Part of Thesis (Ph. D.)--Tulane University, 1969. / Cover title. Includes bibliographical references (p. 157-162).

Thesis (M.Sc.)--College of William and Mary. / Vita. Includes bibliographical references. Also available via the World Wide Web.

Thesis (M.Sc.)--College of William and Mary. / Vita. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 82-86). Also available via the Internet.

With the approval of menhaden oil pending, the food industry is trying to incorporate marine oils high in omega-3 fatty acids into food systems. The main problem obstructing its use as a food ingredient is fishy/painty flavors which occur with low levels of oxidation. The purpose of this study was to follow the formation of volatile compounds in menhaden/soybean oil blends and to correlate total volatiles with sensory odor scores. Specially Processed Menhaden Oil (SPMO) was supplied by Zapata Haynie Corporation (Reedville, VA). Blends of 0%, 10%, 20%, and 100% menhaden oil were stored for 15 weeks at 22 C, in the dark, with air in the headspace. Peroxide Value (PV) was measured. The amounts of pentane and total volatiles produced were measured using the Shimadzu static headspace attachment for the Shimadzu GC-9A capillary gas chromatograph. Total volatiles also were followed using direct injection volatile analysis. Retention times for selected volatiles were compared with those of known standards. Sensory analysis was completed using a modified version of the AOCS oil odor/flavor scorecard, with a panel of 12 trained judges. There was a significant increase in PY for each blend over the 15 week period (p<0.05). Pentane and total volatiles for the 0%, 10%, and 20% oils increased toward the end of the study but not significantly. Odor intensity scores did not increase over the 15 week period for any of the oils. The fifteen-week study period may not have been long enough for sufficient development of volatiles in the 0%, 10%, and 20% oils. The inclusion of the 100% menhaden oil altered the perceptions of the sensory panel since it had a much stronger fishy/painty odor. This caused the differences in the other oils to be overshadowed and poor correlations between sensory evaluation scores and PV and volatiles were obtained. Conditions responsible for the development of off-flavors in menhaden/soybean oil blends need further study before the commercial use of marine oils in food products is feasible. / Master of Science

Menhaden is the major source of fish oil in the United States. Due to a high amount of polyunsaturated fatty acids which are highly susceptible to autoxidation, menhaden oil deteriorates rapidly, leading to objectionable off-odors and off-flavors. The purpose of this study was to investigate if the enzyme lipoxygenase is present in menhaden gill tissue and if it is a contributing factor in menhaden oil oxidation. Peroxide, TBA and anisidine values of undeodorized and deodorized menhaden oils exhibited two maxima during 20 weeks of storage at 30°C. Peroxide values of the undeodorized oil peaked at week 1 with 6.71 meq/kg and at week 12 with 21.50 meq/kg, while in the deodorized oil it peaked at week 8 (9.28 meq/kg) and week 20 (18.71 meq/kg). TBA maxima were observed at week 2 (1416 μMol/kg) and week 12 (4951 μMol/kg) and at week 8 (1397 μMol/kg) and week 20 (4284 μMo/kg) for undeodorized and deodorized menhaden oil respectively. Anisidine values showed maxima at the same weeks. These results indicate that lipid peroxidation of the deodorized oil lagged a few weeks behind the undeodorized oiL In this study, the conjugated diene and fluorescence analyses were found to be poor indicators for monitoring lipid oxidation in menhaden oil. Enzyme assays indicated that lipoxygenase activity is present in menhaden gill tissue with maximum activity at pH 9-10, resembling that of soybean lipoxygenase-l. A sensory panel judged omega-3 fatty acid ester concentrates treated with the enzyme extract as having a significantly (p < 0.03) stronger smell than the control ester for the first four weeks of an eight week study. However, no significant difference was found between the TBA values of the esters. Of the 60 volatile compounds identified by GC-MS in the undeodorized menhaden oil, 19 were aldehydes, 9 were alcohols and 8 were ketones. Volatiles that are potentially Ii poxygenase derived, namely 2-octenal, 1-octen-3-01, 2-nonenal, 2,6-nonadienal (E,Z), and 2,5-octadien-l-ol were among those identified in the undeodorized menhaden oil. The deooorized oil contained fewer total volatiles, and fewer aldehydes (6), ketones (1) and alcohols (8), but more long chain aliphatic compounds such as hydrocarbons, many of which were not possible to positively identify. No lipoxygenase derived volatiles were identified in the deooorized oil. Most of the volatiles in the omega-3 fatty acid ester concentrates were identified as esterified short chain fatty acids. No difference in the amount of total volatiles was found between four esters that were treated with and without the enzyme extract, a boiled enzyme extract and an enzyme extract that was inocculated with esculetin. However, in a repetition of just the control and the enzyme treated ester, a significantly (p < 0.02) higher amount of total volatiles was found in the enzyme treated ester, supporting the results of the sensory analysis. It was not possible to identify specific volatiles in the enzyme treated ester that were present in larger concentrations than in the other ester treatments. Volatiles identified in EPA and DHA ethyl esters were similar to those volatiles found in the undeodorized and deodorized menhaden oil as well as the omega-3 fatty acid ester concentrates, but no lipoxygenase derived volatiles were found. While lipoxygenase activity was found in the gill extract of menhaden, and sensory analysis was able to distinguish between a control and an enzyme incubated oil, the enzymatic activity was low (apparent Km = 16.7 μMol) and volatile analysis of various oils did not support the hypothesis that lipoxygenase is a major contributor to menhaden oil oxidation. Future research should include isolation and purification of menhaden gill lipoxygenase and the study of model systems to develop a better understanding of the contribution of lipoxygenase activity to oxidation of menhaden oil. / Ph. D.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 165-181). Also available via the Internet.

