DIRECT DETERMINATION OF TRANS-OCTADECENOIC ACID IN DIET COMPOSITES USING A COMBINATION OF SILVER ION-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY AND CAPILLARY GAS CHROMATOGRAPHY

Silver ion-high performance liquid chromatography (Ag-HPLC) and capillary gas chromatography (GC) were combined to quantify total trans -octadecenoic acid (18:1t) in diet composites and oils. The 18:1 cis and trans fatty acid methyl esters (FAME) of saponified and methylated (BF₃/methanol) oils and food composite total lipid extracts were separated by Ag-HPLC (ChromSpher5 Lipids column); total 18:1t in the trans fraction was quantified by GC (105m × 0.25mm SP-2560 capillary column). Positional isomers 18:1c and 18:1t which coeluted in direct GC were clearly separated by preparatory Ag-HPLC. Quantitative recovery of 18:1t from a standard mixture of FAME, an oil, and a diet composite was obtained for additions of 4–57 mg. The analytical range for total 18:1t was 1.6–260 mg/mL per aliquot of total lipid extract or oil. Relative standard deviations were < 6% for food composites and < 3% for oils and pure standards.     

AN EXPERIMENTAL STUDY IN CONSUMERS' WILLINGNESS-TO-PAY FOR AN IRRADIATED MEAT PRODUCT

In a nonhypothetical laboratory experiment, participants were willing to pay an average of $0.71 for the right to exchange a typical meat sandwich for a sandwich irradiated to eliminate the potential risk of foodborne bacteria. Forty-one of sixty participants (68.3%) were willing to pay some positive amount. Tobit analysis was used in order to allow for the fact that Willingness To Pay (WTP) was censored at zero. WTP was interpreted as the demand for irradiation to control foodborne disease. A positive WTP was interpreted as acceptance of irradiation. The aggregated WTP greatly exceeds the estimated direct costs of foodborne disease, and the estimated costs of irradiation for many food products. There was a positive relationship between WTP and the perceived risk of foodborne disease, and a negative relationship between WTP and years of education.     

Effects of Harvesting, Transportation, and Cryogenic Processing on the Microflora of Southern Peas

Samples of southern peas [Vigna unguiculata (L.) Walp., cv. Purple Hull Pinkeye] were obtained at critical stages in a normal harvesting, transportation, and cryogenic processing operation and microbiologically analyzed for total plate count (TPC), Enterobacteriaceae count (ENT), and yeast and mold counts. Molds were identified to genera while ENT were identified to species. Operations involving extended holding times tended to increase all counts significantly, although subsequent processing reduced these counts to an acceptable level. Predominant genera of ENT and molds appeared to be soil borne organisms such as Enterobacter agglomerans, Enterobacter cloacae, Klebsella pneumoniae, and Serratia liquefaciens, and Fusarium, Cladisporium, Alternaria, Phoma, and Aspergillus, respectively.     

Cowpeas Tannins Related to Cultivar, Maturity, Dehulling and Heating

Tannins were analyzed on three cultivars of cowpeas at three maturity stages. Cultivars differed in testa darkening which increased during maturation. Darker testa had greater tannin concentrations. Testa tannins increased up to 7-fold during maturation and up to 96% of the tannins were found in the testa. The sum of tannins in individually tested cotyledon and testa was up to 10.7 times greater than that found from analysis of whole cowpea after grinding to 20-mesh. Heating in water reduced whole cowpea tannins 38–76%; cotyledon 53–59%, and testa 66–75%.     

Diffusion Properties of Salt and Acetic Acid into Herring and Their Subsequent Effect on the Muscle Tissue

The diffusion of sodium chloride and acetic acid into herring muscle and their subsequent effects on the myotibrillar proteins were studied at different temperatures and fish:cure ratios. Acid was found to penetrate tissue more quickly than salt. The acid and salt cause an initial “hardening” of the tissue, the extent of which is proportional to the concentration of each, but it is considered that the resultant fall in pH activates muscle cathepsins. SDS PAGE indicated that proteolysis of the myosin heavy chains was concomitant with subsequent tissue softening. Electron microscopy detected little disintegration of myofilaments, but extensive break-up of Z-lines.     

An AMR Capable Finite Element Diffusion Solver for ALE Hydrocodes

We present a novel method for the solution of the diffusion equation on a composite AMR mesh.This approach is suitable for including diffusion based physics modules to hydrocodes that support ALE and AMR capabilities.To illustrate,we proffer our implementations of diffusion based radiation transport and heat conduction in a hydrocode called ALE-AMR.Numerical experiments conducted with the diffusion solver and associated physics packages yield 2nd order convergence in the L₂ norm.