UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

More information is available at Theses and Dissertations at University of Maryland Libraries.

Browse

Filters

2008 - 200912010 - 20141

Settings

Subject: search.filters.subject.food quality

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Physiological responses of Acartia and Eurytemora spp. to changes in the nitrogen:phosphorus quality of their food
    (2014) Bentley, Katherine Marie; Glibert, Patricia; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study addressed how copepods respond to varying nutrient content in their prey. Copepod physiological responses were measured along a gradient of prey nitrogen:phosphorus (N:P) ratios created by altering the P content in diatom prey grown at a constant rate. Acartia tonsa, a broadcast spawner, and Eurytemora carolleeae, a brood spawner, increased excretion of P as prey N:P declined (i.e. P increased). E. carolleeae had higher somatic tissue nutrient content, while A. tonsa had higher egg nutrient content overall and higher P in eggs as N:P decreased. E. carolleeae egg production was greatest when eating high N:P prey while A. tonsa showed the opposite. Egg viability declined at high N:P for both copepods, yet A. tonsa viability was always greater than E. carolleeae viability. Both copepods responded physiologically to food of varying quality, yet regulated their homeostasis differently. Prey nutrient content may be significant in the environmental selection of different copepods.
  • Thumbnail Image
    Item
    MACHINE VISION TECHNOLOGY FOR FOOD QUALITY AND SAFETY INSPECTIONS
    (2008-10-02) Jin, Fenghua; Tao, Yang; Fischell Department of Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    With increased expectations for food products of high quality and safety standards, the need for accurate, fast and objective determination of these characteristics in food products continues to grow. Machine vision as a non-destructive technology, provides an automated and economic way to accomplish these requirements. This research thus explored two applications of using machine vision techniques for food quality and safety inspections. The first application is using a combined X-ray and laser range imaging system to detect bone and other physical contaminants inside poultry meat. For this project, our research focuses on how to calibrate the imaging system. A unique three-step calibration method was developed and results showed that high accuracy has been achieved for the whole system calibration - a root mean square error of 0.20 mm, a standard deviation of 0.20 mm, and a maximum error of 0.48 mm. The second application is separating walnuts' shells and meat. A backlight imaging system was developed based on our finding that the backlit images of walnut shells and meat showed quite different texture patterns due to their different light transmittance properties. The texture patterns were characterized by several rotation invariant texture analysis methods. The uncorrelated and redundant features were further removed by a support vector machine (SVM) based recursive feature elimination method, with the SVM classifier trained concurrently for separations of walnuts' shells and meat. The experimental results showed that the proposed approach was very effective and could achieve an overall 99.2% separation accuracy. This high separation accuracy and low instrument cost make the proposed imaging system a great benefit to the walnut processing industry.