The primary objective of this study was to determine if a small amount (0.5%) of deodorized menhaden oil (DMO) Significantly promotes or accelerates the oxidation of soybean oil (SO). A blend (M/S) of 0.5% DMO in commercial SO, pure SO, DMO and undeodorized menhaden oil (UDMO) were stored in the dark for ten weeks at 30°C. A control or "on the spot" blend was obtained by adding 0.5% DMO to SO prior to testing. The peroxide, anisidine and Rancimat values were determined at weeks 0, 1, 2, 3, 4, 6, 8 and 10. Fifteen panelists determined the differences in rancidity of the control and M/S using the directional paired-comparison test. The peroxide values of the control peaked at weeks 2 and 6 while those of M/S reached maxima at weeks 2 and 8. M/S was slightly but not significantly more stable to oxidation than the control. The peroxide values of UDMO reached a maximum at week 2, earlier than those of DMO. The anisidine values of the two blends were below 2.00 throughout the study. Although the anisidine values of M/S fluctuated more than the control, they were not significantly different from the control over the ten week study. The anisidine values of DMO were always less than those of UDMO. The Rancimat values of M/S were significantly (p<0.05) greater than the control at weeks 2, 6, and 10, and insignificantly greater at weeks 0, 1, 3, and 8. M/S was determined to be significantly (p<0.05) less stable than the control only at week 4. M/S was judged to be significantly (p<0.05) more rancid than the control only at week 3. Most of the results of this study do not support the hydroperoxide seeding action hypothesis of Josephson et al. (1984). / Master of Science

Few studies have described growth rates of age-0 Atlantic menhaden (Brevoortia tyrannus). Growth rates from tidal freshwater habitats of the Mattaponi and James Rivers, Virginia in 2009 were described and compared using otolith microstructural analyses. Larval tidal freshwater growth rates were significantly faster in the culturally eutrophic James River when compared to those collected from the Mattaponi River (p-value < 0.001). Elevated primary production within tidal freshwater habitats promotes favorable conditions for larval Atlantic menhaden growth. No differences between river habitats for juvenile growth rates were evident. Comparisons of age-0 growth rates to higher salinity habitats indicate that tidal freshwater habitats should be considered essential habitat for age-0 Atlantic menhaden.

Scientific evidence shows that dietary intake of the omega-3 polyunsaturated fatty acids is beneficial to human health. Fish oil is a rich source of omega-3 fatty acids. However, fish oil with high levels of omega-3 PUFA is very susceptible to oxidative deterioration during storage. The objective of this study was to investigate the effect of xanthan gum (XG)-locust bean gum (LBG) mixtures on the physicochemical properties of whey protein isolate (WPI) stabilized oil-in-water (O/W) emulsions containing 20% v/v menhaden oil. The O/W emulsions containing XG/LBG mixtures were compared to emulsions with either XG or LBG alone. The emulsions were prepared using a sonicator by first mixing menhaden oil into the WPI solution and then either XG, LBG or XG/LBG mixtures were added. WPI solution (2 wt%) and gum solutions (0.0,0.05, 0.1, 0.15, 0.2 and 0.5 wt%) were prepared separately by dissolving measured quantities of WPI in distilled water. XG and LBG gums were blended in a synergistic ratios of 50:50 for the mixture. The emulsions were evaluated for apparent viscosity, microstructure, creaming stability and oxidative stability. Addition of 0.15, 0.2 and 0.5 wt% XG/LBG mixtures greatly decreased the creaming of the emulsion. The emulsion with 0.15, 0.2 and 0.5 wt% XG/LBG mixtures showed no visible serum separation during 15 d of storage. The apparent viscosity of the emulsions containing XG/LBG mixtures was significantly higher (p < 0.05) than the emulsions containing either XG or LBG alone. The viscosity was sharply enhanced at higher concentrations of XG/LBG mixtures. Microstructure images showed depletion flocculation for LBG (0.05-0.5 wt%), XG (0.05- 0.2 wt%) and XG/LBG mixtures (0.05 and 0.1 wt%) emulsions. Flocculation was decreased with the increased biopolymer concentration in the emulsion. The decrease in flocculation was much pronounced for the emulsion containing XG/LBG mixtures. The rate of lipid oxidation for 8 week storage was significantly (p < 0.05) lower in emulsions containing XG/LBG mixtures than in emulsions containing either of the biopolymer alone. The results suggested that the addition of XG/LBG mixtures greatly enhanced the creaming and oxidative stability of the WPI-stabilized menhaden O/W emulsion as compared to either XG or LBG alone.