In the Columbia Basin, pre-plant soil fumigation is commonly used in potato production for pest control, but fumigation can kill non-target organisms within the soil, result in unintended shifts in the microbial community, and disrupt long-term soil health. Cover crops have been shown to strongly influence the numbers and communities...
Nitrogen (N) fertilizer application can promote nitrate leaching below the rooting zone and into groundwater drinking water sources in many agricultural settings. The proper management of N application can minimize non-point source nitrate pollution to groundwater. This study examines the potential for enhanced efficiency fertilizers, specifically urea treated with a...
Hazelnuts (Corylus avellana) produce a prolific growth in the base of the trunk and roots, known as suckers, which are often removed in order to promote the development of a single trunk tree. Sucker removal facilitates cultural practices and mechanized operations, such as weed management and harvest. Sucker presence can...
Stevia (Stevia rebaudiana) is a perennial herbaceous plant native to Paraguay and used traditionally by the native Guarani peoples for centuries to sweeten medicinal teas. Stevia has only been commercially cultivated over the past 50 years and cultural practice information suitable for implementation by growers is limited. Currently stevia’s commercial...
Spotted wing drosophila (SWD), Drosophila suzukii, is an economically damaging pest on small fruits. The estimated economic impact is hundreds of millions of dollars annually in the U.S. alone, and increasing every year. Current control of SWD relies heavily on chemical insecticides which have many negative impacts on environmental and...
The public controversy over possible health hazards from radioactive fallout from atomic bomb testing began in 1954, shortly after a thermonuclear test by the United States spread fallout world wide. In the dissertation, I address two of the fundamental questions of the fallout controversy: Was there a threshold of radiation...
It has been suggested that cellular damage from oxygen radicals is one of the processes leading to cardio-vascular disease and cancer. Natural antioxidants prevent uncontrolled oxidative reactions by decreasing molecular oxygen levels, scavenging chain-initiating and chain-propagating free radicals, chelating metals, or decomposing peroxides. Beer is rich in antioxidants, derived both...
Sensory evaluation and instrumental methods were applied to the
evaluation of strawberry juice concentrate (68°Brix) stored at
20°C which had been produced both commercially (C-SJC) and in a
pilot plant (SJC). Sensory evaluation included taste and aroma
ratings by intensity scaling and time-intensity of taste, and visual
colorimetry by matching...
Polyphenol oxidase (PPO) from strawberries was purified,
partially characterized, and used to study its role in the degradation
of anthocyanin pigments. The extraction method included the use of a
buffered solution containing the phenolic binders Polyclar AT and
Amberlite XAD-4. Addition of Triton X-100 resulted in an increase of
the...
The taste qualities of acidulants have not been studied in detail despite
the fact that they are widely used by the food industry. Studies on
characterizing the sensory properties of organic and inorganic acids are very
limited. Reported studies are commonly on threshold, equi-sour and the time
intensity values of...
Asian countries have become one of the largest export markets for US food developers during the past decade. Understanding consumer expectations and needs in a cross-cultural framework has gained importance for new products to succeed in the international markets. A sports-drink, which is a functional drink for athletes, has been...
Both liquid and solid wastes from Pacific whiting surimi manufacturing were
characterized and value-added products were recovered. A proteinase in surimi wash
water (SWW) was determined to be cathepsin L with Mr 54,200 on SDS-substrate gel.
Heat treatment and acidification shifted the activity zone to M [subscript r] 39,500. No...
Sperm mobility is defined as the net movement of a sperm population against resistance. Previous research demonstrated that the cell-permeant Ca2+ indicator rhod-2 AM gave a fluorescent signal predominantly in the head region of fowl sperm that differed between sperm mobility phenotypes. This thesis served to explore the role of...
The production of fuel ethanol from lignocellulosic biomass has the potential to replace a significant portion of non-renewable transport fuels. Woody feedstocks are composed of cellulose, hemicellulose, and lignin. Glucose, the monomer of cellulose, is readily utilized by wild-type S. cerevisiae, but xylose, which comprises 60% of the sugar in...
Lemon oil quality is affected by numerous factors including lemon variety, climate,
soil type, extraction method, etc.. Therefore, quality largely depends upon the lemons'
origin, and aroma profiles of oils obtained throughout the world have potential to vary
considerably. This research was conducted to identify differences in the aroma profiles...
A high performance liquid chromatography (HPLC)
procedure using a LiChrosorb-NH₂ column and a eluant
buffer of 75:25 (v/v) of acetonitrile:0.05 M KH₂P0₄, pH
5.95, was developed for the successful separation and
determination of ascorbic and erythorbic acids in selected
food samples.
Application of the method, which is sensitive, rapid
and...
The purpose of the study was to set up an in vitro model of the colon which
would permit the analysis of cellulose fermentation by human colonic microflora. Studies
of the degradation of polysaccharides by colonic bacteria may help to explain the observed
physiological consequences of consuming dietary fiber common...
A commercially important polyelectrolyte, xanthan, was chosen for
a systematic analysis of the relationship between molecular
conformation and surface properties. In the first study the effects
of ionic strength, xanthan concentration and temperature on the
xanthan molecular conformation were investigated by potentiometric
titration. The effects of the same factors and...
The adsorption kinetics exhibited by selected charge mutants of T4 lysozyme at
silanized silica surfaces were monitored with in situ ellipsometry. Mutant lysozymes were
produced by substitution of lysine (Lys) with glutamic acid (Glu). Each substitution
resulted in a decrease in the net charge of the protein by 2 units....