Effect of endogenous triacylglycerol hydrolysates on the mechanical properties of Zein films from ground corn     

Parris N  Dickey LC  Powell MJ  Coffin DR  Moreau RA  Craig JC 《Journal of agricultural and food chemistry》2002,50(11):3306-3308

Dry-milled yellow corn and freshly ground food and nonfood grade yellow and white hybrid corn kernels were pretreated in a solution of lactic acid and sodium metabisulfite followed by extraction with 70% ethanol. Zein was precipitated from the extract by reducing the ethanol content of the extract to 40%. Lipid associated with the zein isolates was between 15 and 20% and contained mostly endogenous free fatty acids. The effect of the endogenous free fatty acids on zein isolate films, with and without free fatty acids, was determined by measuring various film properties. Stress-strain measurements indicated 40-200% greater elongation for zein films containing endogenous free fatty acids. Films prepared from zein isolated from preground corn stored for approximately 4 months (27 degrees C, 17% relative humidity) had approximately 3 times greater elongation values than zein films prepared from freshly ground corn.  相似文献   

Comparison of semiautomated method with official optical somatic cell counting method III for determining somatic cells in milk     

R D Mochrie  D A Dickey 《Journal of the Association of Official Analytical Chemists》1984,67(3):615-617

The new method specifying the Fossomatic-90 differs from the official method, 46.105-46.109, in that the modified instrument includes a halogen lamp; a semiconductor photoelectric detector; a less expensive, bench-top cabinet; manual injection of a larger sample, and a reduced capacity. The new instrument was compared with 2 optical somatic cell counters in routine use. On each of 3 days, 12 subsamples were prepared for each of 5 cell count levels from AM milk with half kept fresh and half preserved with 0.05% potassium dichromate. Subsamples were refrigerated and read 30+ h post-collection. Duplicate sets were read in random order on each machine daily (CV 0.77%). Two sets of slides read by 2 technicians each (strip reticle on 2 smears/slide) gave geometric mean direct microscopic somatic cell count (DMSCC) levels of 296, 526, 772, 930, and 1438 th/mL. Within-technician CV values (from day-level means) ranged from 1.68 to 2.28%. Geometric mean cells in th/mL on the new machine were significantly higher than those on the other two (674 vs 621) and were closer to the DMSCC (694). On the new machine, cell counts were 8.5% greater than on the original machines, were only 2.9% lower than the DMSCC, and showed no significant evidence of bias. Preserved samples averaged slightly greater than fresh (5.3%) but only on the original machines. Carryover by covariance analysis was insignificant. Except for cell levels, high machine precision (error CV value of 1.18%) gave differences with statistical but not practical significance, even for regulatory laboratories.  相似文献   

A dynamic, optimal disease control model for foot-and-mouth-disease: II. Model results and policy implications     

Kobayashi M  Carpenter TE  Dickey BF  Howitt RE 《Preventive veterinary medicine》2007,79(2-4):274-286

A dynamic optimization model was used to search for optimal strategies to control foot-and-mouth disease (FMD) in the three-county region in the Central Valley of California. The model minimized total regional epidemic cost by choosing the levels of depopulation of diagnosed herds, preemptive depopulation, and vaccination. Impacts of limited carcass disposal capacity and vaccination were also examined, and the shadow value, the implicit value of each capacity, was estimated. The model found that to control FMD in the region, (1) preemptive depopulation was not optimal, (2) vaccination, if allowed, was optimal, reducing total cost by 3–7%, (3) increased vaccination capacity reduced total cost up to US$ 119 per dose, (4) increased carcass disposal capacity reduced total cost by US$ 9000–59,400 per head with and without vaccination, respectively, and (5) dairy operations should be given preferential attention in allocating limited control resources.  相似文献   

Enzymatic hydrolysis, grease permeation, and water barrier properties of zein isolate coated paper     

Parris N  Dickey LC  Wiles JL  Moreau RA  Cooke PH 《Journal of agricultural and food chemistry》2000,48(3):890-894

An inexpensive zein-lipid mixture was isolated from yellow dent, dry-milled corn. Grease permeation through zein isolate applied to brown Kraft paper was found to be independent of loading levels at zein isolate levels above 30 mg/16 in.(2). The data shows that water vapor transmission rates depended on the amount of coating applied. Triacylglycerols were the most abundant lipid in milled corn but were absent in the zein isolate (perhaps due to hydrolysis by lipases). Zein from the paper was hydrolyzed enzymatically and the hydrolysis monitored by SDS-capillary electrophoresis. At an E:S ratio of 1:100 no further increase in the hydrolysate peak occurred after 10 and 30 min for alpha-chymotrypsin and pancreatin 8 x; however, zein and lipid were still present 1 h after hydrolysis by pancreatin 1 x.  相似文献   

