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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

THE EFFECT OF NITROGEN AND POTASSIUM FERTILIZATION ON TOMATO FLAVOR

Unknown Date (has links)
The effects of nitrogen and potassium fertilization on tomato flavor were studied. Field-grown Walter c.v. tomatoes were treated with three levels of nitrogen and potassium. Soluble solids, pH, titratable acidity (TA), volatile flavor compounds, and sensory evaluation of overall flavor were studied. / Taste panel tests indicated that the lower fertilization level (100 lb/A N- 150 lb/A K) yielded tomatoes with a more desirable flavor. Tomatoes grown at the two higher levels of fertilization (200 lb/A N-300 lb/A K; 300 lb/A N-450 lb/A K) did not differ in flavor. Soluble solids and TA were found to increase with increasing levels of N and K. There was a modest trend toward lower pH values in tomatoes grown at lower fertilization levels. Although no qualitative differences were observed among volatiles from the three treatments, several compounds were found to change quantitatively with treatment. MS and GC enrichment were used to tentatively identify these volatiles. Hexenal, 2-hexanone, 2,4-hexadienal, benzaldehyde, phenylacetaldehyde, beta-ionone and 6-methyl-5-hepten-2-one were found to increase with increasing levels of N and K fertilization. Farnesol isomers appeared maximally in treatment II and eugenol decreased with increasing fertilization. / This study indicates that tomatoes treated with high levels of N and K do not exhibit desirable flavor despite an increase in both TA and soluble solids. This may be due to the intrusion of undesirable flavors from volatiles whose production is increased under conditions of high N and K fertilization. / Source: Dissertation Abstracts International, Volume: 43-10, Section: B, page: 3182. / Thesis (Ph.D.)--The Florida State University, 1982.
12

THE GEORGIA EXPANDED FOOD AND NUTRITION EDUCATION PROGRAM'S LONG-TERM EFFECTS ON DIETARY INTAKE AND FOOD BEHAVIOR PRACTICES

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 40-07, Section: B, page: 3077. / Thesis (Ph.D.)--The Florida State University, 1979.
13

PURIFICATION AND CHARACTERIZATION OF AN ANTIMICROBIAL SUBSTANCE PRODUCED BY LACTOBACILLUS BULGARICUS (LACTIC ACID BACTERIA, LACTOHACILLI, SUGAR EFFECT, HPLC, MASS SPECTROMETRY)

Unknown Date (has links)
The present study was designed to achieve three goals: (1) to investigate some physical properties of the crude antimicrobial substance (lactobulgarican) produced by Lactobacillus bulgaricus, (2) to test the effect of several types of sugar present in the growth medium of L. bulgaricus on production of lactobulgarican, and (3) to purify and characterize the pure lactobulgarican. / Lactobulgarican was located extracellularly and was more active toward gram-negative than -positive organisms. It had an optimum pH of 4.0. It was reversibly inactivated at pH range of 5.0-12.0 but irreversibly inactivated at pH 1.0. At the optimum pH, lactobulgarican was highly thermostable. It was also stable to refrigerated storage up to 18 days. / Carbohydrate-free formula, with a given type of sugar added, was used to test the effect of sugar on lactobulgarican production. Among the sugars tested, glucose produced the lowest pH value and the largest inhibition zone under a short incubation period, i.e., 48-hours. Under a long incubation period, i.e., 96-hours, both glucose and lactose, at the same concentration, produced comparable results. A ninety-six hour incubation period was the best one among those tested. Fructose and sucrose were not fermented by L. bulgaricus, and did not produce any inhibition zones. / Reversed phase HPLC column was used to purify lactobulgarican. Lactobulgarican did not contain lactic acid or hydrogen peroxide. The UV spectrum of lactobulgarican produced two broad peaks at 198 and 274 nm. Negative and positive chemical ionization mass spectra produced peaks at m/e 181, 180, 163 and 179, 91, 88, 57, respectively. The biuret test for lactobulgarican was negative. Results from the UV and mass spectra indicated the possible presence of a hexose and a phenol-containing compound, possibly phenylalanine. The molecular weight of lactobulgarican was (LESSTHEQ) 507. / Source: Dissertation Abstracts International, Volume: 46-01, Section: B, page: 0012. / Thesis (Ph.D.)--The Florida State University, 1984.
14

