting system

Manual computation of tolerance charts is both tedious and time-consuming. This paper presents an efficient method of automatically determining the working dimensions and their balanced tolerances. With this method, the feasibility of different process plans can be evaluated efficiently and economically. A unique algorithm, based on a special path tracing technique, is developed to reduce the unknown working dimensions to a system of linear equations. The Gauss elimination technique is then employed to solve for the working dimensions. The tolerance balancing process is accomplished using a separate mathematical model. The complete system, comprising the tolerance charting and optimization modules, is finally tested on an example.     

PROPERTIES OF IAA OXIDASE FROM RIPENING TOMATO FRUIT

An indoleacetic acid (IAA) oxidizing enzyme was isolated from the pericarp of ripening tomato fruit by column chromatography fractionation. IAA oxidase from extracts of tomato pericarp exists in a high molecular weight form (>200,000) or in a low molecular weight form (∼40,000) or both depending upon extraction procedures. When IAA was oxidized by the high molecular weight form of IAA oxidase, a relatively long lag time was observed. The low molecular weight form of IAA oxidase activity showed no lag or a very short, 1- to 2-minute lag period. Enzyme activity was optimal at pH 6.1 and was stimulated by 2,4-dichlorophenol (DCP) and MnCl_2. Neither 3-methyleneoxindole nor indolealdehyde were found as a major IAA oxidation products. Moderate increase in activity of IAA oxidase activity was observed during ripening of tomato fruit.     

THERMAL AND HIGH-PRESSURE STABILITY OF PURIFIED PECTIN METHYLESTERASE FROM PLUMS (PRUNUS DOMESTICA)

Pectin methylesterase (PME) from greengage plums (Prunus domestica) has been extracted and purified using affinity chromatography. Only one band on sodium dodecyl sulfate–polyacrylamide gel electrophoresis was obtained, with an estimated molecular weight of 31 kDa. On isoelectric focusing electrophoresis, two bands with neutral isoelectric points (6.8 and 7.0) were detected. The optimal pH and temperature for plum PME activity were 7.5 and 65C, respectively. A study of purified plum PME thermostability was performed at pH 7.5 and 4.0, indicating a higher thermostability at pH 7.5 than at pH 4.0. A biphasic inactivation behavior was observed for thermal treatments (54–70C), whereas its pressure inactivation could be described by a first‐order kinetic model in a pressure range of 650–800 MPa at 25C. Purified plum PME was found to be relatively stable to thermal and pressure (≤600 MPa) treatments, compared to PME from other fruits.     

The effect of varying the calcium-sequestering salt cation on the hydration behaviour of rennet caseins in a simple model system

Di potassium orthophosphate and di-ammonium orthophosphate were used to replace di-sodium orthophosphate in a simple model of cheese analogue manufacture. Rheological changes that occurred as eight rennet caseins, possessing widely differing hydration behaviour, were dispersed in solutions of the different calcium-sequestering salts were determined. Dispersion in the potassium salt resulted in minor differences in hydration behaviour of rennet caseins when compared to the behaviour in di-sodium orthophosphate solution, while dispersion in the ammonium salt resulted in considerably modified hydration behaviours and rheological profiles.     

Elastohydrodynamic Analysis of a Rotary Lip Seal Using Flow Factors

An elastohydrodynamic analysis of a rotary lip seal is performed numerically, incorporating both the fluid mechanics of the lubricating film and the elastic deformation of the lip. Asperities on the lip surface dominate the behavior of the flow field in the lubricating film and are taken into account through the use of flow factors. Because previous analyses treated those asperities deterministically, they required very large computation times. The present approach is much less computationally intensive because the asperities are treated statistically. Because cavitation and asperity orientation play important roles, these are taken into account in the computation of the flow factors. An asperity distortion analysis is introduced to model the complex variations in the asperity distribution on the surface of the lip. Results of the analysis show how the operating parameters of the seal and the characteristics of the asperities affect such seal characteristics as the thickness of the lubricating film, reverse pumping rate, power dissipation, and liftoff speed.     

NEW PERSPECTIVES ON COMMUNITY‐LEVEL DETERMINANTS OF HOMELESSNESS

Understanding the root causes of homelessness is important for developing effective solutions to the problem. This fact has not gone unnoticed by researchers, who have made numerous attempts to identify the underlying structural determinants of homelessness by modeling inter‐community variation in the rate of homelessness as a function of community‐level variables. Yet, prior studies in this area have a number of serious limitations, principally their reliance on methodologically flawed estimates of the size of the homeless population. The present study addresses this and other limitations by using newly available and more reliable estimates from the U.S. Department of Housing and Urban Development to model variation in the rate of homelessness across a large and diverse sample of communities throughout the United States. In doing so, this study builds on the analysis conducted by Lee, Price‐Spratlen, and Kanan ( 2003 ), and its findings have implications for policy and future research.