Sectional notes     

C. L. Fitch  Frank W. Hussey  H. A. Reiley  Eral B. Tussing  J. B. R. Dickey  K. W. Lauer  T. E. Odland 《American Journal of Potato Research》1941,18(8):243-246

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Sectional notes     

E. R. Bennett  W. B. Ward  C. L. Fitch  Frank W. Hussey  H. R. Talmage  Ralph W. Donaldson  Marx Koehnke  Wm. H. Martin  J. B. R. Dickey  K. H. Klages  G. S. Ralston 《American Journal of Potato Research》1935,12(9):257-264

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Sectional notes     

H. G. Zuckerman  C. H. Metzger  B. A. Brown  W. B. Ward  C. L. Fitch  John S. Gardner  Frank W. Hussey  Ralph W. Donaldson  H. C. Moore  H. O. Werner  W. H. Martin  K. H. Fernow  E. V. Hardenburg  W. G. Been  E. B. Tussing  J. B. R. Dickey  K. W. Lauer  T. E. Odland  H. L. Bailey  Chas D. Gaines  J. G. Milward  John Tucker 《American Journal of Potato Research》1935,12(8):222-234

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Sectional notes     

H. W. Poulsen  W. B. Ward  E. R. Bennett  C. L. Fitch  E. L. Nedwick  Ralph W. Donaldson  A. G. Tolaas  E. E. Isaac  H. O. Werner  E. V. Hardenburg  G. K. Middlenton  E. M. Gillig  J. B. R. Dickey  T. E. Odland  K. H. Klages  H. L. Bailey  Charles D. Gaines 《American Journal of Potato Research》1935,12(11):316-324

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Genetic population structure of marine fish: mismatch between biological and fisheries management units     

Henning Reiss  Galice Hoarau  Mark Dickey‐Collas  Wim J. Wolff 《Fish and Fisheries》2009,10(4):361-395

An essential prerequisite of a sustainable fisheries management is the matching of biologically relevant processes and management action. In fisheries management and assessment, fish stocks are the fundamental biological unit, but the reasoning for the operational management unit is often indistinct and mismatches between the biology and the management action frequently occur. Despite the plethora of population genetic data on marine fishes, to date little or no use is made of the information, despite the fact that the detection of genetic differentiation may indicate reproductively distinct populations. Here, we discuss key aspects of genetic population differentiation in the context of their importance for fisheries management. Furthermore, we evaluate the population structure of all 32 managed marine fish species in the north‐east Atlantic and relate this structure to current management units and practice. Although a large number of studies on genetic population structure have been published in the last decades, data are still rare for most exploited species. The mismatch between genetic population structure and the current management units found for six species (Gadus morhua, Melanogrammus aeglefinus, Merlangius merlangus, Micromesistius poutassou, Merluccius merluccius and Clupea harengus), emphasizes the need for a revision of these units and questions the appropriateness of current management measures. The implementation of complex and dynamic population structures into novel and less static management procedures should be a primary task for future fisheries management approaches.  相似文献   

Angiotensin I converting enzyme-inhibitory peptides from commercial wet- and dry-milled corn germ     

Parris N  Moreau RA  Johnston DB  Dickey LC  Aluko RE 《Journal of agricultural and food chemistry》2008,56(8):2620-2623

Bioprocesses were developed to enhance the value of proteins from deoiled corn germ. Proteins were hydrolyzed with trypsin, thermolysin, GC 106, or Flavourzyme to generate the bioactive peptide sequences. At an enzyme to substrate ratio of 1:100, protein hydrolysis of wet-milled germ was greatest using thermolysin followed by trypsin, GC 106, and Flavourzyme. For the dry-milled corn germ, protein hydrolysis was greatest for GC 106 and least for Flavourzyme. Electrophoretic patterns indicated that the hydrolysis conditions used were adequate for generating low molecular weight peptides for both germs. Unhydrolyzed dry- and wet-milled corn germ did not appear to contain angiotensin I converting enzyme (ACE)-inhibitory peptides. After hydrolysis with trypsin, thermolysin, and GC 106 but not Flavourzyme, ACE inhibition was observed. ACE inhibition was greatest for the GC 106 hydrolysate for both wet- and dry-milled corn germ. Denaturing the protein with urea before hydrolysis, in general, increased the amount of ACE-inhibitory peptides found in the hydrolysate. Membrane fractionations of both the wet- and dry-milled hydrolysates indicated that most of the ACE-inhibitory peptides were in the <1 kDa fraction. Examination of the control total protein extracts (before treatment with proteases) from wet- and dry-milled germ revealed that neither had ACE-inhibitory properties. However, when both total corn germ control protein extracts were fractionated, the <1 kDa fraction of wet-milled corn germ proteins exhibited ACE inhibition, whereas the comparable low molecular weight fraction from dry-milled corn germ did not.  相似文献