Walnut (Juglans regia L.) characterization: Protein composition, lipid and tannin content, and sensory quality

Unknown Date (has links)
Walnuts contained about 16.66% protein and 66.90% lipids. Linoleic (61.21%) and linolenic (13.81%) acids accounted for up to 75% of the total fatty acids in walnut lipids. The majority of walnut proteins were soluble in 0.1 M NaOH with a minimum solubility at pH 4. Albumins, globulins, prolamins, and glutelins respectively accounted for 6.81, 17.57, 5.33, and 70.11% of the total protein. Both protein solubility and electrophoretic analyses revealed glutelins to be the major walnut proteins. The total protein contained at least seven major polypeptides with estimated molecular weight range 19,590-21,830 and 33,340-37,150. Lysine was the first limiting essential amino acid in total proteins, globulins, and glutelins. Leucine and methionine plus cysteine were the limiting amino acids, respectively, for prolamins and albumins. Hydrophobic and acidic amino acids dominated the amino acid composition in all protein fractions. Minimum extractability of nitrogen at 0.5-1 M TCA represented the nonprotein nitrogen compounds in defatted walnuts. The nonprotein nitrogen values in walnuts ranged from 6.24 to 6.50% of the total nitrogen. Native or heat denatured walnut glutelins were easily hydrolyzed in vitro by the common digestive proteases. The tannin content of inshell and shelled walnuts was in the range of 889-1095 and 574.4-667.2 mg catechin equiv./100 g walnut, respectively. After three weeks of storage, walnut assayable tannins were reduced by about 20%. Blanched walnuts (BW) retained about 2% of assayable tannins, had a buttery-sweet taste, and rated less astringent then unblanched walnuts (UW). The astringency scores and tannin content of BW were correlated (r = 0.9249). / Source: Dissertation Abstracts International, Volume: 57-03, Section: B, page: 1526. / Major Professor: Shridhar K. Sathe. / Thesis (Ph.D.)--The Florida State University, 1996.
15

PROTON INDUCED X-RAY EMISSION ANALYSIS FOR THE DETERMINATION OF NUTRITIONAL STATUS IN PRESCHOOL CHILDREN

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 37-07, Section: B, page: 3331. / Thesis (Ph.D.)--The Florida State University, 1976.
16

THE EFFECTS OF SERVING STYLE ON FOOD WASTE IN A SCHOOL LUNCH PROGRAM

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 39-11, Section: B, page: 5305. / Thesis (Ph.D.)--The Florida State University, 1978.
17

VEGETABLE EXTRACTS AS ANTIBACTERIAL PRESERVATIVES AND THEIR APPLICATION IN FOODS

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 34-10, Section: B, page: 5015. / Thesis (Ph.D.)--The Florida State University, 1973.
18

STUDIES ON MALONALDEHYDE IN LIPID OXIDATION

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 24-11, page: 4623. / Thesis (Ph.D.)--The Florida State University, 1963.
19

THE ROLE OF PYRIDINE NUCLEOTIDES, SUBSTRATES, AND INTERMEDIATES IN THE ENZYMATIC REDUCTION OF METMYOGLOBIN IN GROUND BEEF

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 28-03, Section: B, page: 0932. / Thesis (Ph.D.)--The Florida State University, 1967.
20

ANTIOXIDANT ACTIVITY OF VEGETABLE FLAVONOIDS IN LIPID-AQUEOUS SYSTEMS

Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 24-12, page: 5326. / Thesis (Ph.D.)--The Florida State University, 1963.

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