Soybean Hulls as an Iron Source for Bread Enrichment

Soybean hulls, a concentrated source of iron, may have potential as a source of iron fortification in baked products. Retention of ⁵⁹Fe in rats from white bread containing intrinsically labeled soybean hulls did not differ significantly (p<0.05) from extrinsically labeled white bread fortified with bakery grade ferrous sulfate (70.4 and 63.1%, respectively). Physical and sensory evaluations of bread containing up to 5% soybean hulls did not differ from white bread in loaf volume, cross-sectional area, tenderness or overall acceptance. These results suggest that soybean hulls are a good source of available iron and may be added to bakery products without deleterious effects in baking performance and sensory acceptability.     

INTROGRESSING PHEROMONE QTL BETWEEN SPECIES: TOWARDS AN EVOLUTIONARY UNDERSTANDING OF DIFFERENTIATION IN SEXUAL COMMUNICATION

As a first step toward understanding how noctuid moths evolve species-specific pheromone communication systems, we hybridized and backcrossed two closely related moth species, Heliothis virescens (Hv) and H. subflexa (Hs), which differ qualitatively and quantitatively in their multi-component sex pheromone blends. We used amplified fragment length polymorphism (AFLP) marker-based mapping of backcross families to determine which of the 30 autosomes in these moths contained quantitative trait loci (QTL) controlling the percentages of specific chemical components in the pheromone blends. In two previous backcrosses to Hs, we found a strong depressive effect of Hv-chromosome 22 on the percentage of three acetate components in the pheromone gland. These acetates are present in Hs and absent in Hv. Here, we describe how we introgressed Hv-chromosome 22 into the genomic background of Hs. Selection for Hv-chromosome 22 started from backcross 3 (BC₃) females. All females that had Hv-chromosome 22 and a low percentage of acetates (< 3% of the total amount of pheromone components present) were backcrossed to Hs males. In BC₅ to BC₈, we determined whether Hv-chromosome 22 was present by a) running only the primer pairs that would yield the markers for that chromosome, and/or b) determining the relative percentages of acetates in the pheromone glands. Either or both genotype and phenotype were used as a criterion to continue to backcross these females to Hs males. In BC₉, we confirmed the isolation of Hv-chromosome 22 in the Hs genomic background, and backcrossed the males to Hs females to eliminate the Hv-sex chromosome as well as mitochondrial DNA. The pheromone composition was determined in BC₃, BC₅, and BC₁₁ females with and without Hv-chromosome 22. All backcross females with Hv-chromosome 22 contained significantly less acetates than females without this chromosome. In addition, BC₃ females with Hv-chromosome 22 contained significantly more Z11-16:OH than BC₃ females without Hv-chromosome 22. However, in BC₅ and BC₁₁ females, the correlation between Z11-16:OH and Hv-chromosome 22 was lost, suggesting that there are separate QTL for the acetates and for Z11-16:OH, and that the relative amount of the alcohol component is only affected in epistasis with other (minor) QTL. Now that we have succeeded in isolating the chromosome that has a major effect on acetate production, we can test in behavioral experiments whether the presence of acetates may have been a driving force for a shift in pheromone composition. Such tests are necessary to move towards an evolutionary understanding of the differentiation in sexual communication in Heliothis spp. moths.     

Using the Magma Computer Algebra System in Abstract Algebra Courses

Students meeting their first serious course in abstract algebra commonly experience difficulty understanding many of the basic concepts. This makes it very hard for them to interpret and generate proofs. The first step in reaching an understanding of such concepts is often best achieved by constructing and manipulating instances in particular algebraic structures. Computer algebra systems open up the possibility of students being able to experiment rapidly and conveniently with such concepts in a variety of structures having non-trivial size and complexity. The new Magma computer algebra system has a syntax and semantics based directly on fundamental algebraic notions, and consequently should provide an appropriate learning environment for those branches of mathematics that are heavily algebraic in nature. This paper describes the development of Magma-based exercises and a course methodology that utilizes Magma as a key learning tool in a Pass-level Rings and Fields course given at the University of Sydney.     

Quality and Shelf-life of Fresh Cut Carrot Slices as Affected by Slicing Method

The effects of slicing method on the quality and storage-life of modified atmosphere packaged carrot slices were determined using microscopy, sensory evaluation, microbial counts and a range of physical and chemical tests. Slicing caused physical damage, physiological stress and enhanced microbial growth. The severity of these effects were in the order of blunt machine blade > sharp machine blade > razor blade. These findings provide insights into the magnitude and basis of slicing effects and also confirm the importance of gentle processing and the use of a sharp blade.     

FACILITATED TRANSPORT OF CARBON DIOXIDE: A REVIEW

The effect of reversible chemical reaction upon the diffusion of carbon dioxide in thin liquid film membranes is reviewed. Particular emphasis is placed upon the hydration reaction of CO₂ and catalysis thereof. Theoretical analysis is developed for equilibrium, near-equilibrium and near-diffusion regimes. The important effects of weak acid buffers, proteins and amines upon CO₂ transport are also discussed, as well as the significance of diffusion potentials, particularly in the case of protein systems. Results of experimental investigations of facilitated CO₂ transport are reviewed, as well as general aspects of CO₂ transport in biological systems and absorbers.     

Vitamin B6 In Ready-To-Eat Cereals: Analysis By High Performance Liquid Chromatography

Twenty-four ready-to-eat cereals obtained locally were analyzed for their vitamin B₆ content by a recently developed high performance liquid chromatographic (HPLC) procedure. The method uses sulfo-salicylic acid as an extraction agent with subsequent qualitative and quantitative analysis by anion exchange chromatography. All six forms of vitamin B₆ plus their metabolite, pyridoxic acid, can be identified and quantified. Spot checks of the results obtained with this method and with a radiometric-microbiological assay give agreement to within 5%. On the other hand, disagreements of up to 38% are found on comparison with the standard AOAC microbiological procedure used by a commercial laboratory. The results indicate no significant variations between boxes within the same lot, but in one-third of the cereals tested, significant variations were found from lot to